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Biomedical subjects

B Korbmacher

Publications and source records attributed to B Korbmacher.

29 records · Page 2Linked to original sources
PubMed1996

Longterm efficiency of high dose inotropic support in an infant after repair of Fallot's tetralogy.

A 23 month old boy with highly symptomatic tetralogy of Fallot (TOF) underwent repair. Inspite of cold Bretschneider cardioplegic solution twice the heart was beating soon after application of the cardioplegic solution each time. Soon after transfer to the intensive care unit the patient developed low cardiac output (LCO). The following days high doses of inotropic support ware necessary to maintain sufficient arterial pressure. The dosages of dobutamine (up to 49 micrograms/kg/min); norepinephrine (up to 5.28 micrograms/kg/min, and epinephrine (up to 16 micrograms/kg/min), respectively, were twice and three times as high as common maximum recommendations. After having recovered from acute renal failure requiring hemodialysis from the 5th to the 37th postoperative day the child was discharged 9 weeks after the intervention. The very unusual and interesting course of this boy is described and the form and grade of the inotropic support is discussed.

Acute Kidney Injury↗
PubMed1995

Left aortic arch and right descending aorta--interruption or severe coarctation of the aortic arch in the newborn.

Three consecutive neonates (aged 7, 14 and 30 days, body-weight 2980 g, 3000 g and 3400 g respectively) with interruption of the aorta (n = 2) and severe coarctation (n = 1) in the presence of left aortic arch and right descending aorta are reported. Associated lesions were an aortopulmonary window in the first case and an unrestrictive ventricular septal defect in the two others. Intractable heart failure and the complexity of the malformation led to the decision of a staged operation. A prosthetic graft was interposed between the ascending and descending aorta via a right thoracotomy in order to bridge the atretic or hypoplastic segment without using extracorporeal circulation. There was no intraoperative complication. One patient developed a thrombocytopenia within the frame of a sepsis syndrome and died on day 5 after operation, death being caused by a massive bleeding into the left thoracic cavity, although the operation was carried out via a right thoracotomy. Angiography 1 year after operation revealed a good flow through the grafts and no stenosis at the site of the anastomoses. The two surviving infants are clinically well without any medication. The reported operative technique provides an alternative palliative possibility to manage critically ill neonates without any obstacle to later definitive repair.

Aorta↗
PubMed1995

Utilization of oxygen by the contractile apparatus is disturbed during reperfusion of post-ischaemic myocardium.

UNLABELLED: Post-ischaemic ventricular function remains depressed (= myocardial stunning) despite nearly normal coronary blood flow during reperfusion. In order to illuminate the causes of this phenomenon, we studied the relationship between ventricular function and myocardial oxygen consumption (MVO2tot) in experiments on 15 isolated rabbit hearts perfused with erythrocyte suspension (hct = 30%). Left ventricular systolic function was assessed by measuring aortic flow (ml.min-1), peak systolic pressure (LVPmax), dP/dtmax, and early relaxation in terms of dP/dtmin during control and 30 min after the onset of reperfusion, following 20 min global no-flow ischaemia. The pressure-volume area was calculated as a measure of total mechanical energy. The external mechanical efficiency (Eext) was assessed from stroke work and MVO2tot. Both contractile efficiency (Econ = inverse slope of the MVO2-PVA relationship) and MVO2 of the unloaded contracting heart (MVO2unl = basal MVO2 + MVO2 for excitation-contraction coupling) were calculated using pressure-volume area and MVO2tot. RESULTS: At matched heart rate (149 +/- 30 vs 147 +/- 31 min-1; mean +/- SD) and end-diastolic volume (1.3 +/- 0.2 ml), the systolic variables were significantly decreased in the stunned myocardium: aortic flow: 38 +/- 13 vs 9 +/- 11 ml.min-1, LVPmax: 112 +/- 19 vs 74 +/- 18 mmHg, and dP/dtmax: 1475 +/- 400 vs 1075 +/- 275 mmHg.s-1. Likewise, dP/dtmin was significantly impaired (-1275 +/- 250 vs -975 +/- 250). The decrease in pressure-volume area (570 +/- 280 vs 270 +/- 200 mmHg.ml.100 g-1) was not statistically significant. In contrast, both Eext (0.75 +/- 0.29 vs 0.18 +/- 0.26 arbitrary units) and Econ (31 +/- 18 vs 14 +/- 7%) were significantly decreased, whereas MVO2tot (40 +/- 9 vs 34 +/- 8 microliters.beat-1.100 g-1) and MVO2unl (26 +/- 9 vs 22 +/- 6 microliters.beat-1.100 g-1) were not. SUMMARY: Ventricular function after brief episodes of ischaemia is decreased whereas MVO2tot is maintained, i.e. external efficiency is decreased. MVO2 for the unloaded contraction remained unchanged, indicating that MVO2 for excitation-contraction coupling is inappropriately high for the depressed contractile state. The decreased contractile efficiency indicates further that O2 utilization of the contractile apparatus is disturbed during reperfusion.

