We examined the quantitative influence of carefully controlled alterations in enddiastolic volume and afterload resistance on multiple simultaneously determined ejection and isovolumetric phase indexes of left ventricular contractile function in 23 isolated supported canine ventricles. The influence of load change on each index was compared with its sensitivity to inotropic stimulation, and this sensitivity was in turn contrasted to the response of the end-systolic pressure-volume relationship (ESPVR). Experimental data demonstrated various degrees of load sensitivity among the indexes, with a generally curvilinear relationship between load and index response for both preload and afterload alterations. The curvilinear nature of these relationships meant that over a select range of loading, many indexes demonstrated relative load independence. They also often displayed greater sensitivity to inotropic change than the ESPVR, and both factors help explain their enduring clinical utility. To further explore the influence of load and contractile state on several of the indexes, we developed a theoretical analysis, using variables common to pressure-volume relationships, in which these dependencies could be derived. The theoretical models fit very well with the experimental data, and reaffirmed the frequently curvilinear nature of the relationships. We conclude that while many clinical indexes of ventricular contractile function show significant load dependence, the information they provide can be reasonably interpreted within defined ranges of load and inotropic alteration. Any advantage of the ESPVR will derive not from the magnitude of its response to inotropic change, which is smaller than most other indexes, but from its relative insensitivity to load alteration over a wider range of load.
Background: Early palliative care (EPC) is recommended but rarely integrated with advanced heart failure (HF) care. We engaged patients and family caregivers to study the feasibility and site differences in a two-site EPC trial, ENABLE CHF-PC (Educate, Nurture, Advise, Before Life Ends Comprehensive Heartcare for Patients and Caregivers).
Background-In preparation for development of a palliative care intervention for patients with heart failure (HF) and their caregivers, we aimed to characterize the HF population receiving palliative care consultations (PCCs).
The end-systolic pressure-volume relationship (ESPVR) as derived from left ventricular pressure-volume loops has gained increasing acceptance as an index of ventricular contractile function. In animal experiments the ESPVR has been defined as a line connecting the upper left corners of several differently loaded pressure-volume (P-V) loops with a slope parameter Ees and a volume axis intercept parameter V.. In the clinical setting, several variants of the ESPVR have been determined with use of peak left ventricular pressure, end-ejection pressure, and end-ejection volume. The maximum P-V ratio has also frequently been measured. We attempted to determine which of these alternatives resulted in good approximations of the reference ESPVR in eight isolated canine ventricles that ejected into a simulated arterial impedance system with resistance, compliance, and characteristic impedance. We determined various versions of the ESPVR from the same set of beats quickly obtained with little change in inotropic background. To vary ventricular pressure wave forms, each of the arterial impedance parameters was independently controlled at 50%, 100%, and 200% of normal. Against each of the nine combinations of the impedance parameters four P-V loops were obtained under four preloads and from each of the sets offour P-V loops, the reference ESPVR, linear regression of the peak pressure on end-ejection volume (ESPVRPP-EEV), and linear regression of end-ejection pressure on endejection volume (ESPVREEPV) were determined. In addition, the maximum P-V ratio (MPVR) was calculated for each P-V loop. At all combinations of afterload impedance parameters ESPVRPP-EEV was shifted to the left (slope 5.4 vs 5.2 mm Hg/ml, intercept 6.6 vs 7.4 ml) and ESPVREEPV was shifted rightward (slope 5.0 mm Hg/ml, intercept 7.7 ml) from ESPVRREF. These differences, however, were quantitatively very small. MPVR was much smaller than the slope of ESPVRREF (4.0 vs 5.2 mm Hg/ml) and was load dependent. We conclude that as long as the P-V measurements are made under a fixed afterload system and different preloads, ESPVRpp EEV and ESPVREEPV, but not MPVR, can be used to approximate ESPVRREF.
The incidence of increased TR postendocardial lead placement was 10.0%; this is lower than prior estimates. Predevice RA area and RVSP are predictors of increased TR after lead placement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.