Study Plan: Using electrical nerve stimulation to control atrial fibrillation Aim 1 will test the hypothesis that subcutaneous (Aim 1A) and transcutaneous (Aim 1B) electrical nerve stimulation are effective in reducing the frequencies of paroxysmal atrial fibrillation (AF) and the ventricular rate in patients with severe symptomatic AF unresponsive to conventional therapies. Aim 2 will test the hypothesis that in healthy subjects, electroacupuncture or TENS at LI-4 and LI-11 can acutely activate or suppress skin sympathetic nerve activity (SKNA). We further hypothesize that chronic TENS will reduce sympathetic output in humans. If confirmed, repeated TENS may be used in the future clinical trials to control AF.