ФИБРОЗ МИОКАРДА ЛЕВОГО ПРЕДСЕРДИЯ ПО ДАННЫМ МАГНИТНО-РЕЗОНАНСНОЙ ТОМОГРАФИИ С ОТСРОЧЕННЫМ КОНТРАСТИРОВАНИЕМ У БОЛЬНЫХ ФИБРИЛЛЯЦИЕЙ ПРЕДСЕРДИЙ

Rationale: Atrial fibrillation (AF) is the most common type of arrhythmia. Left atrial abnormalities in AF require further investigation. Aim: To evaluate characteristics of myocardial structure of the left atrium by magnetic resonance imaging (MRI) with delayed contrast enhancement in patients with AF associated with essential hypertension (EH), in those without any cardiovascular disorders, and in patients with AF after cryoablation of the pulmonary artery orifice. Materials and methods: The study enrolled 53 patients with AF (mean age 56 years). Twenty eight of them had AF without any associated cardiovascular disorders (lone AF, or LAF group), 25 patients had AF related to EH (AF + EH group). Three patients had undergone anti-arrhythmic intervention. Cardiac MRI was performed in all patients with high resolution late gadolinium enhancement (LGE) at 15–20 min after i.v. gadoversetamide (0.15 mmol/kg). For LGE MRI, we used a novel high resolution inversion recovery (inversion times 290–340 ms) magnetic resonance pulse sequence with isotropic voxel (size 1.25 . 1.25 .2.5 mm) and fat saturation. Left atrium walls were segmented semi-automatically on the LGE images. Left atrium fibrosis quantification was performed with the original software LGE Heart Analyzer, developed in Russian Cardiology Research and Production Complex (Moscow). Results: Left atrium fibrosis (mean, 9 [1.7; 18] %) was found both in patients with AF + EH and with lone AF. There was a trend towards more significant left atrial fibrosis in the group of AF + EH, compared to that in the lone AF group (10.972 [6.98; 19.366] % vs 4.37 [0.893; 18.575] %, respectively, p = 0.1). The extent of left atrium fibrosis correlated with left atrium dilatation (r = 0.37, p < 0.001) and with the decreased ejection fraction (r = -0.4, р < 0.001). The patients who had undergone an antiarrhythmic intervention, demonstrated formation of intensive LGE zones in the ablation areas. Conclusion: Quantification of atrial myocardial fibrosis by high resolution LGE MRI in AF patients is feasible with the use of the original software LGE Heart Analyzer.