ECG of Anterior Myocardial Infarction (MI)

00:01 Here, we see an example of an anterior wall myocardial infarct.

00:05 Notice that there's ST elevation in all of the 6 precordial leads.

00:09 A little bit in V1 and a little in V6 but really very impressive huge ST elevation in leads V2, V3, V4, and even pretty impressive in V5.

00:23 These very high ST elevations almost 10 mm in size.

00:29 These are sometimes been called tombstone changes. Why? This is a very, very dangerous myocardial infarct. It's an occlusion.

00:38 Very likely proximal of the left anterior descending coronary artery.

00:42 A huge amount of heart muscle is threatened. This is a real big emergency.

00:47 Off to the cath lab as fast as possible and open up the LAD again.

00:51 So, this is a very nasty anterior MI.

00:55 Here's another one not quite so nasty.

00:59 You'll notice ST elevation in leads V1, V2, and V3 and also in aVL so that suggests that there's a certain lateral component to this.

01:11 So possibly, this is a LAD that has branches in the lateral wall or it may be even an involvement with the left circumflex and the left anterior descending.

01:24 It may be that for example a patient had a previous narrowing of the circumflex and when the left anterior descending goes down, there's lack of good blood flow down the circumflex as well.

01:36 So, in any case, this is another example of anterior MI.

01:41 Also, what's of interest, notice the QRS. Look at the QRS particularly in leads V1, V2, and partly in V3.

01:51 There's a Q wave. The QRS starts with a Q wave.

01:54 Starts with a hole in the heart that's electrically gone and you'll notice also that there's a QS pattern in lead aVL.

02:05 Same thing that this is telling you that there's myocardium that's no longer depolarizing.

02:11 Again, we point that out.

02:14 There are Q waves in leads V2, V3, and aVL and I think if we magnify that enough, there's a little tiny Q wave also in lead V3.

02:23 So here's some unknowns. Look at this ECG. I'll tell you a clue to start with.

02:30 There's a myocardial infarct here. Tell me where it is.

02:41 Is this an acute inferior wall MI? The answer is yes. ST elevation in leads 2, 3, and aVF.

02:48 Also, of interest, notice right at the very beginning there's a standardization.

02:54 The box that's ten points high telling you that this is the right standardization for this ECG.

03:01 Let's look at another one. Take a look at the next one. I'll also tell you this is an MI.

03:09 You tell me where it is.

03:17 Is this an acute anterior? Yes. There's ST elevation in leads V2, V3, V4, and V5.

03:26 So again, acute anterior, that's LAD--left anterior descending artery.

03:31 Acute inferior, usually the right coronary but can be in 10% of people of left circumflex.

03:38 Here, we see the ST elevation arterially.