Biomedical subjects
Publications and source records attributed to K G Zahka.
We describe a patient with the rare association of the heart in the left chest, congenitally corrected transposition, pulmonary atresia and an intact ventricular septum. There were associated fistulous communications between the morphologically left ventricle and the coronary arteries. Diagnosis was made by echocardiography, and subsequently confirmed by cardiac catheterization.
BACKGROUND: The safety and efficacy of transesophageal echocardiography (TEE) during congenital heart surgery is well established. The economic costs and benefits associated with its routine use in this setting are, however, uncertain. We sought to analyze the impact that routine intraoperative TEE had on echocardiographic costs in the setting of congenital heart surgery. METHODS AND RESULTS: A retrospective, case-controlled analysis of echocardiographic costs during the operative and postoperative periods was performed for 63 children undergoing elective, complex intracardiac repair. Similar analysis was performed for a smaller group of patients undergoing simple repairs. To ascertain whether any additional cost savings was realized through the use of TEE, we documented the impact that operative TEE had on altering surgical strategy as well as whether TEE use was associated with any intraoperative complications. Despite the additional expense, routine TEE, in the setting of complex repair, resulted in no significant increases in echocardiographic costs, suggesting the superior information provided may in fact reduce the need for additional postoperative studies in the intensive care setting. Although no child required a return to cardiopulmonary bypass, surgical therapy was altered by TEE findings in 2 (3%) of 63 patients. Complications were rare and self-limited, usually occurring with positioning of the probe in smaller patients. CONCLUSIONS: The findings of improved surgical outcomes in a percentage of patients, coupled with the lack of any significant increment in echocardiographic costs, confirm that intraoperative TEE is a beneficial and cost-effective intervention in children requiring complex cardiac repair.
The rare association, in a left-sided heart with hypoplastic left heart syndrome, of right aortic arch, bilateral patent arterial ducts and origin of the left subclavian artery from the left pulmonary artery are described. Cardiac catheterization was performed because of the abnormal anatomy of the arch noted at echocardiographic examination. This abnormality is of surgical importance when planning the Norwood operation.
Described is a rare association in a patient with the heart in the left chest, namely pulmonary atresia with intact ventricular septum, fistulous coronary arterial connections, a right-sided aortic arch and an aorto-pulmonary collateral artery feeding one lung. The pulmonary arteries were non-confluent, with the right lung supplied by the right arterial duct originating from the under surface of the right-sided aortic arch, and the left lung supplied through the aorto-pulmonary collateral artery arising from the descending aorta. The surgical management is different in the setting of non-confluent pulmonary arteries.
Explore the source record for details and available documents.
OBJECTIVE: To determine the diagnostic accuracy of clinical assessment of heart murmurs in children and specific clinical features that are predictive of cardiac disease. DESIGN: Concurrent case series with pretest-posttest assessment. SETTING: Pediatric cardiology outpatient clinic. PARTICIPANTS: Five full-time academic pediatric cardiologists. MEASURES: For each of 222 consecutive patients who were seen for first-time evaluation of a heart murmur, the clinical findings and diagnostic impressions were recorded after clinical assessment. The results of electrocardiograms and echocardiograms were then reviewed, and changes in diagnostic impressions were recorded and compared with the original impressions. RESULTS: The prevalence of cardiac disease was 33%. Clinical assessment differentiated those patients with pathologic murmurs with a sensitivity of 92%, specificity of 94%, positive predictive value of 88%, and negative predictive value of 96%. If diagnostic uncertainty was considered an indication for echocardiography, then sensitivity and specificity increased to 97% and 98%, respectively. Missed disease included only trivial or minor lesions. Clinical features that were independently predictive of the presence of disease included murmurs that were pansystolic (odds ratio [OR], 54.0), grade 3 or more in intensity (OR, 4.84), heard best at the left upper sternal border (OR, 4.24) and harsh in quality (OR, 2.37), and the presence of an abnormal second heart sound (OR, 4.09) and an early or midsystolic click (OR, 8.35). CONCLUSIONS: Clinical assessment by a pediatric cardiologist is sufficient to distinguish pathologic from innocent heart murmurs. A genetic approach by using specific clinical features that are independently associated with disease may have some practical utility to noncardiologists.
Explore the source record for details and available documents.
