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At least 415 records · Page 23Linked to original sources
PubMed2004

Partial hepatic vein diversion in pulmonary arteriovenous malformations in congenital heart disease.

The late appearance of pulmonary arteriovenous malformations after operations for complex congenital cardiac conditions may be explained in many ways. The necessity of hepatic blood flow to the lungs is now generally accepted for carrying some labile substance that is secreted by the liver and that has not yet been identified. Rerouting of hepatic blood to the lungs in cardiac patients can be accomplished with different methods, most of which are predisposed to thrombosis because of the slow flow in the tunnel. My colleagues and I describe a case of partial diversion of hepatic blood into the pulmonary circulation and suggest a strategy to decrease the likelihood of conduit thrombosis and to treat pulmonary arteriovenous malformations.

Abnormalities, Multiple↗
PubMed1984

Contribution of lung stretch depressor reflex to nonlinear fall in cardiac output during PEEP.

The hypothesis that lung stretch reflexes elicit negative cardiovascular effects during positive end-expiratory pressure (PEEP) application in a ramp procedure up to 15 cmH2O was tested in piglets under steady-state anesthesia and muscle relaxation. The effects of lung stretch on hemodynamics were studied by comparing the differences in responses during PEEP application with two different tidal volumes. In both ventilatory conditions cardiac output and aortic pressure decreased nonlinearly in three phases with the rise of PEEP: a gradual decrease in phase I, a sharp decrease in phase II, and again a more gradual decrease in phase III. Heart rate decreased significantly in phase II. In the series with the larger tidal volume, implying more lung stretch during insufflation, phase II was between a PEEP of 2.6 and 9 cmH2O. In the series with the smaller tidal volume, phase II occurred between 5.7 and 10.5 cmH2O. To assess the contribution of lung stretch reflexes to the decrease in cardiac output we also related cardiac output to the changes in central venous pressure. Again a nonlinear response was observed, indicating that an additional effect besides the rise in mean central venous pressure was involved in the decrease in cardiac output. During ventilation with the smaller tidal volume, phase II of the decrease in cardiac output was also shifted to higher values of mean central venous pressure, which only could be ascribed to the differences in lung stretch at insufflation. It appeared that under circumstances of artificial ventilation the onset of the reflex is determined by a characteristic threshold of lung stretch.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2006

ECG techniques and technologies.

The electrocardiogram (ECG) continues to be a critical component of the evaluation of patients who have signs and symptoms of emergency cardiac conditions. This tool is now approximately 100 years old and has been a standard in clinical practice for more than half a century. Application of new signal processing techniques and an expansion in the use of additional leads allows clinicians to extract more and more information from the cardiac electrical activity. An understanding of the technology inherent in the recording of ECGs allows one to more fully understand the benefits and limitation of electrocardiography.

Biomedical Technology↗
PubMed1992

[Therapy of arrhythmias in clinical practice].

The primary care physician should be cautious and restrictive in the treatment of cardiac arrhythmias and adhere to the well established modalities only. For supraventricular arrhythmias digitalis, verapamil, quinidine and betablocking agents are the drugs of choice. In atrial fibrillation oral anticoagulants and in some cases aspirin seem to be beneficial for the prevention of stroke in selected subgroups of patients. Criteria for their use are outlined in Tables 1 and 2. Ventricular arrhythmias in healthy persons generally should not be treated. In patients with coronary artery disease and severely compromised left ventricular function amiodarone is very effective for the treatment of complex ventricular arrhythmias. If other antiarrhythmics are to be used, the advice of a cardiologist is strongly recommended, as proarrhythmic effects are particularly common in severe cardiac conditions. Severely symptomatic patients with recurrent ventricular tachycardia and syncope should be offered invasive evaluation in order to determine effective medical or surgical treatment.

Anti-Arrhythmia Agents↗
PubMed1987

Transient atypical lymphocytosis in patients with emergency medical conditions.

Lymphocytosis in older adults is unusual and frequently indicates chronic lymphocytic leukemia or other lymphoproliferative disorder. This report describes 73 patients, aged 43 to 93 years, who presented with emergency medical conditions and who had absolute lymphocytosis, with absolute lymphocyte counts ranging from 4.1 to 12.9 X 10(9)/L (4100 to 12,900/mm3). The lymphocytosis was characterized morphologically by atypical lymphocytes and was transient, followed, in most instances, by a neutrophilia. Most of the patients presented with serious cardiac conditions; the remaining presented with other critical disorders including status epilepticus and traumatic injuries. The mortality rate was high (50%). The lymphocytosis in some patients was probably secondary to the administration of epinephrine. The lymphocytosis in those not receiving epinephrine may have represented a physiologic reaction to severe stress.

