Welcome to Stethophone

The regulation of medical devices is specific to each country. Currently different versions of Stethophone are recognized as a medical device in the USA and Ukraine. This means that Stethophone is available for residence of these countries. We are working on offering Stethophone in more countries in the future.

Please select a country of your residence to learn about the version of Stethophone available for you.

False claims and misleading wording in the world of personal health apps

Last week the FDA issued a warning about certain applications and wearables that claim to measure blood glucose levels. The warning was clear: if the application is not FDA approved, it’s not safe. Since 2014, numerous applications have emerged (and sold well) that claim to monitor health concerns that the public is interested in like glucose, heart rhythm, blood pressure etc. Some of these achieved FDA clearance, but the vast majority did not.

A class of application that is particularly concerning are so called heart-health checkers. These involve placing your finger over the camera lens of your phone, or wearing a ring or other wearables that talk to your phone and claim to tell you if your “heart is healthy”. These are (for the very large part) making false claims. Like blood glucose level, heart health measurement is a sophisticated process that depends on diagnostically rich underlying data. Your ring may be able to sense a rough pulse (about the same as what you could do with your finger and a stopwatch), but you should not rely on it to tell you (for instance) anything about having a heart attack. Heart attacks are something that people have been trained to worry about, so many of us are attracted to the idea that we can purchase a device or application that will tell us if we are having one. This is why we see false claims or misleading wording about cardiac health detection in ads promoted on social all the time. Similarly, unless you are wearing a high-quality blood pressure cuff attached to your phone, there is almost no chance any phone application is providing anything more than a guess at your blood pressure, and this low fidelity measurement certainly won’t be an indicator of any kind for overall heart health. Once again the easiest thing to look for is FDA approval for the claims that are being made.

An app that collects diagnostic data for the purpose of medical assessment requires that it be cleared by the FDA as a class II medical device. An app that provides medical reports or feedback of any kind about your physical health most definitely requires FDA clearance through a rigorous and lengthy process. Not only do the producers of these applications need to prove the science behind their device works, but they must also validate it with clinical studies. Even then, they need to prove their companies have rigorous risk assessment and quality management controls to ensure that their device continues to work safely and as indicated, even after being sold.

The mandate is to ensure that people are in no way harmed by the use of the device, or app, or test. For instance an application cannot claim to tell you if you are having a heart attack or not. For the FDA to approve such a claim, the producer of the application would have to prove that accuracy of the device (for heart attack detection) is extremely high. The provider would need to clinically demonstrate a very low probability of producing a false negative result. A false negative, might erroneously convince a user that they are in fact NOT having a cardiac issue and prevent them from otherwise seeking immediate care they actually need. Diagnosing heart attacks is something that needs to be done by qualified doctors using specialized tests and equipment in a diagnostic path. These tests often involved multi-lead ECGs, blood tests, echocardiograms, CTs MRIs or angiograms. In most cases no single test is definitive and there are multiple classes of heart attack that can manifest differently. Protecting the patient is not just limited to the accuracy of a device or the underlying science, it also increasingly involves considerations for cyber security: If electronic devices can be hacked, or the data stolen, or the device functionality compromised, that also represents a risk to the public. The FDA has clear (and equally rigorous) guidelines for such things.

A properly cleared device or application makes specific, clear, and carefully worded statements about what is can and cannot do. The ability of any application to make such claims is limited by the data it can reliably collect. For instance an ECG on your watch, is good at collecting a small slice of your hearts electrical activity, but it can’t claim to replicate the diagnostic ability of a multi-lead system wired to your chest with an expert to interpret the output. Responsible producers of these devices make this clear. The FDA has a webpage where they publish some of the warning letters to companies who are making misleading, unproven or false claims https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/compliance-actions-and-activities/warning-letters

Feedback from the field

Dr. Anna Shkreba – cardiologist: “Very soon after I tried Stethophone, I started it using daily in my practise. The sound quality is extremely high. I now also have the ability to record, listen and analyze sounds anytime later, as well as to compare data to track disease regression or treatment response.”

“Stethophone significantly improved my approach to examining of new patients, especially those who have latent symptoms. It was surprising for me not only to hear high quality sound, but to see it also. Because of Stethophone, I have been able to detect refined details, consequently, patients receive their diagnosis quicker and don’t have to go through repeated cycles of consultations and examinations. 

Using Stethophone is valuable  for both the doctor and the patient and easy to get used to.I see my patients are more relaxed and have a sense of greater security with Stethophone

Welcome to Stethophone

Earlier today, Sparrow Bioacoustics launched a product into the US App Store. We think this represent a new level of offering in the consumer medical and healthcare space.

It’s called Stethophone, and it belongs to a class of product called Software As a Medical Device (SAMD). Stethophone is a class II, FDA cleared application. The first of its kind to be cleared by the FDA for consumer use.

Stethophone is a software application that converts your Smartphone into a medical grade stethoscopic device. Quite simply your phone can now listen to your heart and lungs and record that signal anywhere any time. No gadgets no attachments nothing new to charge or wear.

Using sound to assess the condition of your heart and lungs is not new. In the last two hundred  years doctors leaned how to “hear” dozens of diseases. Sound is extremely rich in diagnostic information. It tells us a great deal about the structural and rhythmic condition of the heart. In many cases it can help doctors catch diseases early – before they progress. Cardiovascular disease is the number one cause of death. CVD kills 5x as many women as breast cancer. Often, it is missed until it’s too late.

So we at Sparrow gathered a team of engineers, bio-acousticians, doctors, and researchers and decided to create a new kind of product. We wanted to see if we could turn the world’s smartphones into cardiac and pulmonary auscultation devices: making collecting diagnostic information about  your heart as easy as using a home thermometer. It will evolve quickly into a system smart enough to help detect disease at scale.

