The s4 gallop

The S4 heart sound is a presystolic heart sound occurring immediately before S1 associated with reduced ventricular compliance. It is best heard with the bell of the stethoscope at the apex of the heart with the patient in the left lateral decubitus position. The characteristic sound of an S4 is created by the movement of blood during diastole from the atria flowing against a stiff ventricular wall caused by hypertension, pulmonary hypertension, ventricular outflow obstruction, or ischemic heart disease. An S4 can also be heard in athletes with physiologic hypertrophy of the ventricles. In patients with a pathologic S4, a longer interval between S4 and S1 represents a poorer prognosis. Detection of an S4 in a patient with risk factors for pathologic reduced ventricular compliance should trigger further cardiac work up and treatment of underlying pathology to decrease progression.