THE ROLE OF CARDIAC-RHYTHM DISORDERS IN THE ETIOLOGY OF VASOVAGAL SYNCOPE

Arrhythmias are a common pathology lying at the basis of circulatory s yncope, including neurocardiogenic s. vasovagal syncope (WS). Therefor e analysis of Holter monitoring (HM) of 26 patients with WS and 20 con trol group volunteers was performed. Type of syncope in vasovagal pati ents, aged 15 to 50 yrs (avg 26, 89.9; 10F, 16M), was diagnosed accord ing to the Vasovagal International Study classification (VASIS-1-mixed type: 16, VASIS-2-cardioinhibitory: 6, VASIS-3-vasodepressive: 4). Va sovagal syndrome in control group volunteers aged 18 to 53 yrs (avg 29 .310.2; 7F, 13M) was negated on the basis of two negative passive head -up tilt tests. In the control group during 24-hour HM the following w as observed: IAV block in 10%, II AV block (Wenckebach type) in 5%, ju nctional rhythm (JR) in 5%, and sinus arrest (1.65sec.) in 5%; all hav ing occured at night. In the vasovagal group IAV block occured in 23%, and junctional rhythm in 3.8% and sinus arrest (2.0 sec.) in 3.8% dur ing 24-hour HM monitoring. The arrhythmias were observed only in type I: AV block I[25%] JR [6.3%], sinus arrest [6.3%] and in type 2: AV bl ock 1[33.3%]. The greatest variety of arrhythmias during head-up tilt test was seen in type 2. In all pts of this group, sinus rhythm (SR) w as observed before syncope (84 bpm) and sinus arrest (8-35 sec)[83.3%] or AV block II/III [16.7%] during syncope. Immediately after syncope, JR (40 bpm) [66.6%] or SR was noted[33.4%]. In pts with type I, SR al ways appeared before syncope (91bpm). In 31% JR (49bpm) appeared durin g syncope, and SR in the remainder (54 bpm). After syncope SR was obse rved in 93.8% of pts and JR in 6.2%. In all pts with type 3, SR of con stant frequency (98bpm) appeared before, during and after syncope. Con clusions: 1) no statistically significant relationship was observed be tween the presence of conduction disturbances and the occurrence of WS . 2) the greatest heterogeneity of arrhythmias during syncope was obse rved in cardioinhibitory type, however the greatest stability of norma l sinus rhythm occurred in vasodepressive type.