Clinical InvestigationCongestive Heart FailureDiastolic dysfunction and left atrial enlargement as contributing factors to functional mitral regurgitation in dilated cardiomyopathy: Data from the Acorn trial
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Population
Echocardiography Core Laboratory at Mayo Clinic, Rochester, MN, performed comprehensive echocardiographic measurements of all patients enrolled in the Acorn trial at 18 different clinical sites. From the baseline echocardiographic data, we identified eligible patients for this study using the following inclusion criteria: (1) no organic mitral valve disease, (2) no history of ischemic heart disease or myocardial infarction causing ischemic functional MR, and (3) presence of sinus rhythm. Of 300
Baseline clinical characteristics
A total of 144 patients (mean ± SD age 53 ± 13 years, 77 men [53%]) were eligible for this study (Table I). Mean ± SD LV ejection fraction was 26.6% ± 8.2%, and LV end-diastolic volume index was 134 ± 45 mL/m2. The mean ± SD duration of heart failure was 5.2 ± 4.2 years. The etiology of DCM was idiopathic in 96 (66.7%), viral in 15 (10.4%), alcoholic in 4 (2.8%), hypertensive in 12 (8.3%), and miscellaneous in 17 (11.8%).
Eighty-seven patients (60.4%) had MR of ≥grade 2 as group 1, and 57
Discussion
Occurrence of functional MR in patients with LV systolic dysfunction is associated with poor prognosis. Hemodynamically significant MR may cause worsening of symptoms and prognosis. Indeed, in previous studies, MR was associated with increased cardiovascular mortality in unselected patients with systolic dysfunction.1, 2
Patients with DCM who have similar LV size and volume frequently have varying degrees of MR, whereas a correlation between LV size and severity of MR is expected if functional
Conclusions
In the Acorn trial of patients with advanced DCM, 60% had MR of grade 2 or greater. The 2 groups of patients categorized by the severity of MR (grade 0 and +1 or grade ≥2) had significant differences in LA volume index and mitral annular size but not in LV volume index. Mitral annular size and LA volume index were closely related even in patients without significant MR. These findings suggest that increased LA volume index caused by more advanced diastolic dysfunction may be a one of the major
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