Association of Left Atrial Fibrosis Extent With Left Ventricular Structural and Functional Remodelling in Patients With Atrial Fibrillation

Abstract

Aim.To investigate the relationships between left atrial (LA) fibrosis extent and left ventricular (LV) structural and functional status in patients (pts) with nonvalvular atrial fibrillation (AF).Material and Methods.The study enrolled 56 pts (mean age 57.1±8.4 years, 25 females), admitted to hospital for primary catheter ablation (CA), including 47 pts with paroxysmal AF and 9 pts with persistent AF. All pts had scheduled transthoracic echocardiography to measure size and volume of cardiac chambers and systolic and diastolic functions of the left ventricle. Based on the calculation of the LV mass index (LVMI) and relative wall thickness (RWT), we categorized all pts into 4 groups: (1) normal geometry (n=27); (2) concentric remodeling (normal LVMI and high RWT, n=13); (3) concentric hypertrophy (high LVMI and high RWT, n=6); and (4) eccentric remodeling (high LVMI and normal RWT, n=10). The assessment of LA fibrosis sizes was based on the allocation of low voltage zones (<0.5 mV) in the process of voltage electroanatomic mapping (VEM) as the first stage of CA. Following indicators were calculated: total square of fibrosis (Sf), % of fibrosis from the total LA square (Sf%), the degree of LA fibrosis (an analog of the UTAH score), and number of LA fibrosis zones. Level of NT-proBNP in blood was determined among other laboratory tests. All pts had preserved LV ejection fraction (LVEF).Results.Results of the study confirmed positive relationships between Sf, Sf% and LA diameter, LVMI, and NT-proBNP level. Negative relationship was noted between Sf, Sf%, the UTAH degree and LVEF. Such LV geometry type as eccentric hypertrophy was associated with a higher number of LA fibrosis zones compared to the normal LV geometry, while significant differences in other types of geometry were not found.Conclusion. Thus, LA fibrosis extent was associated with LA size, LV function, and LV geometric remodeling pattern.