Pulsed Ultrahigh Frequency Spinal Cord Stimulation for Arrhythmia After Myocardial Infarction

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.

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.

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 (P=0.0016). Pathological analysis of the sympathetic and stellate ganglia revealed no significant apoptosis.

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.