A 58-year-old man develops hypotension two days after an inferior myocardial infarction. Central venous pressure reads 20 mmHg. Inspection of the CVP trace shows large positive waves occurring during ventricular systole, fused and reaching 24 mmHg, with an otherwise small a-wave. What abnormality does this trace indicate?

• A Cardiac tamponade with equalisation of diastolic pressures
• B Constrictive pericarditis with a square root sign and prominent y descent
• C Tricuspid stenosis with exaggerated a-waves and attenuated y descent
• D Tricuspid regurgitation producing giant c-v waves that ventricularise the right atrial trace ✓

Explanation

Severe tricuspid regurgitation allows right ventricular systolic pressure to transmit directly into the right atrium, replacing the normal x descent with a large fused c-v wave timed with the ECG T wave and carotid pulsation, a pattern called ventricularisation of the atrial trace. Inferior infarction involving the right ventricle commonly causes this. Tamponade, constrictive pericarditis and tricuspid stenosis each produce characteristic descents rather than giant systolic v waves, which excludes them.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

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