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PubMed1978

Estimation of cardiac function by means of radiocardiographic function analysis.

The radiocardiographic function analysis represents a relatively simple procedure for the clinician to collect information concerning the changes of cardiac dynamics. The advantage of this method is to register non-invasively changes in cardiac dynamics at rest and during exercise such as those of enddiastolic volume, stroke volume, endsystolic volume, ejection time and filling time, and to permit the calculation of mean ejection velocity, etc. After insertion of a cardiac catheter, it is possible to record the corresponding pressure pulse in the right ventricle or in the pulmonary vessels simultaneously.

Cardiac Catheterization↗
PubMed2000

Cardiac function after intermittent antegrade warm blood cardioplegia: contribution of the double-indicator dilution technique.

OBJECTIVE: To evaluate cardiac performance following coronary artery surgery using two different techniques of cardioplegia. DESIGN: Randomized prospective study. SETTING: Adult cardiothoracic intensive care unit in a university hospital. STUDY POPULATION: Thirty patients undergoing isolated coronary surgery. INTERVENTIONS: Patients were randomized to receive either intermittent antegrade warm blood cardioplegia with normothermic bypass (group 1) or combined antegrade and retrograde cold crystalloid cardioplegia with hypothermic bypass (group 2). Hemodynamic evaluation included conventional measurements from a pulmonary artery catheter and data obtained by thermal dye dilution utilizing an arterial thermistor-tipped fiberoptic catheter. RESULTS: The only major difference between groups was a significantly higher right atrial pressure in group 2, from 4 h to 24 h after surgery (8.8 +/- 2.6 vs. 11.8 +/- 3.2 mmHg at 4 h and 11 +/- 3.1 vs. 8.5 +/- 1.8 mmHg at 24 h, P = 0.04). After cold cardioplegia a significant increase in right atrial pressure was observed (7.5 +/- 3.1 before surgery vs. 11.4 +/- 3 mmHg at 8 h, P = 0.003) whereas right ventricular end diastolic volume index did not increase significantly, suggesting impaired right ventricular diastolic compliance in this group. CONCLUSIONS: Until 24 h after surgery cold cardioplegia is associated with impaired right ventricular filling, which seems better preserved by intermittent antegrade warm blood cardioplegia. End-diastolic volume measurement with the double-indicator technique allows differentiation between systolic and diastolic dysfunction.

Analysis of Variance↗
PubMed2001

Peak exercise cardiac power output; a direct indicator of cardiac function strongly predictive of prognosis in chronic heart failure.

OBJECTIVES: This study assessed the prognostic value of peak cardiac power output, measured non-invasively during maximal cardiopulmonary exercise testing, against other exercise-derived haemodynamic variables in patients with chronic congestive heart failure. METHOD AND RESULTS: Two hundred and nineteen unselected, consecutive patients with congestive heart failure (166 men, mean (+/-SD) age of 56+/-13 years) who underwent maximal symptom limited cardiopulmonary treadmill exercise testing with non-invasive estimation of cardiac output using carbon dioxide re-breathing techniques, were followed-up for a mean period of 4.64 (4.47--4.82, 95% CI) years. Cardiac power output was calculated from the product of cardiac output and mean arterial blood pressure. All cause mortality was 12.3% (27 deaths). Peak and resting cardiac power output, peak mean arterial blood pressure, peak and resting cardiac output and peak VO(2)were all predictive of outcome on univariate analyses. Peak cardiac power output, either entered continuously or categorically with a cut-off value of 1.96 watts, was the only independent predictor of mortality (P=0.0004 for values < or >1.96 watts and P=0.001 for continuous values) using multivariate analysis. A relative risk ratio of 5.08 (1.94-13.3, 95% CI) was obtained for a cardiac power output <1.96 watts. CONCLUSION: Peak cardiac power output is an independent predictor of mortality that can be measured non-invasively using cardiopulmonary exercise testing. It can give further prognostic power to a peak VO(2)in the assessment of patients with congestive heart failure.

Adult↗
PubMed1982

Effect of arterial compliance on systolic blood pressure and cardiac function.

To study the effects of arterial compliance on blood pressure and ventricular performance, 33 patients undergoing diagnostic cardiac catheterization who were found to be free of significant cardiac disease were selected. Since blood pressure is a continuous variable, a specific cutting point was not used as a criterion for selection, although 12 patients were classified as hypertensive. The interrelationships between blood pressure, peripheral resistance, arterial compliance, and stroke volume index were investigated by determining the linear correlation between any two desired variables; and by employing partial correlative analysis to determine whether an observed relationship was dependent upon or independent of the influence of a third variable. Peripheral resistance was observed to be independently related to diastolic pressure (r = 0.59, p less than 0.01); while arterial compliance was not only related to stroke volume index (r = 0.67, p less than 0.01) but was also independently related to systolic pressure (r = -0.63, p less than 0.01). Thus, these observations suggest that arterial compliance is a common hemodynamic variable related to both the level of systolic pressure and ventricular performance.

