When performing a cardiovascular assessment, the rhythm and character of peripheral pulses are observed. While palpating the radial or femoral pulses, one may note that although the rhythm is regular, the strength of the pulse may alternate between weaker and more forceful impulses. Hence, the term pulsus alternans.

The beat-to-beat variability of pulsus alternans can be confirmed using a blood pressure cuff and listening closely as the cuff is deflated. Initially, only the stronger Korotkoff sounds are heard, but as the pressure in the cuff continues to deflate, the softer sounds appear, though they will eventually fade away (Bickley et al., 2021).

The presence of pulsus alternans strongly suggests severe left ventricular dysfunction (Bickley et al., 2021; Corlucci & Borlaug, 2021).  Pulsus alternans may be noted in those with dilated cardiomyopathy with left ventricular outflow obstruction, severe aortic regurgitation, or cardiac tamponade, but rarely without the presence of associated left ventricular dysfunction (Gersh, 2021).

Remember…

• Asking the patient to sit upright during physical examination may highlight this finding.
• Pulsus alternans is frequently associated with left ventricular failure, and this finding should prompt further diagnostic investigation.

References:
Bickley, L. S., Szilagyi, P. G., Hoffman, R. M., & Soriano, R. P. (2021). Bate’s Guide to Physical Examination and History Taking (13th ed.). Wolters Kluwer Health: Philadelphia.

Corlucci, W.S. & Borlaug, B.A. (2021, March 4). Heart failure: Clinical manifestations and diagnosis in adults. UpToDate. https://www.uptodate.com/contents/heart-failure-clinical-manifestations-and-diagnosis-in-adults

Gersh, B.J. (2021, November 2). Examination of the arterial pulse. UpToDate. https://www.uptodate.com/contents/examination-of-the-arterial-pulse

More Reading & Resources
Cardiac Assessment [Pocket Card]
Understanding Pulsus Paradoxus
Extra Heart Sounds: Do you hear what I hear?