John Shillingford

Free noradrenaline and adrenaline excretion in relation to the development of cardiac arrhythmias and heart failure in patients with acute myocardial infarction.

Abstract The role of the sympathetic nervous system in the clinical course of acute myocardial infarction has been assessed by measuring serially the urinary excretion of free noradrenaline and adrenaline in 55 patients. In patients developing heart-failure or cardiogenic shock, the urinary level of both free catecholamines rose notably in the first week after infarction. In contrast, in uncomplicated cases, a moderate rise in the noradrenaline level in the first week was associated with only a transient rise in the adrenaline level. Ventricular arrhythmias and multiple different forms of arrhythmia in the same patient were more commonly associated with noradrenaline levels above 75 μg. per g. creatinine and adrenaline levels above 10 μg, per g. creatinine. Supraventricular arrhythmias were not consistently associated with raised catecholamine excretion. Patients developing atrioventricular block had grossly raised levels of both noradrenaline and adrenaline only if they developed heart-failure or cardiogenic shock, these were the patients who required endocardial pacing. Late ventricular arrhythmias, but not late supraventricular arrhythmias, were associated with persistently high catecholamine excretion levels. Sinus tachycardia was usually associated with high excretion levels of both catecholamines, whereas in isolated sinus bradycardia catecholamine excretion was within the normal range. The mean peak excretion of both noradrenaline and adrenaline was significantly greater in the 9 patients who died than in the 46 patients who survived.

Free noradrenaline and adrenaline excretion in relation to clinical syndromes following myocardial infarction

Abstract Serial measurements of excreted free noradrenaline and adrenaline in patients with myocardial infarction have been made. Relations between the amount of amines excreted in the urine and the hemodynamic and clinical features were studied. The amount of noradrenaline excreted varied between a normal level and more than 1000 per cent of the mean normal value, and the amount of adrenaline, between normal and more than 700 per cent of the mean normal value. The relations between the amount of amines excreted, physiologic changes and the patients illness are discussed.

Haemodynamic effects of morphine in patients with acute myocardial infarction.

The administration of analgesic drugs to patients with acute myocardial infarction is routine clinical practice for the alleviation of pain and anxiety or simply to ensure sleep. Because of the potent combination of analgesic and sedative properties, morphine is frequently given. Although the associated depressant effects on the circulatory and respiratory systems have been documented from animal experiments and work in normal man, the haemodynamic consequences of the administration of the drug to patients with acute myocardial infarction have previously not been investigated. The institution of a special unit for the intensive care and study of patients with acute myocardial infarction has enabled hemodynamic measurements to be made throughout the acute illness and before and after the administration of drugs without disturbing the patients. The object of this work has been to measure the changes in cardiac output, stroke volume, heart rate, and arterial blood pressure following the administration of morphine to a variety of patients with acute myocardial infarction and at the same time to observe the clinical effects.

Surface mapping of RS-T segment in acute myocardial infarction.

A method of surface mapping of the RS-T segment deviations that occur in acute myocardial infarction is described. The results observed in i5 patients are recorded and the potential value of this procedure is discussed in (i) diagnosis of myocardial infarction; (ii) delineating the extent of the myocardial ischaemia; and particularly (iii) its use as a method of examining the effect of therapies on the extent of myocardial ischaemia.

Natural history and clinical significance of arrhythmias after acute cardiac infarction.

Continuous monitoring of the electrocardiogram has shown the incidence of arrhythmias in acute myocardial infarction to be much higher than was previously thought. With this method, Julian, Valentine, and Miller (1964) found a serious arrhythmia in as many as 56 per cent of their patients, whereas in an earlier study with routine electrocardiograms, Master, Dack, and Jaffe (1937) found an arrhythmia in only 14 per cent of their patients, premature beats being excluded. An increase in the mortality rate has been noted in association with certain arrhythmias developing during the course of acute myocardial infarction (Woods and Barnes, 1942; Billings et al., 1949; Beard et al., 1960), and it is possible that a more detailed study of these may lead to improvement in their management, and so reduce the mortality in this disease. This paper describes the natural history and clinical significance of the arrhythmias occurring in 50 consecutive patients with acute myocardial infarction. A new clinical grouping of the arrhythmias is proposed based on the over-all cardiac response to the arrhythmia. Their haemodynamic effects are discussed and also their ietiology in relation to necropsy findings. Finally the prognosis and management of individual groups is described.

