[Determinants of malignant vasovagal syncopes with asystole disclosed by the tilting test and therapeutic...

In order to evaluate the determinants of malignant vasovagal syncope with asystole revealed by the tilting test and to determine the possible therapeutic implications, 179 patients (91 women and 88 men, mean age 36.6 +/- 20.1 years) referred for the assessment of unexplained a were studied. The test was performed with a tilt of 60 degrees for 45 minutes. A bolus of isoprenaline (0.02 to 0.08 microgram/kg.min) was injected in the case of a negative passive test. Asystole was defined as a ventricular pause lasting > or = 5 seconds.

Ten (13%) of the 77 patients with a positive tilting test experienced a cardio-inhibitory reaction with prolonged asystole lasting an average of 11.9 +/- 4.9 seconds. Compared to the other 67 patients with a positive test, those with asystole were younger (23/9 +/- 14.8 years vs 32.9 +/- 18.5 years, NS) and had a more frequent history of convulsions (6/10 vs 9/67, p = 0.05) during spontaneous episodes and trauma (9/10 vs 27/67, p = 0.005). Implantation of a pacemaker was chosen first-line treatment for the first 6 patients. Their follow-up tilting tests remained positive (pre S = 4, S = 1) despite DDD stimulation of 45 bpm. Five of these patients and the following 4 patients were retested under beta-blockers. In six patients treated with beta-blockers, the clinical symptoms resolved completely (n = 3) or improved (n = 3), in contrast with 3 other patients in whom the tilting test remained positive with recurrence of asystole. The mean follow-up for the 169 patients is 22.7 +/- 11 months and the ten patients with asystole remained totally asymptomatic.

An asystolic response during the tilting test is characteristic of vasovagal syncope described as malignant. The syndrome essentially affects young patients, with a more frequent history of trauma and convulsions. Beta-blockers appear to be at least as effective as permanent pacemaker to prevent symptoms in this specific subgroup.