Pressurized elastic capsules arise at scales ranging from the 10 m diameter pressure vessels used to store propane at oil refineries to the microscopic polymeric capsules that may be used in drug delivery. Nature also makes extensive use of pressurized elastic capsules: plant cells, bacteria and fungi have stiff walls, ...

The cardiac muscle activation or driver function, is a major determinant of cardiovascular dynamics, and is often approximated by the ratio of the left ventricle pressure to the left ventricle volume. In an intensive care unit, the left ventricle pressure is usually never measured, and the left ventricle volume is ...

Cardiovascular disease is the leading cause of death in patients with end-stage renal disease (ESRD). The aim of this study was to investigate the changes in cardiovascular function induced by a single session of hemodialysis (HD) by the analysis of cardiovascular dynamics using wave intensity wall analysis (WIWA) and of ...

OPINION STATEMENT: The heart is a complex and sophisticated pump that cycles between two phases: diastole, during which a compliant chamber (ventricle) allows the blood to fill from a reservoir chamber (atrium) of low pressure, and systole, during which a stiff chamber with rapidly rising pressure ejects the blood into ...

Our patient had the classic square root sign typical of constrictive pericarditis, but contrary to what we would have expected, his end-diastolic pressures did not equalize.

We have previously shown that a newly developed calpain inhibitor, SNJ-1945 (SNJ), with good aqueous solubility prevents the heart from KCl arrest-reperfusion injury associated with the impairment of total Ca(2+) handling by inhibiting the proteolysis of alpha-fodrin as a cardioplegia. The aim of the present study was to investigate certain ...

A prospective, open-label, 3-month study was conducted to evaluate the feasibility and short-term clinical effect of subcutaneous erythropoietin injections in patients with anemia and heart failure with preserved ejection fraction (ejection fraction, 55%+/-2%). Using a dose-adjusted algorithm to effect a rate of rise in hemoglobin not to exceed 0.4 g/dL ...

OBJECTIVE: To assess differences in left ventricular contractile indices among dogs of 3 body sizes via 2-D speckle-tracking echocardiography (STE) and to determine body weight-independent systolic variables. ANIMALS: 37 clinically normal adult dogs. PROCEDURES: Dogs were allocated into 3 groups on the basis of body weight: small (<7kg), medium (7 ...

The purpose of this study was to assess shortterm effects of transjugular intrahepatic shunt (TIPS) on cardiac function with cardiac magnetic resonance imaging (MRI) in patients with liver cirrhosis. Eleven patients (six males and five females) with intractable esophageal varices or refractory ascites were imaged with MRI at 1.5 T ...

This article focuses on static methods for determining preload, specifically pressure and volumetric indices measured at the bedside. The underlying ventricular function will determine where the patient is located on Frank-Starling ventricular function curve and the patient's response to a fluid challenge. The proper interpretation and use of such measures, ...

BACKGROUND: In ventricular dilatation or hypertrophy, an elevated end-diastolic pressure is often assumed to be secondary to increased myocardial stiffness, but stiffness is rarely measured in vivo because of difficulty. We measured in vitro passive stiffness of volume- or pressure-overloaded myocardium mainly from congenital heart disease. METHODS AND RESULTS: Endocardial ...

The sarcomeric protein titin is a molecular spring responsible for passive tension and restoring forces of cardiomyocytes. Extension of titin as a function of sarcomere length (SL) has been studied in rodents, which predominantly express the smaller, stiffer N2B titin isoform. Large mammals coexpress roughly equal proportions of N2B and ...

BACKGROUND: Volumetric monitoring with right ventricular end-diastolic volume indexed (RVEDVi) and global end-diastolic volume indexed (GEDVi) is increasingly being suggested as a superior preload indicator compared with the filling pressures central venous pressure (CVP) or the pulmonary capillary wedge pressure (PCWP). However, static monitoring of these volumetric parameters has not ...

