A CHARACTERIZED MODEL OF LEFT-VENTRICULAR HYPERTROPHY IN THE RABBIT

A rabbit model of left ventricular hypertrophy is characterized with r espect to blood pressure, heart mass and ventricular refractoriness. H ypertension and left ventricular hypertrophy was induced by unilateral nephrectomy plus wrapping of the contralateral kidney in cellophane. Control or sham operated animals were subjected to a similar procedure except that the kidney was not wrapped in cellophane. No change in co nscious mean arterial blood pressure was shown in the 11 sham operated animals (75 +/- 2 mmHg before operation and 75 +/- 3 mmHg 4-5 weeks a fter). Mean arterial pressure was increased from 73 +/- 2 to 99 +/- 3 mmHg by 4-5 weeks and bad reached a plateau of 110 +/- 3 mmHg 5-6 week s after operation in the 16 animals in which the kidney was wrapped. T he ratios of left ventricular dry weight to body weight and of whole h eart wet weight to body weight were significantly (p < 0.05) higher in the wrap group (0.38 +/- 0.01 and 2.9 7 +/- 0.12, respectively) than in the sham group (0.29 +/- 0.01 and 2.44 +/- 0.08 respectively). Effe ctive refractory period, recorded from the left side of the arterially perfused interventricular septum, was greater in the wrap (266.1 +/- 8.9 ms) than in the sham group (228.2 +/- 3.5 ms). Linear correlations were shown between mean arterial pressure or effective refractory per iod vs the ratio of left ventricular dry weight to body weight or rati o of whole heart to body weight. This study has shown that hypertensio n induced by perinephritis caused left ventricular hypertrophy which w as associated with a prolongation in ventricular refractoriness in the rabbit.