Left atrial size is the major predictor of cardiac death and overall clinical outcome in patients with dilated cardiomyopathy: A long-term follow-up study

Hypothesis: This study was undertaken to determine whether echo-derived left atrial dimension and other echocardiographic, clinical, and hemodynamic parameters detected at the time of entry into the study may influence prognosis in patients with dilated cardiomyopathy during a long-term follow-up. Methods: This was a prospective cohort analysis of 123 patients with dilated cardiomyopathy. Clinical evaluation, chest x-ray, M-mode and two-dimensional echocardiogram, exercise test, 72-h ambulatory electrocardiogram monitoring, and cardiac catheterization study were performed in all patients. The study was divided into two phases: in the first phase, patients were divided into two groups according to the left atrial size (greater than or equal to 45 mm; < 45 mm), with cardiac death as the end point. In the second phase, all patients were further divided into two groups according to their clinical course. A multivariate analysis was performed to determine independent correlated parameters of cardiac mortality and overall clinical outcome. Results: Cardiac mortality rate was 47.9%: 29% in the group without left atrial dilation and 54.3% in the group with dilated left atrium. Multivariate analysis revealed that left atrium greater than or equal to 245 mm, New York Heart Association functional classes III/IV, and the presence of one or more episodes of ventricular tachycardia at Holter monitoring were independent predictors of cardiac mortality, while left atrium greater than or equal to 45 mm, left Ventricular end-diastolic pressure > 17 mmKg, and exercise tolerance less than or equal to 15 min were independent predictors of poor clinical outcome. Conclusions: Our results revealed that left atrial size is the principal independent predictor of prognosis in patients with dilated cardiomyopathy in that patients with left atrial dilation had an increase in mortality and a worse clinical outcome compared with those without left atrial dilation.