Adult↗
PubMedDate not supplied

Effect of low protein diet on cardiac function and ultrastructure of spontaneously hypertensive rats loaded with sodium chloride.

The effects of low protein diet on cardiac metabolic and structural changes subsequent to an extremely high pressure load were investigated. Spontaneously hypertensive rats(SHR) were divided into four groups, and fed the following diets for four weeks: 1) Group A: regular diet (23% protein) and water, 2) Group B: regular diet and 1% saline, 3) Group C: low protein diet (10% protein) and water, and 4) Group D: low protein diet and 1% saline. Two weeks after the start of feeding, there was no significant difference in the left ventricular ultrastructures between the corresponding regular and low protein diet groups. Four weeks after, degenerative findings such as streaming of Z lines, dilatations of smooth endoplasmic reticulum, and disarrangements of myofilaments appeared Group D, while in Group B electron microscopic findings indicated hypertrophy. Incorporation of [14C] leucine into the myocardial myosin B in Group D was significantly low, with a resulting fall of the LVdP/dtmax per integrated isometric pressure (IIP) and a rise of the left ventricular end-diastolic pressure (LVEDP), as compared to that in Group C at four weeks after the start of feeding. These observations suggest that, in the heart with an extremely high pressure load, low protein diet hinders the development of hypertrophy to the load with resulting heart failure.

Animals↗
PubMed1987

Myocardial opiate receptor activity is stereospecific, independent of muscarinic receptor antagonism, and may play a role in depressing cardiac function.

Earlier work has shown that morphine sulfate can produce a dose-related decrease in heart rate (HR) and cardiac output (CO) in isolated working rat hearts. This response is preventable with the use of the opiate receptor antagonist, naloxone hydrochloride. In this study, the stereospecificity of the opiate response was tested with the use of levorphanol tartrate and its d-isomer, dextrorphan, in our Langendorff rat heart model. The interaction of muscarinic receptor activity with the opiate response was tested by first adding bethanechol chloride to the perfusate in the presence and absence of atropine (5 X 10(-9) mmol/L). Our earlier studies with morphine sulfate were then repeated in the presence of the same concentration of atropine. At a concentration of 5 X 10(-6) mmol/L, levorphanol tartrate produced a significant decrease in CO (p less than 0.05), while a similar concentration of dextrorphan produced little change in either HR or CO. Bethanechol chloride, in a concentration of 3 X 10(-6) mmol/L, produced a significant decrease in HR and CO (p less than 0.05), which was prevented by atropine. When morphine sulfate was added to the standard perfusate (3 X 10(-4) mmol/L), HR and CO were significantly decreased (p less than 0.05). This change was not prevented by the addition of atropine. The opiate effect on myocardial function is mediated by a stereospecific opiate receptor, which acts independently of muscarinic receptor antagonism.

Animals↗
PubMed1999

Pulmonary hypertension and cardiac function in adult cystic fibrosis: role of hypoxemia.

STUDY OBJECTIVES: To determine (1) the prevalence of pulmonary hypertension and cardiac dysfunction in adult cystic fibrosis (CF) patients with severe lung disease, (2) the relationship between these cardiovascular abnormalities and hypoxemia, and (3) the impact of subclinical pulmonary hypertension on survival. DESIGN: Single-blind, cross-sectional study. SETTING: Ambulatory clinic of the Adult CF program at a tertiary-level hospital. PATIENTS: Clinically stable patients with severe lung disease (FEV1 < 40% of predicted normal value) who were not receiving supplemental oxygen. A second cohort of patients in stable condition with less severe lung disease (FEV1 40 to 65% predicted) was also recruited to enable multivariate analysis for the determinants of pulmonary hypertension. MEASUREMENTS AND RESULTS: Eighteen patients with severe lung disease (FEV1 28 +/- 7% of predicted normal value) were initially studied. Each patient had overnight polysomnography, pulmonary function tests, and Doppler echocardiography. Arterial oxygen saturation (SaO2) was reduced during wakefulness (87.1 +/- 6.1%) and fell during sleep (84.0 +/- 6.6%) while transcutaneous PCO2 was normal during wakefulness (41.1 +/- 6.9 mm Hg) and increased during sleep (46.6 +/- 4.7 mm Hg). Left ventricular size, systolic function, and diastolic function were normal except in one patient who had had a previous silent myocardial infarction due to coronary artery disease. Qualitative assessment of right ventricular function was normal in all patients. Pulmonary artery systolic pressure (PASP) was increased (> 35 mm Hg) in seven patients without clinical evidence of cor pulmonale. Regression analysis was performed by combining these data with data from an additional 15 CF patients with moderately severe lung disease (FEV1 56.3 +/- 8.9% predicted normal) who were recruited to a modified study protocol that included overnight oximetry, pulmonary function tests, and Doppler echocardiography. None of these patients had evidence of hypoxemia and only three had mild elevation of PASP (36, 37, and 39 mm Hg). Linear regression analysis revealed that PASP was significantly correlated with FEV1 (r = -0.44; p = 0.013), and SaO2 during wakefulness (r =-0.60; p = 0.0003), during sleep (r = -0.56; p = 0.0008), and after 6 min of exercise (r = -0.75; p < 0.0001). Multivariate analysis revealed that awake SaO2 was a significantly better predictor of PASP than FEV1 (p = 0.0104). Clinical follow-up of the original cohort for up to 5 years revealed that mortality was significantly higher in those with pulmonary hypertension than those without pulmonary hypertension (p = 0.0129). CONCLUSIONS: In adult CF patients with severe stable lung disease, left and right ventricular function is well maintained in the absence of significant coronary artery disease; pulmonary hypertension develops in a significant proportion of patients and is strongly correlated with oxygen status, independent of lung function; and subclinical pulmonary hypertension is associated with an increased mortality.

