Cardiac resynchronization therapy (CRT) is one of the most exciting new advances in the treatment of chronic severe (NYHA symptom class) heart failure associated with dyssynchronous ventricular contraction that is refractory to medical treatment. In all randomized trials CR has resulted in improved NYHA symptom class, exercise capacity and quality of life in the majority of patients as compared to patients on optimal medical therapy including angiotensin converting enzyme inhibitor (ACE)/angiotensin receptor blocker inhibitor (ARB) and b adrenergic receptor blockers. These symptomatic...