Graham A.H. Miller

Myocardial Function and Left Ventricular Volumes in Acquired Valvular Insufficiency

The effect of valvular insufficiency on left ventricular volumes was studied by an angiographic method in 37 patients. Ejection of the additional volume load imposed by valvular insufficiency was achieved by an increase in end-diastolic volume and not by increasing the proportion of end-diastolic volume ejected. Of the 37 patients, 16 (43 per cent) had a significant reduction in the fraction of end-diastolic volume ejected per beat. These patients performed significantly less stroke work from a given end-diastolic fiber length (end-diastolic volume) than did the others and evidence is presented that they had impaired myocardial function. An index of myocardial contractility is derived which relates stroke work to end-diastolic volume.The magnitude of left ventricular volumes is determined in part by the severity of the volume load but a further increase in volume without necessarily a further increase in ejection occurs in those patients with impaired myocardial function. Valvular insufficiency is quantitated from the difference between left ventricular ejection volume determined angiographically and forward stroke volume determined from indicator-dilution curves. The results show good agreement with subsequent surgical findings in the 15 patients who underwent operation.

Effect of Chronic Pressure and Volume Overload on Left Heart Volumes in Subjects with Congenital Heart Disease

Left heart volumes were determined angiographically in 50 subjects of whom 18 had no abnormality of the left heart, 12 had lesions causing pressure overload of the left ventricle, and 20 had lesions causing volume overload of the left ventricle. The left heart volumes were in the normal range in the presence of pressure overload, but, with volume overload, end-diastolic, end-systolic, and atrial volumes were in excess of normal. A linear relationship was demonstrated between end-diastolic and end-systolic volumes, regardless of the pressure load on the ventricle. Thus, for all but one of the cases studied, total left ventricular ejection volume formed a nearly constant proportion of end-diastolic volume.

Surgical risk factors in total anomalous pulmonary venous connection

Eighty-three patients underwent surgical correction of total anomalous pulmonary venous connection (TAPVC) between 1973 and 1986. There were 46 boys and 37 girls. Median age at operation was 60 days (1 to 240) and median weight 3.9 kg (1 to 22). The anatomic types encountered included infracardiac connection (16 patients), supracardiac connection (32) and pulmonary venous drainage connected directly to the coronary sinus (27). Mixed anomalous drainage or pulmonary venous return connected directly to the right atrium occurred in 8 patients. Diagnosis was established by cardiac catheterization and angiography (56 patients), clinical examination (3) and cross-sectional echocardiography alone in 24 of the last consecutive 28 patients. Pulmonary hypertension was present in 26 (55%) of those who underwent cardiac catheterization. The median pulmonary vascular resistance was 4.2 units/m2 (body surface area) for all the patients, whereas in those with infracardiac pulmonary venous connection the median value was 10 units/m2. The median interval between admission and operation was 72 hours. Surgical correction was performed using profound hypothermia and circulatory arrest in 68; for the remainder, conventional cardiopulmonary bypass with profound to moderate hypothermia was used. Ten patients developed 1 or more pulmonary hypertensive crises during the early postoperative period. These were diagnosed in 8 by direct pulmonary artery pressure measurement and in 2 by clinical examination. Late reoperation was necessary in 6 patients (10%). Analyses of risk factors for 30-day survival for all patients showed that the risk of early death was associated with the type of anomaly (infradiaphragmatic), occurrence of pulmonary hypertensive crises, year of the operation, set of the patient and pressure of preoperative congestive heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Cor triatriatum: Hemodynamic and angiocardiographic diagnosis

Abstract Three cases of cor triatriatum are reported. Each patient presented with breathlessness and had signs of pulmonary hypertension, with electrocardiographic evidence of right ventricular overload. Plain radiographs of the chest showed moderate left atrial enlargement and changes indicative of pulmonary venous engorgement. Left atrial enlargement was confirmed in 2 cases by angiocardiography and was quantitated by measurement of the left atrial volumes. Hemodynamic studies revealed a considerable increase in the pulmonary arterial pressure (78 mm. Hg systolic and 32 mm. Hg diastolic to 125 mm. Hg systolic and 75 mm. Hg diastolic) and in the “wedge” pressure (28 mm. Hg systolic and 20 mm. Hg diastolic to 65 mm. Hg systolic and 18 mm. Hg diastolic), with normal left ventricular end-diastolic pressures. Angiocardiography was performed in 2 patients, and in each the intra-atrial diaphragm was clearly demonstrated. Removal of the left atrial diaphragm was successful in 2 patients. The third patient, who had severe pulmonary vascular disease, died on the first postoperative day.

Isolated Congenital Mitral Insufficiency with Particular Reference to Left Heart Volumes

Clinical, hemodynamic, and angiocardiographic findings are described in seven cases of congenital mitral insufficiency. The volumes and changes in volume of the left atrium and left ventricle were calculated from the angiocardiograms and were found to be increased above the range of normal. Left ventricular stroke volumes thus obtained were compared with forward flows calculated from indicatordilution curves in order to quantitate regurgitant flow. Regurgitant flows varied between 19 and 94 per cent of the total left ventricular ejection volume, and forward flow was maintained as a result of a considerable increase in left ventricular volume. The left ventricular ejection volume was 50 to 64 per cent of the end-diastolic volume.

Left ventricular volume and volume change in endocardial fibroelastosis

Abstract Three cases are described in which the clinical and hemodynamic findings permit a diagnosis of endocardial fibroelastosis. Left heart volumes were calculated from biplane angiocardiograms. For each case, values of the fraction of end-diastolic volume ejected during systole, peak dp/dt, and “myocardial contractility index” were significantly less than those in children with normal left hearts or with congenital heart disease causing pressure or volume overload of the left ventricle. Such reduced ventricular contraction and systolic emptying will lead to an increase in chamber volume if forward flow is to be maintained. Conclusions about left ventricular volumes and volume changes cannot be made on the basis of visual inspection of angiocardiograms but require actual measurement. Increased endocardial tension results from increased chamber volume but is unlikely to be the cause of endocardial fibroelastosis since comparable values for endocardial tension are found in subjects with volume overload and no endocardial fibroelastosis.

Unilateral rib notching due to systemic to pulmonary anastomoses in the presence of bilateral pulmonary oligemia.

Abstract This report describes a patient with absence of the main pulmonary artery in whom unilateral rib notching developed in association with vascular pleural adhesions seen at exploratory thoracotomy. This notching can be explained by systemic to pulmonary collateral circulation through the pleural adhesions. A role of thoracotomy in causing further development of adhesions and notching is suggested. When unilateral rib notching is attributed to this mechanism it is usually associated with unilateral pulmonary oligemia. This case demonstrates that flow through pleural adhesions can explain unilateral rib notching in the presence of bilaterally equal pulmonary oligemia. Vascular pleural adhesions were confirmed in only 2 of 15 other cases of unilateral rib notching attributed to this mechanism, and the notching developed after thoracotomy in only 1 other case.