Passive constraint is used to prevent left ventricular dilation and subsequent remodeling. However, there has been concern about the effect of passive constraint on diastolic left ventricular chamber stiffness and pump function. This study determined the relationship between constraint, diastolic wall stress, chamber stiffness, and pump function. We tested the ...

We tested the hypothesis that, in heart failure with normal ejection fraction (HFNEF), diastolic dysfunction is accentuated at increasing heart rates, and this contributes to impaired frequency-dependent augmentation of cardiac output. In 17 patients with HFNEF (median age 69 years, 13 female) and seven age-matched control patients, systolic and diastolic ...

OBJECTIVES: This study sought to develop and validate a method for the integrated analysis of systolic and diastolic ventricular function. BACKGROUND: An integrated approach to assess ventricular pump function, myocontractility (end-systolic pressure-volume relationship [ESPVR]), and diastolic compliance (end-diastolic pressure-volume relation [EDPVR]) is of high clinical value. Cardiac magnetic resonance (CMR) ...

AIMS: To test a method to predict the end-diastolic pressure-volume relationship (EDPVR) from a single beat in patients with heart failure. METHODS AND RESULTS: Patients (New York Heart Association class III-IV) scheduled for mitral annuloplasty (n=9) or ventricular restoration (n=10) and patients with normal left ventricular function undergoing coronary artery ...

AIM: The end-systolic pressure-volume relationship (ESPVR) constructed from multiple pressure-volume (PV) loops acquired during load intervention is an established method to asses left ventricular (LV) contractility. We tested the accuracy of simplified single-beat (SB) ESPVR estimation in patients with severe heart failure. METHODS: Nineteen heart failure patients (NYHA III-IV) scheduled ...

BACKGROUND AND OBJECTIVE: Central venous pressure, intrathoracic blood volume, and left ventricular end-diastolic area are reliable measures of cardiac preload under stable clinical conditions. The purpose of this study was to compare different preload parameters over 24 h under conditions of multiple, frequently changing treatments in early septic shock. METHODS: ...

PURPOSE OF REVIEW: To highlight the recent developments in hemodynamic monitoring during liver and lung transplantation. RECENT FINDINGS: Even though a consensus on intraoperative hemodynamic monitoring is still lacking, the most frequently monitoring tool used is the pulmonary artery catheter (PAC). The filling pressures are widely accepted as not being ...

The duration of repolarization of subendocardial, intramural, and epicardial layers of dog ventricles was studied under conditions of volume overload of the heart in situ. Increased preload was modeled by rapid intravenous infusion of saline and rheopolygluquine. The activation-recovery interval was measured by flexible intramural electrodes inserted into the right ...

Pressure-volume loop measurements by cardiac catheterization constitute a highly reliable method for the direct beat-to-beat functional analysis of the heart. We aimed to prove its feasibility for the instantaneous evaluation of right ventricular performance in a novel experimental model of pulmonary regurgitation (PR). Four-month-old sheep (n=18, weighing 35-45 kg) were ...

BACKGROUND: Istaroxime is a novel intravenous agent with inotropic and lusitropic properties related to inhibition of the Na+/K+ adenosine triphosphatase and stimulation of sarcoplasmic reticulum calcium adenosine triphosphatase activity. We analyzed data from HORIZON-HF, a randomized, controlled trial evaluating the short-term effects of istaroxime in patients hospitalized with heart failure ...

BACKGROUND: Reductions in heart rate (HR) with beta-blocker therapy have been associated with improvements in ejection fraction (EF). However, the relative contributions of HR reduction, positive inotropism, afterload reduction, and reverse remodeling to improvements in EF are unknown. METHODS AND RESULTS: Twenty-nine patients (63+/-12 years old) with New York Heart ...

BACKGROUND AND OBJECTIVE: Intraoperative management of patients with end-stage liver disease undergoing liver transplantation requires fluid administration to increase cardiac output and oxygen delivery to the tissues. Filling pressures have been widely shown to correlate poorly with changes in cardiac output in the critically ill patient. Continuous right ventricular end-diastolic ...

