ECG Left Atrial Abnormality and Vascular Brain Injury | Journal Scan
Is atrial disease associated with vascular brain injury in the absence of atrial fibrillation?
The Cardiovascular Health Study prospectively enrolled community-dwelling adults ages ≥65 years. Among participants who underwent magnetic resonance imaging (MRI), associations between electrocardiogram (ECG) left atrial (LA) abnormality and brain infarcts and leukoaraiosis (white matter hyperintensities) were examined. P-wave terminal force in lead V1 was the primary measure of LA abnormality; P-wave area and duration were secondary predictors. Participants with atrial fibrillation were excluded before or on their index ECG. Primary outcomes were incident infarcts and worsening leukoaraiosis from initial to follow-up scan approximately 5 years later. Secondary outcomes were prevalent infarcts and degree of leukoaraiosis on initial MRI. Relative risk (RR) and linear regression models were adjusted for vascular risk factors.
Among 3,129 participants with ≥1 scan, each standard deviation (SD) increase in P-wave terminal force in lead V1 was associated with a 0.05-point (95% confidence interval [CI], 0.0003–0.10) higher baseline white matter grade on a 10-point scale. P-wave terminal force in lead V1 was associated with prevalent infarcts of any type (RR per SD 1.09; 95% CI, 1.04–1.16) and more so with prevalent nonlacunar infarcts (RR per SD, 1.22; 95% CI, 1.08–1.38). Among 1,839 participants with two scans, P-wave terminal force in lead V1 was associated with worsening leukoaraiosis (RR per SD, 1.09; 95% CI, 1.01–1.18), but not with incident infarcts (RR per SD, 1.06; 95% CI, 0.93–1.20). Sensitivity analyses adjusting for incident atrial fibrillation found similar results. P-wave area and duration were not associated with outcomes.
The authors concluded that LA abnormality on ECG is associated with vascular brain injury in the absence of documented atrial fibrillation.
Some studies suggest that premature atrial contractions and paroxysmal supraventricular tachycardia are associated with ischemic stroke even in the absence of atrial fibrillation; this study suggests that isolated ECG evidence of LA enlargement is associated with evidence of stroke or white matter hyperintensities on MRI. Although patients with known atrial fibrillation or atrial fibrillation on the index ECG were excluded, it is not clear how asymptomatic paroxysmal atrial fibrillation was excluded. Other studies make a convincing argument that more aggressive efforts to diagnose atrial fibrillation are needed among patients with otherwise cryptogenic neurologic events (Gladstone DJ, et al. N Engl J Med 2014;370:2467-77 [doi: 10.1056/NEJMoa1311376]).
Keywords: Atrial Fibrillation, Electrocardiography, Cerebrovascular Trauma, Leukoaraiosis, Magnetic Resonance Imaging, Stroke, Embolism, Vascular Diseases, Heart Atria, Risk, Risk Factors, Linear Models
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