ABSTRACT
Catheter ablation has become an important treatment modality for patients suffering from ventricular arrhythmias (VAs). The advent of implantable cardioverter defibrillators (ICDs) has resulted in greater survival of patients at risk for or survivors of sudden arrhythmic death. Since VAs in patients with underlying cardiac disease often arise from abnormal substrate in the form of scar, differentiating normal from abnormal ventricular myocardium is of paramount importance. Different mapping techniques are available and often used in conjunction when treating a patient with VA. Scars typically display fractionated, low-amplitude electrograms. Sometimes, electrograms are separated by an isoelectric interval and the late components are defined as late potentials. Catheter ablation most commonly utilises radiofrequency energy delivered to the distal tip of the ablation catheter resulting in resistive heating of tissue in immediate contact with the catheter tip. A stepwise mapping approach assures that catheter ablation will result in a successful outcome.
