Detektion von paroxysmalem Vorhofflimmern bei Patienten mit zerebraler Ischämie

Abstract

Background and objectives: Atrial fibrillation (AF) is a common cause of cerebral ischemia. Paroxysmal AF is often underdiagnosed by standard diagnostic procedures. Patients with diagnosed AF receive a different secondary prophylactic therapy. This thesis is based on three original publications on improving the detection and prediction of paroxysmal AF in patients with acute cerebral ischemia. In “Enhanced Detection of Paroxysmal Atrial Fibrillation by Early and Prolonged Continuous Holter Monitoring in Patients with Cerebral Ischemia Presenting in Sinus Rhythm” we investigated the diagnostic yield of a 7-day Holter-ECG and the usefulness of an early application. In “Age-dependent yield of screening for undetected atrial fibrillation in stroke patients: the Find-AF study”, we studied the age distribution of paroxysmal AF to find out which age group benefits most from the applied monitoring approach. In “Excessive Supraventricular Ectopic Activity Is Indicative of Paroxysmal Atrial Fibrillation in Patients with Cerebral Ischemia“ we evaluated the predictive value of frequent premature atrial complexes (PAC) and prolonged supraventricular (SV-) runs. Methods: Patients with acute cerebral ischemia were included in the prospective single-center observational trial “Find-AF” (ISRCTN 46104198). Patients without AF at presentation received early and prolonged Holter-ECG-monitoring. To analyse the age distribution of paroxysmal AF, the detection rate was determined in 5-year age clusters from 60 to 85 years. The markers of excessive supraventricular ectopic activity (ESVEA) were analysed in a 24-hour Holter-ECG-interval without AF. The median was chosen as the cut-off level. Results: 281 patients were included. 44 (15.7 %) had AF at baseline. All others received early (median 5.5 hours after presentation) and prolonged (median 6.7 days) Holter-ECG-monitoring. 28 (12.5 %) of 224 patients showed newly diagnosed paroxysmal AF, significantly more than in any 48-hour (6.4 %, p = 0.023) or 24-hour interval (4.8 %, p = 0.015). The detection rates within the seven 24-hour intervals were not significantly different. The detection rate of paroxysmal AF significantly increased with age (p = 0.004), while the number needed to screen to find one patient with paroxysmal AF decreased from 18 (< 60 years) to 3 (≥ 85 years). Patients with frequent PAC (> 4/hour) and those with prolonged SV-runs (> 5 beats) showed significantly more paroxysmal AF: 19.6 % vs. 2.8 % for frequent PAC (p = 0.001) and 17.0 % vs. 4.9 % for prolonged SV-runs (p = 0.003). Multivariate analyses including various clinical AF-predictors confirmed the independent predictive value of both markers. Conclusions: 1.) In patients with acute cerebral ischemia, prolonging the Holter-ECG-interval significantly increases the detection rate of paroxysmal AF. The early initiation appears to be of less importance. 2.) The detection rate of paroxysmal AF increases with age, therefore prolonged Holter-ECG-monitoring is most efficient in elderly patients. 3.) Both frequent PAC and prolonged SV-runs are valid predictors of paroxysmal AF in patients with acute cerebral ischemia.