The rational was simple, your doctor can’t always be there – and symptoms and concerned happen at home. That is where you need to capture  the data.

We want to give people a medically powerful way to do this, and to use the data to get better and faster care. Our goal is to help a million people and beyond. Our sound algorithms make Stethophone of one of the finest stethoscopic devices on the market.  But we are not stopping there. We are teaching machines 200 years of auscultation using with what will soon be the largest  database of human chest sounds in history; so they can help identify anomalies that even doctors can’t always here.

Today is culmination of years of work by dedicated experts, thousands of steps in testing and refinement and regulatory, and great support from our investors, partners, and friends.

Stehophone is off to a great start. Our pilot efforts in Ukraine have involved thousands of people and helped save a few lives. And now, we are available in the US to help people listen and record their heart and lungs at home.  It’s been a long road, but this is still only the first step. The challenge now is fitting it into people’s lives in way that helps them and their doctors now and in the future. In the months ahead, we are listening and watching very closely as we continue to invest, add-value and refine our offering. Stethophone represents our belief that  people can participate more in their own care. When people have real empirical medical data to engage with the health care system it gives them more agency, peace of mind and often better outcomes.

Follow this link for Stethophone in the App Store

Feedback from the field

What’s did you find most valuable about StethophoneTM?

Dr. Satenik Rustamyan – cardiologist and new Stethophone user: I can both hear and see sounds that I would have missed with standard methods. With Stethophone, it’s much easier to catch an extrasystole or determine valve insufficiency in the absence of sounds during traditional auscultation.

The ability to save data is invaluable. A doctor always thinks about their patient, even outside of appointments. And the Stethophone provides the opportunity to reflect further with a solid foundation on objective auscultation data. This is an opportunity that doctors previously didn’t fundamentally have. So, Stethophone is not just a better version of the stethoscope; it’s a conceptually new solution for both doctors and patients.

Another advantage for me, as an educator, is being able to gather several cases from patients with a certain type of cardiac pathology and share and demonstrate them all to medical students. This offers an incomparably deeper understanding of the learning material and a stunning clarity that is unachievable with the classical approach of auscultating and hearing only in real-time.

What about the patient reactions?

Patients get engaged in a way I have never seen before, “So that’s what my arrhythmia sounds like!” I can also find a segments of regular rhythm and visually demonstrate “how it should be.” All of this ensures better patient contact and more successful compliance.

The Power of Agency: The Crucial Link Between Control, Health and Wellness

There exists an undeniable connection between one’s sense of control and their overall state of wellness. The concept of control extends its grasp over various facets of existence, but nowhere is its significance more pronounced than in the realm of health. The profound impact of feeling in control of one’s health on individual wellness cannot be overstated, as it lays the foundation for a harmonious and fulfilling life.

The Power of Agency

At its core, a sense of control over one’s health embodies the empowerment of agency. This agency brings forth a heightened awareness of the choices one makes, paving the way for informed decisions that can significantly impact physical, mental, and emotional well-being. When individuals feel that they have the ability to influence their health outcomes through conscious acts – whether it’s diet, exercise, or monitoring your health at home – they cultivate a positive relationship with their bodies. Importantly this translates into how they participate in their own medical healthcare.  People that are aware of how their bodies are working are better at seeking the right care if something does not feel right.  People who keep logs of symptoms or collect their own biometric data are in a much better position to provide evidence in discussions with doctors and advocate for themselves.

Reducing Stress and Anxiety

A lack of control over health matters can give rise to stress and anxiety, which are notorious culprits in undermining health and wellness. When individuals feel powerless in the face of health challenges, they may experience heightened levels of stress, leading to a cascade of negative physiological responses. Conversely, a sense of control acts as a buffer against stress. The feeling that one is actively participating in their own health journey can foster a greater sense of calm, allowing the body to function optimally and reducing the risk of stress-related ailments. There is strong connection between stress and cardiac health.

Motivation and Resilience

The connection between control and wellness extends beyond physical health; it also influences mental and emotional well-being. People who perceive themselves as having control over their health are more likely to exhibit motivation and resilience. This stems from the belief that they can navigate and overcome obstacles, leading to a positive feedback loop. As they achieve victories through their self-directed efforts, their confidence grows, fuelling their determination to conquer challenges. These are critical tools for people who may be in at-risk groups for cardiac or other diseases that need to work with doctors to drive the best possible outcomes.

Fostering a Holistic Approach

When individuals are in control of their health, they tend to adopt a holistic approach to well-being. This means not only addressing physical ailments but also attending to mental and emotional needs. They become proactive advocates for their overall wellness, seeking balance in various aspects of their lives. This holistic perspective promotes a state of equilibrium where physical health, mental clarity, emotional stability, and even spiritual harmony intertwine to create a vibrant and thriving existence.

Cultivating Long-Term Health

The importance of control in health and its influence on wellness becomes even more evident when considering long-term health outcomes. Individuals who actively engage in their health management tend to be more attuned to early warning signs, leading to timely interventions that can prevent the exacerbation of issues. Self monitoring, regular check-ups, and a vigilant approach to health challenges contribute to a prolonged, high-quality life.

The symbiotic relationship between control, health and wellness is a testament to the intricate nature of human well-being. Empowerment through control not only shapes healthier lifestyle choices but also enhances mental resilience, reduces stress, and fosters a holistic approach to life. By recognizing the power they possess in shaping their health outcomes, individuals can embark on a journey toward well-being that is both enriching and rewarding.

The Art of Clinical Thinking

In today’s medical world, it might seem that the primary task of a doctor is to obtain diagnostic conclusions generated by various scanning devices. Indeed, such reports and descriptions are increasingly perceived as the final and infallible diagnosis—a trend that only grows stronger from one medical generation to the next. But is this really the case? Can modern imaging technologies completely replace a physician in the diagnostic process?