This study sought to determine the extent of anxiety and misperceptions about heart murmurs for consenting parents of 182 children referred for first-time pediatric cardiology assessment (including echocardiography) of a heart murmur. From questionnaires completed before assessment, 22% of parents indicated that they were extremely concerned, and only 16% could define a heart murmur as a sound made by the heart. From 1-month follow-up questionnaires obtained from parents of children without heart disease at assessment, 10% continued to believe that their child had a heart problem. Cardiology assessment may not provide complete reassurance to all families and additional interventions may be necessary.
BACKGROUND: Recent advances in the field of echocardiography have made it possible to obtain a complete morphological and hemodynamic assessment of patients with aortic stenosis. Therefore, comprehensive two-dimensional and Doppler examinations were performed on patients with aortic stenosis returning for the Second Natural History Study of Congenital Heart Defects (NHS-2). METHODS AND RESULTS: Two hundred thirty-two patients with aortic stenosis underwent comprehensive two-dimensional and Doppler examinations. Of these, 96 were in the medically treated group, 49 had undergone aortic valve replacement, and 87 had had aortic valvotomy. The valve replacement group had a significantly smaller left ventricular diastolic cavity than did the medically treated group; both had smaller dimensions than the valvotomy group. There was no significant difference in left ventricular wall thickness or fractional shortening among the three groups. The valvotomy group had a significantly higher mean aortic valve gradient than did either the medically treated group or the valve replacement group. The degree of aortic regurgitation was more severe in the valvotomy group than in the other two groups. For all patients, there was a direct relation between the aortic valve gradient and the mean wall thickness and an inverse relation between the aortic valve mean gradient and fractional shortening. The only echocardiographic parameter that correlated with the presence or absence of symptomatology was the fractional shortening. CONCLUSIONS: These observations provide an objective measurement for assessing the status of the aortic valve and left ventricular response in patients with aortic stenosis returning for NHS-2. Limitations of echocardiography in this study are discussed.
BACKGROUND: Two-dimensional and Doppler echocardiography can provide information about valve morphology, right ventricular size and function, and hemodynamics in patients with pulmonary stenosis. Therefore, two-dimensional and Doppler echocardiographic examinations were performed on patients with pulmonary stenosis returning for the Second Natural History Study of Congenital Heart Defects. METHODS AND RESULTS: Three hundred twenty-five patients with pulmonary stenosis underwent two-dimensional and Doppler echocardiographic examinations. Of these, 115 were in the medically treated group, and 210 had undergone a previous operation. Patients in the valvotomy group had a higher incidence of right ventricular dysfunction and a larger right ventricular diastolic dimension. The valvotomy group had a lower pulmonary valve mean gradient and a lower right ventricular systolic pressure than the medically treated group. For all patients, there was no significant correlation of the echocardiographic variables with the presence or absence of symptoms, reflecting the low incidence of patients with cardiac decompensation. CONCLUSIONS: These observations provide an objective measurement for assessing the status of the pulmonary valve and right ventricular response in patients with pulmonary stenosis. Limitations of echocardiography in this study are discussed.
BACKGROUND: Two-dimensional and Doppler echocardiography can provide structural and hemodynamic information for patients with ventricular septal defects (VSDs). Therefore, two-dimensional and Doppler echocardiographic examinations were performed on patients with VSDs returning for the Second Natural History Study of Congenital Heart Defects. METHODS AND RESULTS: Five hundred fifty-six patients with VSDs underwent two-dimensional and Doppler echocardiographic examinations. Three hundred twenty-four patients were in the medically treated group, and 232 had undergone a previous operation. The location of the VSD was classified in 235 patients. Several Doppler measurements were used to calculate pulmonary artery pressures: tricuspid regurgitation peak systolic velocity, peak systolic velocity of VSD jet, pulmonary regurgitation end-diastolic velocity, and pulmonary artery acceleration time. The two methods that were found to be reliable consisted of the tricuspid regurgitation peak systolic velocity and the pulmonary regurgitation end-diastolic velocity. These measurements were obtained in only 26% of patients at all centers. At one center in which adult and pediatric echocardiography was performed in a single laboratory, these values were obtained in 60% of patients. CONCLUSIONS: Two-dimensional and Doppler echocardiography has the ability to provide a noninvasive method of assessing morphology and hemodynamics in patients with VSDs. However, the reliability and accuracy of hemodynamic measurements are dependent on operator experience.
