Decline of plasma brain natriuretic peptide level after carvedilol therapy to treat dilated cardiomyopathy presenting with mechanical alternans.

Mechanical alternans is observed in patients with severe left ventricular dysfunction. We report a case of dilated cardiomyopathy with mechanical alternans. He presented with a remarkable decrease in plasma brain natriuretic peptide (BNP) levels after beta-blocker therapy despite persistency of the mechanical alternans. Mechanical alternans may persist after improvement of hemodynamics, diastolic function, and plasma BNP levels. Mechanical alternans may reflect persistent organic or functional myocardial damage such as abnormal intracellular Ca(2+) cycling in cardiomyocytes.