URINARY EXCRETION OF FREE NORADRENALINE AND ADRENALINE FOLLOWING ACUTE MYOCARDIAL INFARCTION

Abstract Serial measurements have been made of free noradrenaline and adrenaline in the urine of patients with acute myocardial infarction. The level of excretion of noradrenaline varied from normal values to approximately 800% of the mean normal level, and of adrenaline from normal values to approximately 350% of the mean normal level.

Hemodynamic Changes in Patients with Acute Myocardial Infarction

The hemodynamic changes following acute myocardial infarction have been studied in patients in an intensive care unit. Serial determinations of cardiac output and blood pressure have shown a wide range of hemodynamic patterns in severely ill patients varying from a low cardiac output and high peripheral resistance to a high cardiac output and low peripheral resistance. The progression of changes during the illness and their relation to the clinical findings have been discussed.

PRACTOLOL IN THE TREATMENT OF CARDIAC DYSRHYTHMIAS DUE TO ACUTE MYOCARDIAL INFARCTION

Abstract Practolol (I.C.I. 50,172, Eraldin) was given to forty-seven patients who had cardiac dysrhythmias after myocardial infarction. In fourteen patients with rapid supraventricular dysrhythmias the ventricular-rate was slowed beneficially by practolol and six of these patients reverted to sinus rhythm. Five out of eleven patients with lignocaine-resistant ventricular tachycardia reverted to sinus rhythm after practolol. In nine out of sixteen patients with frequent ventricular extrasystoles, adequate suppression followed intravenous practolol. Side-effects were not prominent. The drug seems to be a valuable addition to the antidysrhythmic agents used after myocardial infarction.

Circulatory changes associated with systemic hypotension in patients with acute myocardial infarction.

Myocardial infarction often leads to a fall in arterial blood pressure. This may occur briefly during the acute stage of the illness, persist for several days, or in some patients, the pressure may fail to return to previous levels. The mechanism by which the blood pressure falls is not always clear, and in order to study the circulatory changes associated with the hypotension, serial hamodynamic investigations have been made during the acute illness and subsequent recovery in patients with myocardial infarction. The purpose of this paper is to show that a fall in arterial blood pressure following myocardial infarction can occur in association with widely differing hmmodynamic patterns. The possible physiological and therapeutic implications are discussed.

THE MEASUREMENT OF SEGMENTAL VENOUS FLOW BY AN INDICATOR DILUTION METHOD

Several methods have been evolved for the measurement of venous flow in animals, but most have a limited application in man as they involve exposure of the appropriate blood vessel. These methods include the Ludwig type stromuhr (Tigerstedt, 1892), the thermostrontuhr (Rein, 1928; Schmidt and Walker, 1935; Shipley et al., 1942), the bubble flow meter (Soskin et al., 1934; Brunner, 1948), the differential pressure flow meters (Gregg and Green, 1940; de Burgh Daly, 1926; Johnson and Wiggers, 1937) and the electromagnetic flow meter (Kolin, 1936, 1941). Fronek and Ganz (1960) report a method for measuring flow in a single blood vessel by a local thermodilution method. They injected a bolus of cool saline into the blood stream and recorded a dilution curve from the change in temperature in the immediate neighbourhood of the injection by a thermistor mounted on the injection catheter. The accuracy of their method was studied in model circulations and in experiments on dogs; good correlation was found with direct methods of measurement. Katsura et al. (1959) endeavoured to measure blood flow using a single thermistor as both heating and the termperature-sensing element. Andres et al. (1954) determined the flow in the human brachial artery by continuous injection of a dye at a constant rate. Peterson et al. (1954) measured the left ventricular output in animals by injecting Evans Blue at a constant rate into the aortic root through a cannula and sampling the resultant mixture in the descending aorta. The purpose of this paper is to describe a method for measuring local venous flow in man by the injection of an indicator substance under pressure at a constant rate through fine holes in the tip of a double lumen catheter and sampling the diluted blood through the other lumen.