[Acute results of left ventricular endocardial pacing for cardiac resynchronization therapy obtained with a...

Although cardiac resynchronization therapy (CRT) is considered a milestone in the treatment of patients affected with chronic congestive heart failure, reduced left ventricular ejection fraction and enlarged QRS, up to 30% of patients can be considered clinical non-responders to this treatment. In these patients, optimization of atrioventricular and interventricular intervals could be of some help, but results of trials are not univocal on the benefit of this procedure. In the last years, left ventricular endocardial pacing for CRT has emerged as a possible solution in non-responders. Several studies have demonstrated its feasibility and safety, and some reports suggest its incremental efficacy in comparison with traditional epicardial pacing, both obtained transvenously or surgically. We describe the cases of two patients already implanted with a CRT device who came to our attention for clinical non-responsiveness to CRT and who have been successfully treated with the addition of a left endocardial lead. A brief literature review on this topic is also reported.