Current application and experience of cardiac resynchronization therapy in patients with chronic heart failure

Congestive heart failure is an important cause of death in Taiwan and affects nearly 15 million people worldwide. Accepted goals of heart failure treatment include: improvement of symptoms; prevention of disease progression; and reduction in morbidity and mortality. Complex pharmacological therapies achieve these goals, but not in all patient with heart failure. Advancement of physiological and hemodynamic knowledge causes a new approach, cardiac resynchronization therapy, in chronic heart failure. Bundle branch block impacts 20 to 30% of patients with New York Heart Association (NYHA) functional class III-IV heart failure and consists predominantly of left bundle branch block. There conduction abnormalities have deleterious effects both on systolic function and LV filling, and they can induce or enhance mitral functional regurgitation. Cardiac resynchronization therapy attempts to correct these deleterious effects. Several observational studies and randomized, controlled trials have shown the benefit of resynchronization therapy in the patients with heart failure and conduction delays, included improved symptoms, exercise tolerance and quality of life. However, further studies are needed to assess long-term clinical effects and prognosis, as well as economic benefit of this new therapeutic approach.