Excessive supraventricular ectopic activity and new-onset ischemic stroke: a retrospective cohort study with prospective outcome ascertainment

Background Excessive supraventricular ectopic activity (ESVEA), a marker of both paroxysmal atrial fibrillation (pAF) and underlying atrial cardiomyopathy, may serve as an earlier electrographic predictor of cryptogenic ischemic stroke than pAF itself. This study aimed to investigate the association between ESVEA and the risks of new-onset ischemic stroke and all-cause mortality in an Asian population, and to explore a potential data-driven threshold that requires external validation. Methods In this retrospective cohort study with prospective outcome ascertainment, data were collected from 446 patients without a history of atrial fibrillation or stroke across three hospitals in China. Based on the results of 24-h ambulatory ECG monitoring, patients in the top 15% of the cohort (premature atrial complex [PAC] rate ≥100 beats/24 h or paroxysmal atrial tachycardia [PAT] episode count ≥22 episodes/24 h) were defined as the ESVEA group; the remainder comprised the non-ESVEA group. The incidence of new-onset ischemic stroke and all-cause mortality was compared between groups during follow-up, after adjustment for confounding factors such as age and hypertension. Results The median follow-up duration was 13 months. In a multivariable Cox proportional hazards model with a time-varying coefficient for age, using new-onset ischemic stroke and all-cause mortality as endpoints, after adjusting for other risk factors, ESVEA was significantly associated with new-onset ischemic stroke (HR:2.798; 95% CI:1.064 to 7.359; p = 0.037) and all-cause mortality (HR:7.584; 95% CI: 1.302 to 44.163; p = 0.024). In subgroup analysis, no significant interaction was observed between age groups for the effect of ESVEA on new-onset ischemic stroke. The rates of new-onset stroke in the ESVEA- group (without PAC/PAT), the ESVEA+/− group (with PAC/PAT not meeting ESVEA criteria), and the ESVEA+ group were 0.70, 5.90, and 16.30%, respectively, demonstrating a stepwise increase. Conclusion In this retrospective cohort study with prospective outcome ascertainment, ESVEA was associated with an increased risk of new-onset ischemic stroke and all-cause mortality in Asian subjects without prior stroke or AF. These exploratory findings suggest that ESVEA may be a useful risk marker, but require validation in larger prospective studies before clinical application.