Brain Emboli After LV Endocardial Ablation
What is the incidence of brain emboli following left ventricular (LV) endocardial ablation?
The authors enrolled 18 patients scheduled for ventricular tachycardia (VT) or premature ventricular contraction (PVC) ablation. Patients undergoing LV ablation were compared with a control group of those undergoing right ventricular (RV) ablation only. Radiofrequency energy was used for ablation in all cases and heparin was administered with goal activated clotting times of 300-400 seconds for all LV procedures. Pre- and post-procedural brain magnetic resonance imaging (MRI) was performed on each patient within a week of the ablation procedure. Embolic infarcts were defined as new foci of reduced diffusion and high signal intensity on fluid-attenuated inversion recovery brain MRI within a vascular distribution.
The mean age was 58 years, one half were men, one half had a history of hypertension, and the majority had no known vascular disease or heart failure. LV ablation was performed in 12 patients (2 VT, 10 PVC) and exclusively RV ablation in 6 patients (1 VT, 5 PVC). Seven patients (58%) undergoing LV ablation experienced a total of 16 cerebral emboli, compared with zero patients undergoing RV ablation (p = 0.04). Seven of 11 patients (63%) undergoing a retrograde approach to the LV developed at least one new brain lesion.
More than one half of patients undergoing routine LV ablation procedures (predominately PVC ablations) experienced new brain emboli after the procedure, although the precise etiology remains unclear.
While the risk of apparent stroke or transient ischemic attack with atrial fibrillation (AF) ablation is under 2%, new cerebral lesions can be found with diffusion-weighted MRI in 8-36% of patients. Separately, there is some evidence that AF ablation may be associated with cognitive decline, although the studies did not include imaging correlation. AF ablation, however, often requires a relatively large set of ablation lesions. The authors of this study point to an even greater incidence of new lesions on MRI with left-sided ablations of PVCs (60%). This is surprising given that the ablated area is very much smaller with PVC ablations. While the exact mechanism for this alarming incidence of brain emboli is not known, one would expect incremental risk stemming from catheter manipulation in the aortic arch and the aortic valve, in addition to the risk of eschar and coagulum formation, as is expected with both AF and PVC ablation. Future studies should assess the incidence of the brain lesions on the MRI in patients who undergo the transseptal versus retrograde aortic approach to the left ventricle.
Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Magnetic Resonance Imaging, Hypertension
Keywords: Arrhythmias, Cardiac, Atrial Fibrillation, Catheter Ablation, Embolism, Heart Failure, Hypertension, Heparin, Intracranial Embolism, Ischemic Attack, Transient, Magnetic Resonance Imaging, Stroke, Tachycardia, Ventricular, Vascular Diseases, Ventricular Premature Complexes
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