The vectorcardiogram in complete transposition of the great arteries: correlation with anatomic and hemodynamic findings and calculated left ventricular mass

The vectorcardiogram in 4 children undergoing the arterial switch repair

Four children with complete transposition (concordant atrioventricular and discordant ventriculo-arterial connections), aged 1.2 to 16.4 years, underwent a delayed repair by the arterial switch procedure from March 1985 to October 1986. Three children had undergone previous atrial diversion repairs in early childhood. Two of these children had developed right ventricular dysfunction with tricuspid incompetence as well as having recurrent and symptomatic supraventricular tachyarrhythmias. They underwent banding of the pulmonary trunk 0.7 and 1 year prior to the final repair. The third child had dynamic obstruction of the left ventricular outflow tract and prior banding was not performed. A fourth child had right ventricular dysfunction on initial assessment in early infancy and then had banding of the pulmonary trunk. Two patients survived the arterial switch operation. Vectorcardiograms were performed on these 4 children before arterial switch repair. The left maximal spatial voltage did not correlate with elevated left to right ventricular pressure ratio at cardiac catheterization before arterial switch repair nor did it relate to survival after operation. The horizontal loop was clockwise in all patients preoperatively. The vectorcardiogram in these children was not a useful indicator that the left ventricle was suitably prepared for the arterial switch repair.

The vectorcardiogram in infants undergoing arterial switch repair

Twenty-five patients with transposition of the great arteries underwent primary arterial switch repair between July 1985 to October 1986. Twenty infants had intact ventricular septum or small ventricular septal defect while 5 infants also had moderate or large ventricular septal defects. Median age of switch repair was 2.9 weeks in those with small ventricular septal defect or intact septum and 7.6 weeks in those with significant defects. Vectorcardiograms were performed weekly preoperatively and then up to 4 to 6 months postoperatively. Cardiac catheterisation was performed preoperatively. Correlation between a left-to-right ventricular pressure ratio of more or less than 0.7 was made with a vectorcardiogram taken near cardiac catheterization. Preoperative vectorcardiograms in patients with essentially intact ventricular septum showed normal maximal spatial voltages in 60 and 65% (left and right) although 70% had clockwise horizontal loops. There was poor correlation between maximal spatial voltages and loops of the vectorcardiogram with the left-to-right ventricular pressure ratio at catheterization. Three of 5 patients with large ventricular septal defects had decreased left maximal spatial voltages or clockwise loops preoperatively. This suggests low left ventricular pressure ratio but at catheterization all had elevated pressure ratios. Despite decreased left maximal spatial voltages or clockwise horizontal loops in many patients in both groups, all survived the arterial switch procedure. Postoperatively, the vectorcardiogram normalized in those with essentially intact septum within a mean of 4 weeks but took longer in the others. The vectorcardiogram is unreliable in assessing suitability for the arterial switch procedure in the first 3 months of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of pulmonary arterial pressures from electrovectorcardiographic data in pediatric patients with rheumatic mitral valve disease

The Frank vectorcardiogram (VCG) and the electrocardiogram (ECG) were used to predict pulmonary arterial pressures in 30 pediatric patients with rheumatic mitral valve disease. The patients' ages ranged from eight to 14 1/2 years. Eleven were male and 19 were female. Sixteen had mitral stenosis, eight had mitral regurgitation and six had mitral stenosis and regurgitation. Mean pulmonary arterial wedge pressure ranged from 5-32 mmHg. All patients underwent complete catheterization and angiocardiographic study. None had significant gradient across the right ventricular outflow tract. Right maximum spatial vector (Rmsv) was calculated using Frank VCG.R in V1 and S in V5 of ECG were also measured. Rmsv, RV1, and SV5 were correlated with pulmonary arterial pressures (systolic, diastolic and mean). Pulmonary artery systolic pressure and Rmsv bear the best correlation (r=0.773). The correlation coefficient for pulmonary artery diastolic pressure and Rmsv was 0.698. Rmsv as calculated from Frank VCG is useful in prediction of pulmonary arterial pressures (systolic and diastolic) in pediatric patients with rheumatic mitral valve disease.

Frank vectorcardiogram in common ventricle: correlation with anatomic findings

The influence on the Frank vectorcardiogram of anatomic features in common ventricle was analyzed by comparison of Frank vectorcardiograms in 51 patients who had common ventricle with those of 36 patients who had large ventricular septal defect, 14 of whom had levotransposition of the great arteries and 22 of whom had dextrotransposition. Frank vector loops in common ventricle differed from those in ventricular septal defect by the frequent occurrence of clockwise horizontal rotation, most common in patients with type C common ventricle (no outflow chamber). There was a statistically significant difference in the amplitude of early forces between patients with common ventricle and those with large ventricular septal defect. The degree of overlap of vectorcardiographic features between the two groups is sufficiently great that the vectorcardiogram has limited usefulness in establishing the diagnosis of common ventricle in any individual patient.