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Query: UMLS:C0018799 (heart disease)
 34,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two animal models for testing foreign substances for the hypoxic type of cardiotoxicity proved to be valid and reproducible: i.e. decreased reserve capacity of the heart in rats recovered from the calciferol cardiopathy and increased heart work provoked by isoproterenol (5 mg/kg i.p.). In both cases obvious hypoxic ECG changes appeared at lower levels of exposure to carbon monoxide (500 ppm, 572 mg.m-3) and carboxyhemoglobin (18%), when compared with nonpretreated animals. The models have shown, that injured or overloaded heart displays a substantially increased sensitivity to CO poisoning.
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PMID:Carbon monoxide poisoning at a lowered myocardial adaptation capacity: animal ECG models. 326 32

Ten normal subjects and 14 patients with chronic Chagas' disease (seven with and seven without heart disease) underwent dynamic exercise on a cycle ergometer. Heart rate (HR), pulmonary ventilation (V), oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory quotient (RQ) were measured. Increasing workloads (25, 50, 100, and 150 W) were applied for 4 min and intercalated with resting periods. The main objective of this protocol was to analyse heart rate response in relation to the other cardiorespiratory variables in order to evaluate the functional conditions of the sympathetic and parasympathetic cardiac efferents. Analysis of the results showed that (a) the group of chagasic patients with heart disease had lower heart rates (p less than 0.05) than normal subjects during the initial 10 s (delta HR 0-10 s) of effort (fast component); (b) the difference between the normal subjects and chagasic patients without heart disease was not statistically significant; (c) the abnormalities in heart rate response were due to depression of parasympathetic efferent action on the sinus node; (d) the slow heart rate response (delta HR 1-4 min), which expresses the degree of sympathetic stimulation of the sinus node, was comparable in the three groups studied, thus showing unimpaired adrenergic responses during dynamic exercise in Chagas' disease; and (e) the V, VO2, VCO2, and RQ values were normal at all workloads in each group, suggesting that vagal dysfunction does not affect oxygen transport at these submaximal levels of dynamic exercise.
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PMID:Functional evaluation of sympathetic and parasympathetic system in Chagas' disease using dynamic exercise. 345 58

During exercise, the oxygen consumption above which aerobic energy production is supplemented by anaerobic mechanisms, causing a sustained increase in lactate and metabolic acidosis, is termed the anaerobic threshold (AT). The oxygen consumption at the AT depends on factors that affect oxygen delivery to the tissues. It is increased when oxygen flow is enhanced and decreased when oxygen flow is diminished. Its value is quite low in patients with heart disease. The AT is an important functional demarcation since the physiological responses to exercise are different above the AT compared to below the AT. Above the AT, in addition to the development of metabolic acidosis, exercise endurance is reduced, VO2 kinetics are slowed so that a steady state is delayed, and VE increases disproportionately to the metabolic requirement and a progressive tachypnea develops. The AT can be measured directly from the lactate concentration with precise threshold detection from a log-log transformation of lactate and VO2. This threshold also defines the VO2 above which the lactate/pyruvate ratio increases. As bicarbonate changes reciprocally with lactate, its measurement can also be used to estimate the lactate threshold. But most convenient are gas exchange measurements made during exercise testing which can be used to noninvasively detect the lactate or anaerobic threshold. These methods are based on the physical-chemical event of buffering lactic acid with bicarbonate, and the increased CO2 output which occurs in association with the acute development of a metabolic acidosis.
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PMID:The anaerobic threshold: definition, physiological significance and identification. 355 13

The efficiency of spontaneous ventilation during halothane anaesthesia was investigated in 18 infants and children with congenital heart disease presenting either with hyperperfusion and left-to-right shunt (group LR: n = 10, body weight 3.7-16 kg) or with hypoperfusion and right-to-left shunt (group RL: n = 8, body weight 3.4-12 kg). Minute ventilation (VE) and tidal volume (VT) were greater in group RL than in group LR (P less than 0.05) while ventilatory rates were similar. Dynamic compliance and total pulmonary resistance were of the same magnitude in the two groups. Alveolar ventilation (VA) calculated from arterial carbon dioxide tensions (PaCO2) was the same in both groups while corresponding deadspace ventilation (VD) was higher in group RL (P less than 0.01). VE/VCO2 and VD/VT ratios were higher in children with a diminished pulmonary blood flow than in children with an increased pulmonary blood flow (P less than 0.05 and P less than 0.01, respectively) indicating a less efficient gas exchange in children with a right-to-left shunt. This was compensated for by an increased inspiratory drive as reflected by higher VT/TI ratio (P less than 0.01) and a more pronounced airway occlusion pressure (P less than 0.05).
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PMID:Congenital heart malformations and ventilatory efficiency in children. Effects of lung perfusion during halothane anaesthesia and spontaneous breathing. 356 93

