Combined hemodynamic overload of the left and right ventricles as a possible cause of interventricular septum preponderance in high blood pressure

We tested whether overload of the two ventricles may be associated with a preponderance of interventricular septum in patients with high blood pressure. The rationale is that the septum is shared by the greater and lesser circulation and that in hypertension the latter shows the same qualitative hemodynamic alterations as the former. Among 65 hypertensive patients, 40 (group 1) showed (echo) posterior wall thickness within the mean +/- 1 SD of 62 normal subjects, and 25 (group 2) had a posterior wall thickness exceeding the mean + 1 SD of the normal population. Both groups were subdivided into subgroups A and B, which included patients whose ventricular septum was similar to (within the mean + 1 SD) and thicker than (exceeding the mean + 1 SD) the posterior wall thickness in the corresponding group, respectively. Resting differences in systemic and pulmonary pressure and vascular resistance among subgroups 1A, 1B, and 2A were not significant; however, in subgroup 2B these variables exceeded those in the other subgroups to a significant extent. During cold pressor testing (CPT) the levels reached and the changes in pressure and resistance from baseline values in both circuits were much greater in subgroups B than in subgroups A. The baseline plasma norepinephrine value showed a trend toward an increase from subgroup 1A to 1B and from subgroup 2A and 2B; during CPT norepinephrine invariably changed and in subgroups B it rose significantly more than in subgroups A. It was not determined whether this caused the hemodynamic overload in subgroups B.(ABSTRACT TRUNCATED AT 250 WORDS)