Welcome to Dr. Warrick's podcast channel. Warrick is a practicing cardiologist and author with a passion for improving care by helping patients understand their heart health through education. Warrick believes educated patients get the best health care. Discover and understand the latest approaches and technology in heart care and how this might apply to you or someone you love. Hi, my name is Dr Warrick Bishop and I'd like to welcome you to my podcast station and to the Healthy Heart Network. Today I'd like to talk a little bit about how we classify heart failure or cardiac failure. There are two main distinctions that we make about how the heart fails. The first is in regard to the timeline and the second is in regard to how well the heart is functioning. whether the problem of cardiac failure develops quickly or slowly and is there for a long period of time. The medical terms we use for rapid onset or recent onset is acute. You may have heard the word acute with things like acute appendicitis. That means that it's come on suddenly. So acute in cardiac failure means things that have brought on cardiac failure rapidly the most common things that will bring on cardiac failure rapidly are some of the common conditions that affect the heart particularly coronary artery disease things like a lack of blood flow to the heart either complete causing a heart attack can change the function of the heart and therefore alter the way it's pumping and therefore lead to cardiac failure but also a severe lack of blood flow to the heart, which doesn't necessarily lead to death of the muscle, but leads to stiffness and failure of function of the muscle, can also lead to a change in function of the pump and a deterioration with acute features of cardiac failure. If the heart rhythm throws out, if suddenly the heart's going way too fast or way too slow, of course these things can very acutely alter the function of the pump. And before you know it, features of cardiac failure ensue. Infection is a possible trigger for acute problems with the heart as well. Infections that affect the heart or even the valves of the heart or the muscle of the heart, but also infections that can affect other parts of the body and drive the circulation, in fact overdrive the circulation and overload the heart. Problems with the valves, a sudden valve failure is also a potential cause of acute cardiac failure. Of course, because suddenly the valve, which should be doing the job in terms of keeping blood flowing in a single direction, allows blood in the opposite direction. This diminishes forward flow, diminishes the effectiveness of the pump, and also, of course, leads to backflow and congestion more often than not within the lungs. That's acute. Chronic cardiac failure is the sort of thing that we tend to see more commonly in clinic. And this is related to the progressive decompensation of heart-related function secondary to some of the etiologies that we've talked about before. Lack of blood flow, valves, long-term high blood pressure. These are some of the most common things that we'll see. So chronic cardiac failure is the cardiac failure that comes through our clinics and tends to be the cardiac failure that we deal with on a day-to-day, week-to-week, people living with it for the rest of their lives scenario. The other way we talk about classification of heart failure is in terms of how well the left ventricle, which is the main pumping chamber of the heart, how well the left ventricle is pumping. Now we talk about the function of the left ventricle with a term called ejection fraction, and we've discussed that a little bit in the past. When we talk about ejection fraction, we're talking about how much blood is expelled from the left ventricle with each beat. For simple numbers, let's imagine that the left ventricle holds 100 ml of blood at the end of filling, at the end of the period that we call diastole. When the heart squeezes, it squeezes through a phase that we call systole, the active part of the cardiac cycle, and in general terms, the heart will expel about 60% of its contents. So if it's holding 100 mils at the end of diastole or the beginning of systole, after it's finished its contraction, it will have expelled approximately 60% or 60 mils. And we would call that an ejection fraction of 60%. That's pretty straightforward. When we look at cardiac failure, there are different types of cardiac failure. We see people whose heart fails when the ejection fraction is not very good. And these are people with what we call heart failure with reduced ejection fraction. These people have an ejection fraction that's 40% or less. We also have people who have features of heart failure and their ejection fraction appears to be pretty close to the normal range or an ejection fraction at 50% or more. These are the people who we've covered in other sessions and have what we call diastolic failure or failure of the heart to relax. These people still have preserved ejection fraction, but they don't have normal function of the heart because it's not relaxing properly. These people have heart failure with preserved. ejection fraction, an ejection fraction greater than 50%. We've got the people with preserved ejection fraction, we've got the people with reduced ejection fraction, as you can imagine there's a gap between 40% and above and 49% and below and these people represent heart failure with moderate reduction of ejection fraction. So there you have it. We classify cardiac failure based on timelines. Is it acute or is it more chronic? And we also classify cardiac failure based on how well the heart is pumping. Is it pumping with a significantly reduced ejection fraction? Is it pumping with a relatively preserved ejection fraction? Or is it pumping with an ejection fraction that's moderately reduced? Well, I hope that clarifies for you how we think about classification of heart failure. As always, if you have any queries or questions, let us know. If you have any ideas for any future podcasts, we would be delighted to hear. And as always, I would like to wish you the very best in your health. Take care and bye for now. Visit his website at drWarrickbishop.com for the latest news on heart disease. If you love this podcast, feel free to leave us a review.
