PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Heart and cardiac system”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1979

The heart and cardiac conduction system in thrombotic thrombocytopenic purpura. A clinicopathologic study of 17 autopsied patients.

The relation between the heart lesions of thrombotic thrombocytopenic purpura and clinical cardiac dysfunction was studied in 17 autopsied patients. Thirteen of the 17 patients had extensive small-vessel thromboses and in some instances hemorrhages and focal necroses within the heart. Congestive heart failure was present in nine of the 17 patients. Thrombotic microcirculatory cardiac lesions and anemia-related high cardiac output may have contributed to cardiac dysfunction. Serial histologic sections of the cardiac conducting system in 10 patients showed microthrombi in seven and associated hemorrhages in five. Lesions were localized to the atrioventricular node and His bundle parts of the system with sparing of the sinoatrial node and bundle branches. Two patients had electrocardiographic evidence suggesting lesions within conducting tissues. Thrombi and hemorrhages are common findings in the conducting tissues in thrombotic thrombocytopenic purpura and may account for cardiac arrest or transient rhythm disturbances.

Adolescent↗
PubMed1978

Effects of indomethacin on cardiovascular hemodynamics of goats in hemorrhagic shock.

We examined effects of indomethacin, meclofenamate, and prostaglandin E1 on systemic arterial pressure, heart rate, cardiac output, and systemic vascular resistance of anesthetized juvenile goats in severe hemorrhagic shock. Hemorrhagic shock was characterized by low systemic arterial pressure, decreased vascular resistance, and reduction in cardiac output. In acute experiments, indomethacin (3.4 mg/kg) attenuated the systemic hypotension of hemorrhagic shock. The increase in systemic arterial pressure following treatment with indomethacin was the result of increased systemic vascular resistance. Systemic arterial pressure, heart rate, and cardiac output fell during intravenous prostaglandin E1 infusions (3 micrograms/kg/min for 5 min) in both controls and goats in shock. The effects of prostaglandin E1 were more pronounced and prolonged in goats that had undergone the hemorrhagic-shock-producing procedure followed by indomethacin than in control animals treated with indomethacin but not hemorrhaged. Not only was meclofenamate less effective than indomethacin in increasing the systemic arterial pressures of goats in this type of hemorrhagic shock, but also it attenuated the pressor effects of indomethacin. Substances synthesized via prostaglandin fatty acid cyclo-oxygenase may be involved in the systemic hypotension that is characteristic of hemorrhagic shock.

Animals↗
PubMed1977

Pulmonary shunt and cardiovascular responses to CPAP during nitroprusside-induced hypotension.

The effects of continuous positive airway pressure (CPAP) on cardiovascular dynamics and pulmonary shunt (QS/QT) were investigated in 12 dogs before and during sodium nitroprusside infusion that decreased mean arterial blood pressure 40-50 per cent. Before nitroprusside infusion, 5 cm H2O CPAP significantly, P less than .05, decreased arterial blood pressure, but did not significantly alter heart rate, cardiac output, systemic vascular resistance, or QS/QT. Ten cm H2O CPAP before nitroprusside infusion produced a further decrease in arterial blood pressure and significantly increased heart rate and decreased cardiac output and QS/QT. Nitroprusside caused significant decreases in arterial blood pressure and systemic vascular resistance and increases in heart rate, but did not change cardiac output or QS/QT. Five cm H2O CPAP during nitroprusside did not further alter any of the above-mentioned variables. However, 10 cm H2O CPAP decreased arterial blood pressure, cardiac output, and QS/QT. These data indicate that nitroprusside infusion rates that decrease mean arterial blood pressure by 40-50 per cent do not change cardiac output or QS/QT. During nitroprusside infusion low levels of CPAP do not markedly alter cardiovascular dynamics, but high levels of CPAP (10 cm H2O), while decreasing QS/QT, produce marked decreases in arterial blood pressure and cardiac output.

Animals↗
PubMed1978

Reorganization of cardiac venous system in patients with atherosclerotic heart disease.

By angioroentgenography, macro- and microscopic examinations the authors investigated the plasticity of intramural blood drainage vessels and the histological structural lesions of venous walls in 50 heart preparations of patients suffering from atherosclerotic heart disease (AHD) that had developed on the basis of coronary sclerosis varying in degree and localization, and in 15 preparations from hearts of practically healthy persons. It was found that in AHD the myocardial capillary network gradually rarefied; the capillaries, postcapillaries, venules, and sinusoids distended, became varicose, and deformed. In the walls of individual segments of the cardiac draining system the authors observed collagenization, and in myocardial small veins, reduction of venous valvules. The degree of the described alterations in the venous system was proportionate to the degree of myocardial sclerotic changes.

