The pacing therapies for congestive heart failure (PATH-CHF) study: Rationale, design, and endpoints of a prospective randomized multicenter study

In conjunction with pharmacologic therapy, pacing has been proposed as a po tential treatment to decrease symptoms in patients with moderate-to-severe congestive heart failure (CHF). Uncontrolled studies of pacing therapy for CHF dealing with different pacing sites, modes of pacing, and atrioventricu lar delays have reported mixed outcomes. The pacing Therapies in Congestive Heart Failure (PATH-CHF) study is a single-blind, randomized, crossover, c ontrolled trial designed to evaluate the effects of pacing on acute hemodyn amic function and to assess chronic clinical benefit in patients with moder ate-to-severe CHF, The effect of pacing on oxygen consumption at peak exerc ise and at anaerobic threshold during cardiopulmonary exercise tests, and o n 6-minute walk distance, have been selected as primary endpoints of the st udy. Secondary endpoints of the trial were changes in New York Heart Associ ation (NYHA) functional class, quality-of-life as assessed by the Minnesota Living with Heart Failure questionnaire, and hospitalization frequency. Fi nally, changes in ejection fraction, cardiac output, and filling pattern we re assessed by echocardiography. The trial was planned to include 53 patien ts from 7 centers in Europe over a period of 3 years. The study was divided into 2 parts: acute testing and chronic follow-up. The acute study, perfor med during the pacemaker implantation, involved extensive testing using a c ustom-designed computer (FLEXSTIM) and a unique burst pacing protocol (FLEX STIM protocol) to determine the best ventricular pacing sites and the mast appropriate atrioventricular delays. The chronic phase consisted of a cross over study designed to test in each patient the best univentricular pacing site and biventricular pacing as assessed by the acute hemodynamic study. T he study started with the first implant in 1995 and has, to date, included 42 patients. The study is expected to be completed by the end of 1998, The results of a first interim analysis showed trends toward improvement in all primary and secondary endpoints during the pacing periods compared with no pacing. (C) 1999 by Excerpta Medica, Inc.