The relationship between the quantitative extent of late gadolinium enhancement and burden of nonsustained ventricular tachycardia in hypertrophic cardiomyopathy: A delayed contrast-enhanced magnetic resonance study.

OBJECTIVES

To examine the relationship between late gadolinium enhancement (LGE) extent and nonsustained ventricular tachycardia (NSVT) characteristics in patients with hypertrophic cardiomyopathy (HCM).

BACKGROUND

NSVT has been shown to be independently associated with sudden cardiac death (SCD) in HCM. Previous studies have found LGE on cardiac magnetic resonance (CMR) to be independently associated with NSVT.

METHODS

Seventy-three patients who had 14-day Holter monitoring for either risk stratification for SCD (n = 62) or evaluation of atrial fibrillation (n = 11) on a CMR study were included. Areas of LGE in left ventricle (LV) were visually identified and analyzed quantitatively for both high (≥6 SD above the mean signal intensity of normal myocardium) and intermediate (≥4 but <6 SD) LGE signal intensity.

RESULTS

Patients with more extensive LGE had longer (P = 0.0028) and more frequent (P = 0.02) episodes of NSVT. In univariate analyses, frequency of NSVT was associated with LGE extent (r  = 0.43, P = 0.001), LV ejection fraction (r  = -0.38, P < 0.001), LV mass (r  = 0.32, P = 0.005), LV maximal wall thickness (r  = 0.28, P = 0.016), and left atrium diameter (r  = 0.29, P = 0.001); maximal length of NSVT was associated with LGE extent (r  = 0.52, P < 0.001), LV ejection fraction (r  = -0.44, P < 0.001), LV mass (r  = 0.37, P = 0.001), and left atrium diameter (r  = 0.3, P < 0.001). In multivariable analyses, LGE extent remained the sole variable independently associated with frequency (P = 0.001) and maximal length of episodes of NSVT (P = 0.001). No significant association was found between the rate of NSVT and LGE extent.

CONCLUSIONS

LGE extent is independently associated with a greater burden and longer episodes of NSVT in HCM. These findings support the association between myocardial fibrosis as represented by LGE and ventricular tachyarrhythmias in HCM.