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

Abstract

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 65Ϯ5% at baseline, 17Ϯ3% at the end of stage 1, and 47Ϯ7% at the end of stage 2. In the MED group, left ventricular ejection fraction was 61Ϯ4% at baseline, 18Ϯ3% at the end of stage 1, and 34Ϯ4% at the end of stage 2. In the CTRL group, left ventricular ejection fraction was 64Ϯ5% at baseline, 19Ϯ5% at the end of stage 1, and 28Ϯ3% at the end of stage 2. Left ventricular ejection fraction was significantly improved in the SCS compared with the MED and CTRL groups (PϽ0.001 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 (27Ϯ17 and 27%, respectively; PϽ0.03) and MED (58Ϯ42 and 33%; PϽ0.05) versus CTRL (88Ϯ52 and 76%) group. After 10 weeks in the phase 2 studies, the greatest recovery in ejection fraction was noted in the SCS (52Ϯ5%) and SCSϩMEDS (46Ϯ4%) groups compared with the MEDS (38Ϯ2%) and CTRL (31Ϯ4%) groups. Conclusion-SCS

Device-Based Approaches to Modulate the Autonomic Nervous System and Cardiac Electrophysiology

“…Similar effects were observed following chronic SCS by Lopshire et al, 60 in which case chronic SCS not only improved LV function in a canine model of ischaemic cardiomyopathy, but also decreased ventricular tachyarrhythmias, over and above the effect seen from standard medical therapy for heart failure.…”

“…53,60 In addition, inhibition of the cardiocardiac reflex may also contribute to the antiarrhythmic effect of SCS. In the setting of ischaemia, Foreman et al 53 demonstrated that SCS decreased afferent output from the intrinsic cardiac nervous system.…”

Interventional and Device-Based Autonomic Modulation in Heart Failure

“…The chronic cardio-protective effect of SCS in HF was best demonstrated by a canine study 15 from the same investigator group. All canines first underwent foam embolization of the left anterior descending artery followed by ventricular tachypacing to create an ischemic HF model.…”

Autonomic nervous system in arterial hypertension and heart failure: current understanding of its pathophysiologic role and innovative treatment approaches

“…В этом же исследо-вании было показано, что позитивные эффекты спи-нальной стимуляции связаны именно с улучшением автономного контроля сердца [81].…”

“…Клиническое улучшение симптомов СН было отмечено на собаках с ХСН, сопровождающейся уменьшением размеров ЛЖ [81]. В этом же исследо-вании было показано, что позитивные эффекты спи-нальной стимуляции связаны именно с улучшением автономного контроля сердца [81].…”