CMR imaging improves diagnosis in arrhythmia patients
MedWire News: Cardiovascular magnetic resonance (CMR)-based imaging improves the diagnosis of patients who present with resuscitated sudden cardiac death (SCD) or sustained monomorphic ventricular tachycardia (SMVT), researchers say.
"Our results support that CMR imaging, inclusive of tissue characterization, has diagnostic utility for the detection of myocardial substrate in patients with malignant ventricular arrhythmia, particularly unsuspected acute injury, incremental to that provided by routinely ordered non-CMR imaging," report James White (Robarts Research Institute, London, Ontario, Canada) and co-authors in Circulation: Cardiovascular Imaging.
They evaluated the diagnostic yield of CMR-based imaging versus non-CMR-based imaging among 82 patients with resuscitated SCD (n=31) or SMVT (n=51). All patients underwent routine non-CMR based imaging, followed by a CMR protocol with comprehensive tissue characterization.
The researchers blindly adjudicated clinical reports of non-CMR imaging studies and used these to assign each patient to one of seven diagnostic categories: no known cause (normal), coronary artery disease (CAD) with no left ventricular (LV) dysfunction, CAD with LV dysfunction, unexplained LV dysfunction, hypertrophic cardiomyopathy, inflammatory cardiomyopathy, and other.
CMR imaging was also blindly interpreted using a standardized algorithm to assign a patient diagnosis category in a similar fashion.
Relevant myocardial disease was identified in just 51% of patients using non-CMR imaging compared with 74% using CMR imaging (p=0.002).
Overall, 41 (49%) patients were reassigned to a new or alternate diagnosis using CMR imaging, including 15 (18%) patients with unsuspected acute myocardial injury.
Indeed, 20 (24%) patients categorized as normal by non-CMR imaging had relevant myocardial disease, eight had acute myocarditis, three had acute myocardial infarction, two had prior myocarditis, one had LV noncompaction, and six had arrhythmogenic right ventricular cardiomyopathy.
"The results of this study suggest that CMR has a broad capacity to identify relevant, but clinically unsuspected, disease in patients with SCD or SMVT, such as acute myocarditis and acute ischemic injury," write the authors.
In a related commentary, Katherine Wu (Johns Hopkins Hospital, Baltimore, Maryland, USA) writes: "The unique ability and strength of CMR to characterize myocardial tissue are increasingly evident and deserving of continued investigation."
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By Piriya Mahendra