We developed a technique to monitor left ventricular ejection fraction (EF) by model-based analysis of the aortic pressure waveform. First, the aortic pressure waveform is represented with a lumped parameter circulatory model. Then, the model is fitted to each beat of the waveform to estimate its lumped parameters to within ...

BACKGROUND: The Parkland formula (2-4 mL/kg/burned area of total body surface area %) with urine output and mean arterial pressure (MAP) as endpoints for the fluid resuscitation in burns is recommended all over the world. There has recently been a discussion on whether central circulatory endpoints should be used instead, ...

The cardiac resynchronization therapy (CRT) effects on the arterial load components, the mechanisms (i.e. haemodynamic changes-dependence) involved in the load reduction and the factors (i.e. basal load conditions) associated with the load changes after CRT, are to be evaluated. Aims: a) to analyze the potential changes in the arterial load ...

Diastolic heart failure (DHF) is present in over 50% of hospitalized heart failure patients, and diastolic dysfunction is known to play a critical pathophysiologic role. Measurement of left-ventricular pressure (LVP) via catheterization is the gold standard for diastolic function (DF) evaluation, but current methods fail to fully capitalize on the ...

The cardiac resynchronization therapy (CRT)effects on the arterial load components, the mechanisms (i.e.haemodynamic changes-dependence) involved in the load reduction and the factors (i.e. basal load conditions) associated with the load changes after CRT, are to be evaluated. Aims: a)to analyze the potential changes in the arterial load components(peripheral resistances, arterial ...

The time-varying elastance concept provides a comprehensive description of the intrinsic mechanical properties of the left ventricle that are assumed to be load independent. Based on pressure-volume measurements obtained with combined pressure conductance catheterization in six open-chest anesthetized sheep, we show that the time to reach end systole (defined as ...

PURPOSE: The transitional changes of the ventricular function at different time points after total cavopulmonary connection (TCPC) were examined. METHODS: A total of 29 patients were divided into a primary TCPC group and a staged TCPC group. In both groups, phase I was defined as within 2 months after TCPC ...

BACKGROUND: As a result of donor heart shortage, resorting to marginal heart donors is being promoted. Dobutamine is usually used to support these potential donors and has been proposed to identify the reversible part of the brain death-induced myocardial dysfunction before potential organ donation. But dobutamine impairs the oxygen supply-demand ...

BACKGROUND: Despite successful repair, patients with coarctation of the aorta (COA) often show persistent hypertension at rest and/or during exercise. Previous studies indicated that the hypertension is mainly due to abnormalities in the arterial bed and its regulatory systems. We hypothesized that ventricular systolic stiffness also contributes to the hypertensive ...

AIM: The study investigated lactic acid and left ventricular function in response to two different sprint cycling schedules varying in their time schedule, in 15 healthy national level cyclists (23+/-1 years). METHODS: During one testing session subjects performed four strenuous bouts in a schedule of increasing time order: 1, 2, ...

Eight normal thoroughbred horses were examined by echocardiography before and 10 minutes after they had been sedated by the intravenous administration of 0.03 mg/kg acepromazine. There were significant (P<0.025) increases in the diameters of the pulmonary artery and the aorta, measured at end-systole, and in the thickness of the interventricular ...

The feasibility of blood-pool pinhole ECG gated SPECT was investigated in healthy mice to assess right and left ventricular function analysis. Anaesthetized (isoflurane 1-1.5%) adult CD1 mice (n=11) were analyzed after intravenous administration of 0.2 ml of 550 MBq of (99m)Tc human albumin. For blood-pool gated SPECT imaging, 48 ventral ...

