C. Rollins Hanlon

Heart Autotransplantation: Effect on Myocardial Catecholamine and Histamine

Complete excision and reimplantation of the canine heart is followed by a fall in myocardial norepinephrine to negligible levels. These decreases are at- tributable to the sympathetic denervation which necessarily accompanies the operative procedure. Myocardial histamine levels in survivors of this operation were not significantly different from those of normal dogs.

Neural Responses Following Autotransplantation of the Canine Heart

Orthotopic autotransplantation of the canine heart is followed by loss of direct sympathetic and parasympathetic neural regulation. Stimulation of the vagus nerve or stellate ganglion fails to alter cardiac rate.Myocardial catecholamines are depleted and[see figure in the PDF file]hypersensitivity to exogenous l-norepinephrine is present for months.One year after the operation, there is evidence of cardiac reinnervation and return of normal responses to catecholamines.

Work Capacity and Efficiency of the Autotransplanted Heart

Total extrinsic denervation of the heart was accomplished in six animals by cardiac autotransplantation. The work capacity and efficiency were studied in the postoperative period, when there was depletion of catecholamine stores. The left ventricular oxygen consumption (VO2) of these six cardiac autotransplants (average body weight, 13.6±0.6 kg) and six normal dogs (average body weight, 14.0±0.4 kg) were compared with a right-heart bypass at similar heart rates, mean arterial blood pressures, and systemic flows. The two groups of animals achieved comparable levels of stroke work (17.3 g-m) over the same range of filling pressures. Average maximum rates of left ventricular pressure development were also similar (autotransplants 2455±278 mm Hg/sec, versus 2267±209 mm Hg/sec for normal dogs). At VO2/100 g left ventricle, autotransplants averaged 9.54±0.97 cc/min and normal dogs 9.62±0.76 cc/min. However, left ventricular weights in the autotransplant group were significantly greater (110.9±6.2 g) than in the normal dogs (96.7±3.4 g), and represented a significantly greater percentage of body weight (8.2±0.5% versus sus 6.6±0.3%). Total left ventricular VO2 was greater in autotransplants during performance of comparable levels of external work and at comparable degrees of contractility. No systematic difference in handling of glucose, lactate, or pyruvate was noted between the groups. Respiratory quotients were 1.0 or greater. The normal dogs showed no net change in circulating catecholamines across the coronary bed, whereas autotransplants always showed a net uptake of catecholamines. Myocardial mitochondria were enlarged in electron micrographs of the ventricular myocardium of the autotransplants.The totally extrinsically denervated cardiac autotransplant can achieve a level of performance similar to that of a normal heart, but is less efficient in doing so. Alterations in utilization of circulating catecholamines may aid the hemodynamic adaptation to the cardiac denervation.

Biochemical Studies of Myocardium and Blood During Extracorporeal Circulation in Man

We have studied samples of myocardium from 40 patients with congenital heart disease for catecholamine, histamine, and glycogen content. Blood samples obtained before, during, and after cardiopulmonary bypass in 53 patients were assayed for total protein, osmolality, catecholamines, histamine, lactic acid dehydrogenase activity, and cholinesterase activity. The data show that (1) adequate cardiopulmonary bypass is accompanied by increased sympathetic activity, (2) myocardial damage, indicated by elevated plasma lactic acid dehydrogenase activity, may occur during operation, and (3) depletion of myocardial catecholamine content may be a concomitant of heart disease with chronic congestive failure.

Cardiac perfusion with dextran-dimethyl sulfoxide for cardiac preservation☆

Abstract Ten canine hearts undergoing perfusion with 200 to 300 ml. of clinical dextran containing 15% DMSO during extracorporeal support maintained the circulation acutely and seven supported life beyond the acute period. The seven long-term survivors maintained their weight, evidenced normal activity, and had unremarkable electrocardiographic tracings. Light microscopy demonstrated a significant myocardial lesion in the surviving heart perfused with the most dextran-DMSO, which may have been related to electrical defibrillation. Electron microscopy revealed no definite abnormalities. Catecholamine content of the myocardium was moderately reduced. Myocardial analysis for electrolytes, fat, carbohydrates, and various glycolytic and citric acid cycle enzymes revealed no major deviations from normal.

Metabolic Assessment of Internal Mammary Artery Implantation in the Dog

The metabolic and physiologic contributions of an implanted internal mammary artery have been assessed in five dogs 24 to 34 months following internal mammary artery implantation and concomitant ameroid constrictor application to coronary arteries. All implants were patent angiographically prior to evaluation by right heart bypass and continual autoanalyzer assessment of myocardial oxygen, pyruvate, and lactate extraction. Control internal mammary artery flow averaged 17.5 ml/100 g LV/min. Occlusion of the internal mammary artery failed significantly to alter myocardial extraction of oxygen, pyruvate and lactate or ventricular function, nor did these patent implants prevent significant changes in oxygen, pyruvate, and lactate extraction and ventricular function during and following occlusion of a remaining patent left coronary artery. In only one animal did internal mammary artery flow increase with left coronary artery occlusion, and this only transiently. These results indicate that demonstration of angiographic patency of an internal mammary artery implant does not necessarily indicate significant metabolic or functional contribution of this extracardiac blood supply to the heart.

Tuberculosis and congenital cyanotic heart disease

Abstract In an attempt to ascertain the incidence of pulmonary tuberculosis among patients with congenital cyanotic heart disease, we have reviewed the roentgenograms of the chest of 800 patients who were submitted to operation for pulmonary stenosis. Thirty-nine of these patients presented radiologic findings consistent with pulmonary tuberculosis. Further study of these thirty-nine patients, including tuberculin tests, excluded tuberculosis in twenty-four instances. In the 800 patients the maximal possible incidence of tuberculosis by these criteria is less than 2 per cent. The experimental work on aggravation of induced pulmonary tuberculosis by circulatory alteration in the lung is reviewed. In the light of this work we have briefly discussed the most suitable operative procedures for correction of congenital cyanotic heart disease complicated by pulmonary tuberculosis. The recommendations are illustrated by two detailed case reports.

Surgery of heart disease.

Mitral stenosis forms the chief subject of this diagnostic clinic. The history of surgery for mitral stenosis is briefly reviewed, together with a discussion of the indirect and direct surgical approaches to the problem. Two patients are presented to illustrate the indications, contraindications and results of direct attack (commissurotomy) on the stenotic mitral valve.Mitral stenosis forms the chief subject of this diagnostic clinic. The history of surgery for mitral stenosis is briefly reviewed, together with a discussion of the indirect and direct surgical approaches to the problem. Two patients are presented to illustrate the indications, contraindications and results of direct attack (commissurotomy) on the stenotic mitral valve.