Heart murmurs and dynamic manoeuvres
Sorts systolic from diastolic murmurs, where each is loudest, and how handgrip, Valsalva and squatting separate HOCM, aortic stenosis and mitral valve prolapse.
First split by timing
A murmur is placed by when it occurs and where it is loudest (with its radiation).
Systolic murmurs
| Murmur | Loudest at | Radiation / character |
|---|---|---|
| Aortic stenosis | Right 2nd space | Carotids; ejection, crescendo-decrescendo; slow-rising pulse |
| Pulmonary stenosis | Left 2nd space | Left shoulder; ejection |
| Mitral regurgitation | Apex | Axilla; pansystolic, blowing |
| Tricuspid regurgitation | Left lower sternal edge | Louder on inspiration (Carvallo's sign) |
| VSD | Left lower sternal edge | Harsh pansystolic |
| HOCM | Left lower sternal edge | Ejection; no carotid radiation |
| MVP | Apex | Mid-systolic click then late systolic murmur |
Diastolic murmurs
| Murmur | Loudest at | Character |
|---|---|---|
| Aortic regurgitation | Left sternal edge, sitting forward, expiration | Early, decrescendo, blowing; wide pulse pressure |
| Mitral stenosis | Apex, left lateral position | Mid-diastolic rumble with opening snap; loud S1 |
| Graham Steell | Left sternal edge | Functional PR of pulmonary hypertension |
Diastolic and continuous murmurs are always pathological. Many soft systolic ejection murmurs are innocent.
Dynamic manoeuvres — the exam favourite
Two principles run everything:
- ↑ venous return / ↑ preload (squatting, passive leg raise) makes most murmurs louder.
- ↑ afterload (handgrip) makes regurgitant/left-to-right murmurs (MR, AR, VSD) louder.
The two exceptions move the opposite way to everything else and are the whole point of the question:
| Manoeuvre | Preload / afterload | HOCM | AS | MVP (click) |
|---|---|---|---|---|
| Valsalva (strain) / standing | ↓ preload | Louder | Softer | Click earlier, murmur longer |
| Squatting / leg raise | ↑ preload (+ afterload) | Softer | Louder | Click later, murmur shorter |
| Handgrip | ↑ afterload | Softer | Little change / softer | Click later |
HOCM and MVP behave paradoxically because reducing LV volume (less preload) worsens the outflow obstruction / brings the mitral leaflets together sooner. Everything else follows flow: more preload = more flow = louder.
Pearl: The murmur that gets louder on Valsalva/standing and softer on squatting is HOCM (or MVP) — the mirror image of aortic stenosis, which loves the extra preload of squatting.
Anchor
Timing → site → manoeuvre. If it grows when the ventricle empties, it is dynamic outflow obstruction (HOCM), not fixed valvular stenosis.
Sources
- Harrison's Principles of Internal Medicine, 21e
- Hutchison's Clinical Methods, 24e