Hemodynamics, Regional Myocardial Blood Flow, and Sarcoplasmic Reticulum Calcium Uptake in Right Ventricular Hypertrophy and Failure
Either right ventricular hypertrophy (RVH) or failure (RVF) was produced by pulmonary arterial banding in 47 piglets aged 3–6 weeks. When sufficient time was allowed to elapse after banding, RVH was present in 30 and had progressed to RVF in 17. These two groups were compared with 24 control, i.e., normal pigs (C). Animals with RVF differed from RVH and C animals by having reduced cardiac output and clinical signs of failure. Both RVH and RVF had significantly elevated right ventricular peak systolic pressures (RVS), weights (GMRV), and RV/LV systolic pressure ratios (these variables all increased >100% compared with C). The RV (dP/dt)max correlated with RVS in C (r = 0.687, P < 0.001), but this relationship was absent in RVH with higher RVS and GMRV. The RV (dP/dt)max correlated closely with RV blood flow/g per min in C (r = 0.638, P < 0.01) and in RVH (r = 0.462, P < 0.02). Calcium uptake by RV sarcoplasmic reticulum (SR) was diminished in RVH compared to C and further diminished in RVF (38%, P < 0.001). Calcium uptake by LV SR also fell in RVF, suggesting that SR calcium uptake is merely a passive reflection of myocardial function. Our results also suggest that hemodynamic and subcellular changes seen in RVF may be detected during the compensated stage of RVH.
KeywordsSarcoplasmic Reticulum Calcium Uptake Ventricular Hypertrophy Myocardial Blood Flow Regional Myocardial Blood Flow
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