Cardiac pacing in severe recurrent reflex syncope and tilt-induced asystole

Abstract

Aim The benefit of cardiac pacing in patients with severe recurrent reflex syncope and asystole induced by tilt testing has not been established. The usefulness of tilt-table test to select candidates for cardiac pacing is controversial. Methods and results We randomly assigned patients aged 40 years or older who had at least two episodes of unpredictable severe reflex syncope during the last year and a tilt-induced syncope with an asystolic pause longer than 3 s, to receive either an active (pacing ON; 63 patients) or an inactive (pacing OFF; 64 patients) dual-chamber pacemaker with closed loop stimulation (CLS). The primary endpoint was the time to first recurrence of syncope. Patients and independent outcome assessors were blinded to the assigned treatment. After a median follow-up of 11.2 months, syncope occurred in significantly fewer patients in the pacing group than in the control group [10 (16%) vs. 34 (53%); hazard ratio, 0.23; P = 0.00005]. The estimated syncope recurrence rate at 1 year was 19% (pacing) and 53% (control) and at 2 years, 22% (pacing) and 68% (control). A combined endpoint of syncope or presyncope occurred in significantly fewer patients in the pacing group [23 (37%) vs. 40 (63%); hazard ratio, 0.44; P = 0.002]. Minor device-related adverse events were reported in five patients (4%). Conclusion In patients aged 40 years or older, affected by severe recurrent reflex syncope and tilt-induced asystole, dual-chamber pacemaker with CLS is highly effective in reducing the recurrences of syncope. Our findings support the inclusion of tilt testing as a useful method to select candidates for cardiac pacing. Study registration ClinicalTrials.gov identifier NCT02324920, Eudamed number CIV-05-013546.

Tilt testing remains a valuable asset

“… 10 , 11 If the history yields a clear diagnosis, TT is not required; nonetheless, TT may provide important patient education and reassurance, together with pathophysiological evidence of the underlying mechanisms, critical for the selection of appropriate therapy. 12 …”

“…Nevertheless, TT can be useful, particularly in post-pacing syncope recurrence in severe VVS 33–38 when combined with other cardiovascular autonomic tests such as carotid sinus massage. 10 , 36 TT can help in pacemaker therapy selection 12 and predict syncope recurrence after pacing; positive tilts pre-pacing are associated with a much higher recurrence rate than negative tilts with similarly positive ILR observations of VVS. 5 , 34–37 An explanation may be that ‘hypotensive susceptibility’ is present even when dominated by cardioinhibition.…”

“…2. TT identifies patients with asystole who may require cardiac pacing based on temporal relationship of bradycardia/hypotension 12 , 39 …”

“…TT shows asystole before or coincides with hypotension points to symptomatic improvement with pacing 12 , 43 …”

Evaluation of Patients with Syncope in the Emergency Department: How to Adjust Pharmacological Therapy

“…The bradycardic phenotype is likely when syncope occurs during a spontaneous or induced asystole lasting more than 3 s [27]. However, syncope due to cardiac arrhythmias or to structural heart disease, syncope occurring in the supine position, vasovagal syncope triggered by emotional distress (blood phobia, instrumentation, visceral or somatic pain), or cardio-inhibitory reflex syncope are less likely to be related to hypotensive medications.…”