Use of Physiologic Pacing After the Canadian Trial of Physiologic Pacing

The Canadian trial of physiologic pacing (CTOPP), published in 2000, demonstrated a reduction in atrial fibrillation (AF), stroke and death with preservation of atrioventricular synchrony, though only the lower rate of AF was statistically significant. The purpose of this study was to determine the effect of CTOPP on pacing mode selection in our region. The British Columbia Cardiac Registry contains prospectively entered data covering a population of 4 millions (M) and 17 implanting centers. It was examined for mode selection trends from 1997 to 2002. At examination, there were data on 22,446 pulse generators (PG) and 29,898 leads. New implant rates per M population were 1997:473; 1998:456; 1999:505; 2000:513; 2001:486; 2002:510. PG replacements also increased, resulting in a total implant rate of 667 PG per M in 2002. Over the 6-year period, DDD use decreased from 321 to 306, but DDDR use, more than doubled from 317 to 750 PG/year. VVI use steadily decreased from 741 to 410 PG/year, while VVIR use increased more modestly from 1997 to 1999, then remained stable. During the 6-year period bracketing CTOPP, use of modes maintaining AV synchrony increased by over 32%, to 53% of PG implanted in 2002. Our PG implant rate was much higher than expected from prior retrospective surveys, and similar to rates in Belgium, France, and Germany. CTOPP did not decrease our use of physiologic pacing but, instead, was associated with a brief pause, then progressively increased in both academic and community centers. Patients' need and widely accepted standards of care proved more important in clinical decision making than the results of a flawed randomized trial.