Dr. Jason T. Jacobson, MD, FHRS, Westchester Medical Center, New York Medical College is joined by Melissa Robinson, MD, FHRS, Providence Heart Institute of Montana, and Dr. Sei Iwai, MD, FHRS, Westchester Medical Center, New York Medical College to discuss:
BACKGROUND Factors determining hemodynamic stability during human ventricular tachycardia (VT) are incompletely understood.
OBJECTIVES This study aimed to characterize sinus rate (SR) responses during monomorphic VT in association with hemodynamic stability and prospectively assess the effects of vagolytic therapy on VT tolerance.
METHODS This is a retrospective analysis of patients undergoing scar-related VT ablation. Vasovagal responses were evaluated by analyzing sinus cycle length before VT induction and during VT. SR responses were classified into 3 groups: increasing ($5 beats/min, sympathetic), decreasing ($5 beats/min, vagal), and unchanged, with the latter 2 categorized as inappropriate SR. In a prospective cohort (n . 30) that exhibited a failure to increase SR, atropine was administered to improve hemodynamic tolerance to VT.
RESULTS In 150 patients, 261 VT episodes were analyzed (29% untolerated, 71% tolerated) with median VT duration 1.6 minutes. A total of 52% of VT episodes were associated with a sympathetic response, 31% had unchanged SR, and 17% of VTs exhibited a vagal response. A significantly higher prevalence of inappropriate SR responses was observed during untolerated VT (sustained VT requiring cardioversion within 150 seconds) compared with tolerated VT (84% vs 34%; P < 0.001). Untolerated VT was significantly different between groups: 9% (sympathetic), 82% (vagal), and 32%
(unchanged) (P < 0.001). Atropine administration improved hemodynamic tolerance to VT in 70%.
CONCLUSIONS Nearly one-half of VT episodes are associated with failure to augment SR, indicative of an underrecognized pathophysiological vasovagal response to VT. Inappropriate SR responses were more predictive of hemodynamic instability than VT rate and ejection fraction. Vagolytic therapy may be a novel method to augment blood pressure during VT.
Article Authors and Podcast Contributors
Article Authors
Margarida Pujol-Lopez, MD,a,b Jeanne Du Fay de Lavallaz, MD, PHD,a Pooja Rangan, MBBS, MPH,b
Andrew Beaser, MD, a Zaid Aziz, MD, a Gaurav A. Upadhyay, MD, a Hemal Nayak, MD, a J. Peter Weiss, MD,b
Michael Zawaneh, MD,b Rong Bai, MD,b Wilber Su, MD,b Roderick Tung, MDb
Podcast Contributors
Dr. Jason T. Jacobson, MD, FHRS, Westchester Medical Center-New York Medical College
Melissa Robinson, MD, FHRS, Providence Heart Institute of Montana
Dr. Sei Iwai, MD, FHRS, Westchester Medical Center-New York Medical College
All relevant financial relationships have been mitigated.
Host Disclosure(s):
J. Jacobson: Honoraria/Speaking/Consulting: Zoll Medical, Abbott Medical, Vektor Medical, Stocks, Privately Held: Atlas 5D, Research: CardioFocus, Inc.
Contributor Disclosure(s):
M. Robinson: Honoraria/Speaking/Consulting: Biosense Webster, Inc., Boston Scientific, Abbott, Membership on Advisory Committees: Medtronic Inc.
S. Iwai: Honoraria/Speaking/Consulting: Alta Thera Pharmaceuticals, Biotronik
Staff Disclosure(s) (note: HRS staff are NOT in control of educational content. Disclosures are provided solely for full transparency to the learner):
S. Sailor: No relevant financial relationships with ineligible companies to disclose.
S. Colbert: No relevant financial relationships with ineligible companies to disclose.