A ventricular or early diastolic gallop (S3) is a low-frequency heart sound associated with rapid ventricular filling in early diastole, occurring approximately 0.15 seconds after S2. Best heard with the bell of the stethoscope, a right-sided S3 is louder on inspiration (lower left sternal border or xiphoid), whereas a left-sided S3 is louder on expiration (apex).

Pathophysiology

S3 results from rapid deceleration of blood entering a compliant or failing ventricle or from accelerated ventricular filling due to volume overload. Physiologic S3 occurs in children, young adults, and during the third trimester of pregnancy and usually disappears by age 40. In adults over 40, S3 is often pathologic, indicating decreased myocardial contractility, volume overload, or early heart failure. When combined with S4, it produces a summation gallop, often seen in advanced heart disease.

History and Physical Examination

• History: Assess for chest pain, palpitations, dyspnea (exertional, at rest, or orthopnea), syncope, cough, prior cardiac disease, or current heart failure therapy.

• Examination: Auscultate in supine, left lateral, and semi-Fowler positions. Evaluate for murmurs, S1 and S2 variations, pulmonary crackles, peripheral pulses, jugular vein distention, hepatomegaly, and edema. Summation gallops indicate simultaneous atrial and ventricular gallops, often in tachycardia or delayed AV conduction.

Medical Causes:

Summation Gallop: Occurs when atrial (S4) and ventricular (S3) gallops coincide, typically due to tachycardia or delayed AV conduction. Best heard at the apex, it indicates advanced heart disease or heart failure, and may signal worsening cardiac function.

Special Considerations

• Monitor for tachycardia, dyspnea, pulmonary crackles, and jugular venous distention.

• Prepare for ECG, echocardiography, gated blood pool imaging, or cardiac catheterization as indicated.

• Administer oxygen, diuretics, and other heart failure therapies (e.g., ACE inhibitors, digoxin) as prescribed.

Patient Counseling

• Educate on fluid and dietary restrictions, scheduled rest periods, daily weight monitoring, and signs of fluid overload.

• Emphasize follow-up appointments and adherence to heart failure management plans.

Pediatric & Geriatric Considerations

• Pediatric: S3 may be physiologic but can indicate congenital heart defects (e.g., VSD, PDA) or heart failure, especially in sickle cell anemia.

• Geriatric: Pathologic S3 is more common due to decreased ventricular compliance with age and often indicates heart failure.

References:

1. Go, A. S., Mozaffarian, D., Roger, V. L., Benjamin, E. J., Berry, J. D., Borden, W. B., … Turner, M. B. (2013). Heart disease and stroke statistics—2013 update: A report from the American Heart Association. Circulation, 127(1), e6–e245.

2. McMurray, J. J., Adamopoulos, S., Anker, S. D., Auricchio, A., Böhm, M., Dickstein, K., … Ponikowski, P. (2012). ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure 2012. European Heart Journal, 33(14), 1787–1847.