The main blood flow velocity patterns in the LVOT and RVOT were recorded by pulsed Doppler echocardiography in 28 normal healthy cases, in two athletes, and in 85 patients with atrial septal defects, pulmonary regurgitation, tetralogy of Fallot, aortic regurgitation, mitral stenosis, aortic stenosis, mitral regurgitation, hypertrophic cardiomyopathy, ischemic heart disease, and pulmonary hypertension. Blood flow velocities were displayed using a graphic system to form a real time sonogram, using Fast Fourier Transformation. In the normal group, the blood flow velocity was 1.69 KHz in LVOT, and 1.71 KHz in RVOT. In AR and T/F but not MS, there was high blood flow velocity in the LVOT, and the peak of blood flow velocity was shifted to mid-to late systole. In ASD and VSD with a L-R shunt, high blood flow velocity occurred in the RVOT, and the peak velocity shifted to early systole. Pulmonary hypertension occasionally produced a W- or V-shaped curve. In normal subjects, a small "a" wave could be detected in the LVOT recording. The "a" wave began at point B on the AML tracer of the M-mode echocardiography, reached maximum velocity at point C, and returned to zero (baseline) at point C'. The "a" wave was coincident with the R wave of the ECG, and with the Ia of the phonocardiogram (PCG). The normal velocity of the "a" wave was 602 Hz, and the a/H ratio was 0.36. In cases of HCM and IHD, the "a" wave velocity and the a/H ratio correlated with the end diastolic pressure and the peak dP/dT. These data suggest that the Doppler blood flow patterns in the LVOT and RVOT can indicate volume overload in the right and left ventricles, and that the "a" wave velocity and a/H ratio can provide new information concerning cardiac performance.