Holter electrocardiographic and clinical predictors of incident paroxysmal atrial fibrillation in patients with acute ischemic stroke

Abstract

Atrial fibrillation (AF) if left untreated, due to its silent nature, could lead to considerable morbidity and mortality due to its thromboembolic complications, especially ischemic stroke. Prolonged ECG monitoring is an increasingly advocated method to detect silent AF and other arrhythmias. The optimum duration of Holter ECG monitoring to detect underlying AF is not clear leading to a variation in practice based on differences in trial results and relevant clinical guidelines. 7-day Holter ECG appears to provide a convenient way of prolonged non-invasive monitoring for AF detection. I looked at the 7-day Holter ECG data from an observational registry from Sandwell and West Birmingham Hospital (SWBH) with an unselected all-comer cohort of 476 patients and the interventional arm of MonDAFIS trial of 1714 patients with acute ischemic stroke to look at detection of new AF. Clinical, echocardiographic and Holter ECG parameters associated with newly detected AF where available went through association testing and logistic regression. The final model fit was tested through the ROC curve analysis. The AF pick-up rate in SWBH cohort was 8.8%. In this cohort, the median age in the AF group was higher than the non-AF group and there was no difference in the gender. AF was more frequently seen when the 7-day Holter ECG was done to investigate palpitations and stroke. With regards to comorbidities, AF was associated with hypertension, coronary artery disease and left-sided valvular disease and for Holter ECG variables. AF patients had a longer duration of recording and higher mean heart rate, more sinus pauses and supraventricular ectopic (SVE) activity. Logistic regression analysis showed that hypertension, previous stroke, left-sided valvular disease and palpitations were independently associated with underlying AF. In the MonDAFIS cohort, the overall AF detection was 4.6% with incremental increase per each day or recording. AF patients were older and had more underlying hypertension, diabetes, renal insufficiency increased LA size and worse LV systolic function. AF patients also had a longer duration of recording, more SVE and ventricular ectopic (VE) activity. Logistic regression analysis showed older age, frequent isolated supraventricular ectopics, SVE runs and LA dilatation as significant predictors of AF. 7-day Holter ECG monitoring has a good diagnostic yield for AF both in stroke survivors as well as an all-comer patient cohort. In general, the AF group had longer monitoring duration. There are other important similarities in the two groups in terms of clinical parameters (advancing age and hypertension in the AF group) and Holter ECG parameters (higher mean heart rates and more supraventricular ectopic activity in AF group). Combining these important clinical and Holter ECG findings can prove useful to identify patients with a high risk of underlying AF. These findings need testing through external validation and can potentially have an important real-time impact on patient care