Atrial fibrillation and left atrium: structural remodeling and evolution of arrhythmia pattern

Mar 28, 2019 Cardiotool Novità Fibrillazione Atriale Commenti disabilitati su Atrial fibrillation and left atrium: structural remodeling and evolution of arrhythmia pattern

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Marco Vitolo (a), Alessandra Reggi (a), Elisa Fantecchi (a), Anna Chiara Valenti (a), Vincenzo Livio Malavasi (a), Giuseppe Boriani (a) 
(a) Cardiology Division, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Policlinico di Modena , Modena , Italy.

Background: There is small evidence on the correlation between AF patterns and atrial structural remodeling, especially concerning its evolution throughout time.

Aim: to analyze the time-course of LA enlargement, categorized by LA volume indexed by body surface area (LAVi) according to the classification published in the ASE 2015 Guidelines and AF pattern’s evolution. Secondary endpoints were: 1) evaluation of the relationship between LA enlargement and clinical variables; 2) evaluation of LA enlargement progression and patients outcome. 

Methods: from February 1^st 2016 to June 30^th 2017, consecutive patients (pts) with AF were enrolled into the study. A full baseline transthoracic echocardiographic evaluation (TTE) was a mandatory requirement for the inclusion. TTE was repeated at 1 year ± 1 month after the enrollment. Logistic regression analysis was performed to evaluate variables independently associated to LAVi dilation. Cox regression analysis was performed to calculate the hazard ratios (HR) and 95% confidence interval for a composite endpoint (death, admissions for heart failure or AF, thromboembolism, NYHA class worsening). 

Results: among the 435 pts enrolled in the registry, 201 had baseline and follow-up TTE. Mean age was 73,3±9,1 years. At baseline normal LAVi was found in 70 pts (34.8%), a mildly dilated LAVi in 45 pts (22.4%), a moderately dilated LAVi in 40 (19.9%) and a severely dilated LAVi in 46 (22.9%). AF was paroxysmal in 48 pts (23.9%), persistent in 55 (27.4%), permanent in 57 (28.4%) and first detected in 41 pts (20.4%). At baseline normal or mildly dilated left atrium was more prevalent in paroxysmal or persistent AF than in other AF patterns (p < 0.001). At follow-up a normal or mildly dilated LA was more common in the non permanent forms of AF (p<0.001). Compared to baseline values, at 1 year, 132 pts (66.3%) showed a further LAVi enlargement and 82 (40.8%) switched to a higher category of atrial dilation. Variables independently associated to atrial enlargement class switch were age ≥ 75 years (OR 3.41; p=0.002), presence of sinus rhythm at follow-up (OR 0.26; p=0.002) and malignancy (OR 4.44; p=0.003). Baseline or follow-up patterns of AF failed to reach statistical significance. After 451± 233 days, 39 (19.9%) pts reached the composite endpoint. Independent predictors of worse outcome were first detected AF (HR 2.59; p<0.001), valvular heart disease (1.52; p=0.024) and EHRA score reduction (HR 1.98; p<0.001) while atrial dilation at follow-up and LAVI value failed to reach statistical significance as well as AF pattern at follow-up. 

Conclusion: non-permanent forms of AF had an anatomically less remodeled LA both at baseline and at follow-up. Age ≥ 75 years, presence of sinus rhythm at follow-up and malignancy were independently associated with LA remodeling. First detected AF and valvular heart disease were a strong predictors for worse outcome while LA remodeling was not.

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