Myocardial Repolarization Dispersion and Late Gadolinium Enhancement in Patients With Hypertrophic Cardiomyopathy

Abstract

Background: Growing evidence suggests that late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) is an additive marker of disease severity, and possibly of arrhythmic risk, in hypertrophic cardiomyopathy (HCM). We investigated the possible relationship between LGE and markers of myocardial repolarization dispersion in HCM. Methods and Results:Eighty-five HCM outpatients underwent CMR and short-period electrocardiogram analysis to calculate the temporal myocardial repolarization dispersion through the QT variance normalized for QT mean (QTVN) and the QT variability index (QTVI). The QT dispersion in the spatial domain was also obtained. Patients with LGE (62%) had higher left atrial volume, maximum wall thickness, and left ventricular mass (P<0.0001), as well as a greater prevalence of non-sustained ventricular tachycardia (P<0.0001) and hypotensive blood pressure response (P=0.044). Both QTVN and QTVI were higher in the group with LGE (P<0.0001). At multivariate analysis, using QTVI as the dependent variable, %LGE (P<0.0001), age (P<0.0001), left ventricular outflow obstruction (P=0.038), and sudden cardiac death risk factor burden (P=0.020) reached statistical significance. Otherwise, only %LGE (P=0.005) and left ventricular mass index (P=0.015) remained associated with QTVN. Conclusions:Temporal myocardial repolarization dispersion correlates with LGE extent. Whether these variables could be useful in HCM clinical management warrants confirmation by larger prospective studies. (Circ J 2014; 78: 1216 -1223

The value of cardiac magnetic resonance and distribution of late gadolinium enhancement for risk stratification of sudden cardiac death in patients with hypertrophic cardiomyopathy

“…We also showed that larger LGE correlated with higher NT-proBNP. As in previous studies, the presence of LGE was associated with increased frequency of nonsustained ventricular tachycardia on ambulatory Holter ECG [24,31,32]. Our results may additionally indicate that nsVT is more frequently seen in patients with LGE located beyond the RV insertion points.…”

Overview of Myocardial T1 Mapping Applications

“…In addition, MRI has the potential to determine the presence and extent of replacement fibrosis using conventional post-contrast LGE techniques [54][55][56]. The evaluation of fibrotic replacement in HCM is of high importance since the extent of fibrosis correlates with several clinical parameters related to patient prognosis such as risk of sudden death, conduction abnormalities, cardiac arrhythmias, and LV remodeling [57][58][59][60]. While the assessment of subtle and/or diffuse myocardial fibrosis is limited by conventional LGE techniques, T1 mapping has the potential to overcome these shortcomings [10,61].…”

Spatial QT Dispersion Predicts Nonsustained Ventricular Tachycardia and Correlates with Confined Systodiastolic Dysfunction in Hypertrophic Cardiomyopathy

“…The Q-T end (QT e ) spatial dispersion on 12-lead surface electrocardiogram (ECG) is considered an easy and noninvasive index of dispersion of myocardial repolarization, the latter closely linked to the HCM arrhythmic risk [7,8,9,10,11,12,13,14,15]. However, a number of clinical variables, such as distribution and magnitude of ventricular hypertrophy and fibrosis, as well as LV dysfunction, might potentially alter this ECG-derived parameter, thus limiting its use in routine clinical practice [7,8,9,10,11].…”

“…However, a number of clinical variables, such as distribution and magnitude of ventricular hypertrophy and fibrosis, as well as LV dysfunction, might potentially alter this ECG-derived parameter, thus limiting its use in routine clinical practice [7,8,9,10,11]. Recently, it has been suggested that the T peak -T end interval (T p T e ) may be a surrogate for transmural dispersion of repolarization and T p T e may be a more sensitive index of the dispersion of ventricular repolarization than the whole QT e or the Q-T peak interval (QT p ), given it closely reflects the termination of repolarization in the 3 myocardial cell layers [16,17,18].…”