BACKGROUND: Myocardial late gadolinium enhancement (LGE) on contrast-enhanced 
magnetic resonance imaging (CE-MRI) of patients with hypertrophic cardiomyopathy 
(HCM) has been suggested to represent intramyocardial fibrosis and, as such, an 
adverse prognostic risk factor. We evaluated the characteristics of LGE on 
CE-MRI and explored whether LGE among patients with HCM was associated with 
genetic testing, severe symptoms, ventricular arrhythmias, or sudden cardiac 
death (SCD).
METHODS AND RESULTS: Four hundred twenty-four patients with HCM (age=55+/-16 
years [range 2 to 90], 41% females), without a history of septal 
ablation/myectomy, underwent CE-MRI (GE 1.5 Tesla). We evaluated the relation 
between LGE and HCM genes status, severity of symptoms, and the degree of 
ventricular ectopy on Holter ECG. Subsequent SCD and appropriate implanted 
cardioverter defibrillator (ICD) therapies were recorded during a mean follow-up 
of 43+/-14 months (range 16 to 94). Two hundred thirty-nine patients (56%) had 
LGE on CE-MRI, ranging from 0.4% to 65% of the left ventricle. Gene-positive 
patients were more likely to have LGE (P<0.001). The frequencies of New York 
Heart Association class >or=3 dyspnea and angina class >or=3 were similar in 
patients with and without LGE (125 of 239 [52%] versus 94 of 185 [51%] and 24 of 
239 [10%] versus 18 of 185 [10%], respectively, P=NS). LGE-positive patients 
were more likely to have episodes of nonsustained ventricular tachycardia (34 of 
126 [27%] versus 8 of 94 [8.5%], P<0.001), had more episodes of nonsustained 
ventricular tachycardia per patient (4.5+/-12 versus 1.1+/-0.3, P=0.04), and had 
higher frequency of ventricular extrasystoles/24 hours (700+/-2080 versus 
103+/-460, P=0.003). During follow-up, SCD occurred in 4 patients, and 
additional 4 patients received appropriate ICD discharges. All 8 patients were 
LGE positive (event rate of 0.94%/y, P=0.01 versus LGE negative). Two additional 
heart failure-related deaths were recorded among LGE-positive patients. 
Univariate associates of SCD or appropriate ICD discharge were positive LGE 
(P=0.002) and presence of nonsustained ventricular tachycardia (P=0.04). The 
association of LGE with events remained significant after controlling for other 
risk factors.
CONCLUSIONS: In patients with HCM, presence of LGE on CE-MRI was common and more 
prevalent among gene-positive patients. LGE was not associated with severe 
symptoms. However, LGE was strongly associated with surrogates of arrhythmia and 
remained a significant associate of subsequent SCD and/or ICD discharge after 
controlling for other variables. If replicated, LGE may be considered an 
important risk factor for sudden death in patients with HCM.