The heart rate of ventricular tachycardia following an old myocardial infarction is inversely related to the size of scarring

Abstract

The purpose of the study was to examine the relationship between the initial cycle length (CL) of ventricular tachycardia (VT) and the size of the myocardial scar and its border zone in patients with old myocardial infarction (MI). Late gadolinium-enhancement cardiac magnetic resonance was performed prior to implantable cardioverter-defibrillator (ICD) implantation in 24 patients. The size of non-scared myocardium, scar, scar core, and border zone were measured as voxel numbers. The number of core islands, contour-regularity of scar and left-ventricular ejection fraction were also calculated. During the first year after ICD implantation, VT was recorded in 20 patients. With univariate regression analysis, the number of core islands had the highest correlation with the CL of VT (R = 0.614, adjusted R² = 0.342, P = 0.004). By multiple regression analyses, the highest correlation was found by the use of scar core and core islands (R = 0.721, adjusted R² = 0.464, P = 0.002). The heart rate of VT (bpm) in patients with old MI is inversely related to the properties of the densest parts of the myocardial scar.