Let’s talk heart sounds!

Here is a classic “lub dub” S1/S2 heartbeat. In a normal heart, you should only hear valves closing—never opening!

(By the way, I’ve decided that, unlike all those other online tutorials, these sounds should be a bit more . . . realistic. Good luck!)

This is mitral regurgitation—one of the three “holosystolic” murmurs. You hear the murmur with the same intensity throughout all of systole, often completely obscuring S1 and S2. The others are tricuspid regurgitation and ventral septal defect.

Aortic stenosis is a classic “peaked” wave—the characteristic crescendo/decrecendo pattern. Early in the disease you may hear the murmur early in systole, but as the valve becomes more stenotic, the murmur shows up later, often becoming louder over time.

Atrial septal defect also presents with a crescendo/decrescendo pattern, but with a widely split and fixed S2 sound owing to delayed closure of the pulmonic valve.

The continuous “machine-like whirring” of this murmur throughout both systole and diastole is due to a failure of the ductus arteriosus to close, which normally happens in the days to weeks after birth.