Simon Dack

The electrocardiogram after standard exercise as a functional test of the heart

Abstract An objective test of cardiac function is of importance in distinguishing functional from organic heart disease. It is useful in diagnosis and is helpful in studying the progress of disease and the degree of physical disability. It is of particular value when other examinations of the heart are negative, i.e., physical examination, electrocardiogram, fluoroscopy, exercise tolerance test, etc. The test to be described in this report consists of recording an electrocardiogram after a definite amount of work, standardized for the patients age, sex, and weight. 1–4 It is essential to utilize a standard amount of work; for even healthy persons, if they exercise to excess, may have abnormal electrocardiographic responses. 5–10 It is therefore important that the exertion to which the patient is subjected will not produce abnormal electrocardiographic changes in any healthy person. This has been verified for the standard two-step test. In addition to recording the electrocardiogram after the two-step test, the patients exercise tolerance can be measured in the ordinary way, that is, by obtaining blood pressure and pulse rate readings before and after exercise. 1, 2

Acute coronary insufficiency: Pathological and physiological aspects: An analysis of twenty-five cases of subendocardial necrosis☆

Abstract 1. 1. A series of twenty-five cases is presented in which recent myocardial changes was found in the absence of acute coronary occlusion. 2. 2. The lesions were confined for the most part to the subendocardial musculature and the papillary muscles of the left ventricle. They varied in extent from a few scattered microscopic foci to widespread disseminated and grossly visible areas. In seven instances almost the entire inner shell of the left ventricle was involved. The possible reasons for the localization of the lesions are considered. 3. 3. The mildest changes consisted of eosinophilic smudging; granularity, uneven staining, and loss of striations of the affected myofibrils; nuclear degeneration; areas of hemorrhage and capillary engorgement. More advanced lesions showed widespread hemorrhage; disappearance of nuclei; homogenization, vacuolization, rupture of muscle fiber; and finally, focal or confluent zones of necrosis with reactive infiltration by polymorphonuclear leucocytes, lymphocytes, and mesenchymal cells. Granulation and fibrous tissue characterized the older lesions. 4. 4. Examination of twenty-four hearts disclosed acute ischemic changes; one showed organizing lesions only. These alterations are believed to have been caused by intense myocardial ischemia due to acute coronary insufficiency. 5. 5. Coronary arteriosclerosis with moderate or severe narrowing was present in nineteen cases. Twenty-two hearts were hypertrophied. Six hearts, in addition, revealed extensive fibrocalcific aortic stenosis; one had mitral stenosis; one had syphilitic aortitis with aortic insufficiency and coronary ostial stenosis; Myocardial ischemia may be produced by acute coronary insufficiency, even in a normal heart. However, hearts with intrinsic diseases (predisposing factors) are much more vulnerable than normal hearts. 6. 6. A variety of factors appeared to have precipitated a state of acute coronary insufficiency. These consisted of tachycardia, acute heart failure, acute hemorrhage, pulmonary embolism, dissecting aortic aneurysm, postoperative shock, and severe infection. In four instances no such initiating mechanism was detected. 7. 7. The inter-relationships between the predisposing and precipitating factors are discussed. 8. 8. Coronary insufficiency is usually precipitated by a physio-pathological mechanism. The clinical recognition of such factor is essential to the accurate differentiation of acute coronary insufficiency from acute coronary artery occlusion and for the definitive therapy of the patient. 9. 9. Where a precipitating factor for the appearance of coronary insufficiency is not detectable, the clinical episode is diagnostic of progressively advancing intrinsic cardiac disease. 10. 10. The preferred terminology in conditions involving acute myocardial ischemia is one that divides acute coronary insufficiency from acute coronary occlusion. This is preferred by virtue of priority and clarity of definition.

DISTURBANCES OF RATE AND RHYTHM IN ACUTE CORONARY ARTERY THROMBOSIS

Excerpt INTRODUCTION Investigators1-5during the nineteenth century observed that ligation of the coronary arteries in animals very frequently produced cardiac arrhythmias either transient or severe...

Postoperative myocardial infarction

Abstract Myocardial infarction and acute coronary insufficiency are important postoperative complications of surgery. Prevention and management depend on recognition and control of the precipitating factors related to anesthesia and surgery. These factors are anesthetic anoxia, tachycardia and hypotension, postoperative hypotension and shock, hemorrhage, dehydration, infection and sepsis, and cardiac arrhythmias. The treatment of the acute attack must be directed primarily to the correction of hemodynamic alterations induced by surgery. The general measures include: (1) relief of pain and sedation; (2) relief of anoxia with oxygen and adequate ventilation; (3) treatment of shock with morphine, oxygen, vasopressor agents and rapid digitalization; (4) treatment of pulmonary edema and heart failure with oxygen, digitalization and diuretics; (5) treatment of thromboembolism with anticoagulants; (6) bed-and chair-rest to reduce the work of the heart; and (7) general measures to minimize postoperative venous stasis and thromboembolism.

