Myocardial Fibrosis Evaluated by Look-Locker and Late Gadolinium Enhancement Magnetic Resonance Imaging in Apical Hypertrophic Cardiomyopathy: Association With Ventricular Tachyarrhythmia and Risk Factors

Purpose: To evaluate the distribution and extent of myocardial fibrosis identified by either contrast-enhanced Look-Locker or late gadolinium enhancement magnetic resonance imaging (LGE MRI) and their relationships between ventricular tachyarrhythmia or risk factors in apical hypertrophic cardiomyopathy (APH). Materials and Methods: Twenty-five APH patients were examined using a 3.0 T or 1.5 T instrument. We used MRI to evaluate myocardial T1 values and scar. We compared the myocardial fibrosis assessed by contrast-enhanced Look-Locker or LGE MRI with ventricular tachyarrhythmia or risk factors for hypertrophic cardiomyopathy. Results: Myocardial scar was present in 17 of the 25 patients with APH. Myocardial scar was distributed predominantly in the apical myocardium (P < 0.01), whereas myocardial T1 values did not differ between the apical, midventricular, and basal septum. The extent of myocardial scar according to 16-segment model and ejection fraction were related to ventricular tachyarrhythmia or risk factors in APH (P < 0.05 for both). The myocardial T1 value was not associated with the tachyarrhythmia or risk factors. Conclusion: In APH, the extent of myocardial scar on LGE MRI is associated with ventricular tachyarrhythmia and risk factors. Quantification of the myocardial T1 value is not necessary for its risk stratification.