Silent Cerebral Lesions in Patients with Non-Valvular Atrial Fibrillation and Structurally Normal Hearts

Purpose: To investigate the presence of asymptomatic cerebral lesions in patients with non-valvular atrial fibrillation (AF) and structurally normal hearts. Methods: Magnetic resonance brain imaging (MRI) was performed in consecutive patients initially diagnosed with first-diagnosed "lone" AF (age <60 at diagnosis and no cardiopulmonary disease). Patients with prior AF ablation were excluded. Results: Of 33 patients aged 54.4±14.4y, 26 (78.8%) were males and 15 (45.5%) had paroxysmal AF. Mean left atrial size and LVEF were 43.5±7.2 mm and 61.9±5.8%, respectively, creatinine clearance (CrCl) 110.9±27.5 mL/min, blood glucose 5.4±0.6 mmol/L, cholesterol 5.5±0.9 mmol/L, hemoglobin 149.3±16.7 g/L, C-reactive protein 3.1±3.3 mg/L, fibrinogen 3.3±0.5 g/L and D-dimer 0.42±0.63 pg/ml. Mean 13.7±8.2 years following first AF, 15 patients (45.5%) remained "lone" AF, 5 (15.1%) aged >60, 12 (36.4%) developed hypertension (plus coronary disease, 1 patient) and 1 (3.0%) developed pulmonary disease. There were no differences in systolic and diastolic blood pressure between hypertensive and "lone" AF patients (121.9±13.9 vs. 113.7±9.5, p=0.066 and 74.7±9.3 vs. 74.0±6.0 mmHg, p=0.798, respectively). Prior to MRI, 17 patients (51.5%) were taking oral anticoagulation for mean 1.6±2.9 years (12 patients developed stroke risk factors [4 suffered symptomatic ischemic stroke] and 5 awaited cardioversion). MRI revealed silent microischemia in 17 patients (51.5%), microangiopathy in 4 (12.1%) and no microbleeds. Univariate logistic regression revealed a significant relation of silent microischemia with age (OR 1.12; 95% CI,1.03-1.22; p=0.006), CrCl (OR 0.94; 95% CI,0.89-0.98; p=0.018), LA diameter (OR 1.19; 95% CI,1.01-1.42; p=0.039), LVEF (OR 0.83; 95% CI,0.71-0.98; p=0.030) and non-paroxysmal AF (OR 2.63; 95% CI,1.04-6.64; p=0.041), whilst the presence of hypertension was of borderline significance (OR 4.88; 95% CI,1.01-23.6; p=0.049); microischemic lesions were detected in 5/15 patients (33.3%) with "lone" AF and 12/18 (66.7%) with hypertension, p=0.059. On the multivariable analysis, only age was significantly related to microischemic lesions (OR 1.16; 95% CI,1.03-1.29; p=0.015). Conclusions: Cerebral MRI detected asymptomatic microischemic lesions in 50% of AF patients with "lone" AF or well-controlled hypertension and structurally normal hearts. Although silent microischemia was less frequent in patients who remained "lone" AF over time, ageing was the only multivariable risk factor for cerebral microischemia in all patients with structurally normal hearts. Neither microischemia nor microbleeding were related to the oral anticoagulant therapy.