Systemic haemodynamic actions of pimobendan (UD-CG 115 BS) and its O-demethylmetabolite UD-CG 212 Cl in the conscious pig.

The cardiovascular effects of the pyridazinone-derivatives pimobendan and its O-demethylmetabolite UD-CG 212 Cl (2-(4-hydroxy-phenyl)-5-(5-methyl-3-oxo-4,5-dihydro-2H-6-pyridazinyl) benzimidazole HCl) were studied in conscious pigs, employing consecutive intravenous 10 min infusions of 10, 25, 50 and 100 micrograms kg-1 min-1 and 2, 4 and 8 micrograms kg-1 min-1 respectively. Pimobendan caused dose-dependent increases in LVdP/dtmax (up to 115%) and heart rate (up to 30%), while cardiac output was slightly elevated (up to 15%) and stroke volume decreased by 12%. Left ventricular end-diastolic pressure decreased in a dose-related manner from 8.7 +/- 1.0 mmHg to 2.7 +/- 1.7 mmHg. Mean arterial blood pressure was not significantly affected because systemic vascular resistance decreased dose-dependently up to 15%. After beta-adrenoceptor blockade, the pimobendan-induced increases in heart rate and cardiac output were attenuated and the increase in LVdP/dtmax almost abolished. The responses of left ventricular end-diastolic and mean arterial blood pressure, systemic vascular resistance and stroke volume were not modified. UD-CG 212 Cl caused dose-related increases in LVdP/dtmax (up to 100%) and heart rate (up to 25%). Cardiac output was minimally elevated (up to 8%) as stroke volume decreased dose-dependently up to 15%. As systemic vascular resistance decreased up to 12%, mean arterial blood pressure was slightly reduced (5%). Left ventricular end-diastolic blood pressure decreased dose-dependently from 9.0 +/- 0.8 mmHg to 3.8 +/- 1.3 mmHg. After beta-adrenoceptor blockade, the UD-CG 212 Cl-induced increases in heart rate and LVdP/dtmax were attenuated and almost abolished and amounted up to 15% and 20%, respectively. The responses of the other systemic haemodynamic parameters were not significantly modified. We conclude that pimobendan and UD-CG 212 Cl are compounds with marked positive inotropic and venodilator properties in the conscious pig. The attenuation of the inotropic effects by pretreatment with propranolol strongly suggests that, in the conscious pig, the beta-adrenergic system is significantly involved in the positive inotropic actions. The lack of effect of beta-adrenoceptor blockade on the vasodilator responses to both compounds suggest a mechanism not related to beta-adrenergic activity.

Persistent chylothorax. Treatment by talc pleurodesis.

Two patients with persistent chylothorax resistant to therapy by special diet, thoracenteses, and tube thoracostomy drainage were successfully treated by talc pleurodesis. In one patient with advanced lymphosarcoma involving pleura and mediastinal nodes, the chylothorax was managed by open thoracotomy and talc powder. The other patient developed chylothorax following resection of a thoracic aortic aneurysm. She was successfully treated by talc suspension introduced through a thoracostomy tube. Pleurodesis with talc should be considered only when the chylothorax persists after an adequate period of medical treatment and pleural decompression. Intrapleural instillation of talc through a thoracostomy tube should be successful if the chylothorax can be evacuated and the underlying lung fully expanded.

Reconstruction of the new atrial septum in the Senning operation. New technique.

A new technique incorporating the left atrial appendage for the reconstruction of the new atrial septum is described as a modification of the original Senning operation for transposition of the great arteries. In reconstruction of the atrial septal flap, the balloon septostomy defect is closed by approximating the inverted left atrial appendage to the anterior margin of the flap. This technique completely eliminates the necessity for foreign material in the repair of the new atrial septum of the Senning operation and has been used in 21 patients with good results.

Use of the Shaw Scalpel in pacemaker operations.

Pacemaker carriers are at risk when undergoing operations involving the use of diathermy. The Shaw Scalpel utilizes a method by which the cutting edge of the blade is heated to a selected temperature that seals blood vessels as they are cut. No electrical currents are passed to or through the patient and there is no sparking or electrical arcing to the tissue. This apparatus was used as the sole method of thermal coagulation in 20 patients undergoing replacement of pacemaker batteries.

Dacron patch enlargement of anterior wall of left ventricle after aneurysmectomy with concomitant infarctectomy.

The basis for left ventricular aneurysmectomy with cardiopulmonary bypass was established 20 years ago. There is a higher risk in patients who undergo operation within 2 months of myocardial infarction. In these patients there may be no clear demarcation between devitalized tissue and residual healthy myocardium. A case is reported in which anterolateral aneurysmectomy with concomitant infarctectomy so compromised left ventricular size that the anterolateral wall of the left ventricle had to be reconstructed with a Dacron patch graft.

Sarcoidosis in Europe: a cooperative study.

The data on the epidemiologic situation of sarcoidosis from 24 countries of Europe have been reviewed. The new facts seem to demonstrate that the differences between the frequency of this disease in the north and south are not real. The actual situation is dependent on the general knowledge of this disease and on the extent and intensity of the active detection of its asymptomatic stage. A new prospective cooperative study of the yearly incidence of all forms of sarcoidosis in the total population of at least some European countries would be desirable.

A simple method for closure of patient ductus arteriosus in elderly patients.

A relatively simple and safe method for closure of the patient ductus arteriosus in the elderly patient is described. It has been done successfully in 4 patients.

Vascular rings: management and a proposed nomenclature.