In our current practice, either the Norwood operation or heart transplantation must be considered reasonable options for neonates born with hypoplastic left-heart syndrome. Clearly some children with this otherwise lethal defect have been helped by both approaches. Is it yet, in 1993, appropriate to delete compassionate care from our group of options? Despite all the advances of the past decade, we are not at the point where we can declare hypoplastic left-heart syndrome "cured" even for the survivors of the Norwood operation or heart transplantation. Compassionate care (including withdrawal of prostaglandin E1) is still appropriate for those families who feel that the chance of success and the quality of life are not great enough to justify the challenges the infants and their families must face. Clearly as technical modifications are made in the Norwood operation and as advances are made in transplantation biology, the number of families who choose compassionate care will decrease.
Fifty-five patients with repair of tetralogy of Fallot were evaluated with treadmill exercise, pulmonary function testing and rest two-dimensional and Doppler echocardiography to determine the relation among cardiopulmonary function, exercise capacity and ventricular arrhythmias. The mean age at repair was 8.1 +/- 2.1 years; age at the time of study ranged from 15 to 37 years (mean follow-up time after repair 18 +/- 5 years). Exercise duration was 92 +/- 17% of predicted. Maximal heart rate was 94 +/- 7% of predicted. No exercise test was stopped because of an arrhythmia. Thirty patients had oxygen consumption and ventilation measured during their final minute of exercise. Peak oxygen consumption was 31 +/- 8 ml/kg per min (86 +/- 18% of predicted). Twenty-five patients (45%) had low vital capacity at rest (less than 80% of predicted). Pulmonary regurgitation was identified in 42 (75%) of the patients and judged to be moderate in 10 (18%). Mild tricuspid valve regurgitation was identified in 64%. Doppler estimated right ventricular outflow gradient was greater than 15 mm Hg in 15% of the patients (mean gradient 24 mm Hg [range 16 to 56]). Age at repair, duration of follow-up and type of repair did not correlate with echocardiographic variables, ventilatory data, exercise performance or arrhythmias. Moderate pulmonary regurgitation was associated with increased right ventricular diastolic area and both were inversely related to exercise duration and vital capacity. Decreased breathing reserve during maximal exercise was associated with moderate pulmonary regurgitation and decreased vital capacity. The results indicate that exercise capacity in these patients is in general good; however, right ventricular volume loading and ventilatory dysfunction may produce exercise limitation.
Between 1958 and 1977, 170 children aged 10 years or less underwent total repair of tetralogy of Fallot at The Johns Hopkins Hospital. Follow-up data were obtained on 128 (90%) of the 143 who survived the operation at 10 to 28 years postoperatively (mean follow-up, 18 years). All patients completed an extensive questionnaire, and 59 returned for a thorough evaluation consisting of a history and physical examination, electrocardiogram, 24-hour Holter monitoring, exercise stress testing, pulmonary function testing, and two-dimensional and Doppler echocardiography. Late survival was excellent with only two of four known late deaths due to cardiac-related causes and with all 59 patients in New York Heart Association class I or II. None had cyanosis or clubbing. Normal sinus rhythm was present in 90%. One patient had complete heart block, and 75% had right bundle-branch block on the electrocardiogram. Right ventricular function was normal by echocardiography in 78%. Residual mild to moderate pulmonary stenosis was noted by Doppler study in 8 patients. Pulmonary regurgitation was present in 78%, but in only 11 patients was it graded as moderate and in none was it severe. Stress testing documented the excellent functional status of most patients, with 92% of predicted exercise time and 94% of maximum heart rate being attained. In the few who had impaired cardiac performance, this correlated best with moderate pulmonary regurgitation. Although the overall late functional status of patients undergoing repair in the first decade of life was very good, these patients need continued follow-up to assess the severity of pulmonary regurgitation and the need of possible intervention.
