P-wave areas, amplitudes, and durations were centrally measured at the Wake Forest Epidemiological Cardiology Research Center using a fully automated program (12-SL, Version 2001, GE Marquette). ECGs were obtained on MAC PC ECG machines (Marquette Electronics, Milwaukee, WI) calibrated at 10 mm/mV with a speed of 25 mm/s. We obtained P-wave measurements from the latest ECG prior to the initial MRI. The predictor variables were P-wave measurements derived from digital 12-lead ECGs done at baseline and each annual study visit. 11 Since our hypothesis was that left atrial disease is associated with subclinical cardiac embolism, which typically results in large or cortical infarcts, 12 we hypothesized that associations would be stronger with non-lacunar rather than aggregate MRI-defined infarcts. We examined both covert brain infarcts and the degree of leukoaraiosis, since cerebral white matter disease has also been associated with vascular risk factors. To investigate this hypothesis, we examined the association of left atrial ECG abnormality with subclinical vascular brain injury detected by magnetic resonance imaging (MRI). 10 Since left atrial ECG abnormality indicates derangements in atrial anatomy and physiology, its association with stroke suggests that left atrial disease may produce a substrate for cardiac thrombus formation and embolization even in the absence of AF. 3, 6 P-wave terminal force in lead V 1 (PTFV 1)-a consistently used marker of left atrial abnormality on a 12-lead electrocardiogram (ECG) 7-has been associated with stroke risk, 8, 9 even in the absence of documented AF. ![]() Prior studies have found associations between premature atrial contractions or paroxysmal supraventricular tachycardia and ischemic stroke, 3– 6 even after accounting for diagnoses of AF during follow-up. ![]() ![]() 2 Recent evidence suggests that atrial disease may be related to vascular brain injury even in the absence of AF. Atrial fibrillation (AF) has long been recognized as a risk factor for vascular brain injury, in both an overt form as ischemic stroke 1 and covert as subclinical brain infarction.
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