BACKGROUND: Right ventricular (RV) hypertrophy is an adaptive process that occurs in the setting of chronic pulmonary hypertension (CPH) and can lead to alterations in normal RV diastolic properties. This study was designed to investigate the effects of NO and milrinone on RV diastolic dysfunction in the setting of CPH ...

Experiments were conducted in 10 isolated rabbit hearts at 25 degrees C to test the hypothesis that vibration-induced depression of myocardial contractile function was the result of increased cross-bridge breakage. Small-amplitude sinusoidal changes in left ventricular volume were administered at frequencies of 25, 50, and 76.9 Hz. The resulting pressure ...

OBJECTIVE: A major cause of early postoperative morbidity and mortality after cardiac transplantation is right ventricular (RV) failure which is attributed to the inability of the donor's RV to acutely compensate for the recipient's elevated pulmonary vascular resistance. This study was performed to determine: (1) the acute effects of brain ...

The aim of the study was the assessment of right ventricular (RV) structure and diastolic function in hypertensive subjects. The study group consisted of 44 patients with untreated, mild to moderate essential systemic hypertension. All the patients were in sinus rhythm, no symptoms of congestive heart failure, ischaemic or valvular ...

It has been suggested that the renin-angiotensin system (RAS) interacts with the endothelin system in the pathogenesis of cardiac remodeling. We examined endothelin system regulation in a model of chronic RAS dysfunction, which is believed to be an important factor in cardiac remodeling. We used the transgenic rat line TGR(mRen2)27, ...

OBJECTIVES: This study sought to investigate the influence of right ventricular (RV) hemodynamic variables and function on the secretion of brain natriuretic peptide (BNP) in patients with isolated RV overload. BACKGROUND: Plasma BNP is known to increase in proportion to the degree of left ventricular (LV) overload. However, whether BNP ...

BACKGROUND: Right ventricular (RV) dysfunction is common after heart transplantation, and myocardial ischemia is considered to be a significant contributor. We studied whether intraaortic balloon counterpulsation would improve cardiac function using a model of acute RV pressure overload. METHODS: In 10 anesthetized sheep, RV failure was induced using a pulmonary ...

We analyzed spontaneous ventricular tachycardias treated by antitachycardia pacing during long-term follow-up in 138 recipients of an implantable cardioverter-defibrillator. An inverse circadian variation of the antitachycardia pacing termination and acceleration rates with the worst antitachycardia pacing success during the time period with the highest episode frequency (morning hours) was demonstrated.

PURPOSE: Pressurisation of the medullary cavity during cemented arthroplasty causes "intravasation" of marrow fat. The purpose of this study was to examine the relationship between the amount of pulmonary intravascular fat and the haemodynamic and echocardiographic changes. METHODS: Anaesthetised mongrel dogs (n = 16) underwent bilateral cemented arthroplasty (BCA) to ...

STUDY OBJECTIVES: Recipient chronic pulmonary hypertension (CPH), secondary to long-standing congestive heart failure, represents a significant risk factor for right ventricular (RV) dysfunction following orthotopic cardiac transplantation (TX). This study was designed to characterize the changes occurring in pulmonary hemodynamics, pre-TX and post-TX, using Fourier analysis, a canine model of ...

The effects of pericardial constraint on cardiac chamber interactions were evaluated by mathematical model analyses based on a novel concept of coupled vs. uncoupled pericardial constraint. We hypothesized that the nature of pericardial constraint can be classified as a "coupled" constraint exerted by uniform liquid pressure or an "uncoupled" constraint ...

BACKGROUND: Right ventricular (RV) failure remains an important risk factor for early morbidity and mortality after orthotopic cardiac transplantation and is most commonly related to preexistent chronic pulmonary hypertension (CPH) in the recipient, which occurs secondary to long-standing congestive heart failure. This study was designed to assess the compensatory mechanisms ...

BACKGROUND: The degree of protection provided to the right ventricle during retrograde continuous normothermic blood cardioplegia (RCNBC) remains controversial. The purpose of this study was to determine whether RCNBC is able to provide "adequate" nutritive flow to both ventricles to prevent ischemic metabolism in normal swine hearts. Localized 31P magnetic ...

