Efficacy of Transcutaneous Vagus Nerve Stimulation to Suppress Paroxysmal Atrial Fibrillation: A Systematic Review.

Paroxysmal atrial fibrillation (PAF) is a common cardiac arrhythmia marked by episodic, irregular heart rhythms, contributing significantly to both morbidity and mortality. Traditional management typically involves antiarrhythmic medications and catheter ablation; however, novel, non-invasive approaches, such as low-level transcutaneous vagus nerve stimulation (LLTS), are emerging as promising alternatives. LLTS aims to modulate autonomic nervous system activity through vagus nerve activation, with potential benefits, including the suppression of arrhythmias and a reduction in systemic inflammation. To evaluate the effectiveness of LLTS in patients with PAF, a systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were performed in the PubMed and ScienceDirect databases covering literature from 2015 to 2024. The review included randomized controlled trials (RCTs), cohorts, and case-control studies that evaluated adult patients with PAF undergoing LLTS interventions. Three RCTs met the inclusion criteria, involving a total of 121 participants who received either LLTS or sham stimulation. LLTS and sham stimulation were standardized among studies and adequately blinded. Outcomes assessed across studies included suppression of arrhythmia episodes, changes in heart rate variability, levels of inflammatory markers, and overall reduction in atrial fibrillation (AF) burden during a six-month follow-up period. Results showed that LLTS significantly reduced AF burden, the time a patient spends in AF, compared to sham stimulation, with reductions of up to 85% observed at six months. Patients receiving LLTS also exhibited lower levels of inflammatory markers, such as tumor necrosis factor-alpha, indicating an anti-inflammatory effect. Importantly, no major adverse events were reported in any of the included trials. However, limitations of the current evidence include small sample sizes, homogeneity in the dose and timing of stimulation (20 Hz for one hour), follow-up time of six months, lack of continuous ECG monitoring, and variability in individual patient responses to LLTS.  In conclusion, LLTS appears to be a safe and effective adjunctive treatment option for PAF, with significant potential for reducing AF burden and inflammation. Although early results are promising, further research involving larger cohorts and longer follow-up periods is necessary to confirm its long-term benefits and identify patient populations that may derive the greatest benefit from this therapy.