['Although previous animal studies clearly demonstrated antiarrhythmic effects of vagal stimulation during acute myocardial ischemia, highly invasive nature of vagal stimulation limited its clinical use. Recently, intravascular parasympathetic cardiac nerve stimulation (IPS) has emerged as a novel approach to the cardiac autonomic nervous system. We hypothesized that IPS might prevent ventricular arrhythmias during acute myocardial ischemia.', 'The IPS (36 V, 10 Hz) was performed in superior vena cava using an expandable electrode-basket catheter. In 18 open-chest dogs, left anterior descending coronary artery ligation was performed without IPS (control group, n= 6), with IPS (IPS group, n= 6) and with IPS and right atrial pacing at 180/min (IPS+P group, n=6). The ECGs were monitored for 60 min. The incidence and severity of ventricular arrhythmias were analyzed.', 'The IPS significantly decreased the frequency of premature ventricular contractions (control group: 9.1 &#177; 4.6/min, IPS group: 0.2 &#177; 0.4 /min, IPS+P group: 10.6 &#177; 4.2 / min; p&lt;0.05). The frequency of ventricular tachycardia was lower in IPS group (0 &#177; 0 /min) than in control group (0.15 &#177; 0.18 /min, p&lt;0.05) and than in IPS+P group (0.17 &#177; 0.12 /min, p<0.05). The incidence of ventricular fibrillation was lower in IPS group (0%) than in control group (33.3%) and than in IPS+P group (33.3%).'] Does intravascular parasympathetic cardiac nerve stimulation prevent ventricular arrhythmias during acute myocardial ischemia?