Changes in the occurrence of mechanical alternans after long-term beta-blocker therapy in patients with chronic heart failure

Mechanical alternans has been observed in patients with severe congestive h eart failure, and the phenomenon is considered to be a terminal sign. Thera peutic strategies for chronic heart failure have significantly developed, b ut it is uncertain whether patients with mechanical alternans can be effect ively treated or not. Seventeen consecutive patients with dilated cardiomyo pathy were enrolled: 11 were treated with beta -blockers on conventional th erapeutic regimens and 6 patients were not indicated for or were unable to continue beta -blockade. Mechanical alternans was detected during cardiac c atheterization in the patients under physiologic tachycardia (110 beats/min ) and stepwise dobutamine loading. In the initial study, mechanical alterna ns occurred in 70.6% of the patients: 8 of the 11 being treated with beta - blockers and 4 of the 6 without beta -blockade therapy, In the second study , none of the patients taking beta -blockers showed mechanical alternans un der the same protocol; the occurrence of mechanical alternans did not chang e in the patients who were not being treated with beta -blockers. The left ventricular ejection fraction increased in patients whose mechanical altern ans could not be induced during the follow up, but decreased in the patient s in whom mechanical alternans was repeatedly inducible. It is concluded th at mechanical alternans is associated with the failing myocardium and maybe potentially correctable.