Effects of ipsilateral ceral vagosysmpathetic trunk stimulation (VTS) on AF inducibility by HFS before and after GP ablation (n = 7). Left VTS was denoted as ‘ipsilateral’ to the left PVs, atrium and atrial appendage while right VTS was denoted as ‘ipsolateral’ to the right PVs, atrium and atrial appendage. After GP (ARGP + IRGP + SLGP + ILGP + LOM) ablation, the measurements of AF threshold at the same VTS voltage as prior to ablation were repeated. The HFS for measurements of AF threshold was set at 200 Hz, 0.01 ms in duration of each impulse, train duration 40 ms, and was delivered within the myocardial refractoriness.