The treatment and the immediate prognosis of coronary artery thrombosis (267 attacks)

Abstract 1. 1. Two hundred and forty-three patients suffering from coronary artery thrombosis were treated by a low calorie diet and prolonged rest in bed. Digitalis, adrenalin, or nitrites were not used. 2. 2. The mortality rate in 267 attacks was 16.5 per cent; in first attacks only 8 per cent. Most patients survive an initial attack of coronary thrombosis. Almost one-half of our patients had suffered one or more previous attacks. 3. 3. Coronary thrombosis is not uncommon in women. The ratio of men to women was 3 to 1. It occurs not infrequently in the fourth and fifth decades and the prognosis in these is better than in the older age groups. The average age in our series was fifty-four years. 4. 4. Hypertension, which preceded the attack in 66 per cent of cases, did not directly influence the prognosis. When coronary thrombosis occurs in women, hypertension or diabetes is usually present. 5. 5. Infarction of the anterior and posterior surface of the left ventricle occurs with equal frequency; there is no difference in prognosis. 6. 6. Irregularities of the heart developing during an attack were transitory in most cases and required no specific treatment. 7. 7. Evidence is given that the good results reported in this series may be attributed in part to the undernutrition therapy which eliminates gastrocardiac reflexes, minimizes the rise in metabolism and cardiac output which usually follows a meal, and gradually lowers the basal metabolic rate. This effects a decrease in pulse rate and blood pressure, and so a diminution in the work of the heart. 8. 8. No ill effects were observed following the use of the low caloric diet. 9. 9. Instances of coronary artery thrombosis occur which are inevitably fatal because of the size of one or several simultaneous infarctions or because of the severe degree of involvement of all the coronary vessels. From this series of cases, however, it appears that in the main the prognosis of an attack is hopeful and, indeed, death in the first attack is infrequent.

Activities associated with the onset of acute coronary artery occlusion

Abstract 1. 1. One thousand four hundred and forty attacks of coronary artery occlusion were analyzed from the standpoint of the patients activities preceding the attacks, the time of day when the attacks occurred, the patients occupations, and other associated factors. 2. 2. The distribution of occupations in this series of cases was approximately the same as that in the general population; therefore, occupation and social status did not predispose to coronary occlusion. 3. 3. The circumstances preceding the onset of symptoms in 890 cases were: sleep, 22.3 per cent, rest, 31.1 per cent, mild activity, 20.2 per cent, moderate activity, 8.5 per cent, walking, 15.8 per cent, and unusual exertion, 2.0 per cent. 4. 4. Correlation of these percentages with the number of hours spent daily by the ordinary person in the same occupations indicated that the circumstances were coincidental and that none of them was causally related to the coronary occlusion. Coronary occlusion occurs irrespective of the state of physical activity of the body. 5. 5. Associated factors in 930 cases were: meals, 9.9 per cent, emotional excitement, 5.6 per cent, surgical operation, 6.6 per cent, infection, 4.3 per cent, and miscellaneous factors, 1 per cent. It was concluded that, with the possible exception of surgical procedures, these factors did not play a role in the pathogenesis of coronary occlusion. Only two attacks of coronary occlusion were associated with trauma. 6. 6. Detailed histories of the activities and emotional state of patients for hours, days, and weeks preceding attacks confirm the belief that physical activity and excitement are not factors in the onset of coronary occlusion. 7. 7. Sixty patients sustained an attack of coronary occlusion after having been bedridden for weeks or months because of some chronic illness. 8. 8. The time of onset of the attack was ascertained in 722 cases. Equal numbers occurred during the afternoon, evening, and night, and a slightly greater number during the morning. The attacks were well distributed throughout all the hours of the day, with peaks at 2 a.m. and 10 p.m. This also indicates that activity is not a factor in the precipitation of coronary occlusion. 9. 9. Premonitory symptoms of the attack, such as chest pain, dyspnea, or weakness, were present in 80 of 170 cases in which these symptoms were investigated. 10. 10. There is no evidence that physical effort or excitement produces intimal hemorrhage in the coronary arteries, which is the usual forerunner of thrombosis and occlusion. Intimal hemorrhage is the end result of the progressive, degenerative arteriosclerotic process and is probably a fortuitous event. It was found at necropsy as frequently in patients who had been bedridden prior to the occlusion as in those who were physically active.