I have been asked more than once, “Why spend time on a personal examination of a patient when you can do an ECG and EchoCG and immediately get a cardiological diagnosis?” There is a somewhat demeaning tone in the question towards the medical profession. If all the answers are already contained in the diagnostic report, then what is the role of a professional who has spent at least eight, or even more than ten years acquiring higher medical education?

My response also does not solely rest on the fact that the accessibility of diagnostics for patient often frustrated by complexity and cost. Long weeks of waiting for scheduled examinations, transportation difficulties, and the high price of tests remain a barrier on every continent.

Instead, I would draw attention to the possibility of errors in imaging as well as the impact of the time factor. A doctor must be able to do more than simply read a diagnostic report, they must also have the capacity to critically analyze it. Most importantly they need to have the ability and wisdom to compare it with other data; otherwise errors are inevitable. As doctors we all know of cases where a mistaken or incomplete evaluation of a diagnostic report have cost a patients their life, or at the very least, they lost a chance for a better prognosis. Only a doctor who possesses deep knowledge and critical thinking can apply diagnostic information relevantly to the clinical situation and accurately formulate a diagnosis.

Heart sounds can provide a great deal of valuable information about the condition of cardiac structures and functions, although they require a high level of skill for their analysis. Fortunately, modern digital stethoscopes can improve auscultation efficiency and make it easier to analyze heart sounds.

We are convinced that the doctor remains the most crucial participant in the diagnostic process, and the Stethoscope is a tool that expands their capabilities. Using all available tools and information is key to making an accurate diagnosis.

Dr. Yaroslav Shpak – cardiologist

The Silent Threat: Reasons Behind Undiagnosed Cardiovascular Disease in the United States

The AHA reports that approximately 82.6 million people in the United States currently have one or more forms of cardiovascular disease (CVD). Though traditionally considered a man’s disease, it is estimated that 1 in 16 women who are over 20 years old have coronary heart disease making it something women of all ages should be aware of. Findings suggest that nearly half of all adults over 40 may have “hidden” heart conditions that go undetected.[i]

Several factors contribute to the prevalence of undiagnosed CVD:

  1. Lack of Symptoms and Silent Nature of CVD

One major challenge in diagnosing CVD lies in its often-silent progression. Many individuals with early-stage CVD might not exhibit obvious symptoms (like chest pain) until the disease has advanced significantly. Symptoms can also be non-specfic and temporary (swelling, fatigue, dizziness, shoulder and neck pain etc.). People as well as their doctors, often don’t consider themselves to be at risk and don’t seek care in time.

  1. Limited Awareness

Another critical factor is the lack of awareness and education about cardiovascular health. Many individuals, particularly those who are younger or don’t have a family history of CVD, might not prioritize regular health check-ups or screenings. Moreover, misconceptions about who is at risk for CVD can deter people from seeking preventive care. A study published in the American Journal of Preventive Medicine found that only 52% of respondents recognized all major heart attack symptoms and knew to call 911. The Centers for Disease Control and Prevention (CDC) reported that about 11 million adults with hypertension (high blood pressure) were unaware of their condition in 2017-2018.

  1. Inadequate Access to Healthcare

Limited access to healthcare, particularly among marginalized and underserved populations, can result in delayed diagnosis or no diagnosis at all. Lack of health insurance, transportation, and financial constraints can all hinder individuals from seeking medical care, including necessary cardiovascular screenings. In 2020, the Kaiser Family Foundation estimated that approximately 29 million non-elderly adults in the U.S. were uninsured.

  1. Stigma Surrounding Healthcare Seeking

The CDC’s Behavioral Risk Factor Surveillance System found that some individuals avoid seeking medical care due to a lack of transportation, cost, and fear of a diagnosis, among other reasons. This avoidance behavior perpetuates the problem of undiagnosed CVD, allowing the disease to progress unchecked.

A US national study reported that one third of respondents claimed to actively avoid seeing a doctor[ii].  A 2014 study identified [iii] three main categories of reasons for avoiding medical care. First, over one-third of people reported unfavorable evaluations of seeking medical care, such as factors related to lack of confidence in physicians, a feeling of being dismissed or not listened to, disappointment in dealing with health care organizations, and affective concerns such as fear of bad news or procedures. Second, a subset of participants reported low perceived need to seek medical care (12.2%), Third, many participants reported traditional barriers to medical care (58.4%), such as high cost (24.1%), and time constraints (15.6%). The findings indicate that, alongside convenience, a patient’s perceived lack of agency is a material barrier. This includes concerns about ineffective or strained communication with providers and concerns about unnecessary tests and lack of confidence that the care they need will not be provided. Four out of five women report that they have felt that healthcare professionals often don’t listen to them,[iv] especially when their symptoms are being dismissed or downgraded.

  1. Fragmented Healthcare System

The fragmented nature of the U.S. healthcare system can also contribute to undiagnosed CVD. With different medical providers and facilities, individuals might not receive consistent care or comprehensive screenings. Lack of coordination between primary care physicians, specialists, and other healthcare professionals can result in missed opportunities for early diagnosis and intervention. A study published in the Journal of the American Heart Association found that a significant number of individuals who experienced a heart attack had not been previously diagnosed with high cholesterol or diabetes, suggesting missed opportunities for early intervention.

CVD is the primary cause of death in both men and women in the United States and worldwide.[v] [vi] Multiple lines of research convincingly demonstrate that early detection or outright prevention of CVD is economically, socially, and humanly superior to even the best medical treatment of manifest CVD.[vii] [viii] [ix] Studies indicate that management of CVD risk factors, including early detection before an event would have prevented or postponed 33% of deaths. This is compared with prevention of only 8% of deaths if “perfect care” was used during an acute event. This data provides strong support for the importance of self‐care in preventing CVD and further events. iii The concept of self-care recognizes that patients have a role in maintaining and monitoring their own cardiovascular health including possible early detection or progression of disease. This is role is particularly relevant when one considers the predominance of disease in the population and the scale of undiagnosed or misdiagnosed cases.