Adult↗
PubMed1985

Nonimmune hydrops fetalis--a rational attitude of management.

A rational attitude of management of the nonimmune hydrops fetalis (NIHF) is stressed in order to achieve an optimal outcome of both the mother and the newborn. Of the two cases reported, both had an underlying cardiac condition. The first was due to rapid supraventricular tachyarrhythmia and responded favorably to intrauterine medication with digoxin and the subsequent delivery of a well baby. In the second case, cesarean section was performed unnecessarily for a fetal indication, since the hydropic infant died soon after birth from a severe cardiac malformation which was not unequivocally diagnosed prior to birth.

Adult↗
PubMed1991

Opioid modulation of pavlovian learning in rabbits: involvement of sublenticular pathways.

Intravenous naloxone enhanced, and D-Ala2-Met-enkephalinamide (DALA) impaired, Pavlovian conditioned heart rate discrimination in rabbits (Oryctolagus cuniculus) during initial training trials, compared with saline; naloxone also delayed subsequent extinction of the discrimination. These effects of the opioid treatments on discrimination were abolished by parasagittal knife-cut lesions in the sublenticular substantia innominata that did not, themselves, impair discrimination. Both naloxone and DALA decreased the magnitude and altered the topography of bradycardiac conditioned responses, and the lesions also abolished these effects of the opioid treatments, but they did not alter the effect of naloxone to decrease bradycardiac orienting response magnitude. These findings suggest that fibers in the sublenticular area mediate specifically the effects of systemic opioids on associative functions during Pavlovian cardiac conditioning and extinction.

Animals↗
PubMed2004

ProBNP-derived peptides in cardiac disease.

The natriuretic peptides constitute a family of structurally related peptides that regulate fluid homeostasis, vascular tonus and growth. After the discovery of an endocrine component of the heart almost 25 years ago, the cardiac natriuretic peptides have now been fully accepted as useful markers in diverse aspects of cardiology including as diagnostic, therapeutic and prognostic markers of cardiac disease. In humans, atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) are mainly synthesized and secreted by the failing heart, whereas the related C-type natriuretic peptide (CNP) appears to be a local regulatory peptide secreted by the vascular endothelium. Accordingly, CNP is not a cardiac peptide. With the recent implementation of sensitive and specific immunoassays, increased plasma concentrations of proBNP-derived peptides have now been associated with several cardiac conditions, where the major application today seems related to ventricular dysfunction. Recently, focus has also turned to ischemic heart disease, since myocardial hypoxia increases the local BNP gene expression. This review recapitulates the established clinical applications of measuring proBNP-derived peptides in plasma. Furthermore, the evidence of increased cardiac BNP expression in ischemic heart disease will be emphasized. In turn, plasma measurement of proBNP-derived peptides may still hold new possibilities in screening for coronary artery disease.

Awards and Prizes↗
PubMed2000

An unusual complication during electroejaculation in an individual with tetraplegia.

Infertility in males is a common problem after spinal cord injury, often requiring interventional methods. In the authors' fertility program they have experienced 4 pregnancies and 3 live births using both electroejaculation (EEJ) and vibratory stimulation techniques. EEJ is a relatively safe procedure with few complications reported in the literature. Here is a case of a 23-year-old with C-6 ASIA A tetraplegia who, while receiving EEJ, developed autonomic dysreflexia that was followed by new onset atrial fibrillation. The patient's cardiac condition required management in the Emergency Department with pharmacologic conversion to a normal sinus rhythm. Although autonomic dysreflexia is a common adverse effect during EEJ, atrial fibrillation has not been previously reported as a complication. It is proposed that the patient's atrial fibrillation developed as a result of cardiac changes induced through autonomic dysreflexia.

Adult↗
PubMedDate not supplied

Systolic time intervals and their derivatives for evaluation of cardiac function.

Systolic time intervals provide a noninvasive indication of global left ventricular performance, are relatively sensitive, and are easily obtained from an M-mode echocardiogram. This paper defines systolic time intervals (preejection period, left ventricular ejection time, and total electromechanical systole) and their derivatives (preejection period/left ventricular ejection time and velocity of circumferential fiber shortening). Their utility and weaknesses, as well as the effects of heart rate, loading conditions, cardiac contractility, and drug therapies on systolic time intervals are discussed. Normal values for systolic time intervals for the dog and cat are provided.

Animals↗
PubMed2004

Impaired cardiac efficiency and increased fatty acid oxidation in insulin-resistant ob/ob mouse hearts.

