The Presence of Electromechanical Mismatch In Nonischemic Dilated Cardiomyopathy Is Associated With Ventricular Repolarization Instability

- We performed Noga electroanatomic mapping in nonischemic DCM patients
- Electromechanical mismatch was present in more than half of patients with DCM
- Electromechanical mismatch was associated with higher QT variability
- Electromechanical mismatch was associated with higher ventricular arrhythmia risk

BackgroundWe analyzed electromechanical mismatch (EMM) and its relationship to ventricular repolarization in patients with nonischemic dilated cardiomyopathy (DCM).Methods and ResultsIn 39 DCM patients with left ventricular ejection fraction (LVEF) <40% and New York Heart Association functional class ≥III, electroanatomic mapping was used to quantify areas of EMM. High-resolution electrocardiograph was used to measure heart rate variability (HRV) and QT variability index (QTVI). EMM was present in 22 patients (56%, group 1), whereas 17 patients presented no mismatched segments (44%, group 2). The groups did not differ in age (56 ± 10 years in group 1 vs 57 ± 7 years in group 2; P = .82), sex (male: 82% vs 94%; P = .40), LVEF (27 ± 8% vs 25 ± 6%; P = .18), or N-terminal pro-B-type natriuretic peptide (2,350 pg/mL vs 2,831 pg/mL; P = .32). Although heart rate and HRV were similar in both groups (rate: 80 ± 20 beats/min in group 1 vs 74 ± 19 beats/min in group 2 [P = .47]; standard deviation of normal-to normal RR intervals: 106 ± 79 vs 88 ± 115 [P = .61]), we found significantly higher QTVI values in patients from group 1 (−1.15 ± 0.46 vs −1.62 ± 0.51 in group 2; P = .005). In patients with implantable cardioverter-defibrillators, ventricular arrhythmias recorded ≤1 year before enrollment were more frequent in group 1 than in group 2 (58% vs 13%; P = .02).ConclusionsEMM is present in a majority of patients with DCM and is associated with ventricular repolarization instability.