Cardiac Syndromes

00:00 Okay. Let's talk about some cardiac syndromes and ischemic heart disease.

00:04 So angina pectoris, chest pain. That's what that means or angina pectoris, either way, angina, angina will have kind of three general flavors.

00:17 So you can have stable angina pectoris.

00:19 So that means that you're pretty much here on the scales of perfusion, demand, perfusion, demand.

00:24 Now, if demand increases relative to perfusion, you're going to have predictably, some degree of angina, chest pain.

00:34 That's associated with that degree of activity. So at rest, I'm fine.

00:37 And then I get up and I run around the block once, and I have chest pain but it's pretty reliable. It happens at that level.

00:45 That's where I've exceeded my balance. So that's a stable angina.

00:50 There is Prinzmetal angina which I've described previously, where you have vasospasm and sometimes, this can be related to the production of catechols, Epinephrine, things like that.

01:01 Sometimes, we don't know necessarily what's driving that.

01:05 And then there's unstable angina.

01:09 And unstable anginas, we'll see in a few slides, actually has three flavors of its own.

01:13 So unstable angina means I'm having brand new onset chest pain that I haven't had before.

01:20 So the first onset of something that may eventually become stable is called unstable angina.

01:25 I'm getting chest pain. Previously, I used to be able to run around the block, no pain.

01:29 Now, I ran around the block today, I got some pain. That's unstable angina.

01:34 It needs to be evaluated as such. You can have - so that's new onset.

01:38 You can have progressive angina. So previously, you ran around the block.

01:43 That gave me angina. But now, I run halfway around the block and I get angina.

01:47 That is unstable. It's progressive. It's getting - it's presenting with less activity.

01:53 Or there can be onset of angina at rest. So I'm not doing anything.

02:00 I'm not increasing supply or demand or anything.

02:02 And suddenly, I've got chest pain. That's a third form of unstable angina.

02:06 And all of those, say, "Oh, things are going wrong somewhere in the coronary artery.

02:11 And yet, needs to be evaluated." Myocardial infarction.

02:17 This is now beyond chest pain. So chest pain is just like, you know, it is a shot across the bow.

02:23 You need to evaluate why this is happening.

02:25 But Myocardial infarction means, now, it's not a shot across the bow.

02:28 It's a shot into the bow. And this is when the severity or the duration of ischemia is sufficient to cause cardiomyocyte death.

02:37 And basically, it's cutting off the blood supply to some portion of the heart for more than 20 or 30 minutes, and those heart muscle cells check out.

02:45 Sudden cardiac death, SCD can occur as a consequence of tissue damage from a myocardial infarct.

02:51 But in the vast majority of cases, sudden cardiac death, meaning, you die within the onset of symptoms, within an hour or so of onset of symptoms, is not usually a consequence of a myocardial infarct but is most commonly a lethal arrhythmia due to myocyte ischemia but not myocyte necrosis.

03:12 It can be due to an infarct.

03:14 But again, more commonly, 90% of cases are going to be due to a fatal lethal arrhythmia.

03:20 And then you can have chronic ischemic heart disease with congestive heart failure.

03:26 So you can have an acute MI, damage part of the muscle.

03:30 You don't die from it, but now, the compensatory mechanisms of the residual viable myocytes try to hypertrophy, try to maintain cardiac output and over a period of time, they fail.

03:42 And if you want to learn more about congestive heart failure, that's another talk.

03:47 But anyway, so that can be one mechanism.

03:49 The other one is you can have tiny little ischemic insults that just like death by a thousand papercuts, eventually cause dysfunction and congestive heart failure.