Determining the optimal pacing intervention rate for vasovagal syncope

Introduction: In this study, patients with rate hysteresis pacemakers impla nted for vasovagal syncope were re-studied using serial tilt testing to det ermine whether, once triggered, pacing was more effective if the interventi on rate was higher than the standard rate. Methods and Results: Twenty patients (mean age 55.4 years, range 23-81, 14 male) were studied, with randomisation to either initial standard rate (80- 90 beats/min) intervention, or to initial high rate (120 beats/min) interve ntion. Although 18 of the 20 reported complete abolition of syncope since p acing, only 8 patients could be objectively assessed. The respective mean t ime to tilt down after symptom onset with standard and high rate interventi on was 193 +/- 234 s and 185 +/- 143 s, (P > 0.05). Conclusion: Repeat tilt testing was only of limited value in assessing the benefit of pacing. There was no advantage with high rate intervention in de laying the loss of consciousness (or intolerable symptoms) after the initia l onset of symptoms.