Cardiac hypertrophy and characteristic impedance in spontaneously hypertensive rats.

Characteristic impedance and systemic arterial compliance were evaluated in 12 anaesthetized spontaneously hypertensive rats (SHR) from analysis of phasic records of pressure and flow in the ascending aorta. Cardiac hypertrophy expressed as the ratio of the left ventricular weight to the body weight was not correlated with arterial blood pressure (systolic, diastolic or mean). In contrast, there was a significant relationship between the left ventricular weight to body weight ratio and the characteristic impedance, suggesting that increased arterial stiffness contributes to left ventricular hypertrophy in SHR.