Some great reference sites worth checking out


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[1] Subclinical Coronary Atherosclerosis and Risk for Myocardial Infarction in a Danish Cohort, A Prospective Observational Cohort Study Andreas Fuchs, MD, PhD, Jørgen Tobias Kühl, MD, PhD, DMSc

[1] Kannan VD, Veazie PJ. Predictors of avoiding medical care and reasons for avoidance behavior. Med Care. 2014;52:336–345. doi: 10.1097/MLR.0000000000000100.

[1] Subclinical Coronary Atherosclerosis and Risk for Myocardial Infarction in a Danish Cohort, A Prospective Observational Cohort Study Andreas Fuchs, MD, PhD, Jørgen Tobias Kühl, MD, PhD, DMSc

[1] Kannan VD, Veazie PJ. Predictors of avoiding medical care and reasons for avoidance behavior. Med Care. 2014;52:336–345. doi: 10.1097/MLR.0000000000000100.

[1] Why do People Avoid Medical Care? A Qualitative Study Using National Data Jennifer M. Taber, Ph.D., Bryan Leyva, B.A, and Alexander Persoskie, Ph.D. J Gen Intern Med. 2015 Mar; 30(3): 290–297. Published online 2014 Nov 12. doi: 10.1007/s11606-014-3089-1, PMCID: PMC4351276 PMID: 25387439

[1] Women’s Health Strategy for England, 30 August 2022, CP 736 ISBN 978-1-5286-3665-0

[1] WHO Regional Office for Europe . Data and statistics. The challenge of cardiovascular disease—quick statistics. Available at: http://www.euro.who.int/en/health-topics/noncommunicable-diseases/cardiovascular-diseases/data-and-statistics. Accessed December 22, 2016.

[1] WHO Regional Office for Europe . The European health report 2015. Targets and beyond—reaching new frontiers in evidence. 2015. Available at: http://www.euro.who.int/__data/assets/pdf_file/0008/284750/EHR_High_EN_WEB.pdf. Accessed December 16, 2016.

[1] Kottke TE, Faith DA, Jordan CO, Pronk NP, Thomas RJ, Capewell S. The comparative effectiveness of heart disease prevention and treatment strategies. Am J Prev Med. 2009; 36:82–88.

[1] Goldman DP, Cutler D, Rowe JW, Michaud PC, Sullivan J, Peneva D, Olshansky SJ. Substantial health and economic returns from delayed aging may warrant a new focus for medical research. Health Aff (Millwood). 2013; 32:1698–1705.

[1] Goldman DP, Gaudette E, Cheng WH. Competing risks: investing in sickness rather than health. Am J Prev Med. 2016; 50(5 suppl 1):S45–S50.

How to Talk to Your Doctor About Heart Health Concerns

Maintaining a healthy heart is essential for overall well-being, and open communication with your doctor is a crucial step in ensuring your cardiovascular health. If you have concerns about your heart health, it’s important to approach these conversations in a proactive and informed manner. By effectively communicating your worries and collaborating with your healthcare provider, you can take control of your heart health journey. Here’s are a few best practices:

  1. Gather your own information: If you have symptoms, keep a log. This is especially important if they come and go.  Things like shortness of breath, palpitations, fatigue are important; but so is anxiety, depression, headaches etc. It is also important to note if you notice any consistent triggers for these symptoms.  If you have the ability, monitor and record your own biometrics: like heart rate, blood pressure, body weight, and relate those back to symptomatic episodes.  Do some research from sources like medical websites, articles from reputable organizations, and academic research to equip you with knowledge to better discuss your concerns with your doctor.
  2. Prepare a list of questions: Assemble a list of questions and concerns you have about your heart health. Be specific about your symptoms, their duration, and any triggers you’ve noticed. Ask about potential tests, lifestyle changes, or treatment options that might be relevant to your situation.
  3. Describe your symptoms: When discussing your concerns, provide your doctor with a clear and detailed description of your symptoms. Include information about when the symptoms occur, their intensity, and any factors that seem to exacerbate or alleviate them. Being precise can help your doctor make a more accurate assessment.
  4. Share your medical history: Inform your doctor about your medical history, including any previous heart-related issues, family history of heart disease, and any pre-existing conditions you may have. This information can provide context and help your doctor understand your risk factors.
  5. Be honest: Your doctor needs to know about your lifestyle habits, such as diet, exercise routine, stress levels, and tobacco or alcohol use. These factors play a significant role in heart health, and your doctor can offer tailored advice based on your habits.
  6. Express your concerns: Clearly communicate your worries and fears to your doctor. Whether it’s anxiety about a potential heart problem or uncertainties about certain treatments, open up about your emotions. A good doctor-patient relationship involves understanding your emotional state and addressing any concerns you may have.
  7. Collaborate on a Plan: After discussing your concerns and sharing necessary information, work with your doctor to develop a comprehensive plan. This could involve diagnostic tests, lifestyle modifications, medications, or referrals to specialists. Your active involvement in the planning process empowers you to take ownership of your heart health. Always take notes during the consultation.
  8. Seek Clarification: If your doctor provides information that you don’t fully understand, don’t hesitate to ask for clarification. It’s crucial to have a clear understanding of your condition, potential risks, and recommended interventions.
  9. Always advocate for yourself: If you think something is wrong or feel unwell, it’s important to be persistent, organized, and informed. Present your information, be specific and seek the best possible care. Doctors are busy and have a lot of urgent cases to deal with, but they are also people and will step up when you do.

Remember, your doctor is a valuable partner in your journey to better heart health. By approaching your concerns proactively, staying informed, and fostering open communication, and sharing your observations and information you’re taking significant steps toward safeguarding your own cardiovascular well-being.

