Second Canadian Trial of Physiologic Pacing (CTOPP II): Pilot Trial

Pacemaker therapy has been recognized as effective for the control of sinus and atrio-ventricular (AV) node dysfunction. Single chamber pacing when compared with dual chamber pacing, has numerous advantages of low complication rates, lower cost, better longevity, with non-inferiority in the quality of life and hard outcomes proven in direct randomized comparisons. However, comparison between single and dual chamber pacers was never adequate, since not more then half of the patients in the trials were actually using pacemakers for the majority of the time. Routine dual chamber pacing using a right ventricle apical lead is also associated with significant increase in peri-operative and remote complications. Some of these complications may be related to ventricular desynchronization secondary to the pacing location, which is potentially avoidable by using biventricular pacing. A randomized trial which will compare single chamber rate responsive pacing to the best available modification of dual chamber pacing (biventricular pacing) in suitable patients is therefore warranted.