The P-wave terminal force in embolic strokes of undetermined source

The Embolic Stroke of Undetermined Source (ESUS) is a recently developed clinical construct which describes stroke patients for whom the embolic source remains undetermined despite recommended investigations. The aim of the study was to characterize the ESUS population according to the abnormality in the P-wave terminal force in lead V₁ (PTFV₁).

We retrospectively identified consecutive patients hospitalized for acute ischemic stroke who met the ESUS diagnostic criteria. The PTFV₁ was obtained from the admission 12-lead ECG. Increased PTFV₁ was defined a value >5000μV·ms. Baseline and diagnostic work-up findings were compared between the PTFV₁ patient groups.

Among 109 patients with ESUS, 31 (28.4%) had evidence of increased PTFV₁. The patients with the ECG-defined left atrial abnormality had higher rates of hypertension (77.4% versus 55.1%; p=0.031), history of prior stroke or TIA (35.5% versus 16.7%; p=0.032), and moderate to severe left atrial enlargement (29.0% versus 7.7%; p=0.004) and ventricular hypertrophy (35.5% versus 16.7%; p=0.032), whereas they were less likely to have patent foramen ovale (9.7% versus 28.2%, p=0.038) and unstable sub-stenotic atherosclerosis of aortic arch and cranial arteries (12.9% versus 32.1%, p=0.041).

The abnormally increased PTFV₁ was observed in about one third of patients with ESUS and it was inversely associated with artery-to artery and paradoxical potential sources of stroke. Left atrial cardiopathy could be involved in the ESUS pathogenesis and the ECG-defined abnormality could point towards the risk of cardiac embolism.