Home orthostatic training in vasovagal syncope modifies autonomic tone: Results of a randomized, placebo-controlled pilot study

Abstract

Aims To detect possible autonomic changes due to home orthostatic training (HOT) and to assess the feasibility of a larger, placebo-controlled study of HOT in vasovagal syncope (VVS). Methods and results Twenty-two consecutive patients, aged 18-85, diagnosed with VVS following a positive head-up tilt-table test were randomized to 40 min of HOT (n = 12) or 10 min of sham training (n = 10) daily for 6 months. Baroreflex sensitivity (BRS) and heart rate variability (HRV) were measured at weeks 0, 1, 4, and 24. Symptom response was assessed by event diaries. Home orthostatic training resulted in increases in up and down slope BRS at week 4 (elog difference = 1.59, 95% CI = 0.84-3.03 and 1.79, 95% CI = 1.00-3.22) and week 24 (elog difference = 1.75, 95% CI = 1.01-3.06 and 1.53, 95% CI = 0.66-2.68) compared with placebo. Relative improvements in low- and high-frequency HRV were also observed in the HOT group compared with placebo at week 4 (elog difference = 3.22, 95% CI = 1.06-9.86 and 3.19, 95% CI = 1.03-10.59) and week 24 (elog difference = 2.11, 95% CI = 0.72-6.17 and 2.13, 95% CI = 0.52-8.79). Fifty percentage of HOT subjects and 20% of control subjects were syncope-free at 6 months. Conclusion This was the first placebo-controlled study in orthostatic training which has demonstrated that such a study is indeed feasible. An enhancement in overall autonomic tone is observed with HOT in tandem with a non-significant trend in symptom improvement. A larger, adequately powered, randomized controlled trial of tilt-training is now needed.