Systolic and Diastolic Murmurs

Systolic murmurs occur between S₁ and S₂ (first and second heart sounds), and therefore are associated with mechanical systolic and ventricular ejection. Mid-systolic murmurs typically have a crescendo-decrescendo character, that is, they start softly and become loudest near mid-systole, followed by a decrease in sound amplitude as shown in the figure. This type of murmur is caused by either aortic or pulmonic valve stenosis. A second type of systolic murmur is holosystolic (sometimes called pansystolic) because the amplitude is high throughout systole as shown in the figure. This type of murmur is caused by mitral or tricuspid regurgitation, or by a ventricular septal defect.

Diastolic murmurs occur after S₂ and are therefore associated with ventricular relaxation and filling. They may be caused by aortic or pulmonic valve regurgitation, or by mitral or tricuspid valve stenosis. They can occur early (e.g., aortic regurgitation), mid-diastolic, or late diastolic (e.g., mitral stenosis).

Revised 04/05/07