Depolarization pattern of ventricular epicardium in two-kidney one-clip hypertensive rats

Abstract

The present study is the first attempt to examine the effect of left ventricular hypertrophy (LVH) on the excitation pattern of the ventricular epicardium in experimental hypertensive rats. The left renal artery was clipped in Wistar rats (n = 8; 6-8 months old; weight, 174-295 g) to produce two-kidney one-clip (2K1C) hypertension. After 4 weeks, blood pressure was measured, and epicardial potential mapping was performed under sinus rhythm from 64 unipolar electrodes regularly distributed over the ventricular epicardium. Systolic blood pressure was ∼40% higher in the rats with a clipped renal artery (162 ± 14 mmHg, mean ± S.D.) than in the normotensive rats (115 ± 3 mmHg). LVH (∼23% increase in the ratio of the left ventricular weight to the body weight, P < 0.05) was observed in the 2K1C hypertensive rats. The depolarization pattern of the ventricular epicardium in the normotensive rats was similar to that in the rats with 2K1C hypertensive LVH. The duration of ventricular epicardial activation was shown to increase (∼35%, P < 0.05) in the hypertensive rats as compared to the normotensive animals. This study provides an explanation for alterations of the body surface potential distribution in hypertensive patients with LVH. © The Physiological Society 2005.