Randomized assessment of syncope trial: conventional diagnostic testing versus a prolonged monitoring strategy.
BACKGROUND
Establishing a diagnosis in patients with unexplained syncope is complicated by infrequent and unpredictable events. Prolonged monitoring may be an alternative strategy to conventional testing with short-term monitoring and provocative tilt and electrophysiological testing.


RESULTS
Sixty patients (aged 66+/-14 years, 33 male) with unexplained syncope were randomized to "conventional" testing with an external loop recorder and tilt and electrophysiological testing or to prolonged monitoring with an implantable loop recorder with 1 year of monitoring. If patients remained undiagnosed after their assigned strategy, they were offered crossover to the alternate strategy. A diagnosis was obtained in 14 of 27 patients randomized to prolonged monitoring compared with 6 of 30 patients undergoing conventional testing (52% versus 20%, P=0.012). Crossover was associated with a diagnosis in 1 of 6 patients undergoing conventional testing compared with 8 of 13 patients who completed monitoring (17% versus 62%, P=0.069). Overall, prolonged monitoring was more likely to result in a diagnosis than was conventional testing (55% versus 19%, P=0.0014). Bradycardia was detected in 14 patients undergoing monitoring compared with 3 patients undergoing conventional testing (40% versus 8%, P=0.005).


CONCLUSIONS
A prolonged monitoring strategy is more likely to provide a diagnosis than conventional testing in patients with unexplained syncope. Consideration should be given to earlier implementation of a monitoring strategy.
Krahn
A D
AD
Division of Cardiology, University of Western Ontario, London, Ontario, Canada.
Klein
G J
GJ
Yee
R
R
Skanes
A C
AC
D000368:Aged; D001919:Bradycardia / Q000150:complications / Q000175:diagnosis; D018592:Cross-Over Studies; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000150:complications* / Q000175:diagnosis*; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D055502:Secondary Prevention; D013575:Syncope / Q000175:diagnosis* / Q000209:etiology*; D018667:Tilt-Table Test; D013995:Time