cardiovascular disorders
Cardiac Auscultation
Systolic heart sounds
Systolic sounds include the following: 1st heart sound (S1) Clicks S1 and the 2nd heart sound (S2, a diastolic heart sound) are normal components of the cardiac cycle, the familiar “lub-dub” sounds. occurs just after the beginning of systole and is predominantly due to mitral closure but may also include tricuspid closure components. It is often split and has a high pitch. S1 is loud in Mitral Stenosis . It may be soft or absent in Clicksoccur only during systole; they are distinguished from S1 and S2 by their higher pitch and briefer duration. Some clicks occur at different times during systole as hemodynamics change. Clicks may be single or multiple. Clicks in congenital aortic stenosis or Pulmonic Stenosis are thought to result from abnormal ventricular wall tension. These clicks occur early in systole (very near S1) and are not affected by hemodynamic changes. Similar clicks occur in severe Clicks due to myxomatous degeneration of valves may occur any time during systole but move toward S1 during maneuvers that transiently decrease ventricular filling volume (eg, standing, Valsalva maneuver). If ventricular filling volume is increased (eg, by lying supine), clicks move toward S2, particularly in mitral valve prolapse. For unknown reasons, characteristics of the clicks may vary greatly between examinations, and clicks may come and go. S1 splitting is normal in many patients and is thought to be caused by mitral valve closure followed by an aortic ejection sound. Recording provided by Jules Constant, MD. High pulmonary artery pressures may dilate the pulmonary artery, stretching the valve ring and causing a click when taut cusps open rapidly. Recording provided by Jules Constant, MD. Sound is that of S1–S2 at rest (“out”) and S1–A2–P2 with inspiration (“in”). S2 splits with inspiration because intrathoracic pressure decreases, drawing more blood into the right ventricle and postponing pulmonic valve closure. Recording provided by Jules Constant, MD. 