Biomedical subjects
Publications and source records attributed to E Krongrad.
Barium esophagrams were obtained in two patients with respiratory problems whose underlying congenital heart disease was pseudotruncus arteriosus type I. The esophagrams revealed vascular indentations on the esophagus, one posteriorly, and the other anteriorly. Both types of indentations were secondary to aorto-pulmonary communicating arteries from the descending aorta.
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Two-dimensional echocardiographic findings and surgical repair in three infants with atrioventricular (AV) canal and pulmonary venous obstruction are described. The AV canal was complicated by cor triatriatum in two patients and by double outlet right atrium in the other. In patients with AV canal, anatomic obstruction of pulmonary venous return should be excluded by detailed cardiac ultrasound examination.
The study was carried out to validate objectively the relationship between clinical impressions of parents and ECG evidence of life-threatening arrhythmias in infants considered to be at high risk. Twenty infants considered to be at high risk were provided with a hospital grade home monitor with a hard copy-recording capability (n = 12) and/or an ECG telephone transmission system (n = 8). There were 93 alarms considered by the parents as true alarms. All of the ECG tracings recorded during the 93 episodes were normal. Infant stimulation was provided for 11 infants and was not administered during 82 of these alarms. None of the infants died and all are well at 1 year of age. Our data raises questions regarding parental clinical ability to correctly perceive a true near miss episode in most cases and may explain, in part, the lack of consistency noted in previously published physiologic studies of "high risk" populations. Finally, the study raises further questions regarding the use of parental impression alone without supportive objective data as an indication for therapy in the majority of such patients. Research efforts and application of therapeutic measures will benefit greatly by development of objective data to support and supplement parental clinical observations.
The conduction system of 23 infant hearts, 15 of sudden infant death syndrome (SIDS) and eight of those dying from known cause, was serially sectioned. A left-sided His bundle was found more commonly in (SIDS) (eight of 15) than in the controls (two of eight). Taking into account a previous study in which a left-sided His bundle was found in only four of 32 hearts from all age groups, this is statistically significant and may be a factor promoting SIDS.
We performed balloon atrial septostomies in six successive infants with transposition of the great arteries, using echocardiographic guidance at the bedside in the neonatal intensive care unit. In all cases adequate septostomy was obtained and instantaneously assessable. PaO2 values increased as expected (mean before septostomy 28 mm Hg; after, 42 mm Hg). In cases of transposition clearly diagnosed echocardiographically, this intervention need not be done in the catheterization laboratory. The need for a full hemodynamic study in the neonatal period is arguable.
Insertion of extracardiac right ventricular (RV)-pulmonary artery (PA) conduits for repair of severe forms of RV-PA discontinuity has become a widely used technique. During a 10-year period, 76 patients had open heart repair with a porcine-valved RV-PA external conduit. The most common diagnoses were truncus arteriosus (15%) and pulmonary atresia with ventricular septal defect (15%). The patients were 18 days to 37 years old (median 7 years). The postoperative median follow-up period was 4 years. Four patients (8%) have been lost to follow-up. Nineteen patients (25%) died in the early postoperative period and there were 10 late deaths (13%). Calculated probability of survival was 66% at 8 years. Thirty-six patients have undergone late hemodynamic studies. A residual shunt was present in 14% of the patients; moderate to severe PA hypertension was present in 25% and significant RV-PA gradients (greater than 30 mm Hg) in 50%. The mean RV pressure for the group was 78.5 +/- 38 mm Hg. The severity of the gradients appeared to be greater in patients who had been followed longer. Ten patients have undergone reoperation because of conduit obstruction or residual shunting; 6 are alive and well. Of the surviving patients, 95% are acyanotic and without significant exercise intolerance and only 5% have cardiovascular symptoms. Thus, open heart repair using an external RV-PA conduit provides a marked improvement in the quality of life in patients who survive.
Ninety children, aged 1 day to 18 years (median 7 months), with electrocardiographic or echocardiographic evidence of left atrial (LA) enlargement were selected to determine if electrocardiographic criteria accurately reflected increased LA dimension as determined by echocardiography. Four cardiac defects known to produce LA enlargement were chosen: ventricular septal defect (24 patients), patient ductus arteriosus (25 patients), cardiomyopathy (27 patients) and mitral regurgitation (14 patients). Different electrocardiographic criteria for LA enlargement were assessed. The data indicated that the overall sensitivity and predictive value of the ECG to detect LA enlargement were 40 and 85%, respectively. The ECG and echocardiogram failed to agree in 62% of the patients. The most predictive variable for LA enlargement was the presence of a notched P wave in the limb leads with a large negative terminal deflection in lead V1. The sensitivity of ECG was highest in patients with chronic LA overload status, in mitral regurgitation (77%), cardiomyopathy (50%) and ventricular septal defect (54%). The results show that in the pediatric population, electrocardiographic criteria are moderately predictive for LA enlargement but not as sensitive as generally believed.