Adult↗
PubMed1984

Physiologic abnormalities of cardiac function in progressive systemic sclerosis with diffuse scleroderma.

To investigate cardiopulmonary function in progressive systemic sclerosis with diffuse scleroderma, we studied 26 patients with maximal exercise and redistribution thallium scans, rest and exercise radionuclide ventriculography, pulmonary-function testing, and chest roentgenography. Although only 6 patients had clinical evidence of cardiac involvement, 20 had abnormal thallium scans, including 10 with reversible exercise-induced defects and 18 with fixed defects (8 had both). Seven of the 10 patients who had exercise-induced defects and underwent cardiac catheterization had normal coronary angiograms. Mean resting left ventricular ejection fraction and mean resting right ventricular ejection fraction were lower in patients with post-exercise left ventricular thallium defect scores above the median (59 +/- 13 per cent vs. 69 +/- 6 per cent [P less than 0.025], and 36 +/- 12 per cent vs. 47 +/- 7 per cent [P less than 0.025], respectively). We conclude that in progressive systemic sclerosis with diffuse scleroderma, abnormalities of myocardial perfusion are common and appear to be due to a disturbance of the myocardial microcirculation. Both right and left ventricular dysfunction appear to be related to this circulatory disturbance, suggesting ischemically mediated injury.

Adult↗
PubMed1979

[The effects of oxprenolol on cardiac function during hypovolemic shock in dogs (author's transl)].

Effects of beta-receptor blockade by oxprenolol, which significantly prevented subendocardial necroses during hemorrhagic shock in dogs, on shock tolerance and myocardial function were analyzed. Overall mortality was not altered by beta-receptor blockade. Cardiac output and contractility (dp/dtmax) before, during and after a hypovolemic period of 120 to 210 min with mean arterial pressure = 40 +/- 5 mmHg showed no significant difference with or without oxprenolol treatment. Increase of heart rate during hemorrhage was abolished completely by oxprenolol and as a consequence of this duration of the diastolic filling period was about three times longer (p less than 0.001) and stroke volumes were greater. Stress metabolism was improved. Hyperglycemia and metabolic acidosis were diminished and arterial oxygen tension was higher in the treated group. Incidence of lethal ventricular fibrillation was higher and pulsus alternans found only in the control group. The beneficial effects of beta-receptor blockage on the course of hemorrhagic shock are explained by the prevention of the catecholamine induced tachycardia and thereby increased coronary perfusion and decreased myocardial oxygen consumption and by the intrinsic sympathicomimetic activity of oxprenolol.

Acidosis↗
PubMed1986

Cardiac function and chronotropic sensitivity to beta-adrenergic stimulation in sepsis.

An organism's cardiovascular response to sepsis is at least partly dependent on hormonal and neural modulation of myocardial function. We have investigated both intrinsic myocardial performance and one aspect of myocardial sensitivity to beta-adrenergic stimulation in a model of sepsis in which animals, at the time studied, exhibited bacteremia, normal arterial blood pressure and cardiac output, elevated heart rate, and elevated plasma catecholamines. Intrinsic myocardial contractile function, studied with the isolated, perfused working heart preparation, was depressed over a range of preloads in septic animals, whereas heart rate was elevated. To determine whether hearts from septic animals could respond normally to beta-adrenergic stimulation, we studied chronotropic responses to isoproterenol in both Langendorff perfused hearts and in isolated right atria. In langendorff perfused hearts from septic animals, basal rates were significantly increased and lower concentrations of isoproterenol elicited greater increases in heart rate. In isolated right atria from septic animals, basal rates were also elevated and the EC50 for the chronotropic response to isoproterenol was significantly less than in atria from control animals. The maximal heart rate response to isoproterenol was not significantly different from control. These results indicate that in sepsis, despite apparently adequate in vivo cardiac performance, intrinsic myocardial function is depressed, but chronotropic sensitivity to beta-adrenergic stimulation is increased.

Animals↗