A Simple Model of Right Ventricular Hypertrophy

Previous models of right ventricular hypertrophy (RVH) created by pulmonary artery (PA) banding in adult large animals have been associated with an unpredictable response of the right ventricle to the band and a high mortality due to the variable degree of acute stenosis. We studied the efficacy of PA banding in young pigs to produce RVH by progressive gradual stenosis during growth. Sixteen Yorkshire pigs at 6 weeks of age had nonconstricting 5-mm wide Dacron™ strips placed around the PA via a left minithoracotomy. The animals were returned for study in 2-3 months. There were no deaths during the growth period. Five sham-operated pigs acted as controls. Right ventricular free wall (RVFW) to total heart weight ratio was greater in the banded group (0.38 ± 0.05 vs. 0.28 ± 0.01, P > 005) as was the RVFW to left ventricular free wall (LVFW) weight (1.09 ± 0.25 versus 0.66 ± 0.03, P > 005). While the LVFW to total heart weight ratio decreased (0.36 ± 0.04 vs. 0.45 ± 0.05, P > 005), the septal ratio did not change (0.26 ± 0.04 vs. 0.29 ± 0.02, NS), indicating concomitant septal hypertrophy. This technique is simple, reliable, and reproducible in creating right ventricular and septal hypertrophy in the young pig with no mortality during maturation