Citations

A definite correlation can be established between the electrocardiogram and the serum potassium level at hypokalemic levels. A study was made at the Mayo Clinic of 130 hypokalemic patients with relatively stable clinical states. Variations in Q-T intervals, P-R intervals, atrial rhythm, P waves, T/R values, and T-wave and U-wave contour in hypokalemia were noted as were the relationships between the T-U complex, electrical repolarization phenomena and potassium metabolism. Since modifying factors such as drugs, certain electrolyte disturbances, variations in cardiac rate, conduction defects, and myocardial ischemia were eliminated by careful selection of patients, only the influence of acid-base imbalance, sodium-potassium ratio, and hypertension on the electrocardiogram was studied. Acid-base imbalance and hypertension often simulated or obscured electrocardiographic evidence of hypokalemia. Electrocardiographic criteria of hypokalemia include various combinations of the following signs: (1) T/U value of 1 or less in lead II or V 3 , (2) U-wave amplitudes of greater than 0.5 mm. in lead II or greater than 1 mm. in V 3 , and (3) S-T depression of 0.5 mm. or more in lead II or leads V 1 , V 2 , and V 3 . It must be remembered that a normal electrocardiogram does not exclude hypokalemia and that an electrocardiogram which fulfills the established criteria does not necessarily indicate hypokalemia unless the factors discussed have been eliminated or minimized.

Of 128 children with anatomically confirmed interatrial communications 74 had ostium secundum, 37 had ostium primum defects, 5 had common atrium, and 12 had total anomalous pulmonary venous connection. Analysis of the medical history, physical examination, roentgenogram, and electrocardiogram resulted in accurate diagnosis in most instances. In 6 of the 128 patients the proper diagnosis was not made: 3 infants with total anomalous pulmonary venous connection died within a few hours after admission to the hospital and did not have proper diagnostic evaluation; the condition of 3 other patients with ostium secundum defects was misdiagnosed as ostium primum defect before surgical treatment. In patients with ostium secundum and ostium primum defects the symptoms, signs, roentgenologic data, and findings at cardiac catheterization are similar, but differences in respect to the electrocardiograms are striking when the latter are subjected to vectorial analysis. The QRS loop is clockwise in the presence of ostium secundum defect and counterclockwise when ostium primum defect is at hand. Clinical and roentgenologic manifestations also are noted among patients with common atrium and total anomalous pulmonary venous connection, and the findings at cardiac catheterization likewise may be similar, but the electrocardiographic differences are significant. The QRS loop is counterclockwise in patients with common atrium and clockwise in patients with total anomalous pulmonary venous connection.

The clinical and follow-up data on 520 non-diabetic patients less than 60 years of age who had a clinical diagnosis of arteriosclerosis obliterans of the lower extremities made at the Mayo Clinic in the period 1939 through 1948 were reviewed from the standpoint of pathogenesis, prognosis, and clinical course of the disease. The ratio of males to females was 11 to 1, and the mean concentration of plasma cholesterol in the male patients with arteriosclerosis obliterans was approximately 50 mg. per 100 ml. greater than that of either of 2 control groups of men without clinical evidence of atherosclerosis. The incidence of smoking among the men with this disease was higher than in a comparable group of men without it. Obesity was not commonly associated with arteriosclerosis obliterans, while hypertension was associated with the disease about 3 times as often as in a control group without the disease. The survival rate for patients with arteriosclerosis obliterans was less favorable than that of a normal population of a similar age and sex distribution, and the survival rate for patients with atherosclerotic aorto-iliac occlusion was significantly less favorable than that of patients with atherosclerotic occlusion of the femoral artery. In approximately three fourths of the patients who died, the cause of death was thought to be disease of the coronary arteries. The presence of atherosclerosis elsewhere than in the arteries supplying the extremities, as manifested by clinical coronary artery or cerebrovascular disease at the time of diagnosis, had an adverse effect on survival. Four per cent of the patients required amputation of a leg shortly after the diagnosis of arteriosclerosis obliterans was made at the clinic, and an additional 4.9 per cent subsequently required amputation during the 5-year period following the initial examination. Only 3.0 per cent of patients with intermittent claudication as the only symptom of their disease required an amputation during this period. Eleven and three-tenths per cent of patients who continued to smoke, but none who abstained from smoking, had amputations within 5 years. Since all patients of the series were treated before the advent of direct arterial surgery for segmental arterial occlusion, it is believed that the subsequent course of the disease in these patients may be used as a basis for comparative evaluation of results in patients subjected to direct arterial surgical procedures.

A study was made of the configuration of the elastic tissue of the pulmonary trunk in 6 cases of idiopathic pulmonary hypertension. The ages of the patients ranged from 12 to 54 years. The pattern was that of the adult pulmonary type in the 5 female patients, whereas it more closely resembled the fetal, aorta-like type in the single male patient. These data are interpreted as indicating that idiopathic pulmonary hypertension is acquired in most cases but that it may be present from birth in a minority of instances.

Estimation of pulmonary blood flow relative to systemic blood flow is a critical point in selecting patients with ventricular septal defect and severe pulmonary hypertension for operation. A detailed medical history, physical examination, thoracic roentgenograms, careful interpretation of electrocardiograms, cardiac catheterization, and biopsy of the lung provide approaches to the problem. In borderline cases, decision still may be extremely difficult. The authors usually favor operation, however, with recognition that this decision may be in error. Obviously proper evaluation for operation cannot assure uniformly good results. Method of conduct of operation, perfusion, and postoperative care determine the results.

This study attempts to bring into focus certain details which have not been described adequately in textbooks of anatomy. This information is now of considerable significance because of its role in the genesis and surgical treatment of mitral stenosis. Variations in the size and shape of the mitral valve are described, with particular reference to the fact that valve commissures, or junctional zones between the leaflets, occur in the normal valve. Measurements of commissures, chordae tendineae and valve leaflets are presented, with a discussion of the significance of some of these measurements.

The spread of the excitatory process in the ventricular septum of the dog's heart has been studied in the isolated organ perfused by the Langendorff technic. It has been possible to remove large portions of the free wall of the right and left ventricles and explore the septal surfaces under direct vision. The mean excitatory pathway in the muscular mass of the dog's ventricular septum has been demonstrated to be from apex to base. The left side of the septum is activated before the right side, and the apical part of the right side is activated before its base.

The purpose of this investigation was to study the incidence and location of systemic arterial occlusion and pulmonary embolism in a consecutive series of cases of fatal acute myocardial infarction. Another consecutive series of cases in which healed myocardial infarction was demonstrated at necropsy was similarly studied. In none of the cases included in this study had anticoagulant therapy been employed. Massive pulmonary embolism was the most frequent fatal thrombo-embolic complication found among the cases of acute myocardial infarction. Cerebral infarction was the most frequent fatal thrombo-embolic complication found among the cases of healed myocardial infarction. Cerebral infarction was the most frequent fatal systemic arterial thrombo-embolic lesion in both groups. Acute splenic and renal infarcts were frequently demonstrated but with one exception appeared to play an incidental role in the clinical course of the patients. Although systemic arterial occlusion was frequently found in association with intracardiac mural thrombi, there were many other cases in which evidence of systemic arterial occlusion was found in the absence of intracardiac mural thrombi. A positive correlation existed between the presence of pulmonary and systemic arterial occlusion and the occurrence of congestive cardiac failure.