The outcome of permanent pacing in patients with class 3 indications

Up to 50% of patients with syncope have no cause found, despite a thorough work-up. Half will continue to have symptoms after one year. Guidelines for permanent pacemaker implantation demand the demonstration of symptomatic bradyarrhythmias, yet the majority of patients have intermittent symptoms that elude investigations. The policy in our department over the last 7 years has been to implant a permanent pacemaker in patients with syncope or pre-syncope where the history suggests that bradycardia is the cause but investigations have been unhelpful. We examined the results of this policy. A review of the pacing database and patient notes identified 210 patients with symptoms but no other accepted evidence for pacing (class 3 indications). A postal survey generated 110 replies. A further 20 patients with class 1 indications and 17 patients with class 2 indications also replied. Class 1 Class 2 Class 3 No more symptoms 15 (75%) 15 (88%) 67 (61%) Improved 5 (25%) 2 (12%) 40 (36%) No change 0 0 2 (2%) Worse 0 0 1 (1%) The effects of pacing were statistically similar in all three classes. Within Class 3 patients neither a history of syncope-associated injury, atrial fibrillation, 12 lead ECG conduction abnormalities nor a resting bradycardia predicted cure rather than improvement in symptoms. These results concur with previous studies that pacing in patients without documented symptomatic bradycardia may offer a substantial benefit. This may be due to a placebo effect of pacing or a high incidence of unconfirmed bradyarrhythmias causing their symptoms.