Figure 1.

RPO Elicits a Reduction in LV Compliance That Prevents Chamber Distension During an Acute Elevation in Afterload

A 60-min intravenous infusion of phenylephrine (PE) elicited a similar increase in arterial systolic blood pressure (SBP) and left ventricular end-diastolic pressure (LVEDP) at the initial study (blue) and after 2 weeks of repetitive pressure overload (RPO) (purple). At the initial study, this was associated with an increase in left ventricular end-diastolic volume (LVEDV) that persisted after cessation of PE despite normalization of SBP and LVEDP. However, transient PE infusion no longer produced a significant increase in LVEDV when the study was repeated after 2 weeks of RPO, which was indicative of reduced LV compliance after RPO. Values are mean ± SEM. *p < 0.05 versus baseline; †p < 0.05 versus initial.