To determine if the pattern of cardiac care is affected by the presence of Down syndrome (DS) we analyzed the records of infants enrolled in the Baltimore-Washington Infant Study, a regional case-control study of congenital cardiovascular malformations. The age at cardiac diagnosis, the timing of cardiac surgery, and the one-year outcome were compared in 160 infants with DS and 540 infants with the same cardiac diagnoses but without chromosomal or other extracardiac anomalies (Isolated cardiovascular malformation [ICM] group). Cardiac referral and diagnosis were accomplished by 13 weeks of age in 78% of infants with DS and 67% of those with ICMs. However, by 26 weeks of age, the proportion of infants in both groups was comparable. Cardiac surgery was performed before 1 year of age in 99 of 160 infants with DS and in 141 of 540 infants with ICMs. The surgical outcome was similar in the two groups. We conclude that for defects of comparable severity, the pattern of cardiac care in the Baltimore-Washington, DC, area for infants with DS is timely and comparable to care for infants with ICMs.
Little is known about the hemodynamic properties of the rapidly expanding arterial bed during embryonic development. Using a servo-null pressure system and 20-MHz pulsed Doppler velocity meter, we recorded simultaneous dorsal aortic pressure and velocity waveforms. The waveforms were digitized at 3-msec intervals and subjected to Fourier analysis. We calculated hydraulic energy and the impedance spectrum to 10 Hz. From stages 18 to 29, heart rate (148 +/- 3 to 193 +/- 9 beats/min), systolic pressure (1.14 +/- 0.12 to 3.04 +/- 0.10 mm Hg), and mean dorsal aortic blood flow (21 +/- 2 to 214 +/- 19 mm3/min) increased. Peripheral vascular resistance (Z0: 30.4 +/- 4.8 to 6.4 +/- 0.7 dyne x sec/mm5), and the impedance moduli (Z1: 6.5 +/- 1.0 to 1.7 +/- 0.2 dyne x sec/mm5; Z2: 6.1 +/- 1.2 to 1.7 +/- 0.1 dyne x sec/mm5; Z3: 7.3 +/- 1.1 to 1.7 +/- 0.2 dyne x sec/mm5) decreased. Total hydraulic power increased from 48 +/- 7 to 2,606 +/- 96 nW, while the proportion of oscillatory energy increased from 29 +/- 2% to 65 +/- 4%. With development hydraulic load decreases, total external work increases and the dorsal aorta and embryonic vascular bed becomes more compliant. A greater proportion of total energy is expanded in pulsatile blood flow, suggesting that ventricular-arterial coupling is less efficient later in development.
To determine the long-term functional impact of the Blalock-Taussig (BT) shunt, we studied handgrip strength in 56 patients (10-28 years) following total repair of tetralogy of Fallot. Of the 56, 16 (29%) had a previous right BT shunt, 5 of 56 (9%) had a previous left BT shunt, and the remaining 35 patients either had a Potts shunt or primary total repair. The mean age at the time of right BT was 2.8 +/- 1.6 (SD) years, left BT 1.7 +/- 1.2 years, and total repair for all patients was 7.1 +/- 2.2 years. Mean age at the time of study was 26 +/- 9 years. Right-and left-handgrip strength were measured with a Jamar dynamometer, averaging the results of grip position 2, 3, and 4 to accommodate variation in hand size. Since absolute values of hand strength were strongly associated with sex (p = 0.006) and body surface area (p = 0.016), we calculated the ratio of right-hand to left-handgrip strength (RL ratio). The RL ratios were: 0.98 +/- 0.13 (right BT), 1.21 +/- 0.11 (left BT), and 1.13 +/- 0.16 (no BT): (p = 0.004 right BT vs. no BT, p = 0.07 left BT vs. no BT, Wilcoxon rank sum test). Thus, although frequently clinically inapparent, handgrip strength tested many years post-BT shunt is reduced on the side of the shunt.
We present a report of cardiac dilatation and symptomatic congestive heart failure in two patients receiving treatment with continuous ambulatory peritoneal dialysis (CAPD). Both patients had previous partial parathyroidectomies and persistent hypocalcemia prior to the development of a congestive cardiomyopathy. The hypocalcemia was unresponsive to treatment with activated vitamin D therapy; however, intravenous replenishment of the ionized serum calcium level was accompanied by improvement in cardiac functional parameters. In one of the two patients, chronic calcium repletion with high dialysate calcium was associated with significant improvement in cardiac symptoms and a decrease in left ventricular dilatation. These observations suggest that partial parathyroidectomy and associated hypocalcemia place patients on CAPD at increased risk of cardiac dysfunction.