Harrison Black

Digitalis, electrolytes and the surgical patient

Abstract Recognition of the complex interrelations between electrolytes and digitalis action is of vital importance in the management of surgical patients with heart disease. Experimental data bearing on this subject have been examined and the literature reviewed. The following pertinent facts emerge: 1. 1. With due recognition that change in a single ion never occurs without other alterations in the total water-electrolyte structure, it is nevertheless clear that in the digitalized patient a decrease in body potassium from whatever cause may precipitate digitalis intoxication. By contrast, administration of potassium will abolish all digitalis-induced arrhythmias even in patients with a presumably normal total of body potassium content. The interaction between digitalis and potassium thus occurs at a cellular level. The cardiac sensitivity to this drug has little relation to the serum potassium concentration. 2. 2. However, toxic doses of digitalis interfere with the disposition of potassium within the body. Administration of potassium to patients with advanced heart failure exhibiting digitalis intoxication may cause serious hyperkalemia. The explanation of this fact appears to be twofold: release of potassium by the liver and interference with its uptake by skeletal muscle when under the influence of digitalis. Thus, the treatment of digitalis intoxication with potassium, while essential, carries special hazards in this group. 3. 3. Calcium and digitalis have similar actions on the contractility and excitability of the isolated heart. In the intact animal a synergism between calcium and digitalis on cardiac excitability is not demonstrable. Acute reduction in the concentration of ionized calcium results in a hypodynamic myocardium leading rapidly to shock and death. This deleterious action can be prevented either by digitalis administration or by the infusion of calcium salts. 4. 4. Magnesium exerts an antiarrhythmic effect on the myocardium and can abolish, transiently, digitalis-induced ectopic rhythms. When the body is chronically depleted of magnesium by dietary deficiency of this ion, the heart becomes sensitized to the toxic action of digitalis. The clinical use of digitalis drugs in the preoperative, intraoperative and postoperative periods is outlined. Simplicity of medication and the avoidance of rapid parenteral digitalization are desirable objectives in surgery. Injudicious rigorous diuresis immediately prior to operation can precipitate serious complications in the digitalized cardiac patient and lead to digitalis toxicity. The diagnosis and management of cardiac arrhythmias in surgical patients is discussed. Rapid heart action with hypotension in the operative or postoperative period is a particularly difficult problem, and necessitates the differentiation of blood volume deficiency, cardiac arrhythmia, underdigitalization or digitalis toxicity as the etiologic factor. The special problems imposed by posttraumatic metabolism in the cardiac patient are reviewed. The biochemical settings for these problems are: post-traumatic hyponatremia with hyperkalemia, oliguria followed by diuresis, acute acid-base changes, and alterations in ionized calcium. Finally, it is to be emphasized that the majority of available data dealing with the interrelations between digitalis and body electrolytes concerns only the effects on cardiac excitability. As yet there is a paucity of information concerning the influence of electrolyte alterations on digitalis-induced changes in cardiac contractility. Clearly, much additional investigation is needed on this subject which also bears importantly on the welfare of the surgical patient.

A clinical study of 1,000 consecutive cases of mitral stenosis two to nine years after mitral valvuloplasty.

A study is presented of 1,000 cases of predominant mitral stenosis operated by valvuloplasty between 1949 and 1956. It is shown that the survival of these patients is better than would have been expected under medical management. Sixty-nine per cent of the survivors of the operation in groups II and III improved, and 55 per cent in group IV. Factors influencing the late results are discussed. After substantial improvement lasting a year or more, 228 of this series deteriorated; the factors affecting this deterioration are discussed, of which mitral insufficiency, an inadequate valvuloplasty, and recurrent rheumatic fever are the most striking.

Dissection of the thoracic aorta. Medical or surgical therapy

Abstract Both medical and surgical therapy are available for the treatment of aortic dissection. To help determine which form of treatment is indicated for which patients, all cases of aortic dissection at the Peter Bent Brigham Hospital from 1963 to 1973 were reviewed. The most important feature in determining the patients clinical status and response to therapy was the site of dissection, that is, the ascending or descending aorta. Of 31 patients with dissection of the ascending aorta, 26 had one or more of the following contraindications to medical therapy: congestive heart failure (8 patients), hemopericardium (8 patients), new aortic insufficiency (13 patients) or jeopardized carotid or coronary arteries (4 patients). Medical therapy was successful in only 1 of 9 patients with dissection of the ascending aorta; 17 of 22 patients having surgical correction of this lesion did well and were discharged. The clinical status of the 14 patients with dissection limited to the descending aorta was quite different. None had a contraindication to medical therapy. Medical therapy was instituted in all 14, and was successful in 6; dissection progressed in 8 patients despite medical therapy, and subsequent surgery was successful in only 2. We conclude that the treatment of choice for dissection of the ascending aorta is prompt surgical therapy. In patients with dissection limited to the descending aorta, medical therapy is usually feasible and often successful.

Reoperation for Mitral Stenosis: A Discussion of Postoperative Deterioration and Methods of Improving Initial and Secondary Operation

A series of 80 reoperations for mitral stenosis in 79 patients is reported and analyzed. The most important causes of deterioration after valvuloplasty for mitral stenosis are inadequate initial operation, restenosis, and mitral insufficiency. Generally more than one of these factors pertain. An adequate mitral valvuloplasty requires the complete opening of both the anterior and posteromedial commissures and the mobilization of the chordae tendineae from each other and from the wall of the ventricle. The advantages and limitations of closed reoperation, open reoperation, the right-sided approach, and the use of the transventricular valvulotome are reviewed. More complete correction of stenosis with mobilization of posteromedial, anterior, and subvalvular chordae is emphasized. This is attained by operating from both the ventral and dorsal aspects of the patient through a left posterolateral thoracotomy incision. An Ivalon operating tunnel sutured to the left atrial wall at reoperation makes it possible to carry out the more extensive valvuloplasty at reoperations. A lower operative mortality, better longterm results, and fewer instances of deterioration are anticipated when this concept of improved valvuloplasty is effected initially.

The surgical correction of calcific aortic stenosis in adults: I. Technique of transaortic valvuloplasty∗

Abstract 1. (1) The life cycle of adults with calcific aortic stenosis is discussed. The ominous significance of left ventricular failure, even as manifested by dyspnea on exertion, is emphasized. 2. (2) A transaortic technique for the correction of this condition is presented. The substantial advantages of using a special Ivalon operating tunnel are reviewed. 3. (3) In the first 100 cases there have been 12 late deaths and 16 operative deaths. The operative mortality has been reduced to 5 in the last 60 consecutive patients. 4. (4) Eighty-six per cent of the surviving patients followed from 6 to 36 months are improved. 5. (5) The gratifying salvage from this fatal disease encourages further use of this method of surgical relief.

Anomalous Inferior Vena Cava Draining into the Left Atrium Associated with Intact Interatrial Septum and Multiple Pulmonary Arteriovenous Fistulae

A 30-year-old woman with cyanotic heart disease due to anomalous drainage of the inferior vena cava into the left atrium in the presence of an intact interatrial septum is reported. The diagnosis was established during life and the defect was successfully corrected by open-heart surgery. The patient failed to survive due to associated multiple pulmonary arteriovenous fistulae. The embryology of the intracardiac defect, the pathophysiology of these fistulae, and the associated advanced pulmonary atherosclerosis are discussed.