BACKGROUND: Right ventricular function plays an important role in the hemodynamic derangement during off-pump coronary artery bypass (OPCAB) surgery. Pressure-volume loops have been shown to provide load-independent information of cardiac function. Therefore, the aim of this study was to investigate the feasibility of construction of right ventricular pressure-volume loops with ...

High-dose dobutamine used in dobutamine stress echocardiography (DSE) has hemodynamically based side effects due to a variable combination of beta1 (inotropic) and beta2 (vasodilator) effects. Of concern is the development of an "empty ventricle syndrome" associated with intracavitary or outflow tract obstruction and resultant symptomatic hypotension. This study was undertaken ...

BACKGROUND: Increased left ventricular stiffness is a distinct finding in patients who have heart failure with normal ejection fraction (HFNEF). To elucidate how diastolic dysfunction contributes to heart failure symptomatology during exercise, we conducted a study using an invasive pressure-volume loop approach and measured cardiac function at rest and during ...

OBJECTIVES: To verify whether the use of a small, oval-shaped patch limits the trend toward re-dilatation compared to endoventricular circular patch plasty and leads to different geometrical and functional results in surgical anterior restoration. METHODS: Thirty-seven patients with ischemic cardiomyopathy after anterior myocardial infarction end-systolic volume index of > or ...

Mechanical interplay between the adjacent ventricles is one of the principal modulators of physiopathological heart function, and the underlying mechanisms of interaction are only partially understood, hence hampering clinically useful interpretation of imaging data. In order to characterize the influence of chamber geometry on ventricular coupling, the ventricles and septum ...

BACKGROUND: Quantitative assessment of ventricular volumes and mass in pediatric patients with single-ventricle physiology would aid clinical management, but it is difficult to obtain with 2-dimensional echocardiography. The purpose of the present study was to compare matrix-array 3-dimensional echocardiography (3DE) measurements of single-ventricle volumes, mass, and ejection fraction with those ...

The objective of the study was to assess the effect of heart rate, filling condition and slice thickness on the accuracy of volumetric analysis based on multidetector-row computed tomography (MDCT) of a cardiac phantom. Retrospective electrocardiogram-gated MDCT of a pulsating phantom was performed under different conditions. End-diastolic volume (EDV) and ...

Cardiac preload is traditionally considered to be represented by its filling pressures, but more recently, estimations of end diastolic volume of the left or right ventricle have been shown to better reflect preload. One method of determining volumes is the evaluation of the continuous right ventricular end diastolic volume index ...

PURPOSE: Sonographic myocardial tissue characterization with integrated backscatter (IBS) is affected by both structural and functional properties of the myocardium. The aim of the present study was to investigate the effect of preload reduction by hemodialysis (HD) on IBS measurements. METHODS: Fifty-two patients on maintenance HD underwent echocardiography before and ...

In this brief review, we have focussed largely on the well-established, but essentially phenomenological, linear relationship between the energy expenditure of the heart (commonly assessed as the oxygen consumed per beat, oxygen consumption (VO2)) and the pressure-volume-area (PVA, the sum of pressure-volume work and a specified 'potential energy' term). We ...

BACKGROUND: Postextrasystolic potentiation (PESP) is a property of cardiac tissue whereby two closely timed depolarizations cause the subsequent contraction to be of increased magnitude. METHODS AND RESULTS: Ten subjects were studied in a single-blind study to evaluate the safety and performance of an atrioventricular coupled pacing (A-VCP) algorithm to produce ...

AIMS: The aim of this study was to assess chronic invasive haemodynamic effects of cardiac resynchronization therapy (CRT) in patients with severe heart failure. METHODS AND RESULTS: Seventeen patients with New York Heart Association (NYHA) class III or IV and QRS duration >120 ms on optimal treatments underwent CRT. Haemodynamic ...

Heart failure is defined as the pathologic state in which the heart is unable to pump blood at a rate required by the metabolizing tissues or can do so only with an elevated filling pressure. Heart failure in adults most frequently results from the inability of the left ventricle to ...