Recently, we proposed that the higher stroke volume (SV) and cardiac output (Q) of endurance-trained (ETR) versus untrained (UTR) individuals are attributable primarily to the enhanced diastolic filling of ETR consequent to a larger blood volume (BV). To test this hypothesis, we examined the effects of manipulating BV on the ...

Sustained ventricular tachycardias (VT) often degenerate into ventricular fibrillation (VF). In the present study, the impact of VT on mean arterial blood pressure (MAP), myocardial blood flow (MBF), and myocardial oxygen consumption (MVCO2) was assessed. In addition, the degeneration of sustained VT into VF was analysed with respect to MAP. ...

BACKGROUND: Heart failure subsequent to myocardial infarction (MI) is accompanied by depressed antioxidants and increased oxidative stress in the myocardium. Antioxidant enzyme activities and oxidative stress were examined in the viable left (LV) and right (RV) ventricles in relation to their hemodynamic function. METHODS AND RESULTS: The left coronary artery ...

STUDY OBJECTIVE: To assess the relations among right ventricular (RV) pressures and volumes in sepsis. DESIGN: Prospective study. SETTING: ICU. PATIENTS: Eighteen patients with sepsis who were in hemodynamically stable condition. INTERVENTION: Stepwise increases and decreases in RV end-diastolic volume (EDV) as induced by military antishock trousers (MAST) inflation of ...

OBJECTIVES: This investigations was undertaken to examine the alteration of electrophysiologic properties, including refractoriness, strength-interval relations and conduction, with the development of heart failure and to characterize the impact of volume loading on these indexes in the cardiomyopathic setting. METHODS: Electrophysiologic properties in eight dogs with pacing-induced dilated cardiomyopathy were ...

STUDY OBJECTIVE: The development of right ventricular (RV) hypertrophy in emphysema is accompanied by involvement of the left ventricle (LV) and its systolic function. Our objective was to study the relation between RV hypertrophy and LV ejection fraction in emphysema by means of MRI. PATIENTS: Ten emphysematous patients (FEV1, 0.99+/-0.32 ...

OBJECTIVES: We sought to evaluate whether prolonged exercise in ultramarathon runners results in left ventricular (LV) damage. BACKGROUND: Strenuous exercise has been reported to cause LV damage. METHODS: Fourteen runners who completed an ultramarathon at high altitude underwent echocardiography, finger-tip oximetry and blood measurements of cardiac troponin I (cTnI) and ...

Color Doppler echocardiography of tricuspid valve regurgitation (TR) is a valid, noninvasive method of determining systolic pulmonary artery pressure (SPAP). In a prospective study the authors examined 56 healthy full-term newborns (group I), 36 healthy preterm newborns (group II), and 10 preterm newborns with severe respiratory distress syndrome requiring surfactant ...

PURPOSE: The purpose of this study was to determine the dynamic changes in right ventricular (RV) and left ventricular (LV) output during positive airway pressure inspiratory hold maneuvers so as to characterize the interaction of processes in creating steady-state cardiac output during positive pressure ventilation. MATERIALS AND METHODS: We examined ...

OBJECTIVE: To recognize patients with unresponsive septic shock and right ventricular (RV) failure and to evaluate the effects of epinephrine on RV performance in these patients. DESIGN: Prospective descriptive study. SETTING: Medical intensive care unit. SUBJECTS: 14 consecutive patients in septic shock unresponsive to fluid loading, dopamine, and dobutamine. INTERVENTIONS: ...

BACKGROUND: Recently, idiopathic ventricular fibrillation (VF) has gained much attention. Although several subgroups have been described, its pathogenesis, mechanism, treatment, and prognosis remain unknown. METHODS AND RESULTS: We studied six cases of idiopathic VF with transient late r' waves and ST elevation (late r'/ST elevation) in leads V1 through V3. ...