Favorable early results have been reported utilizing transthoracic diaphragmatic plication in symptomatic children with phrenic nerve injury. However, little has been published about the late functional results of this technique. Since 1976, 10 of 3,000 patients operated on for congenital heart disease have sustained phrenic nerve injury with subsequent respiratory embarrassment. An additional patient sustained phrenic nerve injury as a result of birth trauma. The diagnosis was confirmed by paradoxical diaphragmatic motion on fluoroscopy. All but 2 patients were less than 5 months old at the time of diaphragmatic plication, and the average weight was 5.4 kg. The indication for diaphragmatic plication was inability to wean from the ventilator in 8 of the 11 patients and persistent postoperative tachypnea, stridor, and CO2 retention in the remaining 3 patients. A more aggressive approach to diagnosis and operative treatment since 1980 has resulted in a substantially shorter duration of endotracheal intubation and a shorter stay in the intensive care unit. Diaphragmatic fluoroscopy 1 to 7 years postoperatively has demonstrated return of normal function in 6 of 6 patients studied.
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PMID:Long-term fate of the diaphragm surgically plicated during infancy and early childhood. 360 60

The recent deaths of two workers with coronary artery disease (CAD) following exposure to carbon monoxide (CO) at work reinforced our appreciation of the hazard of this exposure to individuals with preexisting heart disease. Carbon monoxide acts to precipitate ischemia by reducing oxygen delivery to the myocardium. Animal and in vitro experiments suggest that CO may accelerate the development of atherosclerosis, particularly if exposure is in association with other risk factors. Thus, persons with known CAD who are exposed to CO at work are at risk for both the acceleration of the course of the underlying disease and for precipitation of acute ischemia or infarction following excessive exposure. Particular attention should be given to control of CO exposures in light of this hazard. For various reasons, preplacement evaluations or other job selection procedures do not adequately address his hazard. In view of the high prevalence of CAD in the U.S. and the high frequency of workplace exposure to CO, particular attention should be given to control of CO exposure through industrial hygiene measures.
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PMID:Exacerbation of coronary artery disease by occupational carbon monoxide exposure: a report to two fatalities and a review of the literature. 388 38

In order to provide a pathogenetically oriented differentiation of brain infarctions on the basis of CT-morphological criteria, the CTs of 422 patients with visible brain infarctions were analysed. All of the supratentorial lesions were classified according to topographical features and were associated with the underlying cardio-vascular and other general diseases. This concept lead to a typology of brain infarctions which allowed for a differentiation of ischaemic lesions due to cerebral microangiopathy on the one hand (i.e. lacunar infarctions, subcortical arteriosclerotic encephalopathy), and lesions due to cerebral macroangiopathy on the other. The latter were hemodynamically induced terminal supply area infarctions and watershed infarctions or territorial infarctions due to thromboembolism. A third group of symmetrical subcortical lesions were associated with hypoxia. The frequencies of cerebral lesions within the whole cohort were as follows: 34% cerebral microangiopathy, 45% macroangiopathy, 1% generalised hypoxia, 10% miscellaneous lesions and 10% non-classifiable infarctions. Stenosing lesions of the extracranial brain supplying arteries were found in 22% of the microangiopathy group but in 71% of the macroangiopathy group. Patients with territorial infarctions presented with embolising extracranial vascular lesions in 42% and with embolising heart disease in 21% of the cases. Local thrombosis of the intracranial large arteries was a rare event. Hypoxia occurred due to haemorrhagic shock, carbon monoxide poisoning, air embolism and strangulation. The following conclusions were drawn: In patients with cerebral microangiopathy any procedures aimed at the diagnosis and therapy of major vessel disease are not useful. Therapy should follow the principles of internal medicine. If haemodynamically induced infarctions are present, the clinician's primary task is to look for high grade extracranial vessel lesions. Recanalizing techniques (endarterectomy and ECIC-bypass) are the main therapeutical strategies. In territorial infarctions the embolising extracranial vessel lesions may be haemodynamically non-significant. An intra-arterial source of emboli should be removed by the vascular surgeon. In younger patients, however, and in patients with normal Doppler findings and/or multiple territorial infarctions, a cardiac source of emboli is highly probable and its diagnosis should be pursued consistently. Bilateral symmetrical ganglionic infarctions are indicative of hypoxia and help to exlude other causes of the severe neurological disturbances associated with this condition.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Contribution of computer tomography of the brain to differential typology and differential therapy of ischemic cerebral infarct]. 404 13

