Treatment of Unexplained Syncope, A Multicenter, Randomized Trial of Cardiac Pacing Guided by Adenosine 5
Extraido de Circulation. 2012;125:31-36
Daniel Flammang, MD; Timothy R. Church, PhD; Luc De Roy, MD; Jean-Jacques Blanc, MD;
Jean Leroy, MD; Georges H. Mairesse, MD; Akli Otmani, MD; Pierre J. Graux, MD;
Robert Frank, MD; Philippe Purnode, MD; for the ATP Multicenter Study
Background—The origin of 40% of syncope cases remains unknown even after a complete diagnostic workup. Previous studies have suggested that ATP testing has value in selecting successful therapy. This patient-blinded, multicenter, randomized superiority trial tested whether, in patients with syncope of unknown origin, selecting cardiac pacing in those with a positive ATP test leads to fewer recurrences than those who do not receive pacing.
Methods and Results—From 2000 to 2005,
80 consenting patients (mean age, 75.9_7.7 years; 81% women; 56% without diagnosed structural heart disease) with syncope of unknown origin and atrioventricular or sinoatrial block lasting _10 seconds (average, 17.9_6.8 seconds) under ATP administration (20-mg IV bolus) were recruited from 10 hospitals, implanted with programmable pacemakers, and randomized to either active pacing
(dual-chamber pacing at 70 bpm) or backup pacing (atrial pacing at 30 bpm).
Patients were followed up regularly for up to 5 years for any syncope recurrence, the primary outcome. Mean follow-up was 16 months. Syncope recurred in 8 of 39 patients (21%) randomized to active pacing and in 27 of 41 (66%) randomized to backup pacing (control), yielding a hazard ratio of 0.25 (95% confidence interval, 0.12– 0.56). After recurrence, the 27 recurrent control patients were
reprogrammed to active pacing, and only 1 reported subsequent syncope.
Conclusion—This study suggests that, in elderly patients with syncope of unknown origin and positive ATP tests, active dual-chamber pacing reduces syncope recurrence risk by 75% (95% confidence interval, 44–88).
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