Atrial electrical and structural abnormalities in an ovine model of chronic blood pressure elevation after prenatal corticosteroid exposure: Implications for development of atrial fibrillation

Abstract

Aims: Elevated blood pressure (EBP) is the most prevalent and potentially modifiable risk factor for AF, yet little is known of its atrial effects. We aimed to characterize the atrial electrical and structural changes in a chronic ovine model of EBP after prenatal corticosteroid exposure. Methods and results: Twelve sheep with chronically EBP (mean arterial pressure 94±3 mmHg) and six controls (71±4 mmHg, P<0.01) underwent acute open chest electrophysiologic and pathologic studies. We measured refractoriness at the atrial appendages at 3 cycle lengths (CL); conduction velocities at Bachmann's bundle, both atrial appendages and free walls at 4 CLs; conduction heterogeneity; atrial wavelength ..