Evidence of an increased incidence of myocardial inflammation associated with reduced ventricular function in clinically suspected idiopathic dilated cardiomyopathy - a cardiovascular magnetic resonance study
© Cocker et al; licensee BioMed Central Ltd. 2011
Published: 2 February 2011
Dilated cardiomyopathy (DCM) occurring due to an unknown etiology or genetic predisposition is termed as idiopathic dilated cardiomyopathy (iDCM), although iDCM may also result from viral exposure. However, the incidence of myocardial inflammation and its relation to left ventricular (LV) function in iDCM remains unknown.
Cardiovascular magnetic resonance (CMR) imaging allows for the visualization of myocardial inflammation using early Gadolinium enhancement (EGE). We applied EGE imaging in the setting of clinically suspected iDCM to determine both the incidence and relation of myocardial inflammation to LV function.
26 patients (17 males, age 44±14 years old) were referred to us for the assessment of iDCM following a clinical suspicion of iDCM, based upon the following criteria: ejection fraction below 45%; invasive exclusion of significant coronary artery disease using a cutoff of 50% stenosis; stable clinical course for at least 3-months prior to the CMR study; exclusion of myocarditis within the past 12 months; as well as exclusion of comorbidities which may otherwise account for patient presentation including valvular heart disease.
Standard CMR imaging procedures for the assessment of LV function and EGE were utilized. EGE images were acquired before and early after (over 4 minutes) Gd-DTPA 0.1ml/kgBW contrast injection using T1-weighted images.
LV function was assessed by manually tracing endo- and epicardial contours. Myocardial signal intensity was normalized to skeletal muscle, generating a ratio that had to be greater than or equal to 4 to be considered positive for EGE.
Using CMR-based EGE as a surrogate marker of myocardial inflammation, we provide first evidence for a high incidence of inflammation in patients with clinically suspected iDCM. The extent of myocardial enhancement was directly related to reduced ventricular function. CMR-based assessment of myocardial inflammation may be utilized as a biomarker for patient prognosis and guide medical therapy to target those patients in whom there is active myocardial inflammation.
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