Cardiac effects of trandolapril in hypertension.

Baseline echocardiography was performed on 25 patients with essential hypertension and a supine diastolic blood pressure of 95 to 114 mm Hg while receiving placebo. Once-daily trandolapril was then titrated from 1 to 4 mg. After 3 months of therapy, supine diastolic blood pressure decreased by 7.5% (p < 0.0001). Left ventricular hypertrophy regressed as evidenced by a 23.2% (p < 0.0001) decrease in left ventricular mass index at 3 months and a 12.4% (p < 0.05) reduction of relative wall thickness at 6 months. Although afterload decreased by 12.4% (p < 0.05) at 3 months, left ventricular systolic function remained unchanged, whereas left ventricular contractility, which was assessed from the load-independent relationship of end-systolic wall stress to velocity of circumferential fiber shortening, improved. Left ventricular diastolic function (E/A ratio) improved in 15 of 25 patients with low baseline values from 0.96 +/- 0.14 to 1.18 +/- 0.25 (mean +/- SD, p < 0.0002) at 3 months. We conclude that trandolapril effectively reduces left ventricular hypertrophy and improves diastolic function in patients with hypertension while systolic function is preserved.

Mucopolysaccharidosis I presenting with endocardial fibroelastosis of infancy.

We describe two female infants with Hurler syndrome (mucopolysaccharidosis I) whose deaths are attributed to cardiac failure with associated, autopsy-confirmed endocardial fibroelastosis. One infant had confirmed alpha-L-iduronidase deficiency in cultured dermal fibroblasts, and the other infant had histologic evidence of tissue mucopolysaccharide accumulation at autopsy and a sibling with confirmed alpha-L-iduronidase deficiency and the Hurler syndrome phenotype. Clear cells ("Hurler" cells) were identified within the myocardium and endocardium of both infants. We propose that the ventricular mural accumulation of mucopolysaccharides induced extensive proliferation of elastic or collagen fibers within the endocardium. Cardiac failure may precede recognition of clinical and roentgenographic features of Hurler syndrome. Our findings and a literature review suggest that certain heritable storage disorders, including mucopolysaccharidosis I, should be considered when infants have clinical electrocardiographic and echocardiographic findings consistent with endocardial fibroelastosis or have autopsy-documented endocardial fibroelastosis.

QRS areas improve the electrocardiographic interpretation of right ventricular hypertrophy.

Right ventricular hypertrophy (RVH) is the most frequent abnormality in children with heart disease. We have developed a computer electrocardiogram (ECG) diagnosis program to evaluate new scalar electrocardiographic criteria for the diagnosis of this condition in children. The overall performance of our program was comparable to that of a pediatric cardiologist. Computer program diagnosis was correct in 93% of 60 individuals using standard criteria and in 97% using our newly developed area criteria. The cardiologist's ECG diagnosis in the same individuals was correct in 99%. The sensitivities of our two new criteria, the R/S area ratio in lead V1 and the R wave area in lead V1, were greater than currently used criteria for the diagnosis of RVH. Computer-derived electrocardiographic measurements, such as areas, can improve the accuracy of the ECG diagnosis of RVH.

Racial and sexual differences in the standard electrocardiogram of black vs white adolescents.

Standard 12-lead electrocardiograms were recorded in 114 healthy adolescents to substantiate possible influences of race and sex on the "juvenile pattern" (increased precordial voltages of QRS complex, precordial T wave inversions, and ST-segment elevations considered pathologic in adults) in this age group. Black male subjects had the highest precordial QRS amplitudes and the highest incidence of biphasic or negative precordial T waves and ST-segment deviations. In white male subjects, these findings were less pronounced but were more evident than in black or white female subjects. Results indicate the following: (1) race-specific and sex-specific normal electrocardiographic standards should be developed in adolescents; (2) criteria for left ventricular hypertrophy are race-specific and sex-specific and should be tested against independent anatomic or physiologic information in adolescents with left ventricular overload; and (3) the "juvenile pattern" may be viewed as a predictable continuum of age-related changes starting in childhood and progressing through adolescence on to later life.

Changes in cardiac rhythm in children treated with dopamine.

We reviewed the charts of 31 children receiving dopamine to document possible changes in cardiac rhythm associated with dopamine infusion. Six of these developed a dysrhythmia while on dopamine. All six were receiving dosages greater than 10 microgram/kg/min; in five of the six patients the infusion rate varied from 10-20 microgram/kg/min. Of the remaining 25 patients, 14 had preexisting dysrhythmias of nonventricular origin. Two of these 14 patients converted to sinus rhythm while on dopamine. Eleven patients who were in preexisting sinus rhythm had no rhythm changes on dopamine. Based on the results of this study, we recommend that dopamine should be used cautiously in children in the dosage range between 10-20 microgram/kg/min.