Diabetes alters cardiac substrate metabolism. The cardiac phenotype in insulin-resistant states has not been comprehensively characterized. The goal of these studies was to determine whether the hearts of leptin-deficient 8-week-old ob/ob mice were able to modulate cardiac substrate utilization in response to insulin or to changes in fatty acid delivery. Ob/ob mice were insulin resistant and glucose intolerant. Insulin signal transduction and insulin-stimulated glucose uptake were markedly impaired in ob/ob cardiomyocytes. Insulin-stimulated rates of glycolysis and glucose oxidation were 1.5- and 1.8-fold higher in wild-type hearts, respectively, versus ob/ob, and glucose metabolism in ob/ob hearts was unresponsive to insulin. Increasing concentrations of palmitate from 0.4 mmol/l (low) to 1.2 mmol/l (high) led to a decline in glucose oxidation in wild-type hearts, whereas glucose oxidation remained depressed and did not change in ob/ob mouse hearts. In contrast, fatty acid utilization in ob/ob hearts was 1.5- to 2-fold greater in the absence or presence of 1 nmol/l insulin and rose with increasing palmitate concentrations. Moreover, the ability of insulin to reduce palmitate oxidation rates was blunted in the hearts of ob/ob mice. Under low-palmitate and insulin-free conditions, cardiac performance was significantly greater in wild-type hearts. However, in the presence of high palmitate and 1 nmol/l insulin, cardiac performance in ob/ob mouse hearts was relatively preserved, whereas function in wild-type mouse hearts declined substantially. Under all perfusion conditions, myocardial oxygen consumption was higher in ob/ob hearts, ranging from 30% higher in low-palmitate conditions to greater than twofold higher under high-palmitate conditions. These data indicate that although the hearts of glucose-intolerant ob/ob mice are capable of maintaining their function under conditions of increased fatty acid supply and hyperinsulinemia, they are insulin-resistant, metabolically inefficient, and unable to modulate substrate utilization in response to changes in insulin and fatty acid supply.

Animals↗
PubMed1999

Protection against hypoxia-reoxygenation in the absence of poly (ADP-ribose) synthetase in isolated working hearts.

Peroxynitrite and hydroxyl radical are reactive oxidants produced during myocardial reperfusion injury. They have been shown to induce dysfunction in cardiac myocytes, in part, via the activation of the nuclear enzyme poly (ADP-ribose) synthetase (PARS). These oxidants can trigger DNA single strand breakage, which triggers PARS activation, resulting in cellular NAD+ and ATP depletion and cytotoxicity. Recent work has demonstrated that hypoxia-reoxygenation of cardiac myocytes in vitro also causes peroxynitrite formation, PARS activation and cytotoxicity. In the present study, using hearts from genetically engineered mice lacking PARS, we have investigated whether the absence of PARS alters the functional response to hypoxia reoxygenation. Isolated work-performing mouse hearts were stabilized under the same loading condition (cardiac minute work of 250 mmHg x ml/min, an afterload of 50 mmHg aortic pressure and similar venous return of 5 ml/min, resulting in the same preload). After 30 min equilibration the hearts were subjected to 30 min hypoxia followed by 30 min of reoxygenation. At the end of the reoxygenation, in hearts from wild-type animals, there was a significant suppression in the rate of intraventricular pressure development (+dP/dt) from 3523 to 2907 mmHg. There was also a significant suppression in the rate of relaxation (-dP/dt) in the wild-type hearts from 3123 to 2168 mmHg. The time to peak pressure (TPP) increased from 0.48 to 0.59 ms/mmHg and the half-time of relaxation (RT1/2) increased from 0.59 to 0.74 ms/mmHg. In contrast, in the hearts from the PARS knockout animals, no significant suppression of +dP/dt (from 3654 to 3419 mmHg), and no significant increase in the TPP (from 0.462 to 0.448 ms/mmHg) were found, and the decrease in -dP/dt was partially ameliorated (from 3399 to 2687 mmHg) as well as the half-time of relaxation (from 0.507 to 0.55 ms/mmHg) when compared to the response to the wild-type hearts. The current data demonstrate that the reoxygenation induced suppression of the myocardial contractility is dependent on the functional integrity of PARS.

Animals↗
PubMed2002

Infective endocarditis at a tertiary care centre in Lebanon: predominance of streptococcal infection.

