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Aims The randomized, double-blind Third International Study on Syncope of Uncertain Etiology (ISSUE-3) showed that dual-chamber permanent pacing was effective in reducing the recurrence of syncope in patients ≥40 years with severe asystolic, probably neurally mediated syncope (NMS), documented by implantable loop recorder (ILR). Analysis in ISSUE-3 was performed according to the intention-to-treat principle. In the present study, we performed an on-treatment analysis, which included additionally those non-randomized patients followed up in the ISSUE registry to evaluate in a better manner the effectiveness of cardiac pacing therapy. Methods and results Initially, 504 patients received an ILR, 162 (32%) patients had a diagnosis consistent with NMS within a mean observation period of 15 ± 11 months: 99 (19%) patients had documentation of syncope with ≥3 s asystole or ≥6 s asystole without syncope. Sixty patients affected by asystolic NMS received cardiac pacing therapy and 86 (33 asystolic and 53 non-asystolic NMS) were untreated; 16 patients were lost to follow-up. Paced and unpaced groups had similar clinical characteristics. During subsequent follow-up, syncope recurred in 10 paced (17%) and in 40 non-paced (46%) patients. At 21 months, the estimated product-limit syncope recurrence rates were 27% [95% confidence interval (CI) 15–47] and 54% (95% CI 43–67), respectively ( P = 0.01). With cardiac pacing, the risk of recurrence was reduced by 57% (hazard ratio = 0.43, 95% CI = 0.2–0.8). Complications of pacemaker therapy were haemothorax at implantation in one patient and lead dislodgement that required correction in two patients. Conclusion Permanent cardiac pacing is effective in reducing recurrence of syncope in patients ≥40 years with severe asystolic possible NMS with a few complications. The study shows that 61% of patients with a diagnosis of NMS made by ILR received a pacemaker but 5.1 ILRs had to be implanted to find one patient who finally had a pacemaker implanted.

Background: Current recommendations on the rhythm control strategy for treatment of atrial fibrillation (AF) are more restrictive than a decade ago. Gender may play a role in decisions on the management of AF, including application of electrical cardioversion. Methods: We analyzed clinical characteristics by gender in patients participating in the observational survey about stable patients underlying cardioversion in Spain (CARDIOVERSE) study (n=915), a survey of the practice of electrical cardioversion in 67 Spanish hospitals. We compared these data with those from a previous survey of electrical cardioversion in Spain (REVERSE study) performed 8 years previously. Results: Patients undergoing electrical cardioversion were mainly men (76%). This finding was observed in all age groups, independently of symptoms. Men were younger (6210 years vs. 69 +/- 9 years; p

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 versus asystolic TT). Fifty-two patients (26 TT+ and 26 TT–) with asystolic neurally mediated syncope 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 TT ( P =0.53). Conclusions— Cardiac pacing was effective in neurally mediated syncope patients with documented asystolic episodes in whom TT was negative; conversely, there was insufficient evidence of efficacy from this data set 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— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01463358.

Objective According to the guidelines of the European Society of Cardiology, a presumed diagnosis of neurally mediated syncope (NMS) can be made when patients have a consistent history and competing diagnoses are excluded. In the present study, we compared the initial diagnosis of NMS by means of implantable loop recorder (ILR) documentation. Methods In this prospective multicentre observational study which involved 51 hospitals in nine countries in Europe and Canada, 504 NMS patients ≥40 years, who had suffered ≥3 syncopal episodes in the previous 2 years received an ILR and were followed up for a mean of 15±11 months. Results ILR recorded a spontaneous syncope in 187 cases, with an estimated diagnostic yield of 47% at 3 years. ILR findings were consistent with the initial diagnosis of presumed NMS in 162 (87%) patients whereas did not confirm NMS in another 25 (13%), who had an intrinsic cardiac arrhythmic cause (atrial tachyarrhythmias (#6), long pause on termination of tachyarrhythmia (#8), persistent bradycardia (#3), ventricular tachycardia (#4)) or a non-arrhythmic loss of consciousness (non-syncopal (#3), orthostatic hypotension (#1)). No clinical baseline feature was able to predict an intrinsic cardiac cause with the exception of more frequent non-syncopal atrial tachyarrhythmias on clinical history, which were present in 38% of cardiac versus 5% of NMS patients (p=0.001). Tilt table testing (TT) was positive in 76/136 (56%) presumed NMS and in 9/21 (43%) non-NMS patients (p=0.35); an asystolic response was present in 28/136 (21%) NMS and in 0/21 (0%) non-NMS patients (p=0.03). Conclusions ILR findings showed results other than NMS in a small, although non-negligible, number of patients older than 40 years. TT was unable to discriminate between presumed NMS and non-NMS with the exception of an asystolic response which was highly specific.