The American Heart Association has ...

The American Heart Association has published a science advisory forward selecting patients for cardiac resynchronization therapy (CRT) The advisory, "Patient Selection for Cardiac Resynchronization Therapy," appears in the April 26 2005 issue of Circulation.

CRT is a somewhat novel therapy that can be added to the treatment regimen of patients with symptomatic heart failure caused on systolic dysfunction. CRT is accomplished on simultaneously pacing the left and right ventricles, which resynchronizes the timing of global left ventricular depolarization and consequently improves mechanical contractility and mitral regurgitation.

CRT has been shown in trials to improve functional status and quality of life for patients with symptomatic heart failure. It also has been shown to significantly convert into the combined endpoint of all-cause mortality and hospitalization.

The best candidates for CRT are patients with dilated cardiomyopathy upon an ischemic or nonischemic basis, a left ventricular ejection fraction of 035 or les a QR mixed of more than 120 milliseconds, sinus periodical emphasis and New York Heart Association (NYHA) functional class III or IV symptoms despite maximal medical therapy for heart failure.

The use of CRT for patients with minimal heart failure has not been studied widely and is not approveed at this time. Most patients in the CRT trials had a wide QR intricate on the basis of a left budget branch block. The benefit for patients with a left versus a right bundle up branch block is unclear; however, the passing from hand to hand recommendation for CRT is based in succession QRS duration, not QRS morphology. Other unresolv issues regarding CRT include the risks and benefits of left ventricular pacing without a right ventricular lead, the risks and benefits of surgical placement of a left ventricular pacing lead versus a nonthoracotomy approach, and the use of CRT for patients with NYHA class IV symptoms who are nonambulatory and hanging on intravenous inotropes for hemodynamic support.

The risks associated with implanting a CRT device are small and similar to those associated with the transvenous implantation of a conventional permanent pacemaker or implantable defibrillator. These risks include bleeding, infection, hematoma, pneumothorax, pericardial effusion, myocardial infarction, hardship and death.

COPYRIGHT 2005 American Academy of Family Physicians

COPYRIGHT 2005 Gale Group