Clinical Research
Heart Rhythm Disorder
Myocardial Fibrosis Predicts Appropriate Device Therapy in Patients With Implantable Cardioverter-Defibrillators for Primary Prevention of Sudden Cardiac Death

https://doi.org/10.1016/j.jacc.2010.06.062Get rights and content
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Objectives

The purpose of this study was to evaluate the association between regional myocardial fibrosis and ventricular arrhythmias in patients with cardiomyopathy.

Background

Patients with heart failure are at risk of sudden cardiac death (SCD). Current guidelines recommend implantable cardioverter-defibrillator (ICD) devices for a subgroup based on impaired left ventricular function. A significant proportion of devices never discharge, hence a more accurate method for targeting those at risk is desirable.

Methods

We prospectively enrolled 103 patients meeting criteria for ICD implantation for primary prevention of SCD. Cardiac magnetic resonance imaging was performed before device implantation. Regional fibrosis was identified with late gadolinium enhancement (LGE).

Results

Median follow-up was 573 days (interquartile range: 379 to 863 days). The LGE identified regional fibrosis in 31 of 61 (51%) patients with nonischemic cardiomyopathy (NICM) and in all 42 patients with ischemic cardiomyopathy (ICM). There was a 29% (9 of 31) discharge rate in the NICM group with LGE compared with a 14% (6 of 42) discharge rate in the ICM group (p = NS). There were no ICD discharges in the NICM group without LGE, which was significantly lower than the rate observed in both the ICM patients (p = 0.04) and the NICM patients with LGE (p < 0.01). Left ventricular ejection fraction was similar in patients with and without device therapy (24 ± 12% vs. 26 ± 8%, p = NS) and those with or without LGE (25 ± 9% vs. 26 ± 9%, p = NS).

Conclusions

Patients with advanced cardiomyopathy and myocardial fibrosis demonstrated by LGE on cardiac magnetic resonance imaging have a high likelihood of appropriate ICD therapy. Correspondingly, absence of LGE may indicate a lower risk for malignant ventricular arrhythmias.

Key Words

arrhythmia
cardiomyopathy
heart arrest
magnetic resonance imaging

Abbreviations and Acronyms

CMRI
cardiac magnetic resonance imaging
ICD
implantable cardioverter-defibrillator
ICM
ischemic cardiomyopathy
IQR
interquartile range
LGE
late gadolinium enhancement
LV
left ventricular
LVEF
left ventricular ejection fraction
NICM
nonischemic cardiomyopathy
NYHA
New York Heart Association
SCD
sudden cardiac death

Cited by (0)

Dr. Iles is supported by a National Health and Medical Research Council Post Graduate Research Scholarship, Melbourne, Australia. Dr. Pfluger is supported by a research grant from Swiss National Science Foundation SNSF, Bern, Switzerland. Dr. Butler is supported by an Australian Post-Graduate Award, Monash University, Melbourne, Australia. Dr. Kistler is the recipient of a research investigatorship from the Cardiac Society of Australasia. Dr. Taylor is supported by a National Health and Medical Research Council program grant, and an Australian National Heart Foundation project grant. All other authors have reported that they have no relationships to disclose.