Animals↗
PubMed1995

Comparison between the effects of a novel Ca++ sensitizer and a phosphodiesterase inhibitor on stunned myocardium.

Inotropic agents are used widely for pharmacological bridging of the failing heart either until recovery after surgical intervention or until transplantation. EMD 57033 is a novel specific Ca++ sensitizing agent with purportedly minor phosphodiesterase (PDE) III-inhibiting properties. It acts as an inotropic agent without raising intracellular Ca++ levels. In turn, the PDE III-inhibitor enoximone has been used for several years to treat low cardiac output syndrome. However, little is known about its effects on postischemic reperfused (stunned) myocardium. We investigated the effects of EMD 57033 (EMD; 30 microM) and enoximone (E20 micrograms/ml) on stunned myocardium. The experiments were performed on 16 isolated rabbit hearts perfused with an erythrocyte suspension (hematocrit = 30%; [Ca++] = 2.5 mM). Hearts were reperfused after a 20 min no-flow ischemia. Measurements were performed at control, 30 min after the onset of reperfusion, and after administration of one of the drugs. Both agents significantly improved the depressed systolic function [left ventricular pressure (LVP)max from 61 +/- 12 to 93 +/- 18 mmHg, and its derived pressure (dP/dt)max from 860 +/- 220 to 1340 +/- 300 mmHg/s and LVPmax from 78 +/- 9 to 83 +/- 15 mmHg, and its derivative dP/dtmax from 1040 +/- 230 to 1385 +/- 300 mmHg/s, respectively] and early relaxation (dP/dtmin from 810 +/- 250 to 1260 +/- 345 mmHg/s and from 1000 +/- 200 to 1135 +/- 295 mmHg/s, respectively) that occurred during postischemic reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Two-stage sternal closure after repair of congenital heart disease in neonates.

Closure of the longitudinal sternal incision can lead to unacceptable impairment of the haemodynamic state after prolonged operation for complex congenital heart disease associated with decreased cardiac function which is caused by cardiac dilatation. Between 1981 and 1991, a two-stage sternal closure was used in 21 neonates with dilatation of the heart and low cardiac output after correction of congenital heart disease. The mean age at operation was 14 (range 4-30) days. In 15 patients (group 1), primary closure of the sternum was considered impossible in the operating room; in the remaining six (group 2), the sternum was reopened on the day of operation or on the first or second day after repair. Three of these newborn infants had a total anomalous pulmonary venous connection and 18 a simple transposition of the great arteries. In all patients, temporary closure of the thorax with a dura mater patch was performed. The patch was usually removed on day 4 after operation in the intensive care unit and followed by uncomplicated routine chest closure. There were no problems with mediastinitis, wound infection, osteomyelitis or instability of the sternum. Subsequent deformity of the thorax was not observed. Some 11 of 15 children (73%) of group 1 and four of six (66%) of group 2 survived. Leaving the sternum open resulted in a significant improvement in the haemodynamics in all patients. The technique of two-stage closure of the sternum is very effective after lengthy corrective operation in children with congenital malformations of the heart who require long periods of perfusion or ischaemia.

Cardiac Output, Low↗
PubMed1993

[Pulmonary artery sling. A rare disease picture with variable clinical symptoms].

In two patients with obstruction of the upper respiratory airways, echocardiography, subsequent angio-cardiography and bronchoscopy disclosed the presence of a pulmonary artery sling. The clinical course of the disease, the diagnostic approach and the procedures for surgical repair are described. Embryological as well as differential diagnostic aspects are discussed with regard to the literature.

Airway Obstruction↗
PubMed1992

Intermediate-term clinical and hemodynamic results of the neonatal arterial switch operation for complete transposition of the great arteries.

We prospectively evaluated 49 consecutive hospital survivors of the arterial switch operation for complete transposition and intact ventricular septum by clinical examination, echocardiography, cardiac catheterization, 12-lead and 24-h Holter ECG. The mean length of follow-up was 40 +/- 18 months. Forty-six children are clinically asymptomatic without medication, 2 died due to coronary related left ventricular dysfunction 3 and 12 months after surgery, and 1 required reoperation because of severe bilateral pulmonary branch stenoses. Except for this case, cardiac catheterization (n = 23) revealed a mean gradient of only 17 +/- 8 mmHg between the right ventricle and distal pulmonary arteries. Left ventricular end-diastolic volume was within normal limits except for 2 cases with volumes slightly below normal, the mean ejection fraction was 78 +/- 5%, and end-diastolic and end-systolic ventricular shapes were normal. The mean cardiac index was 4.14 +/- 0.69 l/min/m2. Left ventricular end-systolic wall stress to velocity of fiber shortening relation was normal in all cases examined (n = 15), indicating normal myocardial contractility. Significant neoaortic valve insufficiency was never observed despite considerably enlarged aortic roots. Twenty-four-hour Holter ECG records (n = 46) provided no evidence of serious atrial arrhythmias, especially sinus node dysfunction. These encouraging intermediate-term results make the arterial switch operation the treatment of choice at present, for neonates with simple transposition.

