Incidence and predictors of silent cerebral embolism during pulmonary vein catheter ablation for atrial fibrillation.

AIMS: Left atrial catheter ablation of the pulmonary veins (PV) has evolved as an important therapeutic option for the treatment of atrial fibrillation (AF). We aimed to investigate the incidence and predictors of silent cerebral embolism associated with PV catheter ablation, detected by diffusion-weighted magnetic resonance imaging (DW-MRI). METHODS AND RESULTS: We performed a prospective analysis of 53 consecutive patients with persistent or paroxysmal AF that underwent PV ablation and post-procedural cerebral MRI 1 day after lasso catheter-guided ostial PV ablation. Patients were analysed for possible demographical, medical, echocardiographical, and procedural predictors of embolic events. A mean of 3.5 +/- 0.5 PVs were ablated per patient. In six patients, DW-MRI depicted new clinically silent microembolism after PV ablation (11%). The number of ineffective medical antiarrhythmic agents prior to ablation procedure was significantly higher in the embolism group (3.3 +/- 0.5 vs. 2.2 +/- 1.4, P = 0.014). Coronary heart disease (CAD) was more frequent in patients with cerebral embolisms (33 vs. 2%, P = 0.031); left ventricular volume (130 +/- 12 vs. 103 +/- 26 mL, P = 0.002), and septal wall thickness (13.0 +/- 1.4 vs. 7.9 +/- 4.8 mm, P = 0.025) were significantly increased. CONCLUSION: This study shows a high incidence of silent micro-embolic events after PV ablation. CAD, left ventricular dilatation, and hypertrophy were potential predictors of this complication.

Cerebral diffusion-weighted magnetic resonance imaging: a tool to monitor the thrombogenicity of left atrial catheter ablation.

INTRODUCTION: Cerebral embolism and stroke are feared complications of left atrial catheter ablation such as pulmonary vein (PV) ablation. In order to assess the thrombogenicity of left atrial catheter ablation, knowledge of both clinically evident as well as silent cerebral embolism is important. The aim of the current study was to examine the use of diffusion-weighted magnetic resonance imaging (DW-MRI) for detection of cerebral embolism, apparent as well as silent, caused by PV catheter ablation. METHODS AND RESULTS: Twenty consecutive patients without structural heart disease undergoing lasso catheter-guided ostial PV ablation using an irrigated-tip ablation catheter were studied. Cerebral MRI including DW single-shot spin echo echoplanar, turbo fluid attenuated inversion recovery, and T2-weighted turbo spin echo sequences were performed the day after the ablation procedure. Ten patients also underwent preprocedure cerebral MRI. All ablation procedures were performed without acute complications. A mean of 3.2 +/- 0.6 PVs were ablated per patient. No patient had neurological symptoms following the procedure. In 2 of 20 patients (10%), DW-MRI revealed new embolic lesions, which were located in the right periventricular white matter in one and in the left temporal lobe in the other patient. There was no statistically significant difference in age, history of hypertension, left atrial volume, and procedure duration between the 2 patients with and the 18 patients without cerebral embolism following AF ablation. CONCLUSION: This is the first study using highly sensitive DW-MRI of the brain to detect asymptomatic cerebral embolism after left atrial catheter ablation. Even small, clinically silent, embolic lesions can be demonstrated with this technique. DW-MRI can be used to monitor and compare the thrombogenicity of different AF ablation approaches.