William K. Nasser

Identification of Ultrasound Echoes from the Left Ventricle by Use of Intracardiac Injections of Indocyanine Green

This study was designed to identify the ultrasound echoes originating from the left ventricle. Injections of indocyanine green and saline were made directly in the left ventricular cavity via a cardiac catheter in patients undergoing routine diagnostic cardiac catheterization. The injections produced a cloud of echoes that filled the left ventricular cavity and outlined the left side of the interventricular septum and the endocardial surface of the posterior left ventricular wall. The results of this study verified the origin of echoes that are vital to the ultrasound technics for the detection of pericardial effusion, left ventricular wall size, left ventricular cavity size, and left ventricular stroke volume. This study also provided ways of distinguishing between the true left ventricular wall echoes and intracavitary echoes that often cause confusion.

Atrial myxoma: II. Phonocardiographic, echocardiographic, hemodynamic, and angiographic features in nine cases

Abstract Nine cases of atrial myxoma, seven left and two right, have been diagnosed and successfully treated in the past five years. The phonocardiographic, echocardiographic, hemodynamic, and angiographic features are discussed in detail.

Use of Ultrasound to Measure Left Ventricular Stroke Volume

Several empirical observations made during ultrasound examinations for pericardial effusion have led to the possibility that this diagnostic technique might be used to measure left ventricular stroke volume in man. The hypothesis that left ventricular stroke volume was proportional to the amplitude of an echo originating from a portion of the left ventricle near the mitral ring (MREa) times the distance between the echoes from the anterior and posterior ventricular walls (LVD) has been validated.Ultrasound examinations were performed simultaneously with cardiac output determinations using the direct Fick method on 16 patients proven to have competent mitral and aortic valves. Correlation between the two methods of measuring left ventricular stroke volume was excellent (r = 0.973; P < 0.001). When ultrasound measurements were used in the regression equation to predict stroke volume, the calculated values were within 11 ml or 15% of those determined by the Fick method.The fact that an ultrasound examination is simple, can be done as a bedside determination in a matter of minutes, and is totally harmless to the patient make it a promising diagnostic procedure. The measurement of left ventricular stroke volume represents another addition to the growing list of medical uses for this intriguing technique.

Atrial myxoma. I. Clinical and pathologic features in nine cases.

Abstract During the past five years, nine cases of atrial myxoma, seven left and two right, have been diagnosed and successfully treated at this institution. Seven were female and all were Caucasian except for one Negro man. Dyspnea was the most common symptom, being present in all nine patients. Six of the nine complained of vague chest pain and syncope was present in three. Ankle edema was prominent in eight patients. Emboli, pulmonary and/or systemic, occurred in four patients. Congestive heart failure, right and/or left, was present in eight of the nine; no patient complained of hemoptysis. Four patients were found to have anemia and three noted fever. The atrial myxoma was successfully removed with the aid of cardiopulmonary bypass and all nine patients noted marked symptomatic improvement. The clinical, electrocardiographic, and pathologic features are described.

A Study of Mitral Valve Action Recorded by Reflected Ultrasound and Its Application in the Diagnosis of Mitral Stenosis

The movements of two ultrasound echo signals, believed to arise from the anterior mitral leaflet and from the mitral ring, were studied in 30 normal subjects and in 100 heart-catheterization patients. Fifty patients had proven mitral stenosis. The echo from the anterior mitral leaflet is shown to have a complex pattern of movement. This pattern is analyzed into the opening and closing movements of the leaflet, and the underlying movement transmitted from the mitral ring. In the normal condition, the characteristic feature of leaflet motion is a sharp closing movement that follows the initial opening in diastole. This sharp closing movement is not seen in the presence of mitral stenosis. It is believed that the demonstration of a sustained wide-open poisition of the leaflet in diastole has the same diagnostic significance as the finding of a persistent positive-pressure gradient across the valve. The value of this method in diagnosing the severity of the stenosis is discussed.

Congenital absence of the left pericardium. Clinical, electrocardiographic, radiographic, hemodynamic, and angiographic findings in six cases.

Until the past decade, the diagnosis of congenital absence of the pericardium, partial or complete, had rarely been made prior to postmortem examination or thoracotomy. Since 1963, the condition has been recognized during life in six patients at this institution. Of these six patients, two had partial absence of the left pericardium and four had complete absence of the left pericardium. Characteristic roentgenologic findings were present in all six patients. Associated heart lesions were not present in either patient with a partial pericardial defect. Two of the remaining four had associated heart lesions. One patient had surgical repair of an atrial septal defect. Surgical repair of the pericardial defect was not attempted in any of the six patients. Hemodynamic determinations at rest were normal in all six patients. The two patients with partial pericardial defects, however, had elevation of the pulmonary artery and left ventricular end-diastolic pressures during mild exercise in the recumbent position which suggests that this type of defect is not totally innocuous. In view of the unusual and extreme cardiac mobility in this condition, it is conceivable that a portion of the heart could herniate and transiently incarcerate through the partial defect during exercise. It is suggested that partial pericardial defects may warrant surgical repair. Small defects or complete absence of the left pericardium, however, are apparently without lethal potential and do not require surgical intervention.

