CRT requires implantation of atrial and right ventricular leads, as well as a third lead in the coronary sinus and the lateral or posterior branch to stimulate the left ventricle.

CRT involves a procedure similar to that of a pacemaker placement. In addition to that of the routine implantation of the atrial and right ventricular lead, a third lead is introduced into the coronary sinus and the lateral or posterior branch is accessed for stimulation of the left ventricle. Previously, an epicardial left ventricular lead was implanted after a limited lateral throacotomy. Such epicardial lead implantation is associated with high capture thresholds, suboptimal position for resynchronization, a far more invasive procedure, risk of general anaesthesia and standard complications associated with thoracotomy. However, this approach may be used if the coronary sinus or the appropriate branch cannot be accessed due to anatomical variations, vein stenosis, coronary sinus injury, tortuosity of the coronary sinus and distortion of the ostium.

Cardiology