Fehmi Keçe

Cerebral Embolism during Atrial Fibrillation Ablation 87 3 a decline in cognitive function both in patients with and without ACE. It is difficult to determine which numerical decline (whether or not statistically significant) is also clinically meaningful. There is limited data about cognitive functioning after atrial fibrillation ablation (22). In several studies on other procedures (for example after CABG), statistical techniques have been implemented to determine “true” (i.e., statistically significant) cognitive decline at the individual level (23). In addition, for major neurocognitive disorder as defined by international diagnostic guidelines for mental disorders (24) a meaningful decrease in test performance is typically 2 or more standard deviations below appropriate norms or reference groups (3rd percentile or below). However, as we did not observe any significant difference but also not a trend towards impaired test results in patients with ACE, we believe that a clinically relevant decline in cognitive function is unlikely. Cerebral location of the lesions between studies may explain the differences in cognitive effects of ACE. Lesion- symptom mapping studies have shown that the impact on cognition depends on lesion volume but also on location (25). Lesions in strategic brain regions cause more cognitive impairment. It is more difficult to detect lesions in cortical regions with mechanisms compensating the affected neuropsychological function. In our study, most of the lesions were located in the cortical regions of the brain . 3.4.5 Adverse Events In the PVAC-Gold group 1 patient experienced an asymptomatic pulmonary vein stenosis, which was detected during a second procedure. Since this patient underwent re-ablation of both left pulmonary veins, it is possible that the second ablation contributed to the progression of the stenosis. Importantly, it is well known that pulmonary vein stenosis might be underdiagnosed due to the lack of a specific clinical presentation (26) and the absence of systematic screening after ablation. In a cohort of 62 patients using the first generation PVAC, we also observedmild (25-50%) narrowing in 37% of the PV’s, a moderate (50-70%) narrowing in 9% and severe narrowing (>70%) in 3% (27). Von Bary et al. reported a detectable narrowing of the PV diameter after first-generation PVAC ablation in 23% of the patients (28). 3.4.6 Limitations This was a single center study with a relatively small number of patients in each arm. The size of the study sample was calculated based on the estimates of differences in ACE. Strong conclusions regarding the neuropsychological effects of ACE cannot be drawn and larger trials are required to confirm the results. We have no detailed information available on the INR values and time in therapeutic range for individual patients in the