Key result
CMR infarct mass outperforms LVEF, measuring ~75% larger in patients with inducible MVT.
Why the study?
Cardiac MRI identifies areas of myocardial infarction with high precision, raising the question of whether MRI-based infarct size characterization is a better predictor of inducible VT at EPS than LVEF.
Does infarct size characterization by cardiac MRI better predict inducible ventricular tachycardia at electrophysiologic study than left ventricular ejection fraction in patients with known coronary artery disease?
Observational (n=48)
Blinded outcome assessment
Does infarct size characterization by cardiac MRI better predict inducible ventricular tachycardia at electrophysiologic study than left ventricular ejection fraction in patients with known coronary artery disease?
Infarct surface area and mass measured by gadolinium-enhanced cardiac MRI are superior to LVEF in identifying coronary artery disease patients with a substrate for inducible monomorphic ventricular tachycardia.
Answers are grounded in this paper and cite their sources.
Cardiac MRI infarct metrics may refine monomorphic VT risk stratification beyond LVEF in CAD; leaves open whether they improve outcomes or guide therapy.
Objectives We sought to evaluate whether infarct size characterization by cardiac magnetic resonance imaging (MRI) is a better predictor of inducible ventricular tachycardia (VT) than left ventricular ejection fraction (LVEF). Background Inducibility of VT at electrophysiologic study (EPS) and low LVEF can identify patients with a substrate for VT. Magnetic resonance imaging has been shown to identify, with high precision, areas of myocardial infarction and may therefore be a better tool to evaluate for a substrate for VT. Methods We studied 48 patients with known coronary artery disease who were referred for EPS using cine and gadolinium-enhanced MRI. Wall motion and infarct characteristics were determined blindly and compared among patients with no inducible ventricular arrhythmias (n = 21), those with inducible monomorphic VT (MVT, n = 18), and those with either inducible polymorphic VT or ventricular fibrillation (n = 9). Results Patients with MVT had larger infarcts than patients who did not have inducible arrhythmias (mass: 49 +/- 5 g [SE] vs. 28 +/- 5 g, p < 0.005; surface area: 172 +/- 15 cm(2) vs. 93 +/- 14 cm(2), p < 0.0005). Patients with polymorphic VT/fibrillation had intermediate values (mass: 36 +/- 7 g; surface area: 115 +/- 22 cm(2)). Ejection fraction was inversely related to infarct mass and surface area, with R(2) values ranging from 0.21 to 0.27. Logistic regression and receiver-operating characteristic analysis demonstrated that infarct mass and surface area were better predictors of inducibility of MVT than LVEF. Conclusions Infarct surface area and mass, as measured by cardiac MRI, are better identifiers of patients who have a substrate for MVT than LVEF. Further evaluation of infarct size characterization by cardiac MRI as a predictor of sudden cardiac death is warranted.
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Bello et al. (2005) conducted an observational in Coronary artery disease referred for electrophysiologic study (n=48). Infarct size characterization (mass and surface area) by cardiac MRI vs. Left ventricular ejection fraction (LVEF) / no inducible ventricular arrhythmias was evaluated on Inducibility of monomorphic ventricular tachycardia (MVT) at electrophysiologic study (infarct mass in g) (p=<0.005). Cardiac MRI infarct mass and surface area were significantly larger in inducible MVT vs non-inducible patients (mass 49 vs 28 g, p<0.005; area 172 vs 93 cm2, p<0.0005), outperforming LVEF.
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