Robert G. Sumner

Demonstration of the dynamic nature of idiopathic hypertrophic subaortic stenosis.

Abstract Isoproterenol infusion converted a patient with potential hypertrophic subaortic stenosis into one with all the hemodynamic features of severe hypertrophic subaortic stenosis in less than 15 minutes. This response was not observed during isoproterenol infusion in 15 patients with left ventricular hypertrophy from a variety of causes. Further study of this drug in patients with left ventricular hypertrophy of unknown etiology is indicated. Infusion of isoproterenol may serve as a provocative test to identify those patients with early or latent forms of hypertrophic subaortic stenosis. Such studies will also allow a more careful examination of the hemodynamic features of the syndrome before the signs and symptoms have become so severe as to preclude extensive investigation.

Nucleic Acid Studies in Experimental Cardiomegaly

1. A group of weanling rats was made anemic by an Fe- and Cu-deficient diet consisting of cows milk. An appropriate control group receiving Fe and Cu in addition to milk was also studied. After 86–105 days, the rats were sacrificed; hematocrit levels, heart weights, DNA, RNA, and protein concentrations were determined. Total DNA, RNA, and protein contents of the hearts were calculated. 2. Statistical analysis showed a significantly increased mean heart weight, decreased DNA concentration, increased RNA to DNA ratio, and increased total RNA and protein content in the hearts of the anemie group of rats versus the control rats. There were no statistically significant changes in RNA concentration or total DNA content of the hearts. 3. These data are interpreted as showing that the predominant cellular change in cardiae enlargement in the rat with dietary Fe-and Cu-deficiency is that of increase in size of the myocardial cell.

Hemodynamic Effects of Isoproterenol Infusion in Patients with Normal and Diseased Mitral Valves

Hemodynamic effects of isoproterenol infusion were studied in 26 patients with and without mitral valve disease undergoing combined right and left heart catheterization. The heart rate and cardiac output rose while the left ventricular end-diastolic pressure, pulmonary vascular resistance, and total peripheral resistance fell, regardless of the status of the mitral valve. Infusion produced little change in the mean arterial blood pressure and the diastolic filling period per minute.While the mean left atrial and pulmonary artery pressures fell in patients with normal or insufficient valves, these pressures rose in patients with mitral stenosis. Stroke volume tended to rise in all patients but those with mitral stenosis. In patients with combined mitral stenosis and insufficiency the insufficiency appeared to modify the hemodynamic response associated with mitral stenosis.The presence of a lowered end-diastolic pressure in the left ventricle and an increased pressure in the left atrium in patients with stenosis suggests that isoproterenol has a direct or reflex effect on the left ventricle during diastole.

Idiopathic Enlargement of the Right Atrium

Four patients with idiopathic enlargement of the right atrium are described. All patients were evaluated carefully by clinical means and two were subjected to extensive investigation including cardiac catheterization, angiocardiography, and intracavitary electrocardiography.The diagnosis of idiopathic enlargement of the right atrium is based primarily on radiographic examination with exclusion of other causes of right atrial enlargement by appropriate clinical and laboratory means. In the patients studied no cause for the right atrial abnormality could be established. Nonetheless, it is concluded that this disease is a distinct clinical entity that deserves further recognition and investigation.

Recognition and Surgical Repair of Superior Mesenteric Arteriovenous Fistula

A patient is described with a traumatic arteriovenous shunt from the superior mesenteric artery to the superior mesenteric vein. The patient had no symptoms referable to this fistula 3 months after a gunshot wound to the abdomen. The diagnostic feature was a continuous bruit in the supraumbilical area. The radiographic technics used in determining the nature of this patients fistula are described. This is the first reported case of a traumatic superior mesenteric arteriovenous fistula suspected clinically, demonstrated radiographically, and successfully repaired surgically. Although experience with such fistulas is limited, the fatal outcome of the only other case in the literature (not recognized ante mortem) indicates the need for careful auscultation over all abdominal surgical incisions and sites of trauma at regular intervals.

Atrial dissociation: An electrocardiographic artifact produced by the accessory muscles of respiration

Abstract The electrocardiographic features of so-called atrial dissociation are defined. Tracings obtained from 10 patients are presented wherein the relation of the phenomenon to respiration is illustrated. The origin of this respiratory artifact is discussed with reference to the action of the accessory muscles of respiration. It is concluded that of the tracings reported recently purporting to illustrate the phenomenon of atrial dissociation there are a few which must be regarded as at best doubtful documentation of such an arrhythmia. The majority are considered to be examples of the respiratory artifact as described herein.

THE SECOND HEART SOUND IN CONGENITAL PULMONARY VALVULAR INSUFFICIENCY.

Abstract The nature of the second heart sound in congenital pulmonary valvular insufficiency is discussed in relation to anatomic and physiologic alterations. Three cases are reported to illustrate several of the significant factors which may produce expiratory splitting of the second heart sound in this defect.

Ebstein's Anomaly Associated with Cardiomyopathy and Pulmonary Hypertension

A patient is described with cardiomyopathy and intracavitary electrocardiographic findings typical of Ebsteins anomaly of the tricuspid valve. The cardiomyopathy was characterized by extreme thickness of the left ventricular wall on angiocardiography, elevated end-diastolic pressures of the ventricles, and prominent “a” waves in the atrial pressure pulses. Moderately severe pulmonary hypertension, which has not previously been described in Ebsteins anomaly, was also attributed to the cardiomyopathy. This case illustrates the increasing number of associations with which Ebsteins anomaly has been reported and emphasizes the importance of considering this diagnosis in planning the cardiac catheterization of patients with congenital heart disease. The necessity of demonstrating coexisting Ebsteins anomaly in patients with congenital heart disease is indicated by the formidable mortality of such patients at surgery.

The Value of Inspiratory Leads in Electrocardiographic Diagnosis.

Excerpt During the course of interpreting 1,000 consecutive electrocardiograms, interesting changes in cardiac rhythms were observed in leads III and AVF obtained during the act of deep inspiration...

Prominence of the left epipericardial fat pad: A cause of apparent cardiomegaly

Abstract Two subjects with apparent cardiomegaly due to an unusually prominent left epipericardial fat pad are described. The importance of this condition is explained and the usefulness of tomography and angiocardiography in its recognition is cited.