Pulsus Alternans — FRCA Final MCQ

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HardGeneral AnaesthesiaPulsus AlternansFRCA Final

A 62-year-old man (ASA III, 78 kg) with dilated cardiomyopathy (EF 22%) requires emergency laparotomy for perforated viscus. During arterial line insertion you notice a pulsus alternans pattern. What does pulsus alternans indicate?

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Correct answer: B — Severe left ventricular failure

Pulsus alternans is an alternating pattern of strong and weak arterial pulses with a regular rhythm. It indicates severe left ventricular systolic dysfunction and is a sign of decompensated heart failure. The mechanism involves beat-to-beat variation in stroke volume due to alternating numbers of functioning myocardial contractile units. It should not be confused with pulsus paradoxus (exaggerated respiratory variation, seen in tamponade) or pulsus bisferiens (double-peaked, seen in HOCM and AR).

Reference: RCOA – 2023 – Final FRCA curriculum: cardiovascular monitoring; ESC – 2021 – Heart failure guidelines