Atrial contractile function and fibrosis in patients with paroxysmal atrial fibrillation in sinus rhythm

OBJECTIVES: The aim of the study was to investigate atrial contractile function in patients with paroxysmal atrial fibrillation (AF) in sinus rhythm using transthoracic echocardiography (EchoCG). METHODS AND RESULTS: Thirty-five patients with paroxysmal AF and arterial hypertension (mean age 62 ± 10 years, 43% male) in sinus rhythm were enrolled in the study. The control group was composed of comparable patients with arterial hypertension without heart rhythm disturbances. EchoCG was performed during sinus rhythm according to an extended protocol, which included the ejection fraction (EF) of the left atrium (LA) and tissue Doppler measurements. Myocardial fibrosis was assessed quantitatively by videodensitometry in intraventricular and intraatrial (IAS) septa using an original image post-processing algorithm. We found a significant decrease in the left atrial contraction function during sinus rhythm in patients with AF when compared to controls. LA EF (34 ± 14 vs. 54 ± 17, p = 0.03) and A’ velocity (0.17 ± 0.04 vs. 0.22 ± 0.04, p = 0.008) decreased while A/A’ ratio (2.7 ± 0.2 vs. 1.9 ± 0.1, p = 0.006) increased. Peak A velocity was not affected. Videodensitometric analysis revealed a 2.3-fold increase in IAS fibrosis fraction in AF patients compared with controls (p = 0.01). CONCLUSION: Patients with AF in sinus rhythm have markedly depressed atrial contractile function. Videodensitometry of IAS has the potential to be used as inexpensive method of atrial fibrosis assessment in patients with AF.