| Murmur | Timing | Auscultation Site | Radiation | Key Physical Finding / Sound |
|---|---|---|---|---|
| Aortic Stenosis (AS) | Systolic | 2nd Right ICS | Carotids | Crescendo-decrescendo, Soft S2 |
| Mitral Regurgitation (MR) | Systolic | Apex (5th ICS, MCL) | Left Axilla | Holosystolic (Pansystolic), Blowing |
| Mitral Valve Prolapse (MVP) | Systolic | Apex | None | Mid-systolic click + Late systolic murmur |
| Aortic Regurgitation (AR) | Diastolic | 3rd LICS (Erb’s Point) | Left Sternal Border | High-pitched decrescendo, Bounding pulses |
| Mitral Stenosis (MS) | Diastolic | Apex (Left lateral decubitus) | None | Opening snap + Mid-diastolic rumble |
1. Systolic Murmurs
Aortic Stenosis (AS)
Aortic Stenosis occurs when calcification or congenital bicuspid valves narrow the aortic orifice, creating outflow obstruction during ventricular contraction.
-
Timing & Pitch: Crescendo-decrescendo systolic ejection murmur.
-
Best Heard At: 2nd Right Intercostal Space (RICS) at the sternal border.
-
Radiation: Carotid arteries (bilaterally).
Key Exam & Bedside Takeaways
Associated with classic symptoms: SAD (Syncope, Angina, Dyspnea).
Pulsus parvus et tardus (weak and delayed carotid upstroke).
Loudness increases with squatting (increased preload/afterload) and decreases with Valsalva.
Mitral Regurgitation (MR)
Mitral Regurgitation is caused by retrograde blood flow from the left ventricle into the left atrium during systole, secondary to leaflet prolapse, ischemic papillary muscle rupture, or chordae tendineae rupture.
Timing & Pitch: Holosystolic (pansystolic), high-pitched blowing sound.
Best Heard At: Apex (5th intercostal space, midclavicular line).
Radiation: Left Axilla.
Key Exam & Bedside Takeaways
S3 heart sound often present due to volume overload in the left ventricle.
Intensity increases with Handgrip (increased afterload pushing more blood back into the atrium).
Does NOT change significantly with respiration.
Mitral Valve Prolapse (MVP)
MVP occurs when the mitral valve leaflets bulge retrogressively into the left atrium during contraction. It is the most common cause of MR in developed countries.
Timing: Mid-systolic click followed by a late systolic murmur.
Best Heard At: Apex.
Key Exam & Bedside Takeaways
Valsalva / Standing (decreased venous return) causes the click to occur earlier in systole and makes the murmur longer.
Squatting / Handgrip (increased LV volume) delays the click (later in systole) and shortens the murmur.
2. Diastolic Murmurs
Note: All diastolic murmurs represent pathological clinical conditions and require further echocardiographic evaluation.
Aortic Regurgitation (AR)
Aortic Regurgitation is incompetence of the aortic valve causing backflow of blood from the aorta into the left ventricle during diastole.
Timing & Pitch: Early diastolic, high-pitched blowing decrescendo murmur.
Best Heard At: 3rd Left Intercostal Space (Erb’s Point) with the patient leaning forward and in full expiration.
Radiation: Down the left sternal border.
Key Exam & Bedside Takeaways
Associated with wide pulse pressure (e.g., 160/50 mmHg).
Clinical signs include Water-hammer pulse (Corrigan pulse) and Quincke’s capillary pulsations.
Mitral Stenosis (MS)
Mitral Stenosis is impaired flow from the left atrium to the left ventricle during diastole, most commonly caused by historical Rheumatic Fever.
Timing & Pitch: Low-pitched mid-diastolic rumble.
Best Heard At: Apex in the Left Lateral Decubitus position using the bell of the stethoscope.
Key Exam & Bedside Takeaways
Characterized by a high-pitched Opening Snap (OS) following S2.
The shorter the interval between S2 and the Opening Snap, the more severe the stenosis.
Frequently leads to Left Atrial Enlargement and Atrial Fibrillation.
3. Dynamic Auscultation Maneuvers
Bedside maneuvers alter preload, afterload, or ventricular volume to differentiate subtle cardiac murmurs.
Squatting / Passive Leg Raise
Mechanism: Increases venous return (preload) and systemic vascular resistance (afterload).
Effect:
Increases intensity of AS, MR, AR, and MS.
Decreases intensity of Hypertrophic Cardiomyopathy (HCM) and delays MVP click.
Valsalva Strain / Standing Up
Mechanism: Decreases venous return (preload) and cardiac chamber volume.
Effect:
Decreases intensity of most murmurs (AS, MR, AR, MS).
Increases intensity of HCM and moves MVP click earlier in systole.
References
Bickley, L. S., Szilagyi, P. G., Hoffman, R. M., & Soriano, R. P. (2021). Bates’ guide to physical examination and history taking (13th ed.). Wolters Kluwer.
Lilly, L. S. (Ed.). (2020). Pathophysiology of heart disease: A collaborative project of medical students and faculty (7th ed.). Wolters Kluwer.
Otto, C. M., Nishimura, R. A., Bonow, R. O., Carabello, B. A., Erwin, J. P., 3rd, Gentile, F., Jneid, H., Krieger, E. V., Mack, M., McLeod, C., O’Gara, P. T., Rigolin, V. H., Sundt, T. M., 3rd, Thompson, A., & Toly, C. (2021). 2020 AHA/ACC guideline for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation, 143(5), e72–e227. https://doi.org/10.1161/CIR.0000000000000923
Thomas, S. L., & Flather, M. (2020). Auscultation of heart murmurs: A pragmatic approach. British Journal of Hospital Medicine, 81(4), 1–9. https://doi.org/10.12968/hmed.2019.0345