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At least 991 records · Page 55Linked to original sources
PubMed1984

[Use of balloon catheters for intraoperative control of resting myocardial pressure during cardioplegia].

Twenty-two patients operated on for aortal, mitral and multivalvular prosthesis under pharmacological cardioplegia were examined for the purpose of monitoring myocardial resting tension by the tensometric method and by using modified balloon catheters. The results demonstrated that the use of the balloon catheters permits making not only qualitative and quantitative assessments of myocardial lesions and a prompt evaluation of the function of the arrested heart but also the initial myocardial contractility and the restoration of myocardial contractility after cardioplegic arrest by controlling the contraction and relaxation myocardial rate.

Cardiac Catheterization↗
PubMed1982

Effects of hypothermic and pharmacological protection on myocardial metabolism in temporary heart anoxia.

The authors investigated the myocardial metabolism in 11 patients in the course of the an operation (aortic valve prosthesis) under artificial circulation. In 8 patients the myocardium was protected by combined hypothermic and pharmacological cardioplegia, and in 3 patients, solely by hypothermic cardioplegia. It was found that anoxic heart arrest, regardless of the mode of myocardial protection, was accompanied by biochemical shifts in the myocardium (lactacidaemia, hyperphosphataemia, acidosis); the intensity of the shifts, however, was higher, and the durations longer, in the patients protected by hypothermic cardioplegia alone. The authors discuss the usability of the biochemical shifts in the myocardium for the prognosis of the clinical course in the early postperfusion period.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Causes and prevention of sudden arrest of circulation in surgical treatment of rheumatic mitral defect].

Analysis of case histories of patients operated on in 1965-1995 is presented. Ventricular fibrillation or asystole was observed in 3.34ë 1.1% of 480 patients subjected to closed mitral commissurotomy and in 6.25ë 1.1% of 98 ones subjected to cardiopulmonary bypass surgery for replacing mitral valves. The incidence of complications directly correlated with the stage of mitral valvular disease and reoperations and inversely with monitoring of hemodynamics, blood gases, etc. Examination of the myocardium before the development of ventricular fibrillation or asystole most often revealed 1) myocardial ischemia of different degree and localization; 2) changed stimulation and conduction of the myocardium; 3) total myocardial hypoxia; 4) electric current action in cases with diathermal coagulation of vessels and/or poor grounding of devices; 5) injection of potent drugs, etc. Electromechanical dissociation of ventricular myocardium was observed in 6 patients. Sudden heart arrest was not caused by blocking of the bloodflow in any of the cases. Thus, some signs can be regarded as predicting the risk of sudden arrest of circulation. Monitoring of the functions of the body helps timely detect these signs. If ventricular fibrillation developed, defibrillation was carried out immediately.

Adolescent↗
PubMed1986

Effects of supplementing hypothermic crystalloid cardioplegic solution with catalase, superoxide dismutase, allopurinol, or deferoxamine on functional recovery of globally ischemic and reperfused isolated hearts.

We evaluated whether supplemental pharmacologic interventions that altered formation or degradation of reactive oxygen metabolites, when added to hypothermic crystalloid cardioplegic solution (procaine-free St. Thomas' Hospital solution), alter postischemic function of isolated rabbit hearts. Hypoxic, substrate-free cardioplegic solutions cooled to 27 degrees C were perfused through isolated rabbit hearts for 5 minutes before and after an uninterrupted 2 hour period of global ischemia at 27 degrees C. Hearts were then reperfused with standard buffer for 1 hour at 37 degrees C. In some experiments, the cardioplegic solution was supplemented with the following: superoxide dismutase (30 micrograms/ml; degrades superoxide anion); catalase (1.7 micrograms/ml; degrades hydrogen peroxide); allopurinol (1 mmol/L; inhibits xanthine oxidase); or deferoxamine (Desferal, 0.5 mmol/L; selectively chelates ferric iron). Postreperfusion contractile parameters of supplemented hearts, including left ventricular pressure development and its first derivative, left ventricular compliance, spontaneous heart rate, and coronary vascular resistance, were statistically compared to data obtained from hearts arrested with unsupplemented cardioplegic solution. Catalase supplementation provided statistically significant improvement of most functional parameters; somewhat less protection was obtained with allopurinol. Deferoxamine provided little added protection except for the ability to prevent ischemia-induced increases of coronary vascular resistance. There was no evidence of added protection by superoxide dismutase. The data suggest that an important component of ischemia-induced cardiac cell damage in an asanguineous setting is hydrogen peroxide-dependent, and interventions that either inhibit production of superoxide anion or degrade hydrogen peroxide offer best protection. They may be clinically efficacious additives to crystalloid cardioplegic solutions.

