The author has just written a book on the evolution of the specialty of Pediatric Cardiology over the last 50 years [1]. The intent of this review is to present a summary of this book. Because of large amount of this material, the review is separated into four parts. In these first and second parts, transcatheter interventions (balloon angioplasty/valvuloplasty procedures and percutaneous occlusions) were appraised. In this paper, electrocardiography, echocardiography, and cardiac catheterization will be reviewed.
In this review, contributions of the author pertaining to electrocardiography were examined. These contributions were: A study of normal Frank and McFee vectorcardiograms in the normal adolescent [2], distinguishing right ventricular hypertrophy from postero-basal left ventricular hypertrophy [3], identifying possible cause of alternating failure of mechanical to electrical depolarization (AFORMED) phenomenon [4], examination to see if racial variations in electrocardiograms and vectorcardiograms between black and white children exist and if so, the causes of such variation [5,6], document resolution with medications of congestive cardiomyopathy due to chronic tachycardia (Figure 1) [7], changes in the electrocardiogram (ECG) after balloon pulmonary valvuloplasty (Figure 2) [8,9], utility of electrocardiogram in delineating atrial (Figure 3) and ventricular situs in patients with dextrocardia and heterotaxy syndromes [10-14], and an appraisal of arrhythmias in children [15-17].
A) M-mode echocardiogram of a 3-year-old child who developed arrhythmia-induced cardiomyopathy; note the markedly dilated left ventricle (LV) with poor function (calculated shortening fraction was 13%). B) M-mode echocardiogram (5.5 years later) of the same patient following successful drug therapy; note the normal-sized LV with normal function (calculated shortening fraction was 29%) [7]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-001.jpgPrecordial ECG voltages (R waves in leads V3R and V1 and S waves in V6) prior to and at follow-up after balloon pulmonary valvuloplasty (BPV) in group I (with good results) (left panel) and group II (with poor results) (right panel) are depicted. The mean and standard deviation (SD) are shown. Note the significant (p < 0.05 to 0.01) decrease in the voltages in group I while there was no significant (p > 0.1) change in group II [9]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-002.jpgThe location of the P vector (axis) in the frontal plane is shown for situs solitus (+45°) and situs inversus (+135°). A P vector between 0° and -90° is called coronary sinus rhythm and is not helpful in atrial situs assignment [10]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-003.jpg
Documentation of diagnosis of Ebstein's anomaly of the left atrioventricular valve with congenital corrected transposition of the great arteries by intracavitary electrocardiography [18], ECG features of tricuspid atresia [19,20] and etiology of left axis deviation in patients with tricuspid atresia [19-21] were also presented.
To a large extent, the author has self-learned the echocardiography and Doppler recording techniques as well the skills of interpretation of such recordings; these endeavors helped the author to participate and perform several echocardiographic investigations. The echo studies include, usefulness of echocardiography in estimating the magnitude of left-to-right shunt in isolated ventricular septal defects (VSDs) (Figure 4) [22], usefulness of contrast echocardiography in the diagnosis of anomalous drainage of the right superior vena cava to the left atrium (Figure 5) [23,24], identification of pitfalls of m-mode echocardiography in the evaluation of the aortic root in left ventricular hypoplasia syndromes [25].
Scattergram demonstrating the relationship of the left atrium to aortic root ratio (LA:Ao) with the pulmonary-to-systemic flow ratio (Qp:Qs) in patients with isolated ventricular septal defects. The central line is the regression line and the parallel lines demarcate the confidence interval. The number of patients (N), regression equation and correlation coefficient (r) are shown in the insert at the top left [22]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-004.jpgA) Selected M-mode recordings from the parasternal short axis view of the left atrium (LA), aorta (Ao), and right ventricular outflow tract (RVOT), made while injecting agitated saline into veins of the right (R) hand, which demonstrate the appearance of contrast echoes in the LA (arrow) first and then the Ao (arrow); B) Similar tracings of the left ventricle (LV) and right ventricle (RV) demonstrate the appearance of contrast echoes in the LV (arrow) without contrast in the RV. Similar findings were seen while injecting agitated saline into the veins of the left hand. These recordings indicate the drainage of the superior vena cava into the left atrium. The start of the agitated saline injection is marked with arrows at the bottom of each tracing. ECG: Electrocardiogram [23]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-005.jpg
Other contributions are: Review of evaluation of left ventricular function by echocardiography [26,27], echocardiographic diagnosis of tricuspid atresia [28], utility of contrast echocardiography in the assessment of hypoxemia after open heart surgery [29], quantifying left ventricular muscle mass by m-mode echocardiograms in children [30], racial and sexual differences in echo measurements in children [31], heart size and function in children with sickle cell disease [32], and afterload reduction in the treatment of primary myocardial disease (Figure 6, Figure 7 and Figure 8) [33].