Monocrotaline (MCT)-induced pulmonary hypertension (PH) is associated with impaired endothelium-dependent nitric oxide (NO)-mediated relaxation. To examine the role of NO in PH, Sprague-Dawley rats were given a single subcutaneous injection of normal saline [control (C)], 80 mg/kg MCT, or the same dose of MCT and a continuous subcutaneous infusion of ...

OBJECTIVE: Acute pulmonary hypertension may cause right ventricular (RV) contractile failure. While it has been assumed that restoration of normal loading conditions after acute pulmonary hypertension is sufficient for complete recovery of RV function, this has not been rigorously examined. The purpose of this study was to test the hypothesis ...

BACKGROUND: This study establishes a chemically-induced canine model of chronic pulmonary hypertension (CPH) using monocrotaline pyrrole (MCTP) and then characterizes this model in terms of hemodynamic, morphologic, and cardiac functional changes. METHODS: Thirty-three adult mongrel dogs (22 to 25 kg) were used. All animals underwent pulmonary artery catheterization to measure ...

BACKGROUND: Right ventricular (RV) function is believed to be an important determinant of left ventricular assist device (LVAD) filling. This study was designed to demonstrate this relation in patients. METHODS: To demonstrate the interaction between RV ejection and LVAD filling, 10 patients (mean age, 49 +/- 13 years) supported with ...

We assessed the effect of pressure on the release of prostacyclin (PGI2) from cultured endocardial endothelial cells (EECs) and vascular endothelial cells (VECs). EECs were harvested from the right ventricle (RV) and left ventricle (LV) of porcine hearts, and VECs from pulmonary artery (PA), aorta (Ao) and coronary artery (CA). ...

The effectiveness of dynamic cardiomyoplasty (DCMP) remains controversial. We hypothesized that effectiveness of DCMP using the latissimus dorsi muscle graft (LDMG) depends on the wrapping method. We analyzed pressure-volume relations (PVR), the left ventricular stroke work (LVSW), and the left ventricular end diastolic volume (LVEDV) changes during nonstimulation and stimulation ...

BACKGROUND: Previous studies have shown that left ventricular (LV) unloading alters right ventricular (RV) systolic mechanics, but the effects of LV assist device (LVAD) support on RV diastolic function have not been examined in intact subjects. METHODS: Seven closed-chest, sedated dogs were studied after placement of a LVAD and 27 ...

Right ventricular (RV) failure, which is a leading cause of early morbidity and mortality following cardiac transplantation, is attributed to the inability of the donor RV to acutely compensate for the recipient's elevated pulmonary vascular resistance (PVR). Furthermore, the effect of donor brain death (BD) on RV function is unclear. ...

To determine whether a rat heart model can provide load-insensitive measurements of cardiac function, a recently developed biventricular perfused preparation was tested. Using 29 Sprague-Dawley rat hearts perfused with modified Krebs-Henseleit buffer, ventricles functioned simultaneously with adjustable independent preload (venous reservoirs) and afterload (compliance chambers). Ultrasonic crystal pairs provided continuous ...

BACKGROUND: Current therapy for massive venous air embolism (VAE) may include the use of the left lateral recumbent (LLR) position, although its effectiveness has been questioned. This study used transesophageal echocardiography to evaluate the effect of body repositioning on intracardiac air and acute cardiac dimension changes. METHODS: Eighteen anesthetized dogs ...

PURPOSE: In previous studies the degree of embolization detected by transoesophageal echocardiography (TEE) during cemented total hip arthroplasty (THA) did not correlate with changes in haemodynamic variables nor did it result in persistent ventilation-perfusion mismatching. The aim of this study was to record evidence of embolism and to relate the ...

BACKGROUND: Right ventricle (RV) preload assessment remains controversial because the complexity of RV geometry is an obstacle to wall stress modeling. We developed a method to evaluate end-diastolic RV elastic energy (EL), a variable that integrates all the stretching effects of venous return and that can be easily estimated at ...

We have shown that the cellular contractile dysfunction characteristic of pressure-overload cardiac hypertrophy results not from an abnormality intrinsic to the myofilament portion of the cardiocyte cytoskeleton but rather from an increased density of the microtubule component of the extramyofilament portion of the cardiocyte cytoskeleton. To determine how, in physical ...

