Published Online
on October 22, 2009

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Original Article

Characteristics and Clinical Significance of Late Gadolinium Enhancement by Contrast-Enhanced Magnetic Resonance Imaging in Patients with Hypertrophic Cardiomyopathy

Ronen Rubinshtein¹; James F. Glockner¹; Steve R. Ommen¹; Philip A. Araoz¹; Michael J. Ackerman¹; Paul Sorajja¹; J. Martijn Bos¹; A. Jamil Tajik²; Uma S. Valeti¹; Rick A. Nishimura¹ and Bernard J. Gersh^1,3

¹ Mayo Clinic, Rochester, MN;
² Mayo Clinic, Scottsdale, AZ

^* Corresponding author; email: gersh.bernard{at}mayo.edu

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 intra-myocardial 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—424 HCM patients [age = 55 ± 16 years (range 2–90), 41% females], without prior history of septal ablation/myectomy, underwent CE-MRI (GE 1.5T). 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 defibrillator (ICD) therapies were recorded during a mean follow-up of 43 ± 14 months (range 16–94). 239 patients (56%) had LGE on CE-MRI, ranging from 0.4–65% of the left ventricle. Gene-positive patients were more likely to have LGE (p<0.001). The frequencies of NYHA class 3 dyspnea and angina class 3 were similar in patients with and without LGE [125/239 (52%) vs 94/185 (51%) and 24/239 (10%) vs 18/185 (10%), respectively, p=NS]. LGE-positive patients were more likely to have episodes of non-sustained ventricular tachycardia (NSVT) [34/126 (27%) vs 8/94 (8.5%), p <0.001], had more episodes of NSVT per patient (4.5 ± 12 vs 1.1 ± 0.3, p=0.04), and higher frequency of ventricular extrasystoles/24 hours (700 ± 2080 vs 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%/year, p=0.01 vs 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 NSVT (p=0.04). The association of LGE with events remained significant after controlling for other risk factors.

Conclusion—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.

Key Words: death, sudden (if surviving, use heart arrest) • magnetic resonance imaging • Hypertrophic cardiomyopathy • Late gadolinium enhancement • Risk assessment