QT Interval Dispersion as a Predictor of Clinical Outcome in Acute Ischemic Stroke

 And what fucking good does this prediction do?

QT Interval Dispersion as a Predictor of Clinical Outcome in Acute Ischemic Stroke

 

Hefei Tang^1,2,3,4, Jiayao Sun⁵, Yu Wang^1,2,3,4, Xu Jie^1,2,3,4, Yan Ma⁶, Anxin Wang^1,2,3,4, Yijun Zhang^1,2,3,4, Xingao Wang^1,2,3,4 and Yongjun Wang^1,2,3,4*

• ¹Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
• ²China National Clinical Research Center for Neurological Diseases, Beijing, China
• ³Center of Stroke, Beijing Institute for Brain Disorders, Beijing, China
• ⁴Beijing Key Laboratory of Translational Medicine for Cerebrovascular Disease, Beijing, China
• ⁵Department of Neurology, Zhangjiakou First Hospital, Hebei, China
• ⁶Division of Cardiology, Department of Internal Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China

Background and Purpose: QT dispersion (QTd) abnormalities are widely documented in stroke patients. This study aims to investigate the association between QTd and clinical outcomes in IS patients.

Methods: IS patients registered in the Blood Pressure and Clinical Outcome in transient ischemic attack (TIA) or IS (BOSS) registry between 2012 and 2014 within 24 h of onset were analyzed. In this prospective observational study, we identified 1,522 IS cases with adequate electrocardiographic evaluations to assess QTd after the index stroke. Patients were classified into four groups based on the quartile of QTd, with the lowest group as the reference. The primary stroke outcome was defined as a modified Rankin Scale score ≥3 at 1-year. Multiple logistic regressions were utilized to investigate the association between QTd and outcome events.

Results: The mean QTd across all cases was 57 ms (40–83). Functional dependency or death was documented in 214 (14.98%) cases at 1 year. After adjusting for confounders, the prevalence of death and major disability (mRS ≥ 3) showed significant differences according to the quartile of QTd, with the risk of death and major disability (mRS ≥ 3) at 1 year being significantly higher for patients in Q4 than for those in Q1 (adjusted OR = 1.626, 95% CI:1.033–2.560). However, there were no significant correlation between QTd and the event outcomes at 1 year.

Conclusions: QTd was associated with poor functional outcomes at 1 year. QTd is a useful surrogate marker for adverse functional prognosis, which might help to stratify risk in patients with acute IS.

Introduction

Stroke is one of the most common causes of death and disability (1). A huge variety of factors are known to influence patient outcome, including demographic variables, clinical variables, laboratory tests, or comorbidities (2). But predicting the final neurological outcomes is very difficult after the index stroke because most studies presenting contradictory results (3, 4).

Patients with acute stroke are still at risk for adverse clinical outcomes, as the treatment primarily focuses on neurological recovery and ignores the hierarchical management of cardiovascular complications (5). Furthermore, many stroke survivors are less likely to exercise enough to develop the significant symptoms of cardiac disease due to movement disorders or complete the traditional cardiac examination for risk stratification. Alternative approaches and novel thinking are therefore required in stroke survivors.

Lesions in the central nervous system often cause autonomic dysregulation (6). The major autonomic dysfunctions caused by ischemic stroke (IS) include a loss of heart rate variability and various ECG changes, particularly QT dispersion (QTd), which is an expression of cardiac repolarization abnormalities (7). Several studies have confirmed the association between acute cerebrovascular events and QTd (8–12). In patients admitted to hospital for acute cerebrovascular diseases, QTd may reflect neurologic injury as well as the underlying heart disease. Thus, it can be used as a marker of adverse clinical prognosis after acute ischemic stroke. Unfortunately, many of these early studies either did not differentiate between hemorrhagic and ischemic stroke or were single-center studies with small sample sizes, making it difficult to draw firm conclusions. Furthermore, the existing data regarding the effect of QTd on the long-term outcomes of these patients are contradictory. Therefore, we aimed to assessed whether abnormal QTd are associated with adverse prognosis of patients with acute IS in the BOSS (blood pressure and clinical outcome in transient ischemic attack [TIA] or IS) study.