Adolescent↗
PubMed1976

Autonomic nervous system and arrhythmias: studies in the transplanted denervated human heart.

The function of the cardiac autonomic nervous system (ANS) was evaluated by comparison of normal subjects with cardiac transplant recipients. By use of standard intracardiac His bundle recording techniques, the following conclusions regarding basic cardiac electrophysiology were drawn: (1) the sinus node functions normally at rest despite autonomic denervation; (2) the AV node does not show the expected decrease in functional refractory period with increased heart rate in the denervated state, and (3) the adrenergic receptor of the cardiac conduction system does not depend upon autonomic innervation to function normally. Electrophysiologic studies of digitalis demonstrated: (1) in therapeutic doses, the AV nodal blocking effect of digitalis is autonomically mediated; (2) sinus node slowing by digitalis also requires an intact autonomic innervation. Arrhythmia analysis in 47 transplant patients revealed an increased incidence of ventricular arrhythmias in autonomic cardiac denervation. In addition, sudden death in the ischemic denervated heart does occur, weakening the concept of a primary role of the cardiac ANS in this phenomenon.

Arrhythmias, Cardiac↗
PubMed1978

[Use of the variation pulsimetry in the evaluation of diurnal dynamics of cardiac rhythm in patients with ischemic heart disease and functional disorders of the cardiovascular system].

The results of employing the method of variation pulsimetry and dynamic electrocardiography in 30 patients are discussed. Analysis of the circadian dynamics of the statistical characteristics of cardiac rhythm showed that the activity of the sympathetic part of the vegetative nervous system was higher in patients with ischemic heart disease than in those with functional disorders. Disbalance of neurohumoral control of cardiac rhythm in various types of arrhythmias was disclosed.

Adult↗
PubMed1979

Intraoperative mapping in patients with univentricular hearts.

The location of the specialized cardiac conduction system in patients with univentricular hearts may be extremely variable. Electrophysiologic studies during open heart surgery identified the intraventricular conducting tissue to be consistently located in four sites. In patients with univentricular hearts without an outlet chamber, conducting tissue may be located either at 1. along the posterior wall or 2. along the anterior free wall of the ventricle. In patients with univentricular hearts and an outlet chamber, conducting tissue is uusally located anterior and superior to the bulboventricular foramen and then extends towards the atrium either 1. in between the bulboventricular foramen and the pulmonary valve or 2. along the right margin of the pulmonary artery over the anterior free wall of the ventricle towards the junction of the inter-atrial septum and the right atrial appendage. These electrophysiologic studies are consistent with previously described locations of conducting tissue in similar hearts by histologic methods. The different locations of the intraventricular conducting tissues in patients with univentricular hearts demonstrates the valve and the need for electrophysiologic mapping of the specialized cardiac conduction system during surgical repair of univentricular hearts.

Electrocardiography↗
PubMed1979

Hemodynamic effects of dobutamine in children.

Dobutamine is useful for augmenting cardiovasuclar function in adults. However, no information is available on the action of dobutamine in children. To determine its hemodynamic effects in children, we infused dobutamine into 12 children with congenital heart disease during diagnostic cardiac catheterization. We administered dobutamine in two doses: first 2 and then 7.75 microgram/kg per min for 10 minutes each. We meaured heart rate, cardiac output, systemic and pulmonary arterial, right atrial and pulmonary capillary blood pressures before and during the infusion of dobutamine. Systemic and pulmonary vascular resistances, cardiac index and stroke index were calculated. Cardiac output, cardiac index, stroke volume, stroke index and systemic arterial phasic and mean blood pressures increased sugnificantly (P less than 0.05) and pulmonary capillary mean blood pressure decreased significantly (P less than 0.05) during the infusion of each dose of dobutamine compared with control values. Heart rate, pulmonary and right atrial mean blood pressure and systemic and pulmonary vascular resistance were unchanged with either dose of dobutamine. We noted no adverse effect from the drug.

Adolescent↗
PubMed1979

[Nitroglycerin infusion in patients with or without cardiac failure. Demonstration by multifactorial analysis (analysis of correspondences) of three types of hemodynamic response dependent upon the initial state (author's transl)].

