Ideal site for right ventricular pacing

Ideal site for right ventricular pacing

Ideal site for right ventricular pacing: Right ventricular apical pacing has been found to have certain disadvantages like progressive left ventricular dysfunction leading to heart failure and associated morbidity and mortality as well as a propensity for atrial fibrillation. Hence attempts were made to simulate the natural sequence of ventricular activation by alternate site ventricular pacing. Right ventricular sites which were evaluated include outflow tract, and septum. The presumption was that pacing the septal aspect of the right ventricle would initiate as normal a sequence of ventricular contractions as possible. But the studies gave conflicting results, probably because most of the pacing which was done in the right ventricular outflow tract was not actually on the septal aspect, but the free wall aspect. Right ventricular free wall is one of the last regions to be activated in the normal activation sequence. So if a right ventricular outflow tract pacing causes early activation of the right ventricular free wall, it would not be expected to give the results simulating a normal activation sequence.

The disadvantage in earlier studies was also due to the difficulty in actually pacing the septal aspect of the right ventricular outflow tract. Now special types of stylets are available to direct the lead to the septal aspect of the right ventricular outflow tract which is posteriorly situated. But we will have to wait for the results of the randomized trials which are currently going on to finally conclude whether high septal pacing is indeed superior to right ventricular apical pacing in terms of long term preservation of left ventricular function and preventing heart failure.