Our patient has a holosystolic murmur at the lower left sternal edge. This means that the murmur begins with S1 and lasts until S2. The murmur demonstrates a slight decrescendo shape. [Sounds]
Discussion
The holosystolic murmur begins synchronously with the first heart sound. It can be caused only by a condition that allows blood to flow out of the ventricle before opening of either the aortic or pulmonary valve. In other words, the murmur occupies the isovolumic contraction phase of the cardiac cycle, thereby, identifying it as pathologic. In some patients, turbulence creating the murmur is great enough to produce vibrations that are palpable as well as audible. This is called a thrill.
This is a graphic example of a holosystolic murmur with a slight decrescendo configuration. By simultaneously observing the image and listening, we can further appreciate these auscultatory events. [Sounds]
Pressure curves
These simultaneous aorta and left ventricle pressure curves illustrate the relationship of the hemodynamic events to the timing and contour of the murmur. The murmur begins immediately with S1, as left ventricular pressure begins to rise. Note that the murmur begins before left ventricular pressure reaches aortic pressure, that is, before the aortic valve opens. Normally, the left ventricle is a closed container during this brief interval. Onset of the murmur in this time period indicates blood flow out of the left ventricle before opening of the aortic valve. The murmur extends to S2 because left ventricular pressure exceeds either left atrial pressure or right ventricular pressure throughout systole.