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Biomedical subjects

R E Kavey

Publications and source records attributed to R E Kavey.

At least 37 records · Page 2Linked to original sources

Atenolol therapy for exercise-induced hypertension after aortic coarctation repair.

After successful repair of coarctation of the aorta in childhood, exercise-induced upper body systolic hypertension is well documented. Beta blockade has been shown to reduce the arm/leg gradient in untreated coarctation of the aorta; treatment before coarctation repair has decreased paradoxical hypertension after repair. Ten patients with successful surgical repair of coarctation, defined as a resting arm/leg gradient of less than or equal to 18 mm Hg, were evaluated by treadmill exercise before and after beta blockade with atenolol. Mean age was 5.5 years at repair and 18 at study. At baseline evaluation, systolic blood pressures at termination of exercise ranged from 201 to 270 mm Hg (mean 229 mm Hg). Arm/leg gradients at exercise termination ranged from 30 to 143 mm Hg (mean 84). Follow-up treadmill exercise studies were performed after beta blockade. Upper extremity systolic pressures at exercise termination were normalized in 9 of 10 patients. Maximal systolic blood pressure recorded at exercise termination ranged from 163 to 223 mm Hg (mean 196 mm Hg, p less than or equal to 0.005). Arm/leg gradient at termination of exercise also decreased significantly to a mean of 51 mm Hg (p less than 0.05). No patient had symptoms on atenolol and exercise endurance times were unchanged. The study results in this small series suggest that cardioselective beta blockade can be used to treat exercise-induced upper body hypertension effectively after surgical repair of coarctation. Because a high incidence of premature cardiovascular disease has been well documented after satisfactory surgical repair, the findings are of importance for this group of postoperative patients.

Adolescent↗

The cardiopulmonary effects of calcium infusion in infants with persistent pulmonary hypertension of the newborn.

Low blood ionized calcium levels have been reported previously in association with alkalosis in infants undergoing hyperventilation for persistent pulmonary hypertension. We investigated the effect of acute calcium infusions on the cardiopulmonary status of 10 hypocalcemic, hyperventilated infants with persistent pulmonary hypertension. Acid-base status, arterial partial pressure of oxygen, vital signs, and echocardiographically determined right and left systolic time interval ratios and left ventricular shortening fractions were obtained before and after rapid infusions of calcium gluconate or saline. At 5 and 15 min after calcium infusion, but not after saline infusion, there were significant decreases in both right and left ventricular systolic time interval ratios, and an increase in transcutaneous PO2 and PaO2 that coincided with peak levels of ionized calcium. These findings provide evidence that high levels of ionized calcium in newborns with persistent pulmonary hypertension transiently improve myocardial performance and oxygenation.

Blood Gas Monitoring, Transcutaneous↗

Evaluation of a communication skills course for second-year medical students.

A five-year evaluation and redesign of the communication skills component of the Introduction to Clinical Medicine course was undertaken at the State University of New York Health Science Center at Syracuse College of Medicine. The objectives of the evaluation were to determine the effectiveness of the component in teaching communication skills, identify areas of the component in need of change, and monitor the effectiveness of previous changes. In the first three years, the evaluation focused on the students' perceptions of the importance of communication skills in their training as physicians. Based on the evaluations for those three years, the component was modified substantially. One of the changes was the introduction in years four and five of simulated patients for practicing interviewing skills. The evaluations in years four and five focused on the effectiveness of using the simulated patients and the students' perceptions of how well the course objectives were met.

Communication↗

Sinus node shift after the Senning procedure compared with the Mustard procedure for transposition of the great arteries.

