A prospective randomized comparison of loop recorders versus Holter monitors in patients with syncope or presyncope

BACKGROUND: The initial management of syncope or presyncope typically involves short-term cardiac monitoring using a Holter monitor. A loop recorder is used to extend the period of monitoring to increase the probability of obtaining a symptom-rhythm correlation. Loop recorders and Holler monitors are both used commonly, but their utility has not been compared prospectively. METHODS: Patients with syncope or presyncope referred for a Holler monitor or a loop recorder were assigned randomly to receive either a 48-hour Holter monitor or a loop recorder for 1 month as an initial diagnostic strategy. If the initial strategy was unsuccessful, patients were offered crossover to the alternate strategy. RESULTS: One hundred patients (mean [+/-SD] age, 56 +/- 20 years; 44 women) with syncope (n = 21), presyncope (n = 29), or both (n = 50) were enrolled. Of the 49 patients assigned randomly to an external loop recorder first, 31 (63%) had an arrhythmia identified or excluded, versus 12 (24%) of 51 patients assigned to a Holter monitor initially (P <0.0001). Arrhythmia was identified as a cause of syncope in I patient with a loop recorder, compared with no patients with a Holter monitor (P = 0.31). Of the 29 patients with negative results with Holler monitoring who went on to receive a loop recorder, 13 (45%) had arrhythmia excluded, compared with none of the 4 patients who crossed over to receive a Holter monitor. The overall probability of obtaining a symptom-rhythm correlation was 56% (44/78) for loop recorders versus 22% (12/55) for Holler monitors (P <0.0001). Despite patient education and test transmissions, 13 (23%) of 57 patients who had recurrence of their symptoms failed to activate their loop recorder properly. CONCLUSION: Loop recorders have a much higher diagnostic yield for patients with syncope or presyncope as compared with Holler monitors. The utility of loop recorders is limited by some patients' inability to operate them correctly. (C) 2003 by Excerpta Medica Inc.