Aligning AI Metrics with Business Goals in Healthcare

Nick Pogrebnyakov, PhD

Healthcare companies, like their cousins in other industries, increasingly explore AI to power their products. Many companies create specialized AI teams, separate from the business or product teams. However, while both the AI and the business teams use metrics to evaluate the quality of AI models and track progress, they often use different metrics. It is crucial that both teams understand the technical and business implications of what the metrics show.

A larger difference is often in key objectives of AI and business. When building AI models, AI teams typically strive for improving key metrics, which are often composites such as F1. They also have a broad spectrum of metrics that can be calculated. Business teams, meanwhile, ask other questions relating to performance of AI models: how well the models satisfy business objectives; are they ready for release; and how well the model is likely to behave on real users.

These differences shouldn’t be unsurmountable. The leaders of business and AI teams should jointly discuss company’s business objectives, and then select metrics that reflect models’ performance in meeting these objectives. Consider these factors to prioritize AI metrics depending on the business objectives.

  • Company size
    • Small companies, especially startups, may want to prioritize recall / sensitivity to ensure they don’t miss any positive cases. This is vital for establishing credibility and effectiveness early on.
    • Larger organizations, especially those catering to several markets, may want to emphasize precision / PPV and specificity to reduce both false positives and negatives. This becomes very important for conditions where the cost of a wrong prediction is high.
  • Target market
    • Niche markets value correct predictions. Emphasize precision / PPV and specificity to track occurrences of false positives and false negatives
    • By contrast, broad markets imply solutions that appeal to multiple subgroups. Here, recall  / sensitivity is important.
  • Prevalence of condition in the population
    • If the targeted condition is very rare or very common in a community, training and, importantly, test datasets will be imbalanced. Metrics like F1 or Matthew’s Correlation Coefficient (MCC) are more relevant indicators than straightforward accuracy.
    • Medium prevalence leads to balanced datasets. Use area under the ROC curve (ROC-AUC) or accuracy.
  • Cost of false positives or false negatives
    • The cost of a false negative is high when it’s crucial that the model doesn’t erroneously flag as healthy people who actually have the condition. People who were flagged as having the condition by the model can then be sent for follow-up tests to confirm. Improving detectability of condition here is essential, and recall / sensitivity is a good metric to emphasize.
    • In other instances it’s more important that the model doesn’t mistakenly identify the condition in people who don’t have it: a false positive. This calls for greater accuracy of detection. Highlight the precision / PPV metric.
  • Importance of outliers
    • Some AI models output raw numbers instead of probabilities. A model that predicts blood pressure is a good example. Extremely high or low values, or outliers, may or may not be important in interpreting model output.
    • If outliers are important, use RMSE (root mean squared error) or MSE (mean squared error), which penalize larger errors more (as they square the difference between true and predicted values)
    • When outliers are not essential, use MAE (mean absolute error), as it is less sensitive to outliers

Metrics like precision / PPV, recall / sensitivity and specificity are derived from probabilities output by AI models. Those probabilities need to be converted into a “hard” label like “healthy” or “sick”. This requires setting a decision threshold. Set the threshold at 0.6, and all patients with the predicted probability of disease greater than 0.6 are assigned the label “sick”, while those less than 0.6 are “healthy”. This threshold is a “knob” that the model’s user can adjust. Lower the threshold, and more patients are flagged as sick, increasing the chance of false positives. Increase it, and fewer cases will be flagged, but this increases the chance of incorrectly flagging sick patients as healthy: false negatives. Decide what is more important for you depending on the business requirements.

The key to successful collaboration between the AI and business teams is mutual understanding. To achieve this understanding, have the two teams communicate regularly and educate each other on business implications, trade-offs and usefulness of metrics they use.

Nick Pogrebnyakov is head of AI and Data Science at Sparrow BioAcoustics. Prior to Sparrow Nick was an AI leader at Twitter, early NLP innovator at Thomson Reuters, and a visiting researcher at Stanford University.

The Personal and Societal Costs of Heart Disease: Our Biggest Looming Crisis

Heart disease, often referred to as cardiovascular disease, remains a pervasive and deadly health issue across the globe. Its impact is not limited to individuals alone; the repercussions extend to families, communities, and society at large. With staggering statistics underscoring its prevalence and consequences, understanding the personal and societal costs of heart disease becomes imperative.

Personal Toll: At an individual level, heart disease exacts a profound toll on physical, emotional, and financial well-being. According to the World Health Organization (WHO), cardiovascular diseases claim the lives of 17.9 million people each year, accounting for 31% of all global deaths. The emotional turmoil experienced by those affected, their families, and friends cannot be quantified. The suddenness with which heart disease can strike, altering lives and robbing individuals of their vitality, underscores the urgency of prevention and treatment.

The financial burden of heart disease is equally daunting. Medical expenses related to diagnosis, treatment, and rehabilitation can be overwhelming. A study by the American Heart Association estimates that the total annual cost of cardiovascular diseases in the United States alone will reach $1.1 trillion by 2035. This not only strains individuals’ finances but also contributes to broader economic challenges.

Societal Consequences: The societal impact of heart disease extends beyond individual struggles, affecting healthcare systems, productivity, and public resources. Healthcare systems worldwide are grappling with the increasing demands of heart disease treatment. Hospitalizations, surgeries, and long-term care strain medical resources, leading to longer waiting times for patients in need of critical interventions.

Furthermore, heart disease exerts a significant influence on workforce productivity. Illness-related absenteeism and decreased work capacity among individuals dealing with heart disease not only hinder economic growth but also lead to a reduced quality of life for affected individuals. According to the Centres for Disease Control and Prevention (CDC), coronary heart disease alone costs the United States approximately $9 billion in lost productivity annually.

