Effects of SUN-1165, N-(2,6-Dimethylphenyl)-8-Pyrrolizidine Acetamide Hydrochloride Hemihydrate, a New Class I Antiarrhythmic Drug, on Ventricular Arrhythmias, Intraventricular Conduction, and the Refractory Period in Canine Myocardial Infarction