fourth heart sound (S4)

Etiology

• aortic stenosis
• hypertension
• hypertrophic cardiomyopathy
• cardiac ischemia (the ischemic ventricle may have reduced compliance)
• pulmonary hypertension (S4 gallop)*

* right-sided gallops best heard with the patient supine

* left-sided gallops best heard with patient in left lateral decubitus position

Epidemiology

• S4 is more prevalent in elderly >= 75 years than in younger patients

Pathology

• reflects left atrial contraction into a noncompliant left ventricle

Clinical manifestations

• low-pitched sound preceding S1
• heard best with the bell of the stethoscope at the apex of the heart

Management

• no additional testing needed in asymptomatic hypertensive patients.