Midsystolic murmurs represent an important group caused by organic disease. These movements begin after
S1 and end well before S2, that is, a clear gap between the end of the murmur and S2 (see Fig. 2). Midsystolic murmurs occur when there is obstruction to ventricular flow as observed with aortic or pulmonary valve stenosis. Mid to late systolic murmurs (Fig. 2) are usually caused by mitral valve prolapse. Holosystolic murmurs begin with S1 and continue through the entire systolic inter¬val. This murmur is caused by blood flow from a cham¬ber or a vessel with a higher pressure and resistance
than the receiving chamber or vessel. Holosystolic murmurs are often regurgitant; a common cause is mitral regurgitation.
2. Diastolic Murmurs
These are classified as early mid or late diastolic. The most common early diastolic blood is that caused by aortic valve regurgitation. This murmur is best heard with the dia¬phragm of the stethoscope firmly pressed against the mid-left sternal edge with the patient sitting up at the side of the bed with the breath held after a full exhalation. The high-pitched blowing decrescendo murmur has typical characteristics.
3. Prosthetic Valve Murmurs
Aortic mechanical valves cause turbulence that produces a grade 1 to 2 ejection systolic murmur that is of no significance. Sudden increase in the systolic murmur may reflect obstruction by thrombus. A diastolic murmur is usually abnormal and suggests a perivalvular leak. Bioprosthetic valves produce no sounds, but when they degenerate systolic murmurs emerge. Musical murmurs in this setting suggest a tear of a leaflet.

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