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(Circulation. 2009;120:286-294.)
© 2009 American Heart Association, Inc.

Arrhythmia/Electrophysiology

Spinal Cord Stimulation Improves Ventricular Function and Reduces Ventricular Arrhythmias in a Canine Postinfarction Heart Failure Model

John C. Lopshire, MD, PhD; Xiaohong Zhou, MD; Cristian Dusa, MD; Takeshi Ueyama, MD; Joshua Rosenberger, MPH; Nicole Courtney, BS; Michael Ujhelyi, PharmD; Thomas Mullen, PhD; Mithilesh Das, MD; Douglas P. Zipes, MD

From the Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis (J.C.L., C.D., T.U., J.R., N.C., M.D., D.P.Z.), Medtronic Cardiac Rhythm Management, Minneapolis, Minn (X.Z., M.U., T.M.).

Correspondence to John C. Lopshire, MD, PhD, Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, 1800 N Capitol Ave, Suite E400, Indianapolis, IN 46202. E-mail jlopshir{at}iupui.edu

Received August 2, 2008; accepted June 1, 2009.

Background— Spinal cord stimulation (SCS) reduces the incidence of ventricular tachyarrhythmias in experimental models. This study investigated the effects of long-term SCS on ventricular function in a postinfarction canine heart failure model.

Methods and Results— In stage 1, dogs underwent implantable cardioverter-defibrillator implantation and embolization of the left anterior descending artery followed by right ventricular pacing (240 ppm) for 3 weeks to produce heart failure. In stage 2, 28 surviving animals were assigned to the SCS (delivered at the T4/T5 spinal region for 2 hours 3 times a day), medicine (MED; carvedilol therapy at 12.5 mg PO BID), or control (CTRL; no therapy) group for the initial phase 1 study. In a subsequent phase 2 study, 32 stage 1 survivors were equally randomized to the SCS, MEDS (carvedilol plus ramipril 2.5 mg PO QD), SCS plus MEDS (concurrent therapy), or CTRL group. Animals were monitored for 5 weeks (phase 1) or 10 weeks (phase 2). In stage 3, all phase 1 animals underwent circumflex artery balloon occlusion for 1 hour. In the SCS group, left ventricular ejection fraction was 65±5% at baseline, 17±3% at the end of stage 1, and 47±7% at the end of stage 2. In the MED group, left ventricular ejection fraction was 61±4% at baseline, 18±3% at the end of stage 1, and 34±4% at the end of stage 2. In the CTRL group, left ventricular ejection fraction was 64±5% at baseline, 19±5% at the end of stage 1, and 28±3% at the end of stage 2. Left ventricular ejection fraction was significantly improved in the SCS compared with the MED and CTRL groups (P<0.001 for both). The mean number of spontaneous nonsustained ventricular tachyarrhythmias during stage 2 and the occurrence of ischemic ventricular tachyarrhythmias during stage 3 also were significantly decreased in the SCS (27±17 and 27%, respectively; P<0.03) and MED (58±42 and 33%; P<0.05) versus CTRL (88±52 and 76%) group. After 10 weeks in the phase 2 studies, the greatest recovery in ejection fraction was noted in the SCS (52±5%) and SCS+MEDS (46±4%) groups compared with the MEDS (38±2%) and CTRL (31±4%) groups.

Conclusion— SCS significantly improved cardiac contractile function and decreased ventricular arrhythmias in canine heart failure.

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CLINICAL PERSPECTIVE

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Clinical Summaries
Circulation 2009 120: 267-268. [Extract] [Full Text]