Synonyms: mechanical alternans


  • Pulsus alternans was first described by Ludwig Traube in 1872 and defined as the beat-to-beat variability of the pulse amplitude in a patient with a sinus rhythm, independent of the respiratory cycle.
  • Only the strong beats but not the weak beats are appreciated as phase I Korotkoff sounds when the cuff pressure is initially lowered.
  • Pulsus alternans reflects myocardial dysfunction associated with cyclic fluctuations in preload, afterload, and contractility.
  • Pulsus alternans typically occurs with heart failure and may be precipitated by aortic regurgitation, hypovolemia, and tachycardia.

Associated Conditions

  • Aortic regurgitation
  • Ectopic beats in aortic stenosis
  • Hypovolemia
  • Left ventricular heart failure
  • Sympathetic activation in myocardial ischemia
  • Tachycardia

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