Gender Differences in Patients with Atrial Fibrillation Undergoing Electrical Cardioversion.

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 (62±10 years vs. 69±9 years; p<0.001), more frequently asymptomatic and had a lower prevalence of hypertension and a lower stroke risk. Among asymptomatic patients, the predominance of men was especially evident in older age groups (<65 years, men 76%, women 24%; ≥65 years, men 92%, women 8% (p<0.001). Compared with the REVERSE study, we observed a decrease in the percentage of women among patients undergoing electrical cardioversion (37% REVERSE vs. 24% CARDIOVERSE; p<0.001), mainly in older than 65 years. CONCLUSIONS: Our results support the hypothesis that gender is a determinant in decisions on the most appropriate strategy for managing AF. We observed a decrease in the percentage of women undergoing electrical cardioversion during the last decade, especially in older asymptomatic patients.

Cardiac pacing in patients with neurally mediated syncope and documented asystole: effectiveness analysis from the Third International Study on Syncope of Uncertain Etiology (ISSUE-3) Registry.

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.

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).

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.

Diagnosis of neurally mediated syncope at initial evaluation and with tilt table testing compared with that revealed by prolonged ECG monitoring. An analysis from the Third International Study on Syncope of Uncertain Etiology (ISSUE-3).

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.

Pacemaker therapy in patients with neurally mediated syncope and documented asystole: Third International Study on Syncope of Uncertain Etiology (ISSUE-3): a randomized trial.

BACKGROUND: The efficacy of cardiac pacing for prevention of syncopal recurrences in patients with neurally mediated syncope is controversial. We wanted to determine whether pacing therapy reduces syncopal recurrences in patients with severe asystolic neurally mediated syncope. METHODS AND RESULTS: Double-blind, randomized placebo-controlled study conducted in 29 centers in the Third International Study on Syncope of Uncertain Etiology (ISSUE-3) trial. Patients were ≥40 years, had experienced ≥3 syncopal episodes in the previous 2 years. Initially, 511 patients, received an implantable loop recorder; 89 of these had documentation of syncope with ≥3 s asystole or ≥6 s asystole without syncope within 12 ± 10 months and met criteria for pacemaker implantation; 77 of 89 patients were randomly assigned to dual-chamber pacing with rate drop response or to sensing only. The data were analyzed on intention-to-treat principle. There was syncope recurrence during follow-up in 27 patients, 19 of whom had been assigned to pacemaker OFF and 8 to pacemaker ON. The 2-year estimated syncope recurrence rate was 57% (95% CI, 40-74) with pacemaker OFF and 25% (95% CI, 13-45) with pacemaker ON (log rank: P=0.039 at the threshold of statistical significance of 0.04). The risk of recurrence was reduced by 57% (95% CI, 4-81). Five patients had procedural complications: lead dislodgment in 4 requiring correction and subclavian vein thrombosis in 1 patient. CONCLUSIONS: Dual-chamber permanent pacing is effective in reducing recurrence of syncope in patients ≥40 years with severe asystolic neurally mediated syncope. The observed 32% absolute and 57% relative reduction in syncope recurrence support this invasive treatment for the relatively benign neurally mediated syncope. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359203.

Reproducibility of electrocardiographic findings in patients with suspected reflex neurally-mediated syncope.

The reproducibility of electrocardiographic (ECG) recordings in syncopal recurrences and the diagnostic role of nonsyncopal arrhythmias are not well known. The objective of this study was to analyse the reproducibility of the ECG findings recorded with implantable loop recorders in 41 patients with suspected neurally-mediated syncope who were included in the International Study on Syncope of Uncertain Origin-2 study and that had > or =2 events recorded by implantable loop recorders. In these patients, the electrocardiogram obtained with the first documented syncope (index syncope) was compared with other recorded events. Twenty-two patients had > or =2 syncopes, and their electrocardiograms were reproducible in 21 (95%): 15 with sinus rhythm, 5 with asystole, and 1 with ventricular tachycardia; 1 had asystole at first syncope and sinus rhythm at recurrent syncope. In 32 patients with nonsyncopal episodes, an arrhythmia was documented in 9, and all of them had the same arrhythmia during the index syncope (100% reproducibility); conversely, when sinus rhythm was documented (23 patients) during nonsyncopal episodes, an arrhythmia was still documented in 6 during the index syncope (70% reproducibility; p = 0.0004). In conclusion, the ECG findings during the first syncope are highly reproducible in subsequent syncopes. The presence of an arrhythmia during nonsyncopal episodes is also highly predictive of the mechanism of syncope, but the presence of sinus rhythm does not rule out the possibility of arrhythmia during syncope. Therefore the finding of an arrhythmia during a nonsyncopal episode allows the etiologic diagnosis of syncope, and eventually to anticipate treatment, without waiting for syncope.