Multiparametric identification of subclinical atrial fibrillation after an embolic stroke of undetermined source

Shifting Outcomes: Superior Functional Recovery in Embolic Stroke of Undetermined Source Compared to Cardioembolic Stroke

BACKGROUND/OBJECTIVES

An embolic stroke of undetermined source (ESUS) is a subtype of ischemic stroke characterized by a non-lacunar infarct in the absence of a clearly identifiable embolic source, despite comprehensive diagnostic evaluation. While ESUS patients are typically younger, have fewer cardiovascular comorbidities, and experience milder strokes than those with cardioembolic strokes (CEs), their functional recovery remains underexplored.

METHODS

We retrospectively analyzed data from 374 ischemic stroke patients (n = 94 ESUS, n = 280 CE) admitted to the Department of Neurology, University of Pécs, between February 2023 and September 2024. Functional recovery was assessed using the modified Rankin Scale (mRS). Propensity score matching (PSM) was performed to balance the baseline characteristics, and the mRS-shift was compared between groups. Independent predictors of mRS-shift were identified using Huber regression and extreme gradient boosting (XGBoost).

RESULTS

The ESUS patients were significantly younger (60.7 ± 13.8 years vs. 75.1 ± 11.3 years, p < 0.001), had lower pre-morbid modified Rankin Scale (pre-mRS) scores (0.34 ± 0.91 vs. 0.81 ± 1.23, p < 0.001), were less likely to have hypertension (75.5% vs. 86.1%, p = 0.027) and diabetes (23.4% vs. 36.8%, p = 0.024), and presented with milder strokes (National Institutes of Health Stroke Scale [NIHSS] score at admission: 5.4 ± 4.5 vs. 8.1 ± 6.3, p < 0.001, and 72 h post-stroke: 3.0 ± 4.4 vs. 6.5 ± 6.3, p < 0.001) compared to the CE patients. After adjusting for baseline differences, the ESUS patients demonstrated significantly greater functional recovery than the CE patients (adjusted mRS-shift: 1.84 ± 1.14 vs. 2.53 ± 1.69, p = 0.022). Age, pre-mRS score, and NIHSS score at 72 h post-stroke were the strongest predictors of mRS-shift, with an older age, a higher pre-mRS score, and a greater stroke severity significantly decreasing the odds of recovery.

CONCLUSIONS

The ESUS patients showed superior functional recovery compared to the CE patients, even after accounting for baseline differences. These findings highlight the need for further research into the pathomechanisms underlying ESUSs and the development of optimal treatment strategies to improve patient outcomes.

Predictors of atrial fibrillation after embolic stroke of undetermined source in patients with implantable loop recorders

BACKGROUND

In patients with embolic stroke of undetermined source (ESUS), underlying subclinical atrial fibrillation (AF) is often suspected. Previous studies identifying predictors of AF have been limited in their ability to diagnose episodes of AF. Implantable loop recorders enable prolonged, continuous, and therefore more reliable detection of AF. The aim of this study was to identify clinical and ECG parameters as predictors of AF in ESUS patients with implantable loop recorders.

METHODS

101 ESUS patients who received an implantable loop recorder between 2012 and 2020 were included in this study. Patients were followed up regularly on a three-monthly outpatient interval.

RESULTS

During a mean follow-up of 647 ± 385 days, AF was detected in 26 patients (26%). Independent risk factors of AF were age ≥ 60 years (HR 2.753, CI 1.129-6.713, p = 0.026), P-wave amplitude in lead II ≤ 0.075 mV (HR 3.751, CI 1.606-8.761, p = 0.002), and P-wave duration ≥ 125 ms (HR 4.299, CI 1.844-10.021, p < 0.001). In patients without risk factors, the risk of developing AF was 16%. In the presence of one risk factor, the probability increased only slightly to 18%. With two or three risk factors, the risk of AF increased to 70%.

CONCLUSION

AF was detected in about one in four patients after ESUS in this study. A comprehensive evaluation involving multiple parameters and the existence of multiple risk factors yields the highest predictive accuracy for detecting AF in patients with ESUS.