Abstract 10981: Late Gadolinium Enhancement of Cardiac Magnetic Resonance Imaging Indicates Abnormalities of Time-Domain T-Wave Alternans in Hypertrophic Cardiomyopathy with Ventricular Tachycardia
[Background]: Recently, the presence of myocardial scar detected by late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) has been described as a good independent predictor of mortality in patients with hypertrophic cardiomyopathy (HCM). Time-domain T-wave alternans (TWA) is also a potential predictor of cardiac mortality in patients with LV dysfunction. However, it is unclear whether LGE expansion also affects the TWA.
[Purpose]: To elucidate the relationship between the LGE distribution and TWA in patients with HCM.
[Methods]: CMR and TWA analyses using Holter monitoring were performed in 40 patients with HCM. The LGE was classified into 12 left ventricular segments (Basal - Middle - Apical × Anterior - Septal - Inferior - Lateral). The average transmural extent of the LGE was scored as 1 to 4 in each segment and the sum of the LGE scores (Total LGE score) was calculated in each patient. The time-domain TWA was assessed using the modified moving average method from routine 24-hour Holter ECGs recorded during daily activity. The maximal time-domain TWA voltage at heart rates <120 bpm in either lead V5 or V1 was determined. The correlation of the maximal time-domain TWA voltage and LGE findings were analyzed and the differences in the time-domain TWA, total LGE, and cardiac function assessed by CMR in the presence or absence of VT were also studied.
[Results]: The total LGE score was significantly and positively correlated with the maximal time-domain TWA voltage (r=0.54, p<0.001). Furthermore, the total LGE and maximal time-domain TWA voltage were significantly greater in the patients who had episodes of ventricular tachycardia (VT) (n=24) than in those without (21.3±8.3 vs. 11.3±7.5 (p<0.001), 83.5±26.1μV vs. 63.9±12.6μV (p<0.01), respectively). However, the left ventricular ejection fraction did not statistically differ between the patients with VT and those without (60.2±15.4% vs. 66.6±4.2%, p=0.07).
[Conclusion]: The distribution of the LGE was significantly correlated with the time-domain TWA, indicating that the transmural distribution of the LGE represented myocardial repolarization abnormalities, and might represent fibrotic areas which lead to VT foci in HCM.
- © 2011 by American Heart Association, Inc.