Figure 198b

The apex phonocardiography is displayed simultaneously with the cardiac cycle as recorded by a high fidelity catheter- tipped micromanometers in the central aortic, left ventricle(LV) and left atrium(LA). The first high-frequency component of M1 is coincident with the downstroke of the left atrial "c"wave and is separated from left ventricular-left atrial pressure crossover by an interval of 30ms .