Leonard Scherlis

Right bundle branch block following open heart surgery: Electrocardiographic and vectorcardiographic study∗

Abstract Preoperative and postoperative electrocardiograms and vectorcardiograms were analyzed in patients in whom late conduction delay of the right bundle branch block type developed following open heart surgery for the repair of ventricular septal defects. In the presence of right bundle branch block, the electrocardiographic diagnosis of right ventricular hypertrophy is often difficult. Vectorcardiograms are helpful in detecting the right ventricular hypertrophy in these instances. Following successful cardiac repair of the septal or valvular lesions producing right ventricular hypertrophy, there was often a gradual decrease of the height of R or R′ in the right precordial leads in the electrocardiogram, and a gradual shift of the QRSsE loop to the left with eventual reversal of the direction of inscription from clockwise to counterclockwise. A slowly inscribed late portion of the QRSsE loop to the right and anteriorly is the most important criterion for conduction delay of the right bundle branch block type. The possible mechanisms for the appearance of late conduction delay of the right bundle branch block type following cardiac surgery are discussed.

Atrial septal defect. Electrocardiographic, vectorcardiographic, and catheterization data.

The results of the electrocardiographic, vectorcardiographic, and hemodynamic studies of 70 patients with atrial septal defects are analyzed. Serial electrocardiograms and vectorcardiograms were obtained in 16 patients following surgery. The incidence of the rSR′ and rSr′ patterns in the right precordial leads was 60 per cent. To a limited extent, the configuration of the electrocardiogram is related to right ventricular pressure and PBF/SBF. However, no quantitative assessment could be made by determining the magnitude of R or R′ in lead V1. The vectorcardiogram is an important adjunctto the electrocardiogram in detecting right ventricular hypertrophy. As the right ventricular pressure increases, the QRS sÊ loop tends to shift more to the right and anteriorly. Although it can be generally stated that the rSR′ configuration in atrial septal defects is usually due to right ventricular hypertrophy, this configuration is also due to terminal conduction delay or terminal conduction delay associated with right ventricular hypertrophy in a significant number of instances. The vectorcardiogram is useful in detecting terminal conduction delay in patients with rSR′ in the right precordial leads. It was also of value in determining the presence of right ventricular hypertrophy in combination with terminal conduction delay. The evidence of terminal conduction delay may disappear after successful repair of atrial septal defects. Left axis deviation, superior displacement, and counterclockwise direction of inscription of the QRS sÊ loop in the frontal plane are valuable signs for differentiating ostium primum defects from ostium secundum defects. Each of the eight proved instances of ostium primum defects had these typical features.

Transseptal catheterization of the left heart: Observations in 56 patients

Abstract Transseptal cardiac catheterization has been performed in 56 patients. In each instance, satisfactory pressure tracings were recorded from the left atrium. The left ventricle was entered in 71 per cent of those cases in which entrance was attempted, and satisfactory data were recorded by means of a polyethylene filament catheter inserted through the transseptal needle. The advantages of this procedure as a means of obtaining left heart data have been discussed.

Pulmonary Stenosis Electrocardiographic, Vectorcardiographic, and Catheterization Data

The electrocardiographic, vectorcardiographic, and right heart catheterization data of 100 patients with isolated or complicated pulmonary stenosis were analyzed.All but two patients had normal sinus rhythm. One patient, age 62, had atrial fibrillation; the other, age 8, had the Wolff-Parkin-son-White syndrome.In isolated pulmonary stenosis, P-wave enlargement was far more frequently seen in those patients with right ventricular systolic pressures above 100 mm. Hg as compared to those with pressures less than 100 mm. Hg. This relationship was not observed in patients with complicated pulmonary stenosis.The incidence of rsR′ in V1, QRS widening, and the vectorcardiographic evidence of conduction delay was significantly lower in pulmonary stenosis, isolated or complicated, when compared to atrial septal defects alone. There was one instance of terminal conduction delay of the right bundle-branch block type and one diffuse slowing of the QRS sÊ loop in the present series.The correlation between the amplitude of the R wave in V1 and right ventricular systolic pressure was better in the group of isolated pulmonary stenosis as compared to the groups complicated by interatrial communications or ventricular septal defects.The average right ventricular systolic pressures in patients with type 3 right ventricular hypertrophy was significantly higher than those with either type 1 or type 2 right ventricular hypertrophy on the basis of vectorcardiographic criteria discussed. In the presence of pulmonary stenosis, the electrocardiographic and vectorcardiographic evidence of left ventricular hypertrophy or combined ventricular hypertrophy suggests coexisting lesions such as ventricular septal defect with left-to-right shunts. However, it was not possible to differentiate between isolated pulmonary stenosis and pulmonary stenosis complicated by interatrial communication by either electrocardiograms or vectorcardiograms.The vectorcardiographic features of combined ventricular hypertrophy are discussed.