The course of the blood pressure before, during, and after coronary occlusion

Abstract The course of the blood pressure before, during, and after the attack has been analyzed in five hundred thirty-eight cases of coronary occlusion. The incidence of hypertension increased with age. The blood pressure fell to some extent in every case, although in a few cases the fall was slight. A transitory rise in pressure occurred infrequently at the onset of the attack. A rapid fall was somewhat more common than a gradual one. Occasionally the fall did not occur until after a week. The lowest pressure was usually reached between the twelfth and twentieth days. In some cases the initial fall was soon followed by a temporary or permanent rise in pressure. The trend of the blood pressure was similar in the hypertensive and nonhypertensive groups, although a rapid fall was more common among the nonhypertensive patients who died. The systolic blood pressure rarely fell below 90 mm. in the hypertensive group, but this was common in the nonhypertensive group. When the pressure fell below 80 the patient usually died. In almost one-fifth of patients with a previous pressure of 200 mm. or more the pressure did not fall below 150 mm. Two-thirds of the hypertensive patients regained a hypertensive level; in half of these this took place before discharge from the hospital, and, in the remaining half, usually within one or two years. The height of the blood pressure after the attack did not significantly influence the future course of the patient with respect to subsequent angina pectoris, heart failure, coronary occlusion, or death.

Acute Coronary Insufficiency Due to Acute Hemorrhage: An Analysis of One Hundred and Three Cases

The occurrence of 59 cases of acute coronary insufficiency among 103 patients with acute hemorrhage, chiefly from the gastrointestinal tract, emphasizes the frequency and gravity of this generally unrecognized complication of bleeding. Clinical, electrocardiographic and anatomic manifestations of myocardial ischemia and subendocardial necrosis are prone to appeal in previously diseased hearts, although they may develop in otherwise normal hearts. Consequently, prompt and adequate blood replacement is required in patients with coronary arteriosclerosis, enlarged hearts, valvular heart disease, etc. to prevent as well as to treat coronary insufficiency secondary to hemorrhage.

The roentgenkymogram in myocardial infarction

Abstract Characteristic abnormalities in left ventricular pulsation as recorded roentgenkymographically in 200 cases of myocardial infarction were as follows: 1. (1) Localized diminution or absence of pulsation. 2. (2) Complete systolic expansion or paradoxical pulsation. 3. (3) Partial systolic expansion, indicated by expansion early in systole or a delay in the completion of systole. 4. (4) Marked diastolic splintering. These changes are found in cases of either recent or old infarction. In cases of recent infarction, even slight irregularities and diminution of pulsation may be of significance. These changes were found in 75 per cent of our cases of myocardial infarction, and are likely to be permanent, although progression and regression have been noted often. A persistently normal kymogram does not exclude the possibility of myocardial infarction. In most cases abnormalities appear within three weeks of the attack, if they appear at all, but occasionally characteristic changes do not appear for several months. Characteristic roentgenkymographic findings usually permit one to make the diagnosis of myocardial infarction secondary to coronary artery occlusion.

The significance of an absent or a small initial positive deflection in the precordial lead

Abstract 1. 1. The initial positive deflection in the precordial lead (Q-wave of old, R-wave of new technique) was absent in 2.7 per cent of 4,500 consecutive hospital patients and was small (2 mm. or less) in 3.9 per cent. 2. 2. In two-thirds of the patients, absence of this deflection was associated with recent or old coronary thrombosis and anterior wall infarction, and in one-fifth, with coronary artery disease alone, with or without hypertension. 3. 3. The initial positive deflection was also absent in 14 cases diagnosed as acute and chronic glomerulonephritis, rheumatic and syphilitic valvular disease, pneumothorax, Graves disease, and acute myocarditis. There was no evidence of myocardial infarction in these cases. 4. 4. In patients with an M or W-shaped QRS complex precordial leads obtained from other positions on the chest wall usually demonstrated absence of the initial positive deflection. This holds frequently when a large initial negative deflection precedes a large positive deflection. 5. 5. Absence of this deflection was permanent in the majority of cases even when an abnormal T 4 and abnormal standard leads returned to normal. 6. 6. Absence of the initial positive deflection was accompanied by an abnormal T 4 in 54 per cent of cases. 7. 7. Of the patients with a small initial positive deflection 7.5 per cent had no clinical evidence of cardiovascular disease. The remainder suffered from coronary thrombosis (29 per cent), coronary artery disease with or without hypertension (37 per cent), rheumatic valvular disease (17 per cent), miscellaneous heart involvement (12 per cent). These included cases of intraventricular or bundle-branch block. 8. 8. In only one-fifth of these patients was there an associated abnormal T-wave in the precordial lead. A small initial positive deflection was significant when followed by an intrinsic deflection of at least 10 mm. 9. 9. In a large group of cases with anterior wall infarction, diagnosed electrocardiographically or at autopsy, the initial positive deflection was absent in more than one-half, small in one-sixth, and normal in one-third. In posterior wall infarction this deflection was rarely absent but was frequently small. 10. 10. In 26 patients with a small initial positive deflection, myocardial infarction was found 15 times. Only one case showed normal heart muscle. 11. 11. Comparison of the ordinary method of recording the precordial lead with the “zero potential” method of Wilson revealed no practical advantage of the latter as far as diagnosis was concerned.