Computer analysis of changes in frank vectorcardiograms of 666 normal infants in the first 72 hours of life.

Frank vectorcardiograms (VCGs) were collected on magnetic tape for 666 normal newborn infants at 1, 6, 12, 24, 36, 48, 60, and 72 hours after birth and analyzed by computers. The final total included 1,337 VCGs for white babies and 413 for blacks. No previous report has been made for the normal neonate with such a large sample, and no previous substantiation exists of possible age or sex differences at this early age. This study establishes a statistically significant change in vectorcardiographic patterns over the first three days, specifically in the measurements P duration, QRS duration, maximal spatial QRS amplitude, S in lead x, and T in lead z, as well as for several time-normalized QRS vectors. (P less than or equal to .005.) Racial differences were significant for T waves in lead z. This study supports the use of vectorcardiographic standards sensitive to the age of the newborn as well as to race.

Myocardial sodium extraction at varied coronary flows in the dog. Estimation of capillary permeability of residue and outflow detection.

Sudden injections of boluses containing both 131I-albumin and 24NaCl were made into the coronary artery inflow of isolated blood-perfused dog hearts. Indicator dilution curves were recorded using gamma emissions from both the intact heart and the coronary sinus outflow, with plasma flows, Fs, ranging from 0.3 to 1.8 ml/g min-1. Three measures of sodium extraction, E, during transcapillary passage were obtained from each site by comparison of the sodium and albumin curves. The most useful estimates of E were "instantaneous extractions" obtained from the later part of the upslope and the peak of the venous dilution curves (coronary sinus) or from the corresponding early phase of washout of the externally monitored curves (intact organ). Extractions were lower at higher flows. Permeability-surface area products, PS, were computed (1) by the formula PS equals -Fsloge(1 - E), (2) by fitting the observed dilution curves with a Krogh capillary-tissue cylinder model, and (3) by the approximating formula PS equals -Fsloge (1 - 1.14E). The two latter approaches provided a correction for back diffusion of tracer from tissue to blood. For sodium, the values of PS averaged 0.88 +/- 0.36 (SD) ml/g min-1, (n equals 52). At high flows, with Fs greater than 1.0 ml/g min-1, the values of PS averaged 1.01 +/- 0.38 ml/g min-1 (N equals 11). Assuming S equals 500 cm2/g and plasma to be 93% water, our findings suggest capillary permeabilities for sodium of about 3.1 times 10(-5) cm/sec.

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.

Computer interpretation of Frank vectorcardiogram in normal infant: Longitudinal and cross-sectional observations from birth to 2 years of age.

The evolution of the Frank vectorcardiogram (VCG) was studied from longitudinal observations (60 normal infants) and from cross-sectional observations (231 normal infants) from birth to two years of age. Age specific normal values for the Cartesian coordinates of 14 vectors including maximal QRS-T and timed vectors in the horizontal and frontal plane were determined with both methods of analysis. In longitudinally followed infants the most significant involution of right ventricular forces occurred between the newborn period and 7-14 weeks of age. These changes included disappearance of clockwise horizontal loop rotation and a leftward shift of maximal and terminal forces as well as a rightward shift of initial vectors. Longitudinal observations were useful for prediction of the normal Frank VCG in the 7 to 14-week-old infant from values observed in the newborn period and for prediction of the horizontal loop rotation throughout infancy. Cross-sectional data showed a wider range of normal values than longitudinal data in the same 7 to 14-week-old infants, but age specific normal values were well reflected between 4 and 24 months of age from cross-sectional data.

Etiology of right bundle-branch block pattern after surgical closure of ventricular-septal defects.

An incidence of 60 per cent of postoperative RBBB in the ECG's and available VCG's of 26 patients with isolated muscular VSD repaired was noted after ventriculotomy. In the 38 patients with VSD's near the membranous septum who underwent repair via the tricuspid valve, the incidence of postoperative RBBB was 44 per cent. Results suggested that either ventriculotomy or injury to the right bundle near the VSD can cause RBBB after surgical closure of the defect. Changes in the initial 0.02 second electrovectocardiographic forces in patients with postoperative RBBB were thought to result from central injury to the specialized conduction tissue supplying the interventricular septum. Peripheral RBBB, therefore, could be separated from central RBBB, by the appearance of the initial electrovectorcardiographic forces. For detection of these changes in initial forces, both the ECG recorded at 50 mm. per second and the Frank VCG were useful.