Transient right bundle branch block. An electrocardiographic and vectorcardiographic study.

Abstract The electrocardiographic and vectorcardiographic features of 8 patients who had transient right bundle branch block were studied. The initial 0.04 sec. of the QRS complex in the scalar electrocardiogram and of the QRSsE loop in the vectorcardiogram were unaltered by the development of right bundle branch block. Even without right ventricular hypertrophy the amplitude of R or R ′ in V 1 may increase markedly following the development of right bundle branch block. Thus, the amplitude of R or R′ cannot be considered a reliable criterion for the diagnosis of coexisting right ventricular hypertrophy and right bundle branch block. After the development of right bundle branch block, deep S waves in V 1 may disappear or diminish greatly. However, the tall R waves in the left precordial leads may persist. Therefore, coexisting left ventricular hypertrophy can be suspected when there are tall R waves in the left precordial leads. The QRS axis in the limb leads may also be helpful in detecting coexisting ventricular hypertrophy. Various types of vectorcardiographic changes were described following the development of right bundle branch block. Reversal of the direction of the inscription of the QRSsE loop from counterclockwise to clockwise in the horizontal plane, and from clockwise to counterclockwise in the sagittal plane may occur when right bundle branch block develops. In such a case, coexisting right ventricular hypertrophy may be erroneously diagnosed. In right bundle branch block when the major portion of the QRSsE loop is normally inscribed, it is reasonably correct to state that no coexisting ventricular hypertrophy exists. The evidence of myocardial infarction was not masked by right bundle branch block in either the electrocardiogram or vectorcardiogram.

Isolated ventricular septal defect: Electrocardiographic, vectorcardiographic and catheterization data

Abstract The electrocardiographic, vectorcardiographic and hemodynamic data of 50 cases of isolated ventricular septal defect were analyzed. All but 1 patient had normal sinus rhythm. Ten per cent had first degree A-V block. Patients with rS in V 1 had the lowest right ventricular pressures and relatively small pulmonary to systemic blood flow ratio. The right ventricular systolic pressures were generally increased when V 1 revealed prominent R waves. In adults of this group there was a reduction in the ratio of pulmonary to systemic blood flow as compared to children. There was, however, poor correlation between the height of the R wave in V 1 and right ventricular systolic pressures. The incidence of combined ventricular hypertrophy by electrocardiographic criteria varied from 8 to 22 per cent, according to the criteria applied, and was 24 per cent by vectorcardiographic criteria. The vectorcardiographic features of combined ventricular hypertrophy are discussed.

MITRAL STENOSIS. HEMODYNAMIC, ELECTROCARDIOGRAPHIC, AND VECTORCARDIOGRAPHIC STUDIES.

Abstract The data of transseptal left heart and right heart catheterization were correlated with the phonocardiographic, electrocardiographic, and vectorcardiographic findings in 75 patients with significant mitral stenosis. Measurement of the rate of the “y” descent in the first tenth of a second after the opening of the mitral valve was helpful in detecting the presence of significant mitral stenosis. In the absence of tachycardia, the value of the formula P 1 -P 2 MLAP was 0.3 or less among patients who had predominant mitral stenosis. No significant difference was seen between patients with normal sinus rhythm and those with atrial fibrillation. In the 54 available phonocardiograms, Q-1 minus 2-O.S. was equal to or greater than 0 in all but 7 patients. The electrocardiograms revealed evidence of right ventricular hypertrophy in 26 instances, whereas the vectorcardiograms revealed evidence of right ventricular hypertrophy in 31 instances. Forty-one patients had neither electrocardiographic nor vectorcardiographic evidence of isolated right ventricular hypertrophy. Both the electrocardiogram and vectorcardiogram failed to show patterns typical of right ventricular hypertrophy in 15 patients despite the significantly elevated resting right ventricular pressure. There were 9 patients who had posterior displacement of the QRSsE loop.