The maximal rate of fall in right ventricular pressure (negative dp/dt) was evaluated in 34 patients. Eight had normal pulmonary arterial pressure. Seventeen had pulmonary arterial hypertension, and nine had pulmonary arterial hypertension with right ventricular failure. The right ventricular maximal negative dp/dt in patients with normal pulmonary arterial pressure was 170 +/- 20 mm Hg/sec. In...

A new methodology has been developed to measure the mechanical integrity of a bilayer lipid membrane (BLM) formed over porous substrates. A custom test fixture was fabricated in which a stepper motor linear actuator drives a piston in order to apply pressure to a BLM in very fine increments. The pressure, monitored with a pressure transducer, is observed to increase until the BLM reaches its fa...

Atrial natriuretic peptide levels are elevated in heart failure. However, the hemodynamic responses to exogenous atrial natriuretic peptide infusion in heart failure are blunted. To determine if captopril can restore hemodynamic responsiveness to atrial natriuretic peptide infusion in rats with heart failure, studies were performed in a rat model of heart failure after coronary artery ligation....

O ne of the greatest challenges in the management of patients with chronic heart failure is forecasting and preventing the development of acute worsening leading to hospitalizations. Despite current best practice guidelines, including management within a heart failure clinic, early follow-up after hospitalizations, measuring daily weights, and frequent patient contact, rehospitalization for hea...

A three-dimensional multilayer model of mechanical response for analyzing the effect of pressure on arterial failure is presented in this work. The multilayer arterial wall is considered to be composed of five different layers. The three-dimensional effects are incorporated within the five-concentric axisymmetric layers while incorporating the nonlinear elastic characteristics under combined ex...

The motion and growth of plants is the inspiration for a new biomimetic actuator that uses fluid transport across a bilayer lipid membrane (BLM) to create internal pressure and cause displacement in the actuator. In order for the actuator to be viable the BLM must be able to withstand this internal pressure without failing. In this study BLMs are formed over a porous polycarbonate substrate and...

A variety of lesions of the central nervous system may be associated with disturbances of renal function characterized by either the increased urinary loss of sodium and chloride (1-3) or the retention of salt (3-8). It has also been postulated that changes in the excretion of salt, secondary to alterations in the volume of blood or extracellular fluid, are mediated by a "volume receptor" locat...

In pulmonary arterial hypertension (PAH), right ventricular (RV) adaptation is essential to overcome the chronic increases in RV pressure overload. Ultimately, RV compensatory mechanisms are not sufficient and patients succumb to RV failure. The processes underlying the transition of RV adaptation to RV failure are not well understood. In this review, we propose that important insights in RV ad...

Abbreviations: TEE: Trans esophageal Echocardiography; HF: Heart Failure; HT: Heart Transplantation; LVAD: Left Ventricular Assist Device; ESHF: End Stage Heart Failure; LVHF: Left Ventricular Heart Failure; LV: Left Ventricular; LVEDV: Left Ventricular End Diastolic Volume; PV: Prolonged Ventilation; BNP: B-Type Natriuretic Peptide; VAD: Ventricular Assist Device; LVEDP: Left Ventricular End D...

The aim of the present study was to characterize intraventricular pressure gradients (IVPGs) in an animal model of chronic heart failure. New Zealand rabbits were treated with doxorubicin (heart failure group, n=5) or saline (control group, n=5) and instrumented with pressure catheters placed in the apex and outflow-tract of left ventricle (LV) and with sonomicrometer crystals placed in the ape...