1.13 Cardiac Physical Examination, Murmurs & Antithrombotic Selection
Key Takeaways
- Miscellaneous cardiovascular disease, listed as physical examination findings and murmurs, is a named blueprint subsection.
- Right-sided murmurs increase with inspiration; left-sided murmurs do not, which is the fastest bedside discriminator.
- Standing and Valsalva reduce preload and increase the murmurs of hypertrophic obstructive cardiomyopathy and mitral valve prolapse while softening all others.
- An S3 reflects rapid early diastolic filling into a dilated ventricle; an S4 reflects atrial contraction into a stiff ventricle and is absent in atrial fibrillation.
- Exam stems may present heart or lung sound recordings rather than written descriptions, so auscultation must be practiced with audio.
1. Why Bedside Cardiology Is Still Tested
ABIM explicitly lists Miscellaneous cardiovascular disease (physical examination findings, murmurs) as a blueprint subsection, and states that clinical information in a stem may include recordings of heart or lung sounds. That means some cardiovascular items cannot be answered from a written vignette at all — you must listen and classify. Practice with audio, not only with prose.
2. Timing First, Then Location, Then Maneuvers
Work through every murmur in a fixed order.
Step 1 — Timing.
| Timing | Lesions |
|---|---|
| Systolic ejection (crescendo-decrescendo) | Aortic stenosis, pulmonic stenosis, hypertrophic obstructive cardiomyopathy, flow murmur |
| Holosystolic | Mitral regurgitation, tricuspid regurgitation, ventricular septal defect |
| Late systolic with click | Mitral valve prolapse |
| Early diastolic (decrescendo) | Aortic regurgitation, pulmonic regurgitation |
| Mid-to-late diastolic (rumble) | Mitral stenosis, tricuspid stenosis |
| Continuous | Patent ductus arteriosus, arteriovenous fistula |
Diastolic murmurs are never innocent. A systolic murmur may be a benign flow murmur; a diastolic murmur always requires echocardiography.
Step 2 — Location and radiation. Aortic stenosis radiates to the carotids; mitral regurgitation radiates to the axilla; the murmur of hypertrophic obstructive cardiomyopathy does neither.
Step 3 — Maneuvers. This is where exam questions are won.
| Maneuver | Physiologic effect | Louder | Softer |
|---|---|---|---|
| Inspiration | ↑ right heart venous return | All right-sided murmurs | — |
| Standing / Valsalva strain | ↓ preload | HOCM, mitral valve prolapse | Aortic stenosis, most others |
| Squatting / passive leg raise | ↑ preload and afterload | Aortic stenosis, mitral and aortic regurgitation | HOCM, mitral valve prolapse |
| Sustained handgrip | ↑ afterload | Mitral regurgitation, ventricular septal defect, aortic regurgitation | Aortic stenosis, HOCM |
The reliable shortcut: hypertrophic obstructive cardiomyopathy and mitral valve prolapse behave oppositely to everything else. Anything that reduces left ventricular cavity size — standing, Valsalva strain — worsens dynamic outflow obstruction and brings the prolapsing leaflet into apposition earlier.
3. Distinguishing Aortic Stenosis From Its Mimics
| Aortic stenosis | HOCM | Mitral regurgitation | |
|---|---|---|---|
| Timing | Systolic ejection | Systolic ejection | Holosystolic |
| Radiation | Carotids | None | Axilla |
| Carotid upstroke | Parvus et tardus (weak, delayed) | Brisk, bifid | Normal |
| Valsalva | Softer | Louder | Softer |
| Handgrip | Softer | Softer | Louder |
The carotid upstroke is the most reliable single bedside discriminator between aortic stenosis and hypertrophic cardiomyopathy: fixed obstruction blunts and delays it, whereas dynamic obstruction permits an initially brisk upstroke that is then interrupted.
4. Extra Heart Sounds
- S3 — a low-pitched early diastolic sound from rapid ventricular filling into a dilated, compliant chamber. Pathologic after roughly age 40 and a reasonably specific sign of volume overload in heart failure. It may be physiologic in young adults, athletes and pregnancy.
- S4 — a presystolic sound produced by atrial contraction into a stiff, non-compliant ventricle. Seen in long-standing hypertension, aortic stenosis and hypertrophic cardiomyopathy. An S4 cannot exist in atrial fibrillation, because it requires organized atrial contraction — a frequently tested internal consistency check.
- Opening snap — a high-pitched early diastolic sound in mitral stenosis. A shorter S2-to-opening-snap interval indicates more severe stenosis, because higher left atrial pressure opens the valve sooner.
- Pericardial knock — an early diastolic sound in constrictive pericarditis, occurring earlier and sounding higher-pitched than an S3.
- Ejection click — early systolic, from a bicuspid aortic valve or pulmonic stenosis. A pulmonic ejection click is the one right-sided sound that decreases with inspiration.
5. Peripheral Signs Worth Recognizing
- Pulsus paradoxus — an inspiratory systolic fall greater than 10 mmHg. Classic for cardiac tamponade; also seen in severe asthma, COPD exacerbation and constrictive pericarditis.
- Kussmaul sign — a paradoxical rise in jugular venous pressure with inspiration. Seen in constrictive pericarditis, restrictive cardiomyopathy and right ventricular infarction; characteristically absent in uncomplicated tamponade.
- Water-hammer (Corrigan) pulse — a wide pulse pressure with rapid collapse, characteristic of chronic severe aortic regurgitation.
- Pulsus alternans — alternating strong and weak beats, indicating severe left ventricular systolic dysfunction.
6. Antithrombotic Therapy in Cardiovascular Disease
Antithrombotic therapy is a separate named blueprint subsection, and the recurring exam task is choosing an agent for a given indication rather than reciting a mechanism.
| Indication | Standard therapy | High-yield caveat |
|---|---|---|
| Non-valvular atrial fibrillation | Direct oral anticoagulant | Warfarin required for mechanical valves and moderate-to-severe mitral stenosis |
| Mechanical prosthetic valve | Warfarin, target INR by valve position and type | Direct oral anticoagulants are contraindicated |
| Venous thromboembolism | Direct oral anticoagulant | Antiphospholipid syndrome requires warfarin |
| Stable coronary disease | Single antiplatelet agent | Adding an anticoagulant increases bleeding without ischemic benefit |
| Post-stent acute coronary syndrome | Dual antiplatelet therapy | Duration is shortened when bleeding risk is high |
| Atrial fibrillation plus recent stent | Anticoagulant plus a single P2Y12 inhibitor | Triple therapy is minimized because bleeding risk is additive |
| Primary prevention | Generally not indicated | Bleeding harm offsets benefit in most low-risk adults |
The single most testable principle: when a patient needs both an anticoagulant and antiplatelet therapy, minimize overlap. Prolonged triple therapy is the wrong answer in nearly every vignette.
A 24-year-old man is evaluated for exertional presyncope. A grade 3/6 systolic murmur is heard at the left sternal border. The murmur becomes louder when he stands up from a squat and softer with sustained handgrip. The carotid upstroke is brisk with a bifid contour, and the murmur does not radiate to the carotids. Which lesion best explains these findings?
A 68-year-old woman with non-valvular atrial fibrillation on apixaban undergoes drug-eluting stent placement for an acute coronary syndrome. Her CHA2DS2-VASc score is 5 and she has a prior gastrointestinal bleed. Which antithrombotic strategy best balances stroke and bleeding risk?