Hemodynamic, humoral and volume findings in systemic hypertension with isolated ventricular septal hypertrophy.

To analyze the hemodynamic, endocrine and volume characteristics of isolated septal hypertrophy (ISH) in established systemic hypertension, 22 patients with ISH were compared to 23 patients with symmetric hypertrophy and to 28 without left ventricular (LV) hypertrophy. Mean arterial pressure and 24-hour ambulatory pressure readings did not differ between the 2 groups. At the same level of arterial pressure, patients with ISH had a high cardiac index (p less than 0.02) and a faster heart rate (p less than 0.05); consequently, total peripheral resistance was decreased (p less than 0.05). Although there was no change in intravascular volume, central blood volume was expanded (p less than 0.02), and the ratio of central to peripheral blood volume was increased (p less than 0.02), thereby indicating peripheral venoconstriction. Patients with isolated ISH had greater responses of diastolic pressure and heart rate (p less than 0.05) to isometric stress than the other 2 groups. A hyperdynamic circulatory state is a hemodynamic hallmark of ISH in early essential hypertension that might be produced by increased sympathetic activity.