Multicenter Automatic Defibrillator Implantation Trial–Cardiac Resynchronization Therapy (MADIT‐CRT): Design and Clinical Protocol

Abstract

The planned MADIT-CRT trial is designed to determine if CRT-D will reduce the risk of mortality and HF events by approximately 25% in subjects with ischemic (NYHA class I-II) and non-ischemic (NYHA class II) cardiomyopathy, left ventricular dysfunction (EF ≤ 0.30), and prolonged intraventricular conduction (QRS duration ≥ 130 ms). A.N.E. 2005;10(4)Supplement:34-43MADIT; cardiac resynchronization therapy; heart failure Heart failure (HF) with its associated morbidity and mortality remains a major unresolved public health problem in the United States and throughout the world. It is estimated that HF affects nearly 5 million people in the United States alone and claims more that 300,000 lives annually. 1 The MADIT-II trial demonstrated improvement in overall survival with an implantable cardioverter defibrillator (ICD) in high-risk subjects with prior myocardial infarction and advanced left ventricular dysfunction (ejection fraction ≤0.30) despite the occurrence of HF in this population.2 Similar results were found in the recently published SCD-HeFT and DEFINITE trials.3,4 Cardiac resynchronization therapy (CRT) with biventricular pacing is effective as adjunctive therapy to pharmacologic management of patients with severe HF and intraventricular conduction delay, with improvement in ven-

Cardiac Resynchronization Therapy and its Potential Proarrhythmic Effect

“…As cardiac resynchronization therapy is considered for an expanded population of CHF patients 12,13 and leftsided pacing is considered as an option for pacemakerindicated patients (potentially without ICD backup), 36 the effect of these pacing modalities on the incidence of ventricular tachyarrhythmias must be systematically studied and mechanistically understood. Strategies to prospectively predict the proarrhythmic potential of LV epicardial pacing need to be developed, and therapy accordingly individualized.…”

“…7,8 Other studies, however, have demonstrated the potential for proarrhythmia. 9 -11 As CRT becomes more widely adopted and is considered for an expanded population of heart failure (HF) patients, 12,13 the effect of this pacing modality on the incidence of ventricular tachyarrhythmias must be thoroughly understood. This review attempts to summarize the current information on proarrhythmia in resynchronization therapy.…”

Effectiveness of cardiac resynchronization therapy by the frequency of revascularization procedures in ischemic cardiomyopathy patients

“…Echocardiography recordings were analyzed off-line at the Brigham and Women's Hospital, Boston, Massachusetts as an independent echocardiography core laboratory [11]. Echocardiography investigators analyzing the images were blinded to clinical characteristics, treatment assignment, or outcomes.…”

“…All eligible patients met the guideline criteria for ICD [13]. Patients were excluded with certain clinical characteristics, as described previously [11]. One hundred and ten hospital centers from North America and Europe participated in this international multicenter trial.…”

“…The design, protocol and results of the MA-DIT-CRT study were published previously [11,12]. Briefly, 1,820 patients with ICM (New York Heart Association [NYHA] functional class I or II) or NICM (NYHA functional class II only), LVEF of less than 30% and a prolonged QRS duration > 130 ms were randomized in a 3:2 ratio to receive CRT-D or ICD therapy.…”