Loud S1
| Causes of Loud S1 | |
| Condition | Mechanism |
| Short P-R interval (0.08-0.12 second) | Valve wide open from recent atrial contraction |
| Premature beats, tachycardia | Valves wide open from rapid early diastolic filling |
| Mitral stenosis, tricuspid stenosis, atrial myxoma | Texture of valve; valve maximally open from prolonged ventricular filling |
| Exercise, fever, anemia, thyrotoxicosis, epinephrine, anxiety, pregnancy, A-V fistula | Forcible ventricular contraction (plus tachycardia) |
| Thin chest wall, child | Minimal damping effects |
Patient 1:
This patient has severe mitral stenosis with a loud S1. The other features of mitral stenosis, including the opening snap and diastolic murmur, are not appreciable in this recording.
Loud S1
Annotated
Patient 2:
This patient was admitted to the hospital after suffering multiple embolic events (to brain and kidney) and an episode of severe hemoptysis, and was later determined to have severe mitral stenosis. One of the classic features of mitral stenosis is a loud S1, demonstrated in these videos. You may also note the opening snap and rumbling diastolic murmur with pre-systolic accentuation.
Loud S1
Annotated
Loud S1
Annotated
According to the legend for patient 2, both heart sounds are recorded from the apex using the bell. Why are the 2 sounds so different? Are they the same sound with the second made artificially louder?
Hi Josh thanks for the comment. Both recordings were taken with the scope over the apex area. When these were recorded, we were using a digital scope with many adjustable settings, including volume. This resulted in a wide range in the quality of recordings, even from the same session (generally, phono tracings with “cleaner” baselines – like the top one in the example you referenced – are better quality). Now we are using a more consistent recording device, so there is less variability in quality between recordings.