How murmurs are tested on Step 1

A vignette gives timing, location, and a maneuver response and asks for the lesion — or gives a lesion and asks what a maneuver will do.

workspace_premium Four questions for every murmur

When? (systolic or diastolic) · Shape? (crescendo–decrescendo, holosystolic, decrescendo, rumble) · Where? (location and radiation) · What changes it? (maneuvers and respiration).

Systolic vs diastolic murmurs

Systolic murmurs come from ejection through a narrow outflow or regurgitation through an incompetent atrioventricular valve or septal defect. Diastolic murmurs come from regurgitation through a semilunar valve or flow across a narrowed atrioventricular valve.

MurmursSystolicejectionAS, PS, HOCM,flow murmursHolosystolicMR, TR, VSDLatesystolicMitral valveprolapseEarlydiastolicAortic orpulmonicregurgitationMid-diastolicMitral ortricuspidstenosis
Murmur timing. Continuous "machine-like" murmurs suggest a patent ductus arteriosus.
LesionTiming and shapeLocation and radiationClassic association
Aortic stenosisCrescendo–decrescendo systolic ejectionRight 2nd ICS → carotidsElderly, bicuspid valve; pulsus parvus et tardus
Mitral regurgitationHolosystolic, blowingApex → axillaIschemic papillary muscle, MVP, rheumatic disease
Tricuspid regurgitationHolosystolicLeft lower sternal borderIV drug use endocarditis; louder on inspiration
VSDHarsh holosystolicLeft lower sternal borderSmaller defects are louder
Mitral valve prolapseMidsystolic click → late systolic murmurApexMyxomatous degeneration; Marfan, Ehlers-Danlos
HOCMSystolic ejectionLeft sternal border; no carotid radiationYoung athlete, sudden death; louder with Valsalva
Aortic regurgitationEarly diastolic, decrescendo, blowingLeft sternal border (sitting forward)Wide pulse pressure, bounding pulses
Mitral stenosisOpening snap → diastolic rumbleApex (bell, left lateral)Rheumatic heart disease; atrial fibrillation
PDAContinuous machine-likeLeft infraclavicularPrematurity, congenital rubella

Murmur grade (1–6) reflects loudness; a palpable thrill means grade 4 or higher.

Bedside maneuvers

Maneuvers change preload or afterload, and each lesion responds predictably.

ManeuverPhysiologic effectLouderSofter
Squatting, passive leg raise↑ Preload (and afterload with squatting)Most murmurs (AS, MR, AR)HOCM; MVP click occurs later
Valsalva (strain), standing↓ PreloadHOCM; MVP click earlier, murmur longerMost murmurs (AS, MR, AR)
Handgrip↑ AfterloadMR, AR, VSD (regurgitant)AS, HOCM
Amyl nitrite↓ AfterloadAS, HOCMMR, AR, VSD
Inspiration↑ Right-sided venous returnRight-sided murmurs (TR, PS)Left-sided murmurs

Key pattern: HOCM and MVP move opposite to almost every other murmur with preload changes.

Aortic stenosisFixed valvular obstructionRadiates to carotidsValsalva → softerSquat → louderOlder patient; weak delayed carotidpulseHOCMDynamic septal obstructionNo carotid radiationValsalva → louder (smaller LV)Squat → softer (larger LV)Young patient; bifid carotid pulsevs
AS vs HOCM. In HOCM, a smaller ventricle pulls the mitral leaflet toward the septum (systolic anterior motion), worsening obstruction.

Innocent vs pathologic murmurs

Many murmurs in children and pregnant patients are benign flow murmurs.

More concerningLikely innocentSoft (grade ≤ 2), early systolic, changes withposition, normal S2EvaluateGrade ≥ 3, holosystolic, radiating, abnormal S2Always pathologicAny diastolic murmur, thrill, symptoms (syncope,dyspnea)
Innocent vs pathologic. Echocardiography is the next step for any diastolic murmur or a loud or symptomatic systolic murmur.

Clinical application

Maneuvers are a classic way to separate two systolic murmurs.

functions Worked example — the athlete's murmur

A 19-year-old basketball player has a systolic murmur at the left sternal border that does not radiate to the carotids. It gets louder when he stands from squatting and softer with handgrip. What is the lesion?

  1. Standing reduces preload; a murmur that gets louder with less preload is HOCM (or MVP).
  2. Handgrip increases afterload, keeping the ventricle fuller and reducing outflow obstruction — HOCM softens.
  3. Lack of carotid radiation and a young athlete fit HOCM rather than aortic stenosis.

Answer. Hypertrophic obstructive cardiomyopathy — the leading cause of sudden cardiac death in young athletes. Restrict competitive sports pending evaluation.