A simplified version of the modified echocardiographic subtraction method for measuring right ventricular (RV) volume was used to assess the indices of RV contractile function, the end-systolic pressure-volume (RV Emax) ratio and the +dP/dt(max)-end-diastolic volume (EDV) relationship. RV volumes determined by the simplified subtraction method and the modified subtraction method ...

BACKGROUND: Right ventricular (RV) performance appears to be important in patients with severe heart failure. Although clinical assessments of RV function previously have been limited to load-dependent ejection phase indices, a new method has been developed using the relatively load-insensitive concepts of pressure-volume relations with automated echocardiographic measures of RV ...

We investigated cardiac morphometry 6 wk after sinoaortic baroreceptor denervation (SAD) in Long-Evans rats. SAD (n = 19) was associated with an 11% increase in the weight of the left ventricle (LV) plus septum (P < 0.001) and a 39% increase in that of the right ventricular (RV) free wall ...

BACKGROUND: Right ventricular (RV) dysfunction is a common but poorly understood problem associated with mechanical left heart assist (LHA). Left ventricular unloading may affect RV function even in normal hearts by altering geometry or function of the interventricular septum, although such changes have not been well defined. Accordingly, the purposes ...

OBJECTIVE: To study the effects of incremental concentrations of inhaled aerosolized prostacyclin (PGI2) on pulmonary and systemic hemodynamics after cardiac surgery or heart transplantation. DESIGN: Pharmacodynamic dose-response study. SETTING: Cardiothoracic intensive care unit (ICU) at a university hospital. PARTICIPANTS: Nine patients with pulmonary hypertension after cardiac surgery or heart transplantation ...

OBJECTIVES: The present study was designed to evaluate the effects of the nitric oxide synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) on right ventricular (RV) contractility, both pulsatile and nonpulsatile contributions to afterload, and relate any changes to alterations in performance of the RV as a pump. DESIGN: Prospective drug response. ...

It has been hypothesized that the changes in myocardial stiffness induced by chronic hemodynamic overloading are dependent on changes in the passive stiffness of the cardiac muscle cell (cardiocyte). However, no previous studies have examined the passive constitutive properties of cardiocytes isolated from animals with myocardial hypertrophy. Accordingly, changes in ...

As the myocardium contracts isometrically, it generates vibrations that are transmitted throughout the heart. These vibrations can be measured with an implantable microaccelerometer located inside the tip of an otherwise conventional unipolar pacing lead. These vibrations are, in their audible component, responsible for the first heart sound. The aim of ...

BACKGROUND: Acute graft failure is an important cause of morbidity and mortality in cardiac transplantation, and it may be associated with myocardial changes that occur during brain death (BD). This study investigates the changes in biventricular systolic and diastolic function that occur after BD in a validated canine model. METHODS ...

The availability of the volumetric thermodilution pulmonary artery catheter allows preload assessment based on ventricular volume rather than pressure. This technique has been shown clinically to be a better measure of preload than the pulmonary artery occlusion pressure (PAOP). Critics of the technique argue that the use of thermodilution to ...

The effect of chronic administration of beta-guanidinopropionic acid (GPA) on the protein profiling, energy metabolism and right ventricular (RV) function was studied in the rat heart during the weaning and adolescence period. GPA was given in tap water (1-1.5%) using pair drink controls. The feeding of animals with GPA solution ...

This study was designed to measure the right ventricular (RV) stiffness (delta P/ delta V) with a new method without estimating the RV volume itself. RV stiffness has rarely been measured due to the difficulty in estimating the RV volume. Without measuring RV volume itself, stiffness can be determined by ...

BACKGROUND: The chest wall, lungs, and pericardium limit diastolic filling of the left ventricle in the fetus, neonate, and adult. To determine the effect that these tissues have on the fetal right ventricle (RV), we studied six fetal lambs (142 days of gestation) METHODS AND RESULTS: Pregnant ewes were anesthetized ...