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- Title
'Vasovagal' Response during Ventricular Fibrillation: Incidence and Implications.
- Authors
WALL, T. SCOTT; WASMUND, STEPHEN L.; FREEDMAN, ROGER A.; AKOUM, NAZEM W.; PAGE, RICHARD L.; HAMDAN, MOHAMED H.
- Abstract
Background The purpose of this study was to assess the relationship between changes in sinus node cycle length (SNCL) during ventricular fibrillation (VF) and the peripheral changes in blood pressure (BP) and sympathetic nerve activity (SNA) in human subjects. We hypothesized that patients with no SNCL shortening during VF have a vasovagal-like response with a greater decrease in BP and SNA when compared to patients with SNCL shortening. Methods SNCL, BP, and SNA recordings were attempted in 24 patients undergoing the implantation of a dual-chamber implantable defibrillator. Changes were measured during the first 5 seconds of VF and compared with the 5 seconds prior to VF induction. Results SNCL shortened during VF in nine patients (mean%∆SNCL = -12 ± 8%) and remained unchanged or lengthened in seven patients (mean%∆SNCL = 7 ± 7%). Eight patients had ventriculoatrial (VA) conduction prohibiting assessment of SNCL changes. In patients with SNCL shortening, the %∆MBP (mean BP) was -47 ± 6% compared to -58 ± 8% in patients with no SNCL shortening (P < 0.01). In patients with VA conduction, the %∆MBP was -54 ± 3%. SNA recordings were successfully obtained in four patients. When compared to baseline, SNA increased by 34 ± 30% in two patients with SNCL shortening, decreased by 25% in one patient with SNCL lengthening, and by 90% in the fourth patient with VA conduction. Conclusions We have shown that patients with no SNCL shortening have a significantly greater decrease in MBP during VF when compared to patients with SNCL shortening. The underlying mechanism appears to be reflex mediated with a vasovagal-like response in patients with no SNCL shortening.
- Subjects
UTAH; SYMPATHETIC nervous system physiology; ELECTROCARDIOGRAPHY; ELECTROPHYSIOLOGY methodology; ACADEMIC medical centers; BLOOD pressure; CHI-squared test; FISHER exact test; RESEARCH funding; SINOATRIAL node; TACHYCARDIA; VENTRICULAR fibrillation; DATA analysis software; DESCRIPTIVE statistics
- Publication
Pacing & Clinical Electrophysiology, 2015, Vol 38, Issue 3, p376
- ISSN
0147-8389
- Publication type
Article
- DOI
10.1111/pace.12562