Blood pressure variability (BPV) is a new risk factor for the development of target organ damage associated with high blood pressure. It has been postulated that antihypertensive drugs must be able to control both blood pressure and its variability. Carvedilol is a third generation beta-blocker with consistent antihypertensive efficacy and ability to attenuate the increase in VPA. The aim of this work was to evaluate the effects of the treatment of different antihypertensive agents on central arterial pressure, BPV and target organ damage in spontaneously
hypertensive rats (SHR). Male SHR (200-250 g) received vehicle (n=6), carvedilol 15 mg/kg (n=6) or losartan 10 mg/kg (n=6) for 8 weeks. A fourth group of Wistar rats was used as normotensive control (n=6). At the end of the treatment, echocardiographic evaluation, direct and indirect blood pressure (BP) and shortterm variability measurements were performed. Left ventricle was removed to assess ventricular hypertrophy. Chronic treatment with losartan, but not carvedilol, reduced indirect systolic BP. Both carvedilol and losartan diminished its intraday
fluctuation compared to SHR. Also, both drugs significantly decreased carotid SBP and its short-term variability. Left ventricular mass was significantly reduced by chronic treatment with carvedilol (2.70±0.04 mg/g; P<0.05 vs. vehicle) or losartan (2.70±0.08 mg/g; P<0.05 vs. vehicle) when compared with SHR treated with vehicle
(3.51±0.19 mg/g). Echocardiographic evaluations revealed that carvedilol or losartan revert diastolic anterior wall thickness, diastolic posterior wall thickness, systolic posterior wall thickness and isovolumic relaxation time. Chronic treatment with carvedilol, but not losartan, normalized systolic posterior wall thickness. In conclusion, both carvedilol and losartan are effective in the reduction of central BP and its short-term variability in SHR, resulting in an attenuation of ventricular hypertrophy evidenced by morphological and echocardiographic parameters. Keywords: hypertension, carvedilol, losartan, echocardiography.