OBJECTIVES: Infective endocarditis (IE) remains a disease associated with high morbidity and mortality. Many epidemiological studies have been reported worldwide; however, data from the Middle East is scarce. Most studies have recently shown a trend towards increasing incidence of Staphylococcus aureus endocarditis and decreasing prevalence of rheumatic heart disease as a predisposing condition. METHODS: We conducted a retrospective review of all recorded cases of IE in adult patients admitted between 1986 and 2001 to the American University of Beirut-Medical Centre. RESULTS: The total number of cases was 91. The mean age was 48 years. Fifty-nine percent of patients had a predisposing cardiac condition, rheumatic heart disease being the most common (33%). Blood cultures were positive in 77.5% of the cases: the most commonly isolated organisms were Streptococcus spp. (51%; of which 57% were viridans streptococci.) and Staphylococcus spp. (36%; of which 72% were S. aureus and 28% were coagulase-negative staphylococci). Transoesophageal echocardiography was performed in 36 patients (40%), of which 32 (89%) showed positive findings. When applying the revised Duke criteria, 82% of the patients were classified as definite and 16.5% as possible endocarditis. Surgery was performed in 32% of cases mostly for valvular regurgitation, followed by heart failure. The complication rate was 69% with congestive heart failure, drug-related toxicities, new valvular regurgitation and systemic embolisation being the most common. The in-hospital mortality rate was 18%. CONCLUSIONS: Unlike data reported from the United States and northern Europe, this study confirms that in Lebanon, a developing country, we continue to have a predominance of streptococci as aetiologic agents in IE, and rheumatic heart disease as the most common underlying heart condition. Application of the revised Duke criteria was useful in confirming the diagnosis of IE.

Academic Medical Centers↗
PubMed1995

[Current status of cardiovascular rehabilitation and projections for 2010: results of a survey in the Vaud canton].

Compared to the situation in other European countries and the United States, Switzerland chiefly offers inpatient cardiac rehabilitation programmes (CRP). In the opinion of specialists and medical literature, we can expect an increased number of patients with cardiovascular diseases in the next 15 years, as well as a widening of indications for CRP among older patients and those with advanced cardiac conditions. We conducted an inquiry among professionals practising or prescribing CRP in order to estimate population needs and coverage for CRP and to identify the factors that will determine its future. Based on various sources of information, we estimated the incidence of coronary events and demand for CRP in the Canton of Vaud. Cardiac rehabilitation centers provided their occupation statistics for 1993. Simulations were carried out based on the opinion of specialists and expected demographic trends for the next 15 years. In recent years, 600 to 700 patients have been annually enrolled in CRP. Among patients admitted to acute care hospitals after myocardial infarction, 65% of those under 65 years of age and 14% of those between 65 and 74 entered CRP programmes. Most of them followed inpatient programmes in two private clinics which currently cover CRP needs with a capacity of 1500 patients a year. If we expect a 20% increase in the rate of coronary events over the next 15 years, due to demographic trends, without a change in the incidence of coronary disease, the present resources in residential CRP will remain sufficient. However, we can expect that part of the patient surplus will enter outpatient CRP programmes.

Adult↗
PubMed1997

Beta-adrenergic signal transduction and contractility in the canine heart after cardiopulmonary bypass.

OBJECTIVE: Impaired beta-adrenergic signal transduction has been proposed as a mechanism contributing to myocardial depression after cardiac surgery. This study determined the changes in the beta-adrenergic system in a model of postoperative myocardial dysfunction induced by myocardial ischaemia and reperfusion under cardiopulmonary bypass (CPB). Those changes were then related to contractility and responsiveness to beta-adrenergic stimulation. METHODS: Four groups of dog hearts were studied: 7 hearts harvested immediately after anaesthesia induction (control group representing the preoperative cardiac condition); 6 hearts harvested after three hours of chest opening by sternotomy (open chest group serving as control for the effects of anaesthesia and surgery); 7 hearts harvested during CPB after 30 minutes of global ischaemia (ischaemia group); and 10 hearts from dogs submitted to one hour of CPB involving 30 minutes of global cardiac ischaemia, harvested 30 minutes after CPB (ischaemia-reperfusion group). Myocardial membranes were prepared to assess: (1) beta-adrenergic receptor density using the radioligand [125I]iodocyanopindolol; (2) GTP-sensitive adenylate cyclase activity and its regulation by isoprenaline and forskolin; (3) G protein levels, using an immunoblotting technique. Ventricular trabeculae or papillary muscles served to assess contractility and responsiveness to isoprenaline. RESULTS: The control and open chest groups had comparable beta-adrenergic receptor density, adenylate cyclase activity and cardiac contractility. In the ischaemia group, the left ventricular membranes had a 55% decrease in receptor density as compared to the controls (P < 0.005), similar GTP-sensitive adenylate cyclase activity and significantly lower adenylate cyclase responses to stimulation with isoprenaline and forskolin. In the ischaemia-reperfusion group, a 144% increase in the left ventricular receptor density was found as compared to the controls (P < 0.005), with a 70% increase in GTP-sensitive adenylate cyclase activity (P < 0.05), a similar adenylate cyclase response to isoprenaline and a 61% increase in response to forskolin (P < 0.005). As compared to the controls, the ischaemia and ischaemia-reperfusion groups had comparable Gs alpha levels, but markedly decreased Gi alpha-2 and Gi alpha-3 levels. The baseline tension of the isolated muscles in the ischaemia and ischaemia-reperfusion groups was comparable, but was 61% and 47% lower than the controls, respectively (P < 0.05). The maximal isoprenaline stimulated tension in the ischaemia and ischaemia-reperfusion groups was 66% and 36% lower than the controls, respectively (P < 0.05 between all groups). CONCLUSIONS: The beta-adrenergic system is severely depressed during global cardiac ischaemia under CPB, but recovers to supranormal values after CPB. However the increased cAMP generation by myocardial membranes after CPB is associated with decreased tension generation by corresponding cardiac muscles. Thus decreased contractility after CPB may be better explained by cellular alterations distal to cAMP generation rather than by changes in the beta-adrenergic system.