The burden of heart disease is not distributed equally across societies. Vulnerable populations, including those with lower socioeconomic status, experience a disproportionately higher prevalence of heart disease due to limited access to healthcare, education, and healthier lifestyle choices.

Leading Cause of Social and Financial Inequity: Heart disease is not merely a health concern; it is also a leading cause of social and financial inequity. Vulnerable populations, including those with lower socioeconomic status, experience a disproportionately higher prevalence of heart disease due to limited access to healthcare, education, and healthier lifestyle choices. The disparities in healthcare access, preventive measures, and timely interventions often result in higher mortality rates among disadvantaged communities.

These disparities extend to financial outcomes as well. Individuals with lower incomes are more likely to face challenges in affording necessary medical care and treatments. This perpetuates a cycle of financial burden and reduced economic mobility within these communities, exacerbating existing inequities.

Prevention as the Path Forward: While the personal, societal, and equity-related costs of heart disease are substantial, there is hope in prevention and intervention. Public health campaigns promoting healthier lifestyles, can significantly reduce the risk of heart disease. The biggest unexplored opportunity lies in early detection and management of risk factors in preventing the development of these diseases.

Diagnosing Heart Disease: Understanding Key Tests and Objectives

The diagnostic journey for heart disease is a critical process that involves a series of tests designed to evaluate the health of the cardiovascular system. Each test in the diagnostic cycle serves a distinct purpose, aiming to provide insights into various aspects of heart health. Let’s explore the key tests and their objectives in this comprehensive diagnostic process.

Auscultation (Bioacoustics)

Auscultation involves listening to the heart sounds using a stethoscope. It is a fundamental part of the diagnostic process for heart disease. The primary objectives of auscultation include:

  • Detecting abnormal heart sounds (murmurs) that may indicate heart valve disorders or other structural issues.
  • Assessing the rhythm and rate of the heartbeat.
  • Listening for additional sounds such as extra heart sounds or gallops that might indicate underlying cardiac conditions and structural abnormalities of the heart. In some cases abnormal heart sounds (such as a Ventricular gallop) can indicate acute and highly advanced disease requiring immediate life-saving intervention.

Electrocardiogram (ECG or EKG)

The electrocardiogram is often the initial test performed in the diagnostic cycle for heart disease. It records the electrical activity of the heart over a brief period. The primary objectives of an ECG include:

  • Detecting irregular heart rhythms (arrhythmias) such as atrial fibrillation, bradycardia, or tachycardia.
  • Identifying signs of ischemia or insufficient blood flow to the heart muscle.
  • Evaluating the overall electrical activity and rhythm of the heart.

Echocardiogram

An echocardiogram is a non-invasive imaging test that uses ultrasound to create detailed images of the heart’s structure and function. The key objectives of an echocardiogram include:

  • Assessing the size and pumping function of the heart chambers.
  • Detecting structural abnormalities, such as heart valve defects or congenital heart conditions or damage from heart attacks
  • Evaluating blood flow direction and speed

Stress Test

A stress test, also known as an exercise stress test or treadmill test, evaluates how the heart performs under physical stress. The main goals of a stress test are to:

  • Monitor changes in heart rate, blood pressure, and ECG patterns during exercise.
  • Identify reduced blood flow to the heart muscles, indicating potential blockages in coronary arteries.
  • Assess overall cardiovascular fitness and capacity.

Cardiac Catheterization (Angiogram)

Cardiac catheterization involves the insertion of a catheter into the blood vessels to visualize the coronary arteries and blood flow. The objectives of a cardiac catheterization include:

  • Directly visualizing any blockages or narrowed arteries in the coronary circulation.
  • Determining the severity and location of arterial blockages.
  • Guiding potential interventions such as angioplasty or stent placement.

Blood Tests

Blood tests, including lipid profiles, high-sensitivity C-reactive protein (hs-CRP), and troponin levels, offer insights into different aspects of heart health. The main objectives of blood tests are to:

  • Measure cholesterol levels and identify risk factors for atherosclerosis.
  • Assess inflammation levels, as chronic inflammation can contribute to heart disease.
  • Detect troponin, a protein released during heart muscle damage, indicating a heart attack.

Biomarker Assessment (BNP or NT-proBNP)

Brain Natriuretic Peptide (BNP) and its N-terminal fragment (NT-proBNP) are biomarkers released by the heart in response to stress or strain. The key objectives of measuring BNP or NT-proBNP levels include:

  • Assessing heart failure severity and prognosis.
  • Identifying fluid accumulation in the lungs (pulmonary edema).
  • Helping in distinguishing between cardiac and non-cardiac causes of symptoms like shortness of breath.

The diagnostic cycle for heart disease involves a comprehensive approach, using various tests, to gain a thorough understanding of the cardiovascular system’s health. By combining the insights provided by these tests, healthcare professionals can zero in on a diagnosis and develop tailored treatment plans and interventions to manage heart conditions effectively. Heart conditions are generally progressive so early detection in suspected cases helps patients enter the cycle at the right time and with the appropriate urgency.

Detecting Stroke Risk: Can you Hear it coming?

A stroke, occurs when the blood supply to a part of the brain is compromised, leading to tissue damage and potentially devastating consequences. Vascular conditions that can increase the risk of stroke can be detected quickly and easily using the same techniques doctors have used for over a hundred years when listening to the heart and lung sounds (auscultation).

Detecting Vascular Conditions

Certain vascular conditions, when left untreated, can significantly increase the risk of stroke. Two main conditions that can be detected through auscultation are carotid artery stenosis and atrial fibrillation.

