ECG of Atrial Enlargement

00:01 So let's just talk about right and left atrial enlargement by themselves just to review.

00:05 We've talked about this before. Here's the normal P wave, right? It's 3 boxes in duration or less, not wider than that. It's upright in leads 1 and 2 and doesn't have a big negative deflection for example in V1. In V1, you'll see in a moment the big negative deflection that suggest left atrial enlargement.

00:28 So here we see a very nice example. Spiky, tall, and broad P wave in lead 2.

00:35 Right atrial enlargement. In this case, it's 2.5 mm in height and in V1, it's upright.

00:46 It's not inverted as here in left atrial enlargement, look at the secondary component of the P wave.

00:53 You notice how inverted and deep it is? That's left atrial enlargement.

00:59 And you could see at the length of the P wave is also prolonged more than three little boxes so it's more than a 120 ms and there's the downward deflection of greater than 40 ms and 1 mm wide big deep inverted secondary component of V1 suggest left atrial enlargement.

01:19 Here we see another form of left atrial enlargement.

01:22 This is often seen with mitral stenosis.

01:25 You'll notice the big broad P wave and the double hump on it spelling the letter M.

01:31 So, it says mitral valve disease--mitral stenosis--and over in V1, again, you see a prolonged deep inverted secondary component.

01:42 Both of these suggesting left atrial enlargement.

01:46 Tall P waves higher than 2 little boxes, notice in aVL in green, this suggests right atrial enlargement.