"Vasovagal" Response during XXXX : Incidence and Implications.

@entity1 @entity1817 @entity2224
BACKGROUND: The purpose of this study was to assess the relationship between changes in @entity1817 ( @entity1817 ) during @entity2224 ( @entity2224 ) and the peripheral changes in blood pressure (BP) and sympathetic nerve activity (SNA) in @entity1 subjects. We hypothesized that @entity1 with no @entity1817 shortening during @entity2224 have a vasovagal-like response with a greater decrease in BP and SNA when compared to @entity1 with @entity1817 shortening. METHODS: @entity1817 , BP, and SNA recordings were attempted in 24 @entity1 undergoing the implantation of a dual-chamber implantable defibrillator. Changes were measured during the first 5 seconds of @entity2224 and compared with the 5 seconds prior to @entity2224 induction. RESULTS: @entity1817 shortened during @entity2224 in nine @entity1 (mean%   @entity1817 = -12    8%) and remained unchanged or lengthened in seven @entity1 (mean%   @entity1817 = 7    7%). Eight @entity1 had ventriculoatrial (VA) conduction prohibiting assessment of @entity1817 changes. In @entity1 with @entity1817 shortening, the %   MBP (mean BP) was -47    6% compared to -58    8% in @entity1 with no @entity1817 shortening (P < 0.01). In @entity1 with VA conduction, the %   MBP was -54    3%. SNA recordings were successfully obtained in four @entity1 . When compared to baseline, SNA increased by 34    30% in two @entity1 with @entity1817 shortening, decreased by 25% in one @entity1 with @entity1817 lengthening, and by 90% in the fourth @entity1 with VA conduction. CONCLUSIONS: We have shown that @entity1 with no @entity1817 shortening have a significantly greater decrease in MBP during @entity2224 when compared to @entity1 with @entity1817 shortening. The underlying mechanism appears to be reflex mediated with a vasovagal-like response in @entity1 with no @entity1817 shortening.
