Pulsed Ultrahigh Frequency Spinal Cord Stimulation for Arrhythmia After Myocardial Infarction.

Abstract

BACKGROUND: Acute myocardial infarction (MI) increases sympathetic tone and increases the risk of life-threatening ventricular arrhythmias. We tested the hypothesis that spinal cord stimulation (SCS) using pulsed ultrahigh frequency (PUF) from T1 to T3 remodels the sympathetic activity and reduces ventricular arrhythmias. METHODS: Twenty pigs were used in this study. Six were assigned to the control group, 7 received MI (MI Group), and 7 received MI plus PUF-SCS (MI+SCS Group). Seven pigs underwent a second surgery to implant the spinal stimulator. Echocardiography, 7-day Holter monitoring, and blood analyses were performed at baseline, 1 month after MI, and 1 month after PUF-SCS. All the pigs underwent an electrophysiological study and were euthanized. The left ventricular tissue was extracted for norepinephrine and adrenaline analyses. The sympathetic and stellate ganglia were analyzed. RESULTS: Sympathetic tone and ventricular arrhythmia episodes from the Holter monitor increased after MI but were suppressed after PUF-SCS. The left ventricular ejection fraction decreased in the MI group and improved after PUF-SCS. The ventricular fibrillation induction rates were 17%, 100%, and 29% in the Control, MI, and MI+SCS groups respectively (=0.0016). Pathological analysis of the sympathetic and stellate ganglia revealed no significant apoptosis. CONCLUSIONS: PUF-SCS effectively suppressed sympathetic tone and reduced ventricular arrhythmia burden without causing permanent damage to the sympathetic ganglia. In the MI model, heart function and ventricular fibrillation vulnerability were reversed 1 month after PUF-SCS.