The effects of nitroglycerin on systemic vascular resistance and cardiac output are highly debated. This study demonstrates that these effects depend on the initial haemodynamic condition, and explains the conflicting results previously reported. 31 patients presenting initially with a fairly wide spectrum of various haemodynamic parameters underwent cardiac catheterisation with measures of parameters before and after nitroglycerin infusion. Multifactorial statistical analysis by correspondence analysis identifies 3 types of haemodynamic responses and demonstrates the association of each response with a particular haemodynamic profile. It is demonstrated that systemic vascular resistance is decreased only when it is initially elevated and cardiac output is increased only when initial pulmonary wedge pressure and systemic vascular resistance are elevated and cardiac output is low. The effects of nitroglycerin on cardiac output, systemic vascular resistance, heart rate and arterial pressure differ significantly according to the presence or not of cardiac insufficiency and depend mainly on the initial value of three parameters: systemic vascular resistance, pulmonary wedge pressure and cardiac output.

Adult↗
PubMed1977

Pharmacology of the hemodynamic and myocardial response to occlusion of the mesenteric artery in the cat.

Occlusion of the superior mesenteric artery in the cat produces increases in heart rate, systemic pressure, cardiac output and muscle blood flow. Total peripheral resistance is reduced and regional resistance in skin increased. Blockade of the right and left cardiac nerves with xylocaine lowered basal heart rate and reduced cardiac output. The increase in heart rate produced by occlusion of the artery (MAO) was prevented by blockade of the stellate ganglia and cardiac nerves. Propranolol lowered basal heart rate and cardiac output and subsequently blocked the increase in both parameters during MAO. The increase in muscle blood flow was also blocked resulting in an increase in total resistance. We conclude that, in the cat, MAO reflexly increases myocardial tone and enhances venous return from muscle, the latter by a reflex beta adrenergic vasodilation. Both factors provide for the increase in cardiac output. A reflex beta adrenergic vasodilation in muscle, evoked by vasoconstriction in the mesenteric bed, may contribute to survival in the hemorrhaged animals, since capillary exchange in muscle may be increased by this reflex and fluid shifted from the extra--to the intravascular compartment.

Animals↗
PubMed1975

The heart as a target organ in systemic allergic reactions: comparison of cardiac analphylaxis in vivo and in vitro.

The purpose of this investigation was to define and quantitatively evaluate cardiac anaphylaxis in vivo. Guinea pigs, passively sensitized with graded amounts of rabbit antipenicilloyl antibody, were anesthetized, ventilated, and challenged intravenously with a constant amount of antigen (anaphylaxis in vivo). In other experiments, guinea pig hearts were excised, perfused in a Langendorff apparatus, and challenged (analphylaxis in vitro). During in vivo anaphylaxis, sinus rate increased 10-30 beats/min, conduction arrhythmias occurred in 15 of 22 experiments, and ventricular fibrillation was seen in 8 of 22 experiments. Tachycardia and arrhythmias began approximately 20 seconds after antigen administration and were accompanied, but not preceded, by respiratory and pressor changes. During in vitro anaphylaxis, sinus rate increased 70-110 beats/min, coronary flow rate decreased 2-22%, conduction arrhythmias occurred in 21 of 31 experiments, and ventricular ectopic activity was seen in 13 of 31 experiments. Tachycardia and arrhythmias began approximately 15 seconds after antigen administration. Sinus tachycardia, atrioventricular conduction block, increased ventricular automaticity, and histamine release were characteristic features of cardiac anaphylaxis in vivo and in vitro. Both in vivo and in vitro, the intensity of the cardiac reaction depended on the amount of antibody used in passive sensitization. Our results clearly indicate that the heart reacts as a target organ in systemic anaphylaxis of the guinea pig.

Anaphylaxis↗
PubMed1977

De subitaneis mortibus. XXIII. Rheumatoid arthritis and ankylosing spondylitis.

The conduction system of the heart was carefully examined at necropsy in two cases of rheumatoid arthritis and one of ankylosing spondylitis. All three patients had cardiac electrical instability and two fo the three died suddenly. The electrophysiological abnormalities of the three patients included paroxysmal atrial fibrillation in the first case, sustained atrial fibrillation with complete heart block and escape atrioventricular (A-V) junctional rhythm in the second case, and progressively increasing heart block eventually became complete in the third case. The sinus node exhibited extensive focal degeneration with and without associated inflammation in all three hearts, but the sinus node artery was not remarkably abnormal in any of these. All three hearts had important focal degenerative disease in the A-V node and His bundle, and in each of these there was marked narrowing of the local nutrient arteries, amounting to virtual occlusion in two hearts. The probable relationship of these postmortem histological findings to the electrocardiographic disturbances in each patient is discussed. Abnormalities in the cardiac conduction system of the hearts of these three patients are compared to ones previously reported for disseminated lupus erythematosus, polyarteritis nodosa, and scleroderma heart disease.

Adult↗
PubMed1979

Effects of nitroprusside and dopamine on pulmonary arterial vasculature in children after cardiac surgery.