  1. Carotid Artery Stenosis: The carotid arteries, located on either side of the neck, supply blood to the brain. If these arteries become narrowed due to atherosclerosis (build-up of plaque), blood flow to the brain can be compromised, potentially leading to a stroke. During auscultation, healthcare professionals listen for abnormal sounds called bruits. A bruit is a whooshing sound caused by turbulent blood flow through a narrowed artery. The presence of a bruit over the carotid arteries could indicate the need for further diagnostic tests to assess the degree of stenosis and determine appropriate interventions.
  1. Atrial Fibrillation (AFib): AFib is an irregular heartbeat that can lead to the formation of blood clots inside the heart. These clots can travel to the brain and cause a stroke. During auscultation of the heart, medical professionals can identify irregular heart rhythms, which may prompt them to investigate further and potentially diagnose AFib. Detecting AFib is crucial because appropriate treatments, such as anticoagulants can help reduce the risk of stroke.

Early Intervention and Prevention

The significance of using sound to detect stroke risk lies in its potential to facilitate early intervention. Identifying conditions like carotid artery stenosis and AFib early on allows healthcare providers to initiate appropriate treatments and preventive measures. For carotid artery stenosis, lifestyle modifications, medication, or surgical procedures might be recommended to prevent the stroke. In the case of AFib, anticoagulant medications can be prescribed to prevent clot formation and potential stroke.

Identifying Endocarditis: An Elusive Disease with Grave Consequences

Endocarditis is a serious condition that arises from the inflammation of the heart’s inner lining, typically caused by bacterial or fungal infections. While relatively rare, endocarditis can have severe consequences if not promptly diagnosed and treated. Endocarditis is a medical challenge that often flies under the radar. Despite its potential for grave consequences, endocarditis can be elusive and challenging to diagnose, leading to delayed treatment and heightened risks.

Subtle Symptoms and Slow Onset Pose a Danger

Endocarditis often presents with nonspecific symptoms that can easily be mistaken for other conditions. Common signs like fever, fatigue, and weight loss can be attributed to a range of illnesses, causing doctors to overlook the possibility of endocarditis. The symptoms and clinical presentation of endocarditis can also vary widely among individuals and can steer physicians in the wrong direction when attempting to pinpoint the underlying issue. Endocarditis often develops gradually, allowing the infection to progress without causing immediate alarm. This gradual onset can lead to the false assumption that the symptoms are not urgent.

Individuals at a higher risk of endocarditis are typically those with existing heart valve issues or a history of intravenous drug use, but also may include people with recent dental or surgical procedure. Because of this, physicians might not consider endocarditis as a possibility until the condition has advanced. Definitively diagnosing endocarditis requires a combination of clinical assessment, laboratory tests, and imaging techniques like echocardiography. These tests, while effective, might not always be ordered promptly due to the ambiguous nature of symptoms.

Heart Murmurs as an Early Indicator

Normally, the heart produces a distinct “lub-dub” sound as the valves open and close. However, in cases of endocarditis, the infection can damage heart valves, leading to the formation of vegetations, valve thickening, or regurgitation (backward flow of blood).

These changes in valve structure and function can result in turbulent blood flow, which manifests as abnormal heart murmurs. These murmurs can vary in intensity, timing, and location depending on the specific valve affected and the severity of the infection. In endocarditis, the murmurs might exhibit characteristics such as:

  1. New-Onset Murmurs: A previously absent murmur or a change in the character of an existing murmur can raise suspicion of endocarditis.
  2. Regurgitant Murmurs: If the infection affects a valve’s ability to close properly, it can lead to regurgitation of blood, causing distinct murmurs that signify backflow across the valve.
  3. Changing Murmurs: The intensity and characteristics of the murmur can change as the infection progresses or if complications like abscesses form.

By listening for heart murmurs and noting their characteristics, healthcare professionals can gain valuable insights into the presence, location, and severity of infections or structural abnormalities. The combination of auscultation with other diagnostic methods, such as echocardiography and laboratory tests, forms a comprehensive approach to identifying and managing endocarditis, ultimately contributing to faster, more accurate diagnoses and improved patient outcomes.

After the Heart Attack: Hard Facts about Permanent Damage

A heart attack, also known as a myocardial infarction, is a medical emergency that occurs when the blood flow to a part of the heart muscle is blocked, usually by a blood clot. This interruption in blood flow can cause significant damage to the heart muscle, potentially leading to long-term health implications.

Damage to the Heart

During a heart attack, the affected part of the heart muscle may be deprived of oxygen and nutrients, leading to the death of cardiac cells. Irreversible damage begins within 30 minutes of blockage. The result is heart muscle affected by the lack of oxygen no longer works as it should. This damage can result in decreased heart function and potentially life-threatening complications such as arrhythmias, heart failure, and even death. Scar tissue forms at the site of the damaged cells, affecting the heart’s ability to contract effectively and pump blood efficiently.

The heart’s regenerative abilities are limited compared to other organs. Essentially some of the heart muscle responsible for contraction (the cardiomyocytes) are lost after a heart attack and replaced by scar tissue. Scar tissue does not contribute to cardiac contractile force, so the remaining viable cardiac muscle is thus subject to a greater burden. Over time, the remaining heart muscle can eventually fail leading to the development of heart failure.  500,000 people in the USA are diagnosed annually with heart failure.

Recent research has shown that the heart does possess some degree of healing potential but as it stands, it’s very small.  At the age of 25 years, approximately 1% of the heart’s muscle can renew annually.  This rate decreases to 0.45% at the age of 75 years. During an average life span, fewer than 50% of cardiomyocytes will renew.  Losing any of these permanently to a heart attack presents serious complications.

The extent of the damage during a heart attack depends on several factors, including the size of the affected artery, the timing of medical intervention, the patient’s overall health, and the presence of pre-existing conditions. While some degree of scarring is inevitable, revascularization procedures, such as angioplasty and stent placement, can restore blood flow to blocked arteries, reducing the extent of damage, and saving heart function. In cases of severe damage, heart transplantation may be considered as a last resort.