Over 18 years, 33 patients with congenital vascular rings underwent surgical treatment. All patients had full recovery except 1 who died late. At the one-month follow-up, 66.7% had complete relief of the presenting symptoms. Important aspects of the clinical picture, diagnostic methods, and treatment are presented. A coded nomenclature is proposed; we believe it to be accurate, inclusive, easy to remember, and readily referable to the embryological origin.

Cold blood--potassium cardioplegia.

A technique is described for providing myocardial protection utilizing oxygenated blood that is drawn from the pump oxygenator and passed through two disposable cardioplegic cooling coils, which are joined in series and submerged in ice slush. A potassium-containing cardioplegic solution is run into the oxygenated blood at the level of the cooling coils. The amount of blood used in the blood-potassium cardioplegic mixture is controlled using a screw clamp. This method has been used with excellent results in 150 consecutive patients undergoing aortocoronary saphenous vein bypass grafting.

Cardiovascular effects of UD-CG 212 CL, a metabolite of pimobendan, in anaesthetized pigs.

Systemic and regional haemodynamic effects of UD-CG 212 CL (0.5-16 micrograms X kg-1 X min-1), the major metabolite of the vasodilator and cardiotonic drug pimobendan, were studied in anaesthetized pigs. The drug caused a dose-dependent decrease in left ventricular (LV) end-diastolic and arterial blood pressures while it increased systemic vascular conductance, heart rate and maxLVdP/dt. The decrease in LV end-diastolic pressure was observed at lower plasma concentrations than the increase in systemic vascular conductance. Cardiac output tended to decrease but statistical significance was achieved only with the highest concentration. These effects of UD-CG 212 CL were not altered by the blockade of beta-adrenoceptors with propranolol. The vasodilator action of UD-CG 212 CL was noticed in several organs but the effects were relatively more marked (in decreasing order of magnitude) in the adrenals, kidneys, gastrointestinal tract, brain and LV epicardium. Since both arterial pressure and cardiac output decreased, the blood flow increased significantly only in the adrenals and decreased moderately in the spleen, LV endocardium and skeletal muscles. The effects of UD-CG 212 CL on the renal and skeletal muscle haemodynamics were different from those of pimobendan, which causes vasodilatation in the skeletal muscles but not in the kidneys. The results of this study show that, like the parent compound pimobendan, UD-CG 212 CL has independent cardiotonic and vasodilator actions; the latter being more pronounced on the venous side. However, the contribution of this metabolite to the overall pharmacological activity of pimobendan appears to be limited.

Total excision of a giant angiolipoma of chest wall with A-V malformation and with the use of an autotransfusion system.

An 18 year old girl suffering from a giant angiolipoma of back and chest wall with A-V malformation underwent total excision of the tumor in 4 stages. The first two stages included surgical ligation of the arterial blood supply to the tumor. In the third and fourth stages the tumor was resected with the use of an autotransfusion system. The last stage was complicated with massive bleeding and disseminated intravascular clotting. Control of bleeding was achieved by the use of autotransfusion system, right thoracotomy and massive transfusion of blood and its components. After long convalescence period associated with renal and respiratory failure the patient recovered completely without sequellae. This case demonstrates the complexity associated with the treatment of these rare tumors.

Late partial tamponade of the right atrium. A case report.

An unusual case of late partial tamponade of the right atrium is reported in a patient 35 days after aortic valve replacement. Chest x-rays, echocardiograms and ECG were not helpful. The diagnosis was made by emergency bedside right heart catheterization which showed a 7 cm H2O gradient between the junction of the superior vena cava and right atrium and also a 12 cm H2O pressure difference between the femoral vein and the right atrium with a normal capillary wedge pressure. Re-thoracotomy with evacuation of blood clots and control of bleeding points improved the hemodynamics dramatically. However the patient succumbed 3 weeks later due to irreversible brain damage. This is thought to be the first report of a late partial right atrial tamponade in the English medical literature.

Prosthetic valve replacement in infants and children.

A review of 41 children from 10 months to 16 years of age who had a valve replacement between the years 1966 to 1981 is reported. Sixty-one per cent of the valve deformities were rheumatic and 39% congenital. Twenty-two children had the mitral valve replaced, 14 had an aortic valve and 5 had both aortic and mitral valve replacement. There was a hospital mortality of 9.7% and only one later death during a mean follow up period of 6.75 years. Three children have required a second mitral valve replacement. Thrombo-embolic episodes were encountered in 4 children. The special problems of valve replacement in infants and children are discussed.

Coarctation of the aorta in infancy.

Twenty-five infants under 1 year of age (mean weight 3.4 kg) underwent repair of coarctation of the aorta between the years 1965 and 1982. Three patients had coarctation only, three had coarctation with patent ductus arteriosus (PDA), and 19 had associated intracardiac anomalies. Eleven patients underwent resection of the aorta and end-to-end anastomosis. Eight had subclavian flap arterioplasty, five had patch graft arterioplasty, and one had subclavian-to-aortic anastomosis. Additional procedures were performed on seven patients: banding of the pulmonary artery on one, repair of total anomalous pulmonary venous drainage on one, mitral valve replacement on one, aortic valvotomy on one, and aortic valvotomy plus pulmonary artery banding on one. Twenty-one survived the operation. All patients who died had associated intracardiac anomalies. The 21 survivors have been followed from 3 months to 13 years, with three late deaths that were associated with intracardiac anomalies. Five of the survivors underwent additional second operations: one had repair of the re-coarctation, one had replacement of the prosthetic mitral valve, one had aortic valvotomy, and two had pulmonary artery debanding and closure of a ventricular septal defect. Two of the 18 surviving patients have mild hypertension associated with a residual gradient. The others are in good health.