Left and right ventricular hypertrophy in response to high salt intake is blood pressure independent

Objective: To evaluate the mechanisms of myocardial hypertrophy induced by salt overload. Methods: Eighteen-week-old Wistar rats were fed a normal (NS: 1.3% NaCl), a high 1 (HS1 4%) or a high 2 (HS2 8%) salt diet since weaning. HS2 group was divided into HS2 and HS2+hydralazine (HZ: 15mg/kg/day - since 7 weeks of age). Body weight (BW), tail cuff blood pressure (BP), left (LVM) and right (RVM) ventricular mass, echocardiography and urinary sodium (US) were evaluated. Results [mean±SEM – p<0.05, (n=4–8/group)]: The BW from weaning to adulthood did not differ among the four groups. At 18 weeks of age, the BP (mmHg) was higher on HS1 (150±2) and HS2 (154±3) than on NS (123±2). BP on HS2+HZ (126±2) did not differ from NS. US (mEq/24h) was higher on HS1 (9±0.5), HS2 (13±1.0) and HS2+HZ (13±1.5) than on NS (2±0.3). LVM (mg/g) was higher on HS1 (2.26±0.06), HS2 (2.46±0.05) and HS2+HZ (2.50±0.09) when compared to NS (2.03±0.06). RVM (mg/g) was higher on HS2 (0.69±0.01) and HS2+HZ (0.85±0.09) compared to NS (0.69±0.02) group. Interventricular septal thickness, left ventricular end-diastolic dimension - and left ventricular posterior wall thickness - LVPW (mm) were higher on HS1, HS2 and HS2+HZ compared to NS (LVPW: HS1 0.16±0.002, HS2 0.19±0.005, HS2+HZ 0.16±0.003, and NS 0.13±0.002). Conclusions: Left and right ventricular hypertrophy in response to high salt intake is not dependent on BP.