We report a case of polymorphic ventricular tachycardia and ventricular fibrillation (PVT/VF) storm associated with ischemic cardiomyopathy (ICM). The electrocardiogram (ECG) monitor revealed frequent premature ventricular contractions (PVCs) initiated PVT/VF. Electroanatomic mapping revealed the plausible origins of PVCs were located in the scar border zone at the posterior septum of the left ventricle. Purkinje-like potentials (PLPs) always preceded PVCs and a decremental property for the PLPs and infarcted myocardium junction was observed. Ablation at these sites eliminated both PVCs and PVT/VF.