Allopurinol↗
PubMed1990

Effect of hypothermia and cardioplegia on intramyocardial voltage and myocardial oxygen consumption.

Intramyocardial voltage and myocardial oxygen consumption were measured in the fibrillating heart between the temperatures of 37 degrees C and 25 degrees C and in the arrested heart after infusion of potassium cardioplegic solution in 10 adult mongrel dogs. Electrical activity from the myocardium was recorded using specially designed plunge electrodes, and intramyocardial voltage was monitored by an in-line voltmeter. Myocardial oxygen consumption gradually decreased from 5.8 +/- 0.6 ml O2/min at 37 degrees C to 2.3 +/- 0.5 ml O2/min at 25 degrees C. In contrast, hypothermia did not cause a similar decrease in intramyocardial voltage which remained within a range of 1.8 +/- 0.5 mV to 2.4 +/- 0.5 mV between the temperatures of 37 degrees C and 25 degrees C. The infusion of potassium cardioplegic solution resulted in a dramatic decrease in voltage to 43 +/- 5 microV, and myocardial oxygen consumption fell to 0.5 +/- 0.3 ml O2/min. Our data demonstrated that the mean voltage of the fibrillating heart remains constant between the temperatures 37 degrees C and 25 degrees C and myocardial oxygen consumption decreases with hypothermia, which suggests that voltage does not correlate with the level of myocardial oxygen consumption. Myocardial oxygen consumption and intramyocardial voltage, however, decrease dramatically when cardioplegia is instituted.

Animals↗
PubMed2001

A comparison of ischemic preconditioning versus terminal warm cardioplegia with controlled reperfusion in open heart operation.

BACKGROUND: The purpose of this study was to evaluate the effects of three different methods of cardioprotection in patients undergoing valve replacement. METHODS: Ninety patients undergoing elective valve replacement were randomly divided into three groups. In group 1 (n=30), the patients received intermittent cold blood cardioplegia. In group 2 (n=30) they received terminal warm cardioplegia and controlled reperfusion, and in group 3 (n=30), the patients received two cycles of ischemia (2 minutes) and reperfusion (3 minutes) before heart arrest induced by cold blood cardioplegia. The parameters of cardiac function, creatine kinase MB, and clinical outcomes were recorded to assess the effects of experiment. RESULTS: The major preoperative and intraoperative variables are comparable within the three groups. The number of patients requiring the support of inotropic agents was 70% (21/30), 33% (11/30) and 40% (12/30) in group 1, 2 and 3, respectively (p<0.05). The doses of inotropic agent in groups 2 and 3, were significantly lower than in group 1 (1.5+/-0.3 and 1.8+/-0.4 versus 4.5+/-0.8 microg x kg x min(-1), p<0.01) during the first 24 hours after operation. Two deaths (30 day-hospital mortality) occurred, one in group 1 and one in group 2. The cardiac index at 2 hours after bypass discontinuing were 2.2+/-0.04, 3.0+/-0.1 and 2.8+/-0.05 L/m(2) in group 1, 2 and 3, respectively (p<0.01). The left ventricular stroke work index were 24.8+/-1.3, 34.5+/-1.6 and 31.6+/-1.2 g/m x m(2) in group 1, 2, 3, respectively (p<0.01). The release of CK-MB in group 2 and 3 were lower than in group 1 (68+/-7, 81+/-9 versus 116+/-10 IU/L, p<0.01). CONCLUSIONS: Terminal warm cardioplegia with controlled aortic root reperfusion and ischemic preconditioning equally improve cardiac function and reduce the requirement of inotropic agents in patients undergoing valve replacement.

Adult↗
PubMed1997

Efficient gene transfer method into the whole heart through the coronary artery with hemagglutinating virus of Japan liposome.

