[Background]:
Late gadolinium enhancement (LGE) on cardiac MRI (CMR) predicts the mortality in hypertrophic cardiomyopathy (HCM) patients. T-wave alternans (TWA) is a potential cardiac mortality predictor. However, whether LGE localization affects TWA is unclear.
[Purpose]:
To elucidate the localization relationship between the LGE and maximal TWA lead (TWAmax-lead) and maximal TWA voltage (TWAmax) using 12-lead Holter ECGs (Holter12) in HCM.
[Methods]:
Holter12s and CMR were performed in 46 HCM patients. TWA was assessed using a modified moving average method and the TWAmax was determined in each lead. The average transmural LGE extent was scored using a 4 point score (Score 0:no LGE, 1:1-25%, 2:26-50%, 3:51-75%, 4:76-100%) in 12 left ventricular segments and the sum (LGEtotal) was calculated. Left ventricular LGE sites were classified into anterior, septal, inferior, and lateral. Corresponding ECG lead groups were defined as V3-4 for anterior, V1-2 for septal, II, III, aVF for inferior, and I, aVL, and V5-6 for lateral. The TWAmax was analyzed depending on the Score of the 5 stages, and the coincidence between the LGE distribution and TWAmax-lead was investigated. Furthermore, the differences in the TWAmax, LGEtotal, and left ventricular ejection fraction (LVEF) in the presence or absence of ventricular tachycardia (VT) were also studied.
[Results]:
The TWAmax was 50±11μV for Score=0, 54±13μV for Score=1, 61±18μV for Score=2, 67±20μV for Score=3, and 47±16μV for Score=4. The TWAmax for Scores 2 and 3 was significantly greater than for Score=0 (p<0.001, p<0.001, respectively), but there was no significant difference between Scores 1 and 4, and Score=0 (p=0.14, p=0.41). The TWAmax-lead revealed scores ranging from 1 to 3 in all segments. The LGEtotal and TWAmax were significantly greater in patients with VT (n=23) than without (17±7 vs. 10±7 [p<0.01], 83±17μV vs. 64±18μV [p<0.001], respectively). The LVEF did not statistically differ between the two groups (48±16% vs. 54±10%, p=0.21).
[Conclusions]:
The LGE distribution correlated with the TWA, i.e., a 50-75% transmural extent of the LGE yielded the maximal local TWA. The spatial distribution of the LGE strongly affects myocardial repolarization abnormalities indicated by TWA as VT substrates in HCM.
Clinical significance of late gadolinium enhancement in pediatric patients with hypertrophic cardiomyopathy
