Log in to MyACC
Myocardial Fibrosis on CMR Predicts Ventricular Arrhythmias and Sudden Death
Quick Takes
- Myocardial fibrosis on CMR imaging is a powerful predictor of sudden cardiac death and serious arrhythmic events.
- The absence of visually apparent fibrosis on CMR is associated with a 98% negative predictive value.
- Presence of fibrosis on CMR has a low positive predictive value of <10%.
Study Questions:
What are the prognostic implications of fibrosis seen on cardiac magnetic resonance (CMR) imaging for ventricular arrhythmias and sudden cardiac death (SCD) in patients with cardiac implantable electronic devices (CIEDs)?
Methods:
Patients with diagnostic quality CMR prior to CIED implantation from a single UK health trust were retrospectively evaluated. Patients with congenital heart disease, primary valvular disease, channelopathies, hypertrophic cardiomyopathy, arrhythmogenic ventricular cardiomyopathy, and infiltrative heart disease and those with CIED prior to CMR were excluded. Fibrosis was evaluated from late gadolinium enhancement (LGE) images as present or absent on visual assessment as well as quantified as total fibrosis and gray zone fibrosis (corresponding to mixed fibrosis and normal tissue). The primary endpoint was SCD and the secondary endpoint was the composite of SCD, resuscitated cardiac arrest, sustained ventricular tachycardia, ventricular fibrillation, or appropriate implantable cardioverter-defibrillator therapy.
Results:
A total of 700 patients were followed for up to a median 6.9 years (interquartile range, 5.8-9.3 years). Most patients had reduced left ventricular ejection fraction (LVEF; 76.4% had LVEF ≤35%). Overall, 388 patients died (55.4%), including 254 cardiac deaths. Twenty-seven patients experienced the primary endpoint of SCD. Visually apparent myocardial fibrosis was associated with a markedly increased risk of SCD (adjusted hazard ratio, 22.3; 95% confidence interval [CI], 2.85-2877). The secondary composite endpoint occurred in 121 patients, of whom 118 had visually apparent myocardial fibrosis. After adjustment, the hazard ratio for the composite secondary endpoint was 15.8 (95% CI, 5.1-48.7). Quantified total fibrosis and gray zone fibrosis were also related to the outcomes. The positive predictive value of visual and quantified fibrosis for SCD was poor, ranging from 7% to 9% depending on which variation was used. However, negative predictive value was excellent at 97% to 99%. Similarly, for the secondary composite endpoint, fibrosis measures had positive predictive values of only 24% to 34% but had excellent negative predictive value of 89% to 91%.
Conclusions:
LGE CMR is a powerful predictor of SCD and composite ventricular arrhythmias.
Perspective:
This large study adds to the body of literature supporting the prognostic value of LGE fibrosis measures on CMR for adverse arrhythmic events. This study raises questions about the potential value of using CMR to risk stratify patients without LGE and certain other cardiomyopathies who may have substantially less benefit from CIEDs. However, it is important to recognize the positive predictive value of these measures remains poor. Nonetheless, if CIEDs were only implanted in the 118 patients with visually apparent LGE instead of all 700 patients, the use of CIEDs could potentially be reduced by 83%, while still capturing 98.6% of all composite secondary arrhythmic events. The use of LGE CMR as a rule out test for patients unlikely to benefit from CIED implantation could potentially reduce low value invasive procedures and reduce health care costs, but needs further validation in multicenter prospective studies.
Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Magnetic Resonance Imaging
Keywords: Arrhythmias, Cardiac, Contrast Media, Death, Sudden, Cardiac, Defibrillators, Implantable, Diagnostic Imaging, Fibrosis, Gadolinium, Heart Arrest, Heart Failure, Magnetic Resonance Imaging, Myocardial Ischemia, Primary Prevention, Stroke Volume, Tachycardia, Ventricular, Ventricular Fibrillation, Ventricular Function, Left
< Back to Listings
