Delayed Enhancement on Cardiac MRI Depicts Spatial and Temporal Repolarization Abnormalities in Patients with Lethal Ventricular Arrhythmias

Abstract

Purpose: To elucidate whether the delayed enhancement (DE) distribution on cardiac MRI (CMR) correlates with the rate adaptation pattern and QT/RR diurnal variability in patients with lethal ventricular arrhythmias. Methods: CMR and QT/RR analyses using Holter monitoring were performed in 34 patients (24 males, 59.7±10.5 years) with VT and/or VF. DE on CMR was depicted and the depth was scored as 1 to 4 from the endocardium to epicardium in 17 left ventricular segments. The sum of the scores (Total DE score) was calculated in each patient. The QT/RR slope and day-time/night-time QT/RR ratio (Day/Night ratio) were calculated. The correlation of the slope or Day/Night ratio and DE findings were analyzed. Results: All patients were divided into 23 DE positive (DE(+)) and 11 DE negative (DE(−)) patients. The QT/RR slope was significantly steeper in the DE(+) than DE(−) patients (0.212±0.026 vs. 0.128±0.021 (p<0.001)), and correlated significantly with the Total DE scores (r=0.83 (p<0.001)). The Day/Night ratio was significantly greater in the DE(+) patients than DE(−) patients (1.37±0.38 vs. 0.91±0.33 (p<0.005)). Conclusions: The transmural DE distribution was deeply related to the QT dynamicity pattern in addition to the diurnal QT/RR variability. These results indicate that myocardial scar demonstrated by DE results in increases in the repolarization dispersion in healthy and damaged myocardium, causing severe ventricular arrhythmias in organic heart disease patients.