Hemodynamic Studies Before and After Instrumental Mitral Commissurotomy A Reappraisal of the Pathophysiology of Mitral Stenosis and the Efficacy of Mitral Valvotomy

Hemodynamic studies including simultaneous right heart, transseptal left heart, and retrograde left heart catheterizations were done on 35 patients before and at least 6 months after instrumental mitral commissurotomy to evaluate the efficacy of this type of surgery and to enhance our understanding of the pathophysiology of mitral stenosis. Although surgery produced a significant increase in calculated mitral valve area, the degree of improvement varied markedly. The younger patients had the greater increase in mitral valve area. The change in cardiac index and pulmonary vascular resistance correlated well with the change in mitral valve area. Only those patients whose mitral valve area increased over 1.0 cm2 had a significant increase in cardiac index and a fall in pulmonary vascular resistance. The data indicate that the reduced cardiac index and elevated pulmonary vascular resistance in patients with mitral stenosis are related to the mitral valve obstruction and are at least in part reversible and that the elevated pulmonary vascular resistance during mild exercise is related to elevated left atrial pressure.An almost universal fall in left atrial and pulmonary artery pressures followed surgery, but this apparent improvement did not necessarily correlate with an increase in mitral valve area. A significant increase in exercise left ventricular end-diastolic pressure in patients who had the greatest increase in mitral valve area raises the question as to the status of the left ventricle in patients with mitral stenosis. Decreased left ventricular compliance is offered as a possible explanation for this observation.The concomitant existence of mild or moderate preoperative aortic insufficiency in eight of the patients and the development of significant mitral insufficiency in seven of the 35 patients following surgery did not alter the surgical results significantly. Whether the poorer results in patients with atrial fibrillation were a result of age or the arrhythmia could not be determined.

Korotkoff Sounds: Observations on Pressure-Pulse Changes Underlying Their Formation

We have studied Korotkoff sounds in 10 subjects by recording pressures and sounds simultaneously through a brachial arterial needle at locations both beyond and beneath the inflatable cuff. The Korotkoff sounds coincided with a small dip and ensuing steep rise in pressure immediately beyond the distal edge of the cuff. Sound intensity paralleled not only the rate and the acceleration of this steep ascent, but also the total pressure through which it was maintained. Pressures beneath the midportion of the cuff showed a more pronounced sharp initial negative dip, usually followed by a rapid reversal and steep rise, and the sounds were also recorded here in association with these rapid pressure changes. This study supports the hypothesis that the initial Korotkoff sound is produced by rapid changes of pressure both beneath and distal to the compressing cuff, sufficient in rate to impart sonic vibrations to the vessel wall and surrounding tissues. We have attempted to explain how these rapid pressure changes are produced.

Congenital Absence of the Left Pericardium

A case of complete absence of the left pericardium, suspected from plain chest x-rays and proved by diagnostic left pneumothorax, has been reported. The significance of the pericardium in relation to cardiac function is discussed. Because absence of the left pericardium is a benign and relatively asymptomatic anomaly that usually requires no treatment, it behooves the clinician and radiologist to become cognizant of its presence.

Congenital absence of the left pericardium

Abstract Until the past decade, the diagnosis of congenital absence of the pericardium, partial or complete, was rarely made before postmortem examination or thoracotomy. Roentgenologic findings are usually characteristic in complete absence of the left pericardium and consist of the following: levoposition of the heart associated with midline trachea, prominence of the pulmonary artery segment, an indistinct right-sided heart border that is usually hidden by the spine, a tongue of lung projecting between the aorta and main pulmonary artery and interposition of lung between the left hemidiaphragm and inferior border of the heart. In partial left pericardial defects the heart is usually in normal position, and the abnormality consists of prominence of the pulmonary artery or left atrial appendage, or both. Since cases have been reported of sudden death with herniation and strangulation of a portion of the heart through a partial pericardial defect, it appears that partial absence of the left pericardium is not always innocuous. The presence of symptoms and the possibility of sudden death in partial defects, accompanied by angiographic evidence of herniation of the left atrial appendage through a pericardial foramen, argue strongly for surgical correction of this lesion. However, extremely small defects, or complete absence of the left pericardium, are apparently without lethal potential and do not require surgical intervention.