Report from SCMR: CE MRI rules out risk of sudden death from ventricular tachyarrhythmia
Contrast-enhanced MR myocardial perfusion imaging is known to be a powerful test for detecting infarction and predicting the potential success of revascularization after an ischemic event. Researchers are finding it may also help predict the risk of sudden death for patients with ventricular tachyarrhythmia.
The underlying mechanism that causes sustained monomorphic tachyarrhythmia shaped the design of the MRI protocol for this application, according to Dr. Igor Klem, a medical research associate at the Duke University Medical Center.
Extraventricular stimuli, such as myocardial scarring, induce ventricular arrhythmias, Klem said. He found that patients with myocardial scarring have a much higher risk of potentially fatal malignant ventricular tachyarrhythmias than patients without scarring. Klem spoke earlier this month at the Society for Cardiovascular Magnetic Resonance annual meeting in Barcelona.
Among 58 patients, CE MRI and cine MRI found scarring in all 18 high-risk patients who had sustained monomorphic ventricular tachyarrhythmia (MVT) induced with electrophysiological stimuli.
The percentage of patients with scarring decreased significantly as the risk of sudden death associated with subclassifications of the disease fell, Klem said. Six of 10 (60%) patients with polymorphic VT or ventricular fibrillation exhibited myocardial scarring. Fifteen of 27 (44%) with noninducible VT showed scarring, and none of three patients with idiopathic VT for fascicular/bundle-branch reentry VT or right ventricular outflow tract VT revealed evidence of myocardial scarring.
Myocardial scarring appears to stratify risk better than ejection fraction, the preferred test, according to Klem. As expected, small ejection fractions were measured in patients with high-risk MVT, but no significant differences were seen in the other groups.
The results suggest that CE MRI myocardial perfusion imaging can be used to screen patients at risk for malignant ventricular tachyarrhythmias. But it should be used with electrophysiological stimuli to gain additional measures of risks linked to polymorphic and idiopathic disease as well, he said.
For more information from the Diagnostic Imaging archives:
