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Electrical isolation of the left atrial appendage (LAA) is associated with a lower rate of atrial fibrillation (AF) recurrence in patients undergoing radiofrequency catheter ablation. However, LAA isolation can significantly impair LAA contractility. This study was performed to evaluate whether electrical isolation of the LAA is associated with an increased risk of ischemic stroke or transient ischemic attack (TIA). Consecutive patients with AF undergoing radiofrequency catheter ablation at Korea University Medical Center Anam Hospital were analyzed. Of 2352 patients, 39 (1.7%) had LAA isolation. Patients with LAA isolation had a significantly higher rate of ischemic stroke or TIA than did those without LAA isolation (log-rank, P < .001; hazard ratio 23.6; P < .001). There were significant differences in the baseline characteristics of the 2 groups, including type of AF (34 [87.2%] and 911 [39.4%] patients with and without LAA isolation had nonparoxysmal AF, respectively). After multivariate adjustment, LAA isolation was found to be a significant risk factor for ischemic stroke or TIA (adjusted hazard ratio 11.3; P < .001). Propensity score-matched analysis also revealed an increased risk of ischemic stroke or TIA in patients with LAA isolation compared with those without LAA isolation (log-rank, P = .001). The LAA flow velocity of post-LAA isolation status was not significantly different between patients who did and did not experience ischemic stroke or TIA (30.3 ± 17.7 cm/s vs 33.9 ± 17.9 cm/s; P = .608). A significantly increased risk of ischemic stroke or TIA was observed in patients with electrical isolation of the LAA. In addition, postisolation LAA flow velocity is not a reliable marker to predict future ischemic events.

Korean Circulation Journal 대한심장학회지 순환기 Roh SY, et al. Korean Circ J. 2021 Oct;51(10):866-874. https://doi.org/10.4070/kcj.2021.0127

Previous studies have reported a considerable association between the VerifyNow (Accumetrics, San Diego, CA, USA) P2Y12 assay results and hematocrit. No reports, however, have described an association between the multiple electrode platelet aggregometry (MEA; Dynabyte, Munich, Germany) adenosine diphosphate (ADP) assay results and hematocrit. This study was conducted to evaluate the influence of hematocrit on the results of 2 different point-of-care platelet function tests. A total of 462 consecutive patients who were undergoing percutaneous coronary intervention were enrolled. Platelet function was evaluated with both the VerifyNow P2Y12 and MEA ADP assays. Anemic patients (n = 152, 32.9%) demonstrated a significantly higher rate of cardiac death, myocardial infarction, and stroke (5.3% vs. 2.3%, p = 0.046) during the follow-up (median: 18.8 months). Although the VerifyNow P2Y12 assay results demonstrated a significant inverse correlation with hematocrit (r = −0.409, p<0.001), there was no such correlation between the MEA ADP assay results and hematocrit (r = 0.039, p = 0.401). In the multivariate analysis, anemia was an independent predictor of high on-treatment platelet reactivity, defined as a VerifyNow P2Y12 reaction unit level of ≥252.5 (odds ratio = 2.21, 95% confidence interval = 1.39–3.52; p = 0.001). Importantly, this association was independent of an intrinsic change in platelet reactivity as measured by the MEA ADP assay. Adjusting for the influence of hematocrit improved the strength of the correlation between the VerifyNow P2Y12 and MEA ADP assay results. Hematocrit significantly influenced the VerifyNow P2Y12 assay results, a phenomenon that was presumably in-vitro. Hematocrit level should therefore be considered when interpreting results of the VerifyNow P2Y12 assay.

Evidence of an association between atrial fibrillation (AF) and sudden cardiac arrest (SCA) in young adults is limited. In this study, we aim to evaluate this association in a general population aged between 20 and 39 years. Young adults who underwent health check-ups between 2009 and 2012 were screened from a nationwide healthcare database in South Korea. A history of AF diagnosis before the health check-ups was identified based on the relevant International Classification of Diseases, 10th edition codes reported in the database. Associations between an established diagnosis of AF and the risk of SCA during follow-up were examined. A total of 6 345 162 young people were analysed with a mean follow-up duration of 9.4 years. The mean age was 30.9 ± 5.0 years, and 5875 (0.09%) individuals were diagnosed with AF. During follow-up, SCA occurred in 5352 (0.08%) individuals, and the crude incidence was 0.56 and 0.09 events per 1000 person-years for participants with and without AF, respectively. Individuals with AF had a 3.0-fold higher risk in a multivariate model adjusted for age, sex, lifestyle, anthropometric data, and medical comorbidities (adjusted hazard ratio 2.96, 95% confidence interval 1.99–4.41, P < 0.001). Both incident and prevalent AFs were associated with an increased risk of SCA, with no significant differences between the two groups. Atrial fibrillation was associated with a significantly higher risk of SCA developing in healthy young adults. Whether the rate or rhythm control influences the risk of SCA in young patients with AF remains to be examined. AF, atrial fibrillation; CI, confidence interval; SCA, sudden cardiac arrest.