Late Gadolinium Enhancement on Cardiac Magnetic Resonance and Phenotypic Expression in Hypertrophic Cardiomyopathy
Is there an association between late gadolinium enhancement findings on cardiac magnetic resonance (CMR) imaging and known clinical/morphological risk factors for sudden death among patients with hypertrophic cardiomyopathy (HCM)?
From January 2005 to August 2009, 124 patients with HCM (53 ± 17 years, 86 men) were prospectively evaluated with CMR, with assessment of left ventricular (LV) hypertrophy, LV function, and late gadolinium enhancement.
In univariate analysis, patients were divided into tertiles according to the number of segments positive for late gadolinium enhancement (first tertile 0.3 ± 0.4 segments, second tertile 2.2 ± 0.4 segments, third tertile 5.2 ± 1.9 segments). The number of segments with late gadolinium enhancement was associated with male gender (p = 0.05), left atrial dilation (p = 0.04), “telesystolic volume” (p = 0.04), LV mass (p = 0.02), maximum LV wall thickness (p = 0.002), ejection fraction <50% (p = 0.02), nonsustained ventricular tachycardia (p = 0.001), and perfusion defects (p ≤ 0.001). In multivariable analysis, male gender (p = 0.007), maximum LV wall thickness (p = 0.006), LV mass (p = 0.03), and perfusion abnormalities (p = 0.02) were independent predictors of the extent of late gadolinium enhancement.
There was an independent association between late gadolinium enhancement extent and maximum LV wall thickness, LV mass, and perfusion defects in patients with HCM. It was not determined whether the presence and extent of late gadolinium enhancement is associated with subsequent clinical events.
Late gadolinium enhancement on CMR has been shown to correlate with the presence of myocardial fibrosis. This study used nonoutcome endpoints to associate late gadolinium enhancement in patients with HCM with other markers of adverse prognosis, including LV wall thickness/mass and perfusion abnormalities (presumably also reflecting the presence of myocardial fibrosis). As the authors suggest, the presence or absence of an association between CMR abnormalities and clinical outcomes will be of greater importance. (‘Telesystolic volume’ was undefined in the manuscript; a quick Google search was unrevealing, but this might be used as another name for end-systolic volume.)
Keywords: Hypertrophy, Left Ventricular, Gadolinium DTPA, Ventricular Function, Left, Cardiomyopathy, Hypertrophic, Gadolinium, Risk Factors, Magnetic Resonance Imaging, Cardiomegaly, Prognosis, Tachycardia, Ventricular, Phenotype, Magnetic Resonance Spectroscopy, Death, Sudden, Cardiac
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