The hemodynamic effects of nitroprusside and dopamine were studied in 28 children early after intracardiac repair. Children were placed in six groups, five according to their anatomic lesion and one made up of those who had postoperative pulmonary artery hypertension, to evaluate the possible differences in response of the pulmonary arterial vasculature to the drugs. Seven children had repair of an atrial septal defect; six, repair of tetralogy of Fallot; four, repair of ventricular septal defect; five, surgery for pulmonary stenosis; one, closure of a left ventricular to right atrial tunnel; and five, postoperative pulmonary artery hypertension. Dopamine was infused at 8 microgram/kg/min, and nitroprusside at 3 microgram/kg/min. With dopamine, the heart rate increased an average of 10% and the cardiac index 11%; both increases were statistically significant. Changes in systemic and pulmonary vascular resistance, however, were not. With nitroprusside, the heart rate increased an average of 9% and the cardiac index 5%, while there was a significant decrease in both systemic (-20%) and pulmonary (-27%) vascular resistance. With the combination of dopamine and nitroprusside, both the cardiac index (+13%) and heart rate (+20%) increased significantly while systemic vascular resistance fell an average of 23% from control, and the pulmonary vascular resistance decreased 21%. Drug response among all five anatomic subgroups tended to be similar. We conclude that an afterload-reducing agent, such as nitroprusside and an inotropic drug such as dopamine, may have potential clinical advantages when used together in children providing heart rate does not become excessive.

Adolescent↗
PubMed1977

The use of 201thallium for myocardial perfusion imaging in sarcoid heart disease.

Cardiac dysfunction due to systemic sarcoidosis is most of ten due to severe restrictive pulmonary diseases. Although the diagnosis is frequently missed during life, direct granulomatous infiltration of the myocardium may occur with systemic sarcoidosis and, when present in the heart, is a major cause of death. To explore the possible use of radioactive 201thallium, a new agent for myocardial imaging, for improved clinical recognition of sarcoid heart disease, myocardial perfusion imaging with 201Tl was performed in six normal volunteers and in five patients with documented systemic sarcoidosis and clinically apparent cardiac dysfunction. Two of the patients with sarcoidosis had severe restrictive pulmonary disease. Their myocardial perfusion scans revealed relatively uniform uptake of 201Tl by the left ventricle, similar to that found in the normal volunteers; however, the right ventricular uptake of 201Tl and right ventricular thickness in these two patients with sarcoidosis was greater than normal. The other three patients with sarcoidosis had unexplained congestive heart failure, mitral regurgitation, or arrhythmias. Myocardial perfusion imaging in these patients revealed normal right ventricular uptake of radioactivity but segmental defects in the left ventricle compatible with an infiltrative disease of the myocardium. Segmental myocardial infiltration by sarcoid was confirmed by autopsy in one of these patients and at operation in another. Thus, myocardial imaging with 201Tl may provide a noninvasive technique for the improved clinical recognition of primary myocardial sarcoid and for distinguishing it from cardiac dysfunction secondary to pulmonary disease.

Adult↗
PubMed2025

A Simple Method to Analyze Context- and Tissue-Specific Cis-Regulatory Modulations of Homeotic (HOX) Genes Using ChIP.

Homeobox genes (HOX), the master regulators, deploy a unique set of target genes to coordinate and orchestrate the spatiotemporal development of an organism. HOX encoded transcriptional factors regulate the expression of target genes by binding to the specific sequences on the genome. Chromatin Immunoprecipitation (ChIP) and Chromatin Immunoprecipitation with Sequencing (ChIP-Seq) are widely used to map and understand specific gene locus and global regulatory regions on the genome. ChIP is a powerful technique of cross-linking the proteins bound to the DNA, fragmenting DNA to the desired size, and pulling them down using specific antibodies to enrich and analyze the protein-bound DNA. Based on the mapping information, a differential ChIP can be performed to understand cis-regulatory modulations at a defined locus by two developmental stages. This chapter describes the differential ChIP used to identify new targets by comparing two different developmental stages simultaneously using Drosophila melanogaster.

Animals↗
PubMed1977

A monitor for the continuous assessment of left ventricular performance after open-heart operations.

A cardiac monitoring system has been developed that incorporated phasic aortic blood flow measurement by an extractable electromagnetic flow probe and high-fidelity arterial blood pressure recordings. Cardiac output, stroke volume, and peak aortic blood flow are measured continuously; using logarithmic amplifiers, the pressure-flow derivatives of left ventricular function, such as cardiac power and stroke work, are obtained beat by beat. This monitor is used to follow the postoperative course of patients undergoing cardiac operations and to evaluate the hemodynamic effect of therapeutic agents.

Cardiac Surgical Procedures↗