Left bundle branch block characterization depending on the frontal and horizontal QRS axes, and global and individual leads QRS duration: Is it useful for cardiac resynchronization therapy patient stratification?

摘要

To the Editor:Dr. Moss in his insightful commentary published in the November-December, 2012 issue of the Journal, pertaining to the selection of high-risk patients for device intervention, and in reference in particular of the good clinical response to cardiac resynchronization therapy (CRT) of patients with a left ventricular ejection fraction (LVEF) <30%, and a left bundle branch block (LBBB) with a QRS duration (QRSd) of > 150 ms, finishes his remarks with the following: "It is clear that the left bundle branch block creates a unique myocardial dyssynchrony that is very responsive to pacing of the left ventricle through pacing leads positioned in the coronary veins. Further electrical characterization of the subdivisions of the left bundle branch block conduction disturbance may be helpful in improving risk stratification for cardiac resynchronization therapy".