5 Discussion
AIS during radiofrequency ablation procedure were often reported in those atrial fibrillation patients with high risk of thromboembolism. On the other hand, AIS during radiofrequency ablation of PVC patients was rarely reported.4 To our knowledge, this is the first case report on AIS during catheter ablation of PVC. AIS during radiofrequency ablation may be associated with char formation at the ablation tip. However, in our reported case, upon the patient’s manifestation of the neurological symptoms, no charring was identified on the tip of the withdrawn ablation catheter. Therefore, AIS might not have been associated with charring in this case. The reasonable and speculative source of the embolus was the tissue debris caused by the ablation or catheter manipulation. Histopathological examination of a retrieved embolus would be very helpful for identifying the precise etiology and pathogenesis of this AIS. However, emergency cerebral arteriography and interventions was refused. Nevertheless, considering that the neurological symptoms were developed about 40 seconds after the retrograde transaortic manipulation (at that time, reinforcement ablation was not performed), it was reasonable to associate the AIS with the retrograde transaortic manipulation. Therefore, this is the first case report that AIS was associated with retrograde transaortic manipulation due to the high contact force, but not due to the char formation.
Retrograde transaortic catheter manipulation is a widely used and first-line access route for mapping and ablation of ventricular arrhythmias arising from the left ventricle.1Generally, retrograde transaortic approach was safe.1,3 However, as presented in this case, the retrograde transaortic manipulation could potentially result in AIS. The excessive contact force during the aortic valve crossing by the ablation catheter could potentially lead to dislodgement of unstable atherosclerotic plaques, which was frequently found in those patients with uncontrolled hypercholesteremia. The dislodged debris could lead to thromboembolism, if the debris was occluded in an important artery, such as the anomalous left vertebral artery indicated in this specific case. Therefore, cautious the retrograde transaortic manipulation should be performed by limiting the contact force as low as possible.
In clinical practice, AIS encountered during catheter ablation may often have specific neurological symptoms. However, greater attention should be given to those patients with nonspecific neurological symptoms, such as dizziness, vertigo, and limb ataxia. Radiological examinations should be performed for those patients with sudden onset and agnogenic neurological symptoms during catheter ablation. For the patient in this case, examinations confirmed the diagnosis of AIS (the left cerebellar infarction), which may be a result of the occlusion of the anomalous left vertebral artery by dislodged debris caused by the retrograde transaortic catheter manipulation. Appropriate treatments were administered for this patient to relieve her neurological symptoms after the confirmed diagnosis. Fortunately, her symptoms were relieved after the appropriate treatments and encountered no neurological sequelae during the follow up. Therefore, the vigilance is crucial to evaluate the risk of stroke and to give the appropriate treatments, especially in patients with nonspecific neurological symptoms.
In conclusion, this report highlighted that AIS could be encountered in some patients resulting from repeated retrograde transaortic manipulation with excessive contact force.