Introduction: Besides the traditional concept of AF perpetuating atrial remodeling (“AF begets AF”), there is increasing evidence that structural alterations precede AF as an atrial myopathy. There is need for better characterization of this myopathy in terms of a fibrotic substrate and its influencing factors.
Objective: This study aimed to assess atrial remodeling by late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) and its influencing clinical risk factors in non-AF individuals. Second, we aimed to establish a scoring system for predicting presence of AF using left atrial LGE, in addition to clinical parameters, to generate a hypothesis for future prospective studies.
Methods: N=91 non-AF individuals without a history of structural heart disease were recruited from the colonoscopy clinic, n=91 age- and sex-matched AF individuals served as controls. All patients underwent LGE-MRI on either a 1.5 or 3 Tesla scanner. Late enhancement ≥20% was considered extensive atrial remodeling.
Results: The mean left atrial LGE in non-AF and AF individuals was 8.8±6.5% and 12.5±5.8%, respectively. A body-mass index >30kg/m2 was identified as predictor of LGE, while diastolic dysfunction failed to demonstrate a significant association. A scoring system for the prevalence of AF (two points for arterial hypertension and LVEF ≤55%, respectively; 5 points for LGE >6%) was derived. Comparing to patients with a low risk for AF, patients in the intermediate and high risk group showed a significantly increased risk for AF (OR 3.5).
Conclusions: This study reports an unexpectedly high percentage of atrial LGE in a non-AF cohort, highlighting the hypothesis that structural alterations precede AF onset in a significant proportion of individuals. BMI was identified as significant predictor of remodeling, providing a basis for studies investigating the influence of lifestyle modification and drug interventions, i.e. weight reduction, on structural remodeling. The newly derived risk score for AF prevalence provides the basis for further prospective studies on AF incidence in individuals before AF onset.