Radi Macruz

Hemodynamic determinants of coronary constriction in human myocardial bridges

To study the physiopathology of myocardial bridges, we assessed the degree of systolic coronary artery constriction (%SC) in different hemodynamic situations in six patients submitted for coronary angiograms. There was an increase of %SC (p less than 0.05) with sodium nitroprusside (NP), no modification during fast atrial stimulation (AS), and a decrease (p less than 0.05) during noradrenaline infusion (Nor). Hemodynamic studies indicate an inverse relation (p less than 0.05) between %SC and systolic and diastolic aortic pressure and left ventricular dP/dt. There was no correlation between changes in %SC and changes in Vmax or heart rate. Thus we conclude that changes in systemic arterial pressure and coronary perfusion pressure may significantly affect the degree of severity of myocardial bridges, possibly through an influence upon intraluminal coronary pressure and an intramyocardial tension relationship.

Ebstein's disease

Abstract The electrocardiograms and vectorcardiograms of 12 patients with Ebsteins disease are analyzed and correlated with the radiologie findings. In 6 patients, there was anatomic confirmation, in 3 during surgery for implantation of a Starr-Edwards prosthesis in the right atrioventricular ring and in 3 by autopsy. In the 6 remaining patients, the confirmation was made by angiocardiographic studies. A tendency to normal heart rate or bradycardia was observed in most cases. In all, the diagnosis of right atrial overloading could be made by analyzing the amplitude, configuration and durations of the P wave and P-R interval. The duration of the P wave was greater than normal in 53 per cent of the cases. The duration of the P-R interval was greater than normal in 73 per cent of the cases. There was a clear relation between the increased duration of the P wave and that of the P-R interval. The increases of the P wave and of the P-R interval were closely related to the increase of the cardiac silhouette. The P/P-R segment index was less than 1.2 (considered the mean normal value), in spite of the increase of P wave duration, in all but 1 case. We support the hypothesis that the increase in P wave and P-R interval is dependent mainly on right atrial overloading and not only on congenital conduction disturbance. In the patients with very large hearts, lead V1 tended to show polyphasic, low voltage QRS complexes, whereas in those with smaller hearts, V1 tended to show “pure” R waves. An increase in QRS duration was registered in all cases, probably not because of real right bundle branch block but because of intraventricular conduction disturbance. The increase in QRS duration, the configuration in V1 and the degree of cardiomegaly were closely related. The greater the enlargement of the right heart chambers, the more important were the leftward and posteriorly directed portions of the QRS vectorcardiographic loop. The vectorcardiographic studies demonstrated that the cases of lesser cardiomegaly corresponded to those in which there was increased duration of the QRS complexes in the horizontal plane and predominance of the rightward portions.

The electrocardiogram in tetralogy of Fallot: A study of 142 cases

Abstract One hundred and forty-two cases of tetralogy of Fallot were studied from both the scalar and the vectorial electrocardiographic points of view. We have concluded that in the majority of the cases of this congenital heart disease the ECG shows a uniform behavior which relates to the hemodynamic picture. We have established the criteria for the diagnosis of the left ventricular enlargement which may eventually co-exist, indicating a predominant left-to-right shunt through the interventricular septal defect (atypical Fallot). Finally, we have emphasized the presence of qR patterns in the right precordial leads in cases of TF associated with marked cardiomegaly and evident enlargement of the right auricle.

The vectorcardiogram in interatrial septal defect and persistent atrioventricular canal

Abstract Thirty-six cases of interatrial septal defect (IASD) of the septum secundum type (2 of these cases showed association of rheumatic alteration of the mitral valve) and 9 cases of persistent atrioventricular canal (PAVC) were studied from the vectorcardiographic point of view. Attention is drawn to the following points: (1) clockwise rotation in the horizontal plane in IASD of the septum secundum type, in spite of normal or slightly elevated right ventricular systolic pressure; (2) high incidence of intraventricular conduction disturbance (55 per cent of the cases of IASD); (3) persistence of the morphology of complete right bundle branch block (RBBB) in the VCG in cases of isolated IASD after surgical correction of the defect and normalization of the cardiac area and of pressure in the right ventricle; (4) value of the VCG in the diagnosis of PAVC; and (5) vectorcardiographic data for the differential diagnosis between PAVC and isolated IASD (of the septum secundum type) and interventricular septal defect (IVSD), with the QRSsE loop oriented upward and to the right.

The vectorcardiogram in ventricular septal defect associated with pulmonary stenosis A study of 60 cases

Abstract We have analyzed the vectorcardiographic behavior in 60 cases of ventricular septal defect plus pulmonary stenosis (VSD plus PS). We have discussed the criteria for the recognition of the so-called “systemic right ventricle”, biventricular overloading, and right bundle branch block associated with right ventricular overload, and we have emphasized the different behavior of the vectorcardiogram in the cases of VSD plus PS with venoarterial and arteriovenous shunt.

Surgical Treatment of the Congenital Fistulae of Coronary Arteries

Six cases of coronary artery fistulae surgically treated are presented. All patient but one was male; the ages varied from 4 to 44 years. The fistulae originated from the left coronary artery in three cases from the right in two cases and from both arteries in one case. The draining heart chambers were the right atrium in three, the right ventricle in two and the pulmonary artery in one case. Associated lesions were present in three cases. One patient died on the early postoperative period and the evolution was satisfactory in five cases.

Successful Correction of Double-Outlet Right Ventricle with a Ventricular D-Loop and L-Malposition of the Great Arteries, Bilateral Conus, Pulmonary Stenosis and Subaortic Ventricular Septal Defect

The authors present the case of a fifteen-year old girl with double outlet right ventricle with ventricular d-loop and l-malposition of the great arteries, bilateral conus, pulmonary stenosis and subaortic ventricular septal defect, who was operated on successfully. This is the fourth case of double outlet right ventricle with l-position of the aorta that has been surgically corrected. The subaortic position of the interventricular defect favours the creation of the tunnel connecting the left ventricle with the aorta without obstructing the right ventricular outflow tract. The patient was doing well 11 months postoperatively.

Myocardial oxygenation and its influence on the electrogenesis of ventricular overloading patterns.

Abstract We have studied in different forms of heart disease an index of myocardial oxygenation (Io) expressed by the correlation between the availability and consumption of oxygen by the myocardium. Its variations in comparison with electrocardiographic changes are analyzed. From a hemodynamic point of view (with coronary arteries presumably within normal limits), the normal oxygenation index is not followed by electrocardiographic changes while a low index (hypoxia) is represented by T wave, S-T and QRS changes. It is apparent that organic changes of the coronary arteries, which are frequently associated with the hemodynamic disturbances, would modify these conclusions. The importance of the vascular factor can be estimated through the possible electrocardiographic changes in cases with no alteration or slight alteration of the index of myocardial oxygenation.