The Benefit of Pacemaker Therapy in Patients with Presumed Neurally-Mediated Syncope and Documented Asystole is Greater when Tilt Test is Negative. An Analysis from the Third International Study on Syncope of Uncertain Etiology (ISSUE-3).
Circ Arrhythm Electrophysiol. 2013 Dec 12;
Authors: Brignole M, Donateo P, Tomaino M, Massa R, Iori M, Beiras X, Moya A, Kus T, Deharo JC, Giuli S, Gentili A, Sutton R
BACKGROUND: -In the Third International Study on Syncope of Uncertain Etiology (ISSUE-3) cardiac pacing was effective in reducing recurrence of syncope in patients with presumed neurally-mediated syncope (NMS) and documented asystole but syncope still recurred in 25% of them at 2 years. We have investigated the role of tilt testing (TT) in predicting recurrences.
METHODS AND RESULTS: -In 136 patients enrolled in the ISSUE-3, TT was positive in 76 and negative in 60. An asystolic response predicted a similar asystolic form during implantable loop recorder monitoring, with a positive predictive value of 86%. The corresponding values were 48% in patients with non-asystolic TT and 58% in patients with negative TT (p=0.001 vs asystolic TT). Fifty-two patients (26 TT+ and 26 TT-) with asystolic NMS received a pacemaker. Syncope recurred in 8 TT+ and in 1 TT - patients. At 21 months, the estimated product-limit syncope recurrence rates were 55% and 5%, respectively (p=0.004). The TT+ recurrence rate was similar to that seen in 45 untreated patients (control group), which was 64% (p=0.75). The recurrence rate was similar between 14 patients with asystolic and 12 with non-asystolic responses during tilt testing (p=0.53).
CONCLUSIONS: -Cardiac pacing was very effective in NMS patients with documented asystolic episodes in whom TT was negative; conversely, there was insufficient evidence of efficacy from this dataset in patients with a positive TT even when spontaneous asystole was documented. Present observations are unexpected and need to be confirmed by other studies Clinical Trial Registration-clinicaltrials.gov; Identifier: NCT01463358.
PMID: 24336948 [PubMed - as supplied by publisher]