Haemodynamic changes early in prodromal symptoms of vasovagal syncope.

AIMS: Vasovagal syncope (VVS) is often preceded by prodromal symptoms. The haemodynamic changes occurring during the prodrome have not been systematically investigated. The aim of the present study was to investigate the behaviour of blood pressure (BP), heart rate (HR) and sympathetic activity at the beginning of the prodrome in patients with tilt-induced VVS. METHODS AND RESULTS: Sixty-three patients with VVS underwent tilt testing. BP and HR were measured and blood samples for plasma catecholamine determination were obtained during the test. Twenty-seven patients developed syncope of whom all had a prodrome. From the last scheduled measurement before prodromal symptoms to the beginning of the prodrome, both systolic and diastolic BP decreased in all patients (from 105 +/- 16 to 74 +/- 20 mmHg, P<0.001, and from 68 +/- 13 to 51 +/- 12 mmHg, P<0 001, respectively) and HR decreased in 18 (67%) (from 89 +/- 22 to 80 +/- 25 beats/ min P<0 02). At the onset of loss of consciousness both BP and HR showed a further decrease (P<0.001). Plasma adrenaline significantly increased from the last sample before prodromal symptoms to the beginning of the prodrome (P<0.01) and showed a further increase during loss of consciousness (P