Effects of orthostatic self-training on head-up tilt testing and autonomic balance in patients with neurocardiogenic syncope.J Cardiovasc Pharmacol. 2003 Jan; 41 Suppl 1:S73-6.JC
To investigate the effectiveness and the mechanisms of an orthostatic self-training program for the prevention of neurocardiogenic syncope, 28 patients were treated with an orthostatic self-training program. Syncope was induced by head-up tilt testing (+ 80 degrees for 30 min) in all patients. The onset time of the tilt-induced syncope was 14 +/- 7 min following placement in the upright position. The orthostatic self-training program included standing against a wall without moving twice a day every day for a planned duration of up to 30 min at home. The head-up tilt response was re-evaluated after 24 +/- 6 days based on results of the self-training. In 12 of the 28 patients, the sympathovagal balance was also determined during the head-up tilt test before and after the training with power spectral analysis of heart rate variability using a maximal entropy method. Syncope was not observed in any patient after the training. Although the low frequency/high frequency ratio in the supine position was not different before and after the training, the ratio after 3 min in the upright position after the training decreased significantly compared with that before the training. High-frequency components in the supine and upright positions were not different before and after the training. We concluded that orthostatic self-training significantly improved symptoms in patients with tilt-induced neurocardiogenic syncope. Decreased sympathetic activity in the early stage of the upright position period may play an important role in the mechanisms of this therapy.