Cardiac resynchronization therapy (CRT) has come a long way from its inception as a last-ditch attempt to salvage intractable heart failure (HF) to its current status as a routine mainstream therapy for mild to moderate HF.The increase in popularity of CRT is due to two main factors: large scale randomized clinical trials demonstrating prognostic and symptomatic benefits and better tools (catheters, leads and pulse generators) that facilitate treatment delivery.Despite