Canadian Trial of Physiological Pacing: Effects of physiological pacing during long-term follow-up.
BACKGROUND
The Canadian Trial of Physiological Pacing (CTOPP) reported that the risk of stroke or cardiovascular death was similar between patients receiving ventricular versus physiological pacemakers at the end of the original follow-up period of 3 years. However, the occurrence of atrial fibrillation was significantly less frequent with physiological pacemakers. To assess a potential delayed benefit of physiological pacing, follow-up of patients in this study was extended to 6 years.


RESULTS
A total of 1474 patients requiring a pacemaker for symptomatic bradycardia were randomized to receive ventricular and 1094 to physiological pacemakers. The primary outcome was stroke or cardiovascular death. The study was completed in July 1998, and follow-up was extended to July 2001. At a mean follow-up of 6.4 years, there was no difference between treatment groups in the primary outcome of cardiovascular death or stroke. There was no significant difference in total mortality or stroke between groups. There was a significantly lower rate of development of atrial fibrillation in the physiological group, with a relative risk reduction of 20.1% (CI, 5.4 to 32.5; P=0.009).


CONCLUSIONS
The CTOPP extended study does not show a difference in cardiovascular death or stroke, or in total mortality, or in stroke between patients implanted with ventricular or physiological pacemakers over a mean follow-up of >6 years. However, there is a persistent significant reduction in the development of atrial fibrillation with physiological pacing.
Kerr
Charles R
CR
Room 344, Division of Cardiology, St Paul's Hospital, 1081 Burrard St, Vancouver, BC, Canada, V6Z 1Y6. ckerr@providencehealth.bc.ca
Connolly
Stuart J
SJ
Abdollah
Hoshiar
H
Roberts
Robin S
RS
Gent
Michael
M
Yusuf
Salim
S
Gillis
Anne M
AM
Tang
Anthony S L
AS
Talajic
Mario
M
Klein
George J
GJ
Newman
David M
DM
D001281:Atrial Fibrillation / Q000453:epidemiology; D001919:Bradycardia / Q000628:therapy; D002170:Canada; D002304:Cardiac Pacing, Artificial; D002318:Cardiovascular Diseases / Q000401:mortality; D005500:Follow-Up Studies; D006801:Humans; D010138:Pacemaker, Artificial; D020521:Stroke / Q000453:epidemiology; D016896:Treatment Outcome