Phasic aortic flow velocity in patients with pulsus alternans.

Phasic aortic flow velocity was recorded in two patients with pulsus alternans using a flow velocity probe connected to a Doppler ultrasonic flowmeter system. The variations in beat-to-beat peak velocity paralleled the variations in arterial and ventricular systolic pressures. This study provides direct evidence that stroke volume varies during this abnormal haemodynamic status.