Pulsus Alternans: Sensitivity and Specificity

virtually pathognomonic of severe left ventricular failure

characterized by evenly spaced alternating strong and weak peripheral pulses. It is best appreciated by applying light pressure on the peripheral arterial pulse, and can be confirmed by measuring the blood pressure. When the cuff pressure is slowly released, phase I Korotkoff sounds are initially heard only during the alternate strong beats; with further release of cuff pressure, the softer sounds of the weak beat also appear. The degree of pulsus alternans can be quantitated by measuring the difference in systolic pressure between the strong and the weak beat.