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Current time:0:00Total duration:6:16

Video transcript

so heart failure is a pretty broad disease you know it's essentially defined as this inability to meet the body's demands right but how do we go about diagnosing that or how do we figure that out well there's a couple ways that doctors can do this and the first group of ways is just by imaging the harder essentially just taking a look at it so what we might do is we might take an x-ray of the chest area now x-rays use this electromagnetic radiation that's blocked by certain structures more than others so that's why you might see the bones show up as white and then other organs might show up as gray so this lets doctors kind of visualize the current state of both the heart and the lungs so usually they're looking for the outline of the heart right and one thing that might look for in the heart is any sign of enlargement where the heart just looks bigger than it normally should because remember with both systolic and diastolic failure the heart can actually get bigger and this can sometimes be seen on x-ray and then another thing that doctors might take a look at is your lungs because remember with left-sided heart failure you can have this congestion or like a fluid buildup in the lungs and this fluid is sometimes visible on x-ray and this can give doctors a clue as to both how severe the heart failure is and also whether it's left-sided or not so that was x-rays but another diagnostic imaging technique that we sometimes use it's probably actually more common for heart failure is the echocardiogram and so if we take a look at the first part of this word echo it kind of closes into it's meaning this diagnostic uses sound waves actually instead of electromagnetic radiation like with x-rays specifically you have this thing called the transducer that sends out sound waves and then it waits for the sound waves to bounce back or to echo and by knowing certain properties of the tissues like how fast the sound waves are going to move through them we can get this image and even sometimes a real-time video and so since you can see the heart moving via this video these tests are super valuable for measuring the heart's pumping ability or your ejection fraction which you know if we remember is this percentage of blood ejected from the heart with each beat and by measuring the ejection fraction the echocardiogram is a super useful tool for doctors to figure out it's diastolic failure or systolic failure because with diastolic failure remember that you can have a preserved ejection fraction whereas with systolic failure your ejection fraction is typically a lot lower than normal all right so besides imaging techniques another thing we can look at is a blood test with a blood test we're looking for certain substances that are secreted or associated with heart failure and one in particular that we're going to focus on is called b-type natriuretic peptide and that's a mouthful so I'm just going to refer to it as BNP so BNP is this really important indicator because it's secreted by the hearts ventricles in response to this excessive stretching of the muscle cells and changes in pressure in the ventricles remember that with heart failure the preload or the pressure in the ventricles tends to increase right which causes the muscle cells to stretch more and the heart to enlarge so when this happens the ventricles secrete this BNP into the blood and so the more severe the heart failure the more stretch of the ventricles and the more BMP that's secreted and so it makes sense that if we take a small sample of blood we might be able to analyze it and see how much BNP is present so BMP levels below a hundred picograms per milliliter of blood indicates no heart failure and this is a really small amount but it's still measurable and BMP levels between 100 and 300 picograms per milliliter might suggest the presence of heart failure between 300 and 900 might be considered mild to moderate heart failure and then above 900 picograms per milliliter would indicate a severe case of heart failure but beyond imaging and a blood test the doctor will often use a couple of classification systems to describe the severity of the symptoms basically so they can get an idea on how best to treat each individual patient and the first is the stress test and which is also known as the New York Heart Association functional classification this looks at how well you respond to physical exertion because we know that with more activity in exertion your body demands more blood right so depending on how well your heart can respond to increasing demands by increasing this activity we can start to understand how severe the heart failure is so the doctor might monitor you while you either walk on a treadmill or ride a stationary bike and the first class or Roman numeral one is no limitation to physical activity meaning that this activity doesn't cause any out-of-the-ordinary fatigue palpitations or shortness of breath class Roman numeral two is some limitation to physical activity meaning that you might be comfortable at rest but any normal physical activity results in some symptoms of heart failure class three however is a lot of symptoms during physical activity but still no symptoms at rest finally class four indicates a complete inability to undertake really any physical activity without feeling those symptoms and furthermore those symptoms even occur at rest so the second classification system is the American Heart Association stages of heart failure and this one's more defined at the objective level by the amount of structural heart disease that's present with each patient so with stage a the patient might be at risk for heart failure but there aren't any structural changes to the heart so at this point it might be a patient with maybe diabetes or high blood pressure but there haven't been any changes to the heart in response and there aren't any symptoms of heart failure in stage B patients have some sort of measurable structural heart disease so like maybe their ejection fraction is lowered or they have an enlarged chamber but with stage B symptoms of heart failure still haven't developed at stage C both a structural heart disease has occurred in symptoms of heart failure are present and finally stage D indicates an advanced level of heart disease and continued symptoms of heart failure and this level usually requires aggressive medical therapy and intervention so using these two systems together doctors can get an idea on how best to treat each patient based on both their class and stage of heart failure