Murmurs can be systolic, diastolic, combined systolic and diastolic, or continuous, depending upon in what part of the cardiac cycle they occur (Table 4.11). The place in the cycle refers to ventricular events, not to atrial events. Constriction of the ventricle's outflow tract, as in aortic stenosis*, produces a crescendo-decrescendo systolic murmur which begins when the aortic valve opens, and ends at S2.
In mitral insufficiency* blood flows back into the left atrium during left ventricle contraction, producing a more or less continuous murmur which begins at S1 and extends beyond S2 until mitral valve opening.
A ventricular septal defect (VSD) extends over a similar period, but has a less continuous sound quality (a pansystolic murmur).
Go to Next Page
Return to Previous Page
Return to Index