Many diagnostic and therapeutic advances have been reached for congestive heart failure (HF). However, despite clinical improvement and longer survival conferred by new pharmacological options, this syndrome is associated with high morbidity and mortality. Atrial-synchronized biventricular pacing (cardiac resynchronization therapy, CRT) has proven to be effective treatment in symptomatic patients with reduced left ventricular ejection fraction and electromechanical dyssynchrony. To date, many papers have been published on the role of CRT in improving quality of life, functional and neurohormonal parameters and reducing mortality and hospitalization. Eligible studies were randomized controlled trials of CRT for the treatment of chronic, symptomatic left ventricular dysfunction. Our search began dating back to 1994 and was updated to October 2006. Pooled data from the 6 selected studies showed that CRT reduced all-cause mortality by 28% (hazard ration [HR] = 0.72; 95% confidence interval [CI]: 0.60-0.86) and new hospitalizations for worsening HF by 37% (HR = 0.63; 95% CI: 0.44-0.91). This meta-analysis showed that patients with implantable cardiac defibrillators (ICDs) alone and ICD+CRT had a significant reduction of worsening HF hospitalization rate compared to no CRT-no ICD patients. Among patients with ICDs, CRT showed a slight effect on all-cause mortality reduction but no clear impact on worsening HF rehospitalization.