Key Points
- To establish the precise electrophysiological mechanism by which a right ventriculotomy induces a right bundle branch block pattern on scalar electrocardiograms.
- Conducted an intraoperative evaluation in N=15 patients with congenital heart defects undergoing open heart surgery requiring right ventriculotomy.
- Performed ventriculotomies sequentially in 3 to 7 discrete 1-cm incisions, recording six simultaneous scalar ECG leads prior to surgery and after each incision to evaluate QRS duration.
- A right bundle branch block (RBBB) pattern developed in 12 of 15 patients (80%), whereas the remaining 3 patients (20%) did not develop RBBB.
- The entire increase in QRS duration occurred abruptly during a single specific incision rather than incrementally across the full ventriculotomy incision length or sequence.
- The critical incision site provoking RBBB was situated between 40% and 73% of the distance from the pulmonary artery annulus to the inferior border in 9 patients, and higher on the free wall in 3 patients.
Structured PICO
PPopulation15 patients with various congenital heart defects requiring right ventriculotomy for correction during open heart surgery
IInterventionRight ventriculotomy carried out in steps (3 to 7 incisions of approximately 1 cm in length)
OOutcomeDevelopment of right bundle branch block (RBBB) pattern and QRS duration on scalar ECGsurrogate
The study demonstrates that ventriculotomy-induced RBBB is likely caused by the disruption of specific distal branches of the right bundle rather than a continuous Purkinje network.