Hemodynamic differences in isometric counter-pressure maneuvers and their efficacy in vasovagal syncope

Background Isometric counter-pressure maneuvers (ICM) were proposed as first-line treatment in patients with vasovagal syncope (VVS). The aim was to study hemodynamic mechanisms and effectiveness of ICM in prevention of head-up tilt (HUT)-induced and spontaneous VVS. Methods In 38 patients with VVS (9 men, 28 women, mean age 35.82 ± 15.2 years), following ICM were performed—squatting (SQ), leg crossing with muscle tensing (LCMT), whole-body tensing (WBT), heel raises (HeR), toe extension (TE), and unilateral handgrip (HG). Hemodynamic parameters were recorded during ICM using photopletysmographic principle: blood pressure, heart rate, cardiac output, stroke volume, and total peripheral resistance. Clinical efficacy of ICM was assessed during HUT-induced presyncope. The recurrence of syncope and quality of life were also evaluated during 26 ± 7 month follow-up period. Results All maneuvers increased mean arterial pressure. The hemodynamic background of ICM was not uniform. In most ICM (LCMT, WBT, HeR, and TE), an increase in CO due to simultaneous increase in HR and SV was observed. In SQ, the underlying mechanism was augmentation of stroke volume by increased venous return. In unilateral HG, a rise in peripheral resistance was the principal mechanism. ICM were able to prevent syncope in 47% of patients during HUT-induced presyncope and in 71% of patients during spontaneous presyncope. Quality of life improved in all patients. Conclusions ICM increase blood pressure by variable hemodynamic mechanisms. ICM effectively counteract the HUT-induced and spontaneous vasovagal syncope and improve quality of life.