P564Silent cerebral ischemic lesions after left-sided ablation for paroxysmal supraventricular tachycardia
Authors: Schvartz N , Pribojszki M , Sellei A , Gion K , Kincses T , Riesz T , Kupo P , Miklos M , Benak A , Kohari M , Makai A , Bencsik G , Pap R , Saghy L 
Published: June 2020

Pulmonary vein isolation is associated with silent cerebral ischemic lesions detected by diffusion-weighted magnetic resonance imaging (MRI), with an incidence between 1% and 40%. Recent studies have shown that these cerebral lesions can occur after radiofrequency ablation for left ventricular extrasystole.  Risk of these lesions in conventional ablation has not been evaluated.

Aim of this study was to investigate silent cerebral ischemic lesions following left-sided conventional ablation.

In a prospective study 296 consecutive patients scheduled for paroxysmal supraventricular tachycardia (PSVT) ablation were screened, and 26 patients meeting study criteria were enrolled. Patients were excluded for age under 18 years or over 80 years, clinically significant neurovascular or valvular disease, proven left atrial thrombus, thrombophilia, previous pacemaker or ICD implantation, documented paroxysmal atrial fibrillation, or any contraindication to MRI. Participants underwent cerebral MRI 24 hours prior and after the ablation, in case of new ischemic lesions a repeated MRI was planned within 3-6 months. Two sequences were used, a 3D T2-weighted fluid-attenuated inversion recovery (FLAIR) and an axial diffusion-weighted (DW) sequence. By definition acute lesions appear as hyperintensities on the postprocedural diffusion-weighted images which correlate with the hypointense signals on the apparent diffusion map and can not be detected on the preprocedural images.

Patients were planned to be divided into three groups

patients with and without silent cerebral ischemic lesions who underwent left-sided ablation, and a control group undergoing only right-sided ablation. Groups were compared based on clinical and procedural characteristics.

The mean age was 43.9 ± 17.3 years, 42% (n = 11) were men, 35% (n = 9) had a history of hypertension. In all groups radiofrequency energy was used and the ablation was performed with a 4 mm tip non-irrigated  catheter. In case of a left-sided procedure left atrium was approached by transseptal puncture controlled by intracardiac echocardiography. Before the transseptal puncture intravenous heparin was administered. Activated clotting time was aimed to be 200-300 seconds.

None of the postprocedural MRI in the left-sided or the right-sided group revealed any evidence of new cerebral ischemic lesions. Mean procedural time of left-sided ablations was 176.9 ± 74.7 minutes which was significantly longer (p = 0.0077) compared to the right-sided procedures with 132 ± 72.2 minutes total time. Mean left atrial procedural time was 69.1 ± 7.8 minutes, average ACT was 265 ± 28.2 seconds.

No silent ischemic cerebral lesions were detected by MRI after catheter ablation of left-sided PSVT substrate in comparison with the historical population undergoing ablation for atrial fibrillation or ventricular extrasystole. Presumably, cerebral lesions occur at a lower rate or might not appear at all after these less complex procedures.