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.

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.