A heart attack can have a profound impact on an individual’s life, but with timely medical intervention, a commitment to lifestyle changes and close monitoring, and ongoing research, the heart’s ability to adapt can also lead to significant improvements in function and quality of life.

Understanding Heart Murmurs: Why Should You Care?

A heart murmur is a medical phenomenon often heard by healthcare professionals during a routine examination. It’s the sound of turbulent blood flow within the heart or its surrounding blood vessels, creating a swishing or whooshing noise that can be heard through a stethoscope. While heart murmurs are prevalent and often benign, they can sometimes indicate underlying heart conditions that require further investigation and management.

Causes of Heart Murmurs:

Heart murmurs can arise from a variety of factors, ranging from harmless to serious. Some common causes include:

  1. Innocent (Physiological) Murmurs: These are benign murmurs that occur in individuals with structurally normal hearts. They’re often heard in children and adolescents during growth spurts or periods of increased blood flow. Innocent murmurs tend to fade as the individual grows older.
  2. Valvular Abnormalities: Heart valves ensure the unidirectional flow of blood within the heart. If a valve does not close properly or is stenotic (narrowed), blood flow can become turbulent and create a murmur. Conditions like mitral valve prolapse, aortic stenosis, and aortic regurgitation can cause murmurs and are extremely serious.
  3. Structural Defects: Congenital heart defects, present from birth, can lead to abnormal blood flow and murmurs. Ventricular or atrial septal defects, where there are openings between heart chambers, can cause blood to flow abnormally.
  4. Cardiomyopathies: Conditions that affect the heart muscle’s structure and function, like hypertrophic cardiomyopathy, can result in turbulent blood flow and produce murmurs. In Hypertrophic obstructive cardiomyopathy, the walls of the left ventricle become thick and stiff. Over time, the heart can’t take in or pump out enough blood during each heartbeat to supply the body’s needs. It can lead to blood clots, heart failure, stroke and arrythmias that cause cardiac arrest.  It is a major cause of sudden cardiac death in people younger than 35.
  5. Anemia and Hyperthyroidism: Conditions that alter blood viscosity or heart rate and pumping intensity can contribute to the development of murmurs.

The significance of a heart murmur depends on factors such as its intensity, timing, pitch, and accompanying symptoms.

  •  Murmurs caused by heart conditions like valvular abnormalities or structural defects warrant closer evaluation. Additional diagnostic tests such as echocardiograms, electrocardiograms (ECGs), and possibly cardiac catheterization may be necessary to determine the underlying cause and plan appropriate management.
  • If a murmur is accompanied by symptoms like chest pain, shortness of breath, fatigue, or fainting, it may indicate a more serious condition that needs immediate medical attention.

If you or someone you know has been diagnosed with a heart murmur, consulting a healthcare provider is essential for accurate diagnosis and appropriate care.

Understanding Cardiovascular Disease

Cardiovascular disease (CVD) is a term used to describe a class of conditions that affect the heart and blood vessels. It encompasses a range of disorders, including coronary artery disease, heart failure, stroke, and peripheral artery disease. CVD is a significant global health challenge, being one of the leading causes of death and disability worldwide.

Types and Causes of Cardiovascular Disease:

Cardiovascular diseases are most frequently a result of the accumulation of fatty deposits, cholesterol, and other substances in the arteries, a process known as atherosclerosis. This buildup restricts blood flow to the heart and other organs, increasing the risk of various complications. Some common types of CVD include:

  • Coronary Artery Disease (CAD): This occurs when the arteries that supply blood to the heart muscle become narrowed or blocked, often leading to chest pain (angina) or heart attacks.

  • Stroke: A stroke happens when there’s a disruption of blood supply to the brain, resulting in brain damage. Ischemic strokes are caused by blocked blood vessels, while hemorrhagic strokes result from bleeding in the brain.

  • Heart Failure: Heart failure doesn’t mean the heart has stopped beating; rather, it indicates that the heart isn’t pumping blood as effectively as it should, causing fatigue, breathlessness, and fluid retention.

  • Peripheral Artery Disease (PAD): PAD occurs when there’s a narrowing of blood vessels in the limbs, usually the legs, leading to reduced blood flow and potentially causing pain and difficulty walking.


Cardiovascular disease has a profound impact on public health globally. According to the World Health Organization (WHO):

  • Leading Cause of Death: Cardiovascular disease is the leading cause of death worldwide, accounting for an estimated 17.9 million deaths each year.

  • Economic Burden: CVD places a significant economic burden on societies through healthcare costs, lost productivity, and premature deaths.

  • Geographic Variation: While CVD affects people of all ages and regions, its prevalence varies. Low- and middle-income countries often experience a higher burden of CVD due to factors such as urbanization, unhealthy diets, lack of physical activity, and limited access to healthcare.

  • Lifestyle Factors: Unhealthy lifestyle choices, including tobacco use, unhealthy diet, physical inactivity, and excessive alcohol consumption, greatly contribute to the development of CVD.


While cardiovascular diseases are widespread, they are also largely preventable. Lifestyle modifications play a pivotal role in reducing the risk:

  • Healthy Diet: Adopting a diet rich in fruits, vegetables, whole grains, lean proteins, and healthy fats can help reduce the risk of CVD.

  • Regular Exercise: Engaging in regular physical activity can improve heart health, lower blood pressure, and maintain a healthy weight.

  • Avoiding Tobacco: Quitting smoking significantly reduces the risk of CVD and other health problems.

  • Managing Chronic Conditions: Controlling conditions like diabetes, high blood pressure, and high cholesterol is crucial for preventing CVD.


Early Detection: Routine medical check-ups can help detect risk factors early and enable timely intervention. People with a family history of CVD or otherwise considered to be at risk, need to take an active role in their own health: Keep a record of symptoms and share them with the doctor, understand what tests may be ordered and what they mean, always ask questions. 

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