Pre-ejection period (PEP)/left ventricular ejection time (LVET) ratio (open circles) and shortening fraction in percent (%) (closed circles) are shown from prior to the start of hydralazine therapy (0) and at 1, 3, 6, 9, 12, 18, 24, 30, 36 and 42 months following its initiation. The means and standard deviations (SD) are shown. The number of subjects at 30, 36 and 42 months is small and therefore, only the mean values are shown. Note the gradual improvement in PEP/LVET ratio and shortening fraction. A statistically significant (p < 0.05 to < 0.001) change becomes apparent from the 12-month follow-up onwards [33]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-006.jpgA) Selected M-mode recordings from the parasternal short axis view of the left ventricle (LV) made prior to and B) following hydralazine therapy. Note a significant improvement in the LV size and function [1]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-007.jpgChest X-rays in antero-posterior view, prior to A) and following B) Hydralazine therapy. A) Moderate cardiomegaly and pulmonary venous congestion were seen prior to therapy; B) Which improved remarkably after therapy [1]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-008.jpg
Also reviewed were usefulness of echo-Doppler studies in the assessment of the results of balloon pulmonary valvuloplasty [34], utility of Doppler studies in the estimation of pressure gradients across the pulmonary valve in pulmonary stenosis [35], appraisal of Doppler echocardiography in non-invasive diagnosis of heart disease in children [36], echo-Doppler studies in the appraisal of the results of balloon procedure for coarctation of the aorta (Figure 9) [37], importance of Doppler in the prediction of pressure gradients across aortic coarctation [38], description of foramen ovale and transatrial Doppler velocity patterns in the normal fetus (Figure 10) [39], establishing the correlation of shunt flow and angiographic size to stretched diameter of the atrial septal defect by echocardiograms [40], echocardiographic assessment of balloon-stretched diameter of secundum atrial septal defects [41], development of echocardiographic predictors of success of buttoned device closure of atrial septal defect [42], pointing out of limitations of echo in complete assessment of mixed type of total anomalous pulmonary venous connection [43], echocardiographic follow-up results of buttoned device occlusion of atrial septal defect [44], review of ultrasound studies [45-47], collaborative echo-Doppler studies [48-50], echocardiographic evaluation of the results of balloon pulmonary valvuloplasty [51], editorials on echo topics, aneurysm of the ventricular septum producing pulmonary outflow tract obstruction in the morphologic left ventricle in corrected transposition of the great arteries [52-54] and echo descriptions of CHDs.
A) Two-dimensional (2D) echo images prior to and; B) following balloon angioplasty of aortic coarctation show improvement in B; C) Continuous wave Doppler flow velocity recordings from suprasternal notch directing the Doppler signal towards the descending aorta prior to and; D) immediately following balloon angioplasty of aortic coarctation and; E) at six months after angioplasty are shown. Note the reduction of peak Doppler flow velocity from C to D, with further fall in E. Also note that the diastolic flow is seen throughout the entire diastole (pandiastolic) prior to angioplasty (C), and is seen only is early diastole immediately after angioplasty (D). At six-month follow-up (E), there was no diastolic flow at all [37]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-009.jpgPlot of the diameter of the foramen ovale against the diameter of the aorta. The numbers indicate the number of subjects with that particular measurement. Note the excellent correlation with an r value of 0.84, y intercept of 0.605 and slope of 0.817 [39]. https://www.clinmedjournals.org/articles/ijcc/ijcc-8-225-010.jpg