OBJECTIVE: To confirm gene transfer techniques especially into the whole heart, we tried out a gene transfer method involving liposome with the viral envelope hemagglutinating virus of Japan liposome as an alternative to existing techniques such as cationic lipofection or other viral vectors. METHOD: For this study, hemagglutinating virus of Japan liposome (H group) or cationic liposome (L group) was used to compare the efficacy of gene transfection of oligonucleotide labeled with fluorescein isothiocyanate and cDNA of beta-galactosidase and human manganese-superoxide dismutase. Fluorescein-labeled oligonucleotide, cDNA of beta-galactosidase, or manganese-superoxide dismutase was complexed with liposomes, DNA-binding nuclear protein, and the viral protein coat of hemagglutinating virus of Japan. After donor rat hearts arrested by cardioplegia had been harvested, the coronary artery during cardioplegic arrest was infused via an aortic cannula with the liposome-gene complex. Next, the hearts were transplanted into the abdomen of recipient rats of the same strain, and all recipients were put to death after 3 days of transfection. RESULTS: Fluorescein isothiocyanate was detected in the nuclei of more than 70% of the myocytes (75% +/- 14%, n = 5) in the H group compared with fewer than 10% in the L group (7% +/- 5%, n = 5). The intensity of fluorescein isothiocyanate was significantly higher in the H group (979 +/- 112 FI) than in the L group (116 +/- 68 FI). beta-Galactosidase was expressed in the cytosol of more than 50% of the myocytes in the H group (61% +/- 7%, n = 5) compared with none in the L group (0%, n = 5). After 3 days of gene transfection, and when exposed to ischemia (30 minutes, 37 degrees C) and reperfusion (30 minutes, 37 degrees C) with Langendorff apparatus, the hearts transfected with manganese-superoxide dismutase (S group, n = 5) showed a significantly higher percentage of recovery of left ventricular end-diastolic pressure (S vs C, 86% +/- 3% vs 54% +/- 12%) and coronary flow (98% +/- 2% vs 66% +/- 12%) than did the control hearts (C group, n = 5). Western blotting analysis showed an apparent increased expression of manganese-superoxide dismutase in the hearts transfected with manganese-superoxide dismutase compared with the control hearts. These results clearly demonstrated that the donor hearts were transfected with fluorescein-labeled oligonucleotide and the beta-galactosidase gene as a result of coronary infusion of the hemagglutinating virus of Japan liposome during cardioplegic arrest at the time of harvest. Furthermore, the hearts transfected with manganese-superoxide dismutase showed significant improvement in tolerance against ischemia reperfusion injury. CONCLUSION: We believe that this method represents a novel in vivo gene transfer technique for the heart and thus may provide a new tool for research and therapy of heart transplantation.

Animals↗
PubMed1994

Oxygen exchange in the isolated, arrested guinea pig heart: theoretical and experimental observations.

A model of oxygen transport in perfused myocardial tissue is presented. Steady-state conditions are assumed in order to mimic the metabolic rate of the arrested heart. The model incorporates Michaelis-Menten dependence of mitochondrial oxygen consumption, oxymyoglobin saturation and oxyhemoglobin saturation on oxygen partial pressure (PO2). The transport equations model both the advective supply of oxygen via the coronary circulation and the diffusive exchange of oxygen between tissues and environment across the epicardial and endocardial surfaces. The left ventricle is approximated by an axisymmetric prolate spheroid and the transport equations solved numerically using finite element techniques. Solution yields the PO2 profile across the heart wall. Integration of this profile yields the simulated rate of metabolic oxygen uptake determined according to the Fick principle. Correction for the diffusive flux of oxygen across the surfaces yields the simulated true metabolic rate of oxygen consumption. Simulated values of oxygen uptake are compared with those measured experimentally according to the Fick principle, using saline-perfused, Langendorff-circulated, K(+)-arrested, guinea pig hearts. Four perfusion variables were manipulated: arterial PO2, environmental PO2, coronary flow and perfusion pressure. In each case agreement between simulated and experimentally determined rates of oxygen consumption gives confidence that the model adequately describes the advective and diffusive transport of oxygen in the isolated, arrested, saline-perfused heart.

Animals↗
PubMed1975

[The effect of ischemic and cardioplegic heart standstill on the myocard metabolism in normal and less perfused heart (author's transl)].

The tolerance of ischemia in normal and less perfused myocard during an ischemic and cardioplegic heart standstill was investigated. A decrease of ATP and ADP and an increase of the lactate, pyruvate and AMP was established during an ischemia of 20 minutes. The less perfused hearts gave considerably worse results regarding the energy transformation than normal hearts. In less perfused hearts the energy reserve of myocardial metabolism showed a considerably better behaviour during a cardioplegic heart standstill of 45 minutes than an ischemic one of 20 minutes. During the recuperation period this trend was emphasised.

Adenosine Diphosphate↗