Diagnosis and Therapy – Cardiovascular Disease

00:00 Well, let’s talk a little bit about the kinds of symptoms that patients have that bring them to the cardiologist. In fact, symptoms are critical in making a diagnosis. What do I mean by that? I mean, of course, that individuals with heart disease will usually come to the cardiologist complaining of some problem, some symptom. For example, “Doctor, every time I walk up a hill, I get short of breath.” Or “Doctor, I have noticed for the last few months that I have had swelling in my ankles.” Or “Doctor, I have noticed that every once in a while, I feel my heart racing and I get lightheaded, and I have to sit down because I think I might faint.” Clearly, these are three of the commonest symptoms that bring patients to see a cardiologist.

00:52 It turns out that when the cardiologist makes a diagnosis, 90% of the information that leads to the correct diagnosis is in what the patient tells them, which is why the doctor sits usually for a significant number of minutes with the patient and asks or, as we say in the medical world, elicits a very detailed description of what symptoms the patients are having.

01:17 And most patients, when they tell us this story or this history, will point us in the direction of the right diagnosis. Only about 10% of the diagnosis comes from the physical examination and the laboratory tests. Usually, the physical examination and the laboratory tests are used to confirm what we thought was going to be the diagnosis based upon what the patient told us. Now, there are a whole variety of tests that the cardiologists use that help us to hone in on the particular disease that we think the patient has. Some of them are very simple office tests and they are done not only often by cardiologists, but by primary care doctors in the office. The electrocardiogram, you have already heard about. It records the electrical activity as it runs through the heart. We often do a chest x-ray and that can also often be done in the office or usually at a nearby center that does x-rays. A very useful test to the cardiologist is echocardiography. This is an ultrasound test that actually gives us very exquisitely accurate pictures of the structures within the heart - the valves, the muscle, how well the heart is contracting, whether the heart is dilated or not dilated and so forth. I am going to show you some examples of… of echocardiography in subsequent lectures, but it is probably, these days, the number one help to the cardiologist in making a diagnosis. Sometimes, particularly for patients where we suspect coronary artery disease, we will do a stress test that is either with exercise or with drugs, we will push the heart rate up, get the heart to beat faster and see if we can identify abnormalities in blood flow in the heart. So, let’s say you have a narrowing in a coronary artery and we put you on the treadmill and we run you until you absolutely say, “Hey, I am so short of breath,” or else “I am having chest discomfort, I need to stop.” We can then, often with the electrocardiogram and sometimes with radionuclear or echo examination of the heart, identify areas of the heart that are not getting enough blood flow. And that can lead to further testing. For example, one can then go on to do a cardiac catheterization with an angiogram that it shows us where the narrowings are and sometimes we can fix that. Another two non-invasive tests that are used are the CT scans or sometimes fondly called “CAT scans” and also, magnetic resonance imaging. Both of these tests give us beautiful pictures of the heart and the heart muscle, but they are usually only used in very special patients. Most individuals will make the diagnosis using the history, the physical, the electrocardiogram, maybe a stress test and then often an invasive test - the cardiac catheterization. And here you can see listed the invasive tests.

04:27 This consists of placing small plastic catheters in the bloodstream, taking pressure measurements, measuring the cardiac output - the pumping ability of the heart, and then in addition, we often will inject through the catheter dye, which will show us the motion of the heart and also the interior of the blood vessels to see if there are narrowings in the blood vessels. That kind of catheterization, called “coronary angiography,” is the commonest catheterization done. It’s a procedure that’s done millions of times throughout the year throughout the world. Now, there are also a number of very specialized tests for very specialized conditions. So, for example, the cardiac electrophysiologist - the person interested in electrical short circuits in the heart, may order an electrocardiogram which is recorded for 24 hours. The patient wears a little tape recorder and little electrodes and walks around and sleeps, does the full normal daily activities. And this device will record 24, 48 or even 48 hours worth of heartbeats as we attempt to find evidence that every once in a while, the patient is having a cardiac arrhythmia. And of course, we have talked about standard chest x-rays and also, sometimes we will use ultrasound or echo to image not just the heart, but we may also look at peripheral blood vessels, the veins and the arteries.

05:59 Now, let’s take a typical patient through a cardiac presentation to the… to the cardiologist, all the way through the testing and all the way through into therapy. And I think from this, you will get a feel for what I, as a cardiologist, do every single day when I am working with patients who think they might have heart disease or whose primary care doctor has sent them to see me because the primary care doctor is concerned that this individual may have heart disease. So, here’s Mr. AB. He’s a middle-aged man who has come to me because he notes when he exerts himself, particularly climbing stairs or going up a hill, when he’s walking up a hill, he develops chest discomfort. Why do I call it “chest discomfort?" Some people call it “chest pain,” but it’s not really pain. When you and I think of pain, we think of being burned with a match or we think of having a needle stuck in us or we think of a broken bone. In fact, the pain that comes from the heart is often difficult for the patient to describe because it’s not a true pain. It’s a discomfort, a vague sense of heaviness, tightness, constriction. Some people describe it as indigestion. It’s a vague, uncomfortable feeling in the chest which, when it is due to narrowing in the blood vessels in the heart, occurs when you push the heart like run up a flight of stairs.

07:28 You are demanding the heart to work a lot harder. It’s not getting enough blood flow to… to answer that demand and it signals you, “Hey, I am not getting enough blood flow.” We call that discomfort “angina pectoris,” and it has certain characteristics.

07:45 First of all, it’s deep inside, so the patient doesn’t point and say, “Oh, it hurts right here, Doctor.” They often make a motion like this with their hand or like this. It’s more diffuse and it is usually central. Sometimes the patient can feel it occurring down into the left arm as well, sometimes up into the neck and the jaw. Everybody’s pain pattern’s a little different, just like everybody’s fingerprints are a little different. But, there are a number of characteristics that suggest that this is pain coming from the heart as opposed to pain coming from indigestion or pain coming from a pulled muscle in the chest. Now, this is the disease we are interested in. Eventually, if this patient follows through with the pattern that they are having and… and we decide yes, it’s coronary artery disease, this is a picture of an angiogram.

08:36 This is actually the right coronary artery in a patient with atherosclerosis. If you follow the course of the artery down, you will see a severe narrowing in the middle portion of that artery. And that narrowing is the thing that impairs blood flow into the… a part of the heart muscle, so that when the patient exerts themselves, they run up a flight of stairs, their heart rate and blood pressure increase. The heart’s demanding, “Send me more oxygen! Send me more nutrients!” In fact, it’s not going to get that because of the narrowing in that blood vessel and that patient might experience the discomfort that Mr. AB was describing just to me a moment ago when he came into the office. So, this is the disease we are looking for. We are going to talk more about the angiogram in a few minutes. Okay. So, what’s the next step? We have done history. We are suspecting angina, and as I have told you, angina is due to an imbalance in supply and demand. There’s not enough supply of oxygen and nutrients carried by the blood for the demand that’s being imposed upon the heart. Why doesn’t the patient have angina at rest? Usually, they don’t because you are not asking the heart to do a lot more work. When angina occurs at rest, it usually means that there’s a very severe narrowing in the coronary artery and that’s an emergent thing that has to be dealt with just like a myocardial infarct. It’s often called a “threatened” myocardial infarct or an “impending” myocardial infarct.