Adenylyl Cyclases↗
PubMed2002

Transient Brugada-type electrocardiographic abnormalities in renal failure reversed by dialysis.

The Brugada syndrome (BRS) is a hereditary cardiac condition (characteristically with a gene mutation affecting sodium channel function) identified by an elevated terminal portion of the QRS complex (prominent J wave) followed by a descending ST-segment elevation ending in a negative T wave in the right precordial leads, and malignant tachyarrhythmias in patients without demonstrable structural heart disease. We report a patient with a previous history of epilepsy treated with psychotropic drugs (with a sodium channel blocking effect) and chronic renal failure on haemodialysis who developed hyperkalaemia (6.6 mmol/l) and ECG findings resembling BRS. This condition was manifested by the prominent J wave, the coved-type ST-segment elevation and the negative T wave in the right precordial leads. These ECG changes disappeared after haemodialysis when the potassium became normal. Subsequently, a flecainide test did not reproduce ST-segment elevation. We conclude that hyperkalaemia associated with cardiac membrane active drugs may cause ECG changes mimicking the Brugada syndrome.

Adult↗
PubMed1991

The language of breathlessness. Use of verbal descriptors by patients with cardiopulmonary disease.

The main objective of the present study was to test the hypothesis that patients with cardiopulmonary disease can reliably identify different sensory qualities of their experience of breathlessness. A secondary aim was to examine whether there was any relationship between such specific descriptors of the sensation of breathlessness and a patient's clinical diagnosis. A randomly ordered list of 45 descriptors of breathing discomfort related to exertion was administered on two occasions to 208 patients with cardiopulmonary disease; patients identified the descriptors that applied to their own experience. A total of 169 patients were considered reliable in that their responses were repeatable between questionnaires; there was evidence that an individual's reliability could be assessed by asking repeat questions within a questionnaire. With these patients, individual descriptors generated different degrees of yes and no response and were answered with a variable consistency, suggesting that some questions may be more useful than others in discriminating between the quality of patients' sensations. Overall, patients with obstructive disorders (asthma and chronic obstructive airways disease [COAD]) answered yes more often than those with restrictive or cardiac conditions, possibly reflecting differences in severity of disease. A cluster analysis separated the descriptors into 12 groups which appeared to describe different aspects of breathing discomfort. Relative to their response to other clusters, COAD patients were more inclined to identify distress, asthma patients to indicate wheeziness, restrictive patients to report rapid breathing, and the cardiac group to describe a need to sign. A second cluster analysis separated patients into 12 groups based on responses for the descriptor clusters.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1976

[Significance of Alfatesine in anesthesia for multiple dental extractions before major cardiac surgery].

This technique of anaesthesia used for oral surgical operations such as, multiple dental extractions, apical resection, carried out in cardiac patients before major cardiac surgery under extra-corporeal circulation, for insertion of valvular prostheses or aorto-coronary by-pass operations, has passed by various stages. The present technique associating phenoperidine-alfatesine-suxame-thonium-N2o-o2, was used in the last 58 cases. It presents a certain number of advantages compared with previous techniques: -very stable level of anaesthesia whatever the duration of the operation, -satisfactory cardio-vascular stability, -almost constant absence of hypo-excitability of the myocardium even in patients in poor cardiac condition before the operation with uninterrupted treatment with digitalis and diuretics, -good quality of awakening.

Adolescent↗