Child, Preschool↗
PubMed1992

Malignant fibrous histiocytoma of the heart--case report of a rare left-atrial tumor.

The present report describes the case of a 57-year-old patient with malignant fibrous histiocytoma of the left atrium operated on for a suspected atrial myxoma. Surgery was performed as radically as possible and included resection of the atrial wall. Clinical investigation and echocardiography performed 29 months after surgery revealed no signs of tumor recurrence. Diagnostic procedures, topography, pathohistology as well as options for therapy are discussed with regard to the latest literature. A radical surgical approach represents the only effective therapeutic measure. Owing to a lack of sufficient experience, there is no additional therapeutic recommendation on hand. Neither radiation nor chemotherapeutic treatment concepts have proved efficient. Echocardiography represents the best examination procedure for both diagnosis and follow-up in patients with cardiac tumor.

Heart Atria↗
PubMed1991

The arterial switch-operation: early and midterm (6 years) results with particular reference to technical problems.

Since February 1985 the arterial switch operation (ASO) has become the surgical treatment of choice for newborns with simple TGA, appropriate forms of complex TGA and double outlet right ventricle (DORV) as well at our institution. Between 1985 and 1990 a total of 87 patients underwent surgery. In 60 patients with simple TGA and 8 patients with complex TGA or DORV, respectively, an arterial switch-operation was performed. Because of coronary artery anomalies (n = 13), dysplastic pulmonary valves (n = 3) or pressure drop in the left ventricle (n = 1), the initially planned arterial switch operation was discarded and a Mustard type procedure was in 17 patient. Finally there were two primarily performed Mustard operations. The hospital mortality after arterial switch for simple TGA was 15% (9/60), 0/8 in patients with complex TGA. Late mortality was calculated to be 12% (1/8) in patients with complex TGA and 3/60 in patients with simple TGA. Within the Mustard group there were 2/19 hospital deaths and one late death. Causes of early death after arterial switch were: intraoperative myocardial infarct (n = 3) low cardiac output syndrome (n = 2), intractable bleeding (n = 2), metabolic acidosis (n = 1), and septicemia (n = 1). Late after surgery there was one death due to chylothorax after thrombotic obstruction of the SVC, and 3 more deaths secondary to intraoperative infarct, progressive LV dysfunction and meningitis, respectively. Among the long-term survivors 2 patients developed a severe supravalvulary pulmonary stenosis. There were no significant arrhythmias, supravalvulary pulmonary aortic stenoses, aortic insufficiency or myocardial perfusion disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMedDate not supplied

Improved ventricular function by enhancing the Ca++ sensitivity in normal and stunned myocardium of isolated rabbit hearts.

A possible cause for the decreased function in postischemic reperfused (= stunned) myocardium could be a decrease in Ca++ sensitivity. To test this hypothesis, we used an agent with reportedly Ca++ sensitizing properties (EMD 57033) and performed experiments on a total of 17 isolated rabbit hearts that were perfused with an erythrocyte-containing medium in a modified Langendorff setting (hct = 30%; Ca++ = 2.0 meq/l). The hearts were divided into two groups. In one group (n = 9), the Ca++ sensitizer (30 microM) was administered to nonischemic myocardium, and in a second group (n = 8), the Ca++ sensitizer was administered after 30 min of reperfusion that followed a period of 20 min normothermic, no-flow ischemia. In the nonischemic group, addition of the agent, improved left ventricular (LV) function significantly. In the ischemic group, LV-function was depressed at 30 min reperfusion compared to control. Again, the agent improved LV-function significantly. The increase in systolic and diastolic function was comparable in both groups as well as the oxygen consumption that was significantly increased after administration of the agent. In both groups, the agent neither exhibited significant, positive chronotropic nor arrhythmogenic effects. We summarize that the novel Ca++ sensitizer acts as a potent positive inotropic agent in the isolated blood-perfused rabbit heart. Because of the agent's properties to ameliorate postischemic contractile dysfunction, this general strategy may be useful for treating poorly functioning reperfused myocardium.

Animals↗