Cutaneous infiltration of dilute solutions of epinephrine for hemostasis during halothane anesthesia can result in ventricular dysrhythmias. Our clinical experience, published reports, and a study comparing piglets with adult swine suggest that children may be less susceptible than adults to dysrhythmias under these conditions. We therefore undertook a prospective survey of heart rate and rhythm in halothane-anesthesized children who received subcutaneous epinephrine for hemostasis. Mass spectrometry was used to quantify end-tidal halothane and to avoid hypercarbia. In 83 children anesthesized with halothane, we continuously recorded ECG, heart rate (HR), end-tidal halothane (ETHalo), and carbon dioxide (ETCO2). The surgeons injected 0.4--15.7 micrograms/kg of epinephrine (in saline or 1% lidocaine) to provide hemostasis at a variety of sites. No child developed a ventricular dysrhythmia. One child had self-limited premature atrial contractions (PAC). Sixty-three children had some increase in heart rate after epinephrine injection, while seven increased their HR 15% or more above pre-injection levels. No relation between any increase in HR and epinephrine dosage, ETHalo, ETCO2, physical status, or age was found by multiple linear regression; however, HR was increased significantly in patients receiving epinephrine in head and neck sites other than the palate. The authors conclude that children tolerate higher doses of subcutaneous epinephrine than adults during halothane anesthesia. The arrhythmogenic dose of epinephrine in children receiving halothane has yet to be determined, but at least 10 micrograms/kg of epinephrine infiltration may be used safely in normocarbic and hypocarbic pediatric patients without congenital heart disease. The presence of PAC and tachycardia emphasize the need for continuous ECG monitoring and caution during halothane anesthesia with epinephrine injection.
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PMID:Epinephrine-halothane interactions in children. 633 28

The typical occupational cohort study includes all causes of mortality. However, emphasis is usually placed on the presence or absence of excess cancer mortality. A systematic review of completed occupational cohort studies to assess the findings and patterns of cardiovascular mortality would be useful. Although many of these studies will illustrate the "healthy worker effect" with deficits in mortality, particularly from cardiovascular causes, a thorough review should indicate certain exposures needing further research. A recently published study of heart disease mortality in the rubber industry illustrates the potential use of such a literature review with subsequent follow up. Production workers in the rubber industry have shown small excesses in CAHD mortality. A follow-up study at one plant confirmed the known association between carbon disulfide and atherosclerosis, as well as suggested two new causal associations between CAHD and the use of phenol and ethanol as solvents. What additional techniques can be used to generate hypotheses on heart disease and occupation? Some possibilities include: A recent article describes the use of the results of occupational disease surveillance systems for occupational cancer research. A review of such systems for heart disease would be equally useful. It would be useful to review the quality and quantity of occupational data that has been collected in prospective cohort studies, such as those in Framingham and Evans County. The importance of examining the association between occupational exposures and heart disease include: Assessing whether adequate protection is afforded by current limits on exposure to substances known to cause heart disease (carbon disulfide, nitrates, and carbon monoxide).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cardiovascular disease and work place exposures. 638 Apr 27

To validate the CO2-rebreathing method ( Defare 's method) for estimating cardiac output in children and young adults, measurements were compared to thermodilution ( TDCO ) cardiac output in 16 subjects (age 7-19 yr) with congenital heart disease. Data were collected at rest (N = 11) and during 4-min stages of supine bicycle exercise (N = 13). Estimated arterial-venous (-v-a)CO2 content differences related linearly to the measured CO2 content difference (Y = 0. 29X + 2.47, r = 0.65, P less than 0.001). With this (v-a)CO2 difference correction for all patients (N = 16), the correlation between CO2-rebreathing cardiac output and the TDCO was r = 0.87 (SEE = +/- 1.8 l X min-1). The correlation was higher for exercise (r = 0.81) than for rest (r = 0.65). We conclude that the CO2-rebreathing method, with a (v-a)CO2 content difference adjustment, is a simple, noninvasive technique providing estimates of cardiac output in children and young adults with congenital heart disease. Individual estimates should be treated with caution, especially when used for clinical evaluations.
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PMID:Validity of CO2-rebreathing cardiac output during rest and exercise in young adults. 643 Dec 21


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