Atrial fibrillation and left ventricular dysfunction: cause or consequence (analysis of the dilated cardiomyopathy registry)

Objective. To evaluate the correlation of different forms of atrial fibrillation (AF) with severity of myocardial dysfunction in patients with dilated cardiomyopathy (DCM). Material and methods. The study included 435 patients with DCM syndrome (140 female and 295 male, mean age 49.2±13.0 years), left ventricular ejection fraction (LVEF)<55% and LV end-diastolic dimension >5.5 cm. Exclusion criteria were various forms of CAD, heart defects, thyrotoxic, hypertensive heart, hypertrophic cardiomyopathy, etc. Laboratory and instrumental examination included evaluation of anti-heart antibodies (87% of patients), coronary angiography (48%), cardiac MRI (49%), myocardial biopsy (41%). The follow-up period was 15 [5; 45] months. Results. Various forms of AF were diagnosed in 61% of patients with DCM syndrome. There were no significant differences between patients with and without AF regarding LV dilatation, EF (32.6±10.6 vs 32.9±11.8%) and other indices of systolic function. Successful electrical cardioversion was performed in 44 patients with persistent AF. In this subgroup, we observed the greatest increment of EF (up to 50% by the end of the follow-up) and predominance of myocarditis (with immunosuppressive therapy) among causes of DCM syndrome (75% definite and 7% probable) compared to patients without persistent AF and patients with persistent AF/unsuccessful cardioversion. When analyzing the incidence of endpoint ‘death+transplantation’, we found significant differences between patients with successful cardioversion (11.4%) and persistent AF (27.9%, p=0.041). In multivariate analysis, the underlying disease and baseline EF, but not AF status had significant effect on outcomes. Conclusion. In patients with DCM syndrome, AF is not associated with more severe structural and functional left ventricular changes. Simultaneous atrial fibrillation and LV dysfunction with reduced EF require verification of disease that causes both arrhythmia and systolic dysfunction. In case of myocarditis, cardioversion is quite effective and can be performed before the effect of baseline therapy is achieved to promote recovery of structural and functional parameters of the heart.