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Ventricular fibrillation (VF) is a frequently reported terminal cardiac electrical activity in adults. Such data are unavailable for pediatric patients. Terminal cardiac electrical activity determined in 100 pediatric patients was bradycardic arrest throughout the death process in 88% of newborns, 67% of infants, and 64% of children. Although bradycardic arrest was more common, the incidence of ventricular tachyarrhythmias was higher in patients who had congenital heart disease, who had received cardiopulmonary resuscitation, who were beyond the neonatal period, and/or who weighed greater than 2.23 kg. No definite associations could be established between arterial blood gases, electrolyte values, and type of terminal cardiac electrical activity. The development of VF may be related to cardiac mass and the developing autonomic nervous system and therefore is less likely to occur in patients with a small heart.
Eighteen patients with congenitally corrected transposition of the great arteries had open heart repair for intracardiac associated defects. Fourteen patients (78%) are alive during the follow-up period (mean 4.5 years). Seventeen (94%) of the 18 patients had ventricular septal defect closure, and 12 (66%) insertion of a pulmonary artery conduit. Surgical repair of the tricuspid valve was required in 6 patients (33%) during the first operation and in 3 additional patients during a second operation (total 50%). When hemodynamic overload or cardiac compromise was detected after surgery it was directly related to identifiable residual defects such as atrioventricular valvular insufficiency, residual ventricular septal defect, or pulmonary conduit stenosis. Repeat open heart operation for residual defects was common during the follow-up period (8 of 18 patients, 44%). No patient showed primary systemic or pulmonary ventricular dysfunction during the follow-up period. None of the last 11 patients developed complete heart block. Postoperative intraventricular conduction defects were common and are presumably caused by surgical injury of the bundle branches. Our observations suggest that surgical repair of congenitally corrected transposition of the great arteries can be currently achieved with acceptable risk. Improved knowledge of the precise location of the specialized conduction system resulted in a marked decrease in the incidence of atrioventricular (A-V) block in patients with congenitally corrected transposition of the great arteries undergoing intracardiac repair. In the absence of postoperative residual defects it can be expected that longevity and quality of life will improve considerably, but many of these patients may require a repeat operation.
Electrocardiograms of 802 patients with isolated scoliosis followed and/or operated at Columbia Presbyterian Medical Center were reviewed. There were 586 patients younger than 18 years and 216 patients older than 18 years of age. There were 86 males and 716 females. Eleven patients had associated congenital heart disease. Effects of age, site of scoliosis, side of convexity and severity of curvature on multiple electrocardiographic variables were analysed. Electrocardiographic variables such as heart rate, Q-Tc, P wave amplitude, P-R interval, amplitude of R and S waves in V1 and V6 were similar to data reported in the normal population without scoliosis. The effect of age on these electrocardiographic variables was similar to changes reported in the normal population and were not affected by site of scoliosis or side of curvature. The frontal QRS axis was within normal limits of 94% in patients under 18 years of age with right-sided thoracic scoliosis and in 87% of patients over 18 years. Evidence of right axis deviation (5%) and right ventricular hypertrophy (2%) were present equally in patients younger and older than 18 years of age and 8% of patients over 18 years old. Since in our patient population the degree of scoliosis severity increased with age it is likely that the increasing incidence of left axis deviation found in patients over 18 years of age with scoliosis is related to scoliosis severity and the altered intrathoracic cardiac orientation. Because right axis deviation and right ventricular hypertrophy are noted occasionally in patients with scoliosis and because congenital heart disease and pulmonary disease are more prevalent in this patient population, it is recommended that the presence of right axis deviation and right ventricular hypertrophy on the ECG should lead to a complete cardiopulmonary evaluation and exclusion of possible additional cardiac or pulmonary anomalies.
Between 1974 and 1979 nine patients, aged 10 months to 4 years, underwent left ventriculotomy for closure of single or multiple defects in the muscular ventricular septum. The vertical incision paralleled the anterior descending branch of the left coronary artery near the apex of the left ventricle and ranged from 2.5 to 3.5 cm in length. Four patients also had a right ventriculotomy with closure of a high perimembranous ventricular defect in two. Serial electrocardiograms indicated changes of myocardial ischemia or necrosis. Left bundle branch block did not develop in any patient. Three patients died in the early postoperative period. The six surviving patients are living and well 2 to 7 years later. There is apparent complete closure of the ventricular defects, which was documented by cardiac catheterization in four cases. Two patients had cardiomegaly and left ventricular dysfunction as assessed with echocardiographic and angiographic study, whereas four displayed good cardiac function. In three of the latter patients, cardioplegia or deep hypothermia techniques were utilized intraoperatively. The observations indicate that left ventriculotomy of limited size is an acceptable approach to the difficult problem of repair of muscular ventricular defects but may involve some risk of compromise of the coronary circulation.
