Ablation of ventricular tachycardia in structural heart disease has evolved to include techniques to ablate the myocardial substrate in sinus rhythm for ventricular tachycardias that are noninducible or hemodynamically unstable. The intricacies of the complex functional and fixed components of the myocardial scar involved in the arrhythmic mechanisms require careful consideration in identifying targets for substrate ablation identified in sinus rhythm.
The substrate ablation approach referred to as 'scar homogenization’ aims to thoroughly abolish any abnormal electrical activity inside the scar. However, this extensive approach may target bystander abnormal activity that is not necessarily related to arrhythmias. Recently, different substrate ablation strategies have been developed to more selectively target areas of the scar responsible for ventricular tachycardia. New technologies have also been introduced to provide offline analysis of the electroanatomical substrate, and to improve high-density mapping of the myocardial scar.
Recent advances have improved the ability to ablate ventricular tachycardia using techniques that allow targeting the responsible myocardial substrate while in sinus rhythm. Further research using higher-density mapping with more sophisticated online and offline analysis will aid in the assessment of the complex arrhythmogenicity of the scar and improve efficacy of ventricular tachycardia ablation.
aMcGill University Health Center
bCardiology Division, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke
cHôpital Sacré-Coeur de Montreál, Montreal, Quebec, Canada
dCardiology Department, Luigi Sacco Hospital, Milan, Italy
Correspondence to Vidal Essebag, MD, PhD, FRCPC, FACC, Director of Cardiac Electrophysiology McGill University Health Centre, 1650 Cedar Avenue, Room E5-200, Montreal, QC, H3G 1A4, Canada. Tel: +1 514 934 1934, x43158; fax: +1 514 934 8377; e-mail: firstname.lastname@example.org