Fosinopril improves the electrophysiological characteristics of left ventricular hypertrophic myocardium in spontaneously hypertensive rats

This study investigated the effects of fosinopril on the electrophysiological characteristics of the left ventricular hypertrophic myocardium in spontaneously hypertensive rats (SHRs). Twenty-four 10-week-old male SHRs were divided into fosinopril and non-fosinopril groups (n = 12 each). Twelve 10-week-old Wistar–Kyoto rats were used a control group. Left ventricular mass index and ventricular fibrillation threshold (VFT) were measured after 8 weeks of fosinopril or saline treatment. L-type calcium current (I CaL), sodium current (I Na), and transient outward potassium current (I to) were measured in left ventricular myocytes after 8 weeks of fosinopril or saline treatment using the whole-cell patch-clamp technique. VFT was higher in the fosinopril group than in the non-fosinopril group (17.5 ± 1.2 mA vs. 15.6 ± 1.1 mA, P < 0.01). The density of I CaL was lower in the fosinopril group than in the non-fosinopril group (−7.17 ± 0.13 pA/pF vs. −7.87 ± 0.13 pA/pF, P < 0.05). The density of I to was higher in the fosinopril group than in the non-fosinopril group (14.46 ± 0.28 pA/pF vs. 12.66 ± 0.25 pA/pF, P < 0.05). I to was positively correlated with VFT (r = 0.90, P < 0.001) and was found to be associated independently with VFT (P < 0.001). Fosinopril improves the electrophysiological characteristics of the left ventricular hypertrophic myocardium in SHRs.