A method for recording electrical activity of the sinoatrial (S-A) node and automatic atrial foci in human subjects is described. To record S-A nodal electrograms, an electrode catheter was inserted percutaneously into the femoral vein and advanced under fluoroscopic control to the superior vena caval-right atrial junction. The distal terminal of the catheter was placed in the area of the S-A node and the proximal terminal on the free right atrial wall or in the right atrial lumen. Polarity was reversed from the conventional electrocardiographic recording; high amplification (about 100 microV/cm) and selective filters (0.1 to 20 hertz) were used. S-A nodal electrograms recorded with this method in human subjects were similar to electrograms obtained previously from the dog and rabbit and revealed negatively directed diastolic and upstroke slopes preceding the P wave of the electrocardiogram. Sinoatrial conduction time measured from the S-A nodal electrograms in 15 cases was 34.9 +/- 2.1 ms(mean +/- standard error of the mean) for a sinus cycle length of 736.4 +/- 38.6 ms. The coronary sinus electrograms in a patient with coronary sinus rhythm were recorded by the same technique except that the distal terminal of the catheter was placed at the coronary sinus ostium. A negatively directed diastolic slope preceding the P wave was consistently recorded. This method for recording electrograms of the S-A node and ectopic automatic atrial foci should prove useful in (1) assessment of both normal and abnormal S-A nodal function, (2) direct determination of conduction time from the S-A nodal pacemaker to the atrium, and (3) localization of automatic atrial foci.
Recent reports have shown that it is possible to record extracellular electrograms from the rabbit and dog sinoatrial (SA) node. We applied similar techniques to record SA nodal activity in 23 patients who underwent cardiac surgery for various forms of heart disease. Both a bipolar technique, using pairs of electrodes at various interelectrode distances, and a unipolar technique, using an exploring and an indifferent electrode, were used. To record SA nodal electrograms, polarity was reversed from the conventional electrocardiographic recording; high amplification (100 microV/cm) and low-pass filters (0.15-20 Hz) were used. SA nodal electrograms were recorded from eight of 12 patients using the bipolar method and from nine of 11 patients using the unipolar method. There were no significant differences in the success rate or quality of the recording between the two methods. However, the unipolar method allowed a more accurate localization of the SA node. Human SA nodal electrograms resembled those of the dog and rabbit and showed two distinct slopes: a diastolic slope and an upstroke slope preceding the P wave of the ECG, SA conduction times were 32.4 +/- 2.8 msec (mean +/- SEM) at sinus (PP) cycle lengths of 587.6 +/- 35.6 msec for the bipolar method, and 38.2 +/- 3.2 msec at sinus (PP) cycle lengths of 712.2 +/- 50.7 msec for the unipolar method. These methods for recording of extracellular SA nodal electrograms in man may prove useful in 1) localization of the SA node during open heart surgery and 2) assessment of SA nodal function in health and disease.
To evaluate echocardiographic assessment of ventricular function in a changing hemodynamic situation, 20 infants and children undergoing open heart surgery were examined preoperatively and 1,4 and 24 hours postoperatively by this technique. Clinical evaluation and measurements of cardiac output were obtained simultaneously with each echocardiogram. On the basis of their clinical course and cardiac output, the patients were divided into two groups: group 1 - cardiac index > 2.3 1/min/m2 without inotropic support (n = 9); and group 2 - cardiac index less than or equal to 2.3 1/min/m2 and/or need for inotropic support (n = 11). Of the echocardiographic measurements obtained, the left ventricular systolic time interval ratio (left ventricular preejection period/left ventricular ejection time ([LVPEP/LVET] correlated significantly with the clinical course, separating the two groups of patients completely at each determination. The aortic root velocity (AoV), a new index defined as the anterior excursion (in degrees) of the aortic root from the horizontal plane with systole, also correlated with the clinical course, although this was not statistically significant. Serial change in LVPEP/LVET and AoV crrrelated with changes in clinical status and cardiac output for individual patients. Using a formula based on the opening slope of the mitral valve, echocardiographic estimations of cardiac output correlated well with those determined by dye dilution. The results indicate that selected echocardiographic indexes can be used for serial assessment of cardiac performance in patients with a changing hemodynamic state.