To investigate the nature of the dominant intrinsic cardiac pacemaker activity after the Senning procedure, endocardial mapping of the systemic venous atrium was accomplished a mean of 13 months after operation in 10 patients, aged 22 +/- 6 months. Multiple endocardial sites were measured to find the earliest atrial electrical activity timed back from the QRS complex. These data were compared with data from endocardial mapping performed in 6 patients late after the Mustard procedure. In 8 of 10 patients who had undergone the Senning procedure, the earliest activation time, corresponding by definition to the origin of the intrinsic pacemaker, was located in the inferior medial portion of the superior limb of the systemic venous atrium. In the other 2 patients who had undergone the Senning procedure, the earliest activity was in the high superior limb of the baffle at its junction with the superior vena cava. In contrast, the earliest activity in all patients who underwent the Mustard operation was at the junction of the superior vena cava and the superior limb of the systemic venous atrium. In response to programmed extrastimulation, the electrophysiologic behavior of the intrinsic pacemaker in the Senning group was abnormal compared with known normal sinus node (SN) data in only 3 of 10 patients, whereas all patients in the Mustard group had SN dysfunction. Abnormal SN function was noted in both patients in the Senning group, in whom a shift in the position of the earliest endocardial activation point was not seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗

The modified Blalock-Taussig shunt: analysis of adequacy and duration of palliation.

The modified Blalock-Taussig shunt provides excellent palliation for patients with cyanotic heart disease and may be the optimal shunt for infants less than 3 months old. The duration of palliation with flow limited by a fixed conduit between the subclavian and pulmonary artery is unknown. Between October 1980 and June 1985 forty-nine patients received 55 shunts. Age at operation was 1 day to 15 years (median 2 weeks), with 29 patients less than 3 months old. Weights were 1.7 to 53 kg, with 31 patients less than 5 kg. There were two early (4%) and four late (9%) deaths, none shunt related. The 43 late survivors were followed from 2 to 60 months (mean 27 +/- 16). Late study in 32 patients revealed a mean PO2 of 52 +/- 2 mm Hg. No patient had pulmonary arterial distortion or hypertension. In 10 patients inadequate shunt function was noted from 12 to 34 months after operation (mean 28 +/- 10). There were no sudden failures and all shunts remained patent. Univariate analysis revealed that age less than 3 months (p = .0154) and weight less than 3.6 kg (p = .0110) were risk factors predictive of earlier shunt failure. The mean satisfactory shunt survival time for these two groups was 38 +/- 3.6 and 35 +/- 3.7 months, respectively. The presence of pulmonary atresia (p = .1175) and the specific diagnostic group (p = .7620) were not of themselves risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Vessel Prosthesis↗

Postoperative functional assessment of a modified surgical approach to repair of tetralogy of Fallot.

Since February 1982, we have used a modified technique to repair tetralogy of Fallot with transatrial closure of the ventricular septal defect, a short infundibular incision with avoidance of muscle resection, and anterior expansion of the right ventricular outflow tract using a patch in every case. The pulmonary anulus is approached in the usual manner. Twenty-six patients have had repair with this technique without mortality, and 20 patients (Group 1) have been evaluated 1 to 3 years postoperatively. Their results are compared with those of all patients followed up in our division who had had repair by the traditional technique in the 5 years before February 1982, with the same evaluation within 4 years of operation (Group 2, n = 22). Ten of 20 patients in Group 1 and 14 of 22 in Group 2 required a transannular patch. At cardiac catheterization, right ventricular outflow tract obstruction was effectively relieved in both groups (right ventricular systolic pressure [mean +/- standard error], Group 1 versus Group 2, 45 +/- 5 versus 49 +/- 4 mm Hg). No patient with the modified technique had a residual ventricular septal defect. By M-mode echocardiography, right ventricular-left ventricular end-diastolic dimension ratio was significantly lower for Group 1 patients (0.58 +/- 0.03 versus 0.78 +/- 0.04; normal less than 0.45; p less than 0.001). With radionuclide ventriculography, right ventricular ejection fractions were significantly higher for Group 1 patients with the modified repair (38% +/- 2.2% versus 33% +/- 1.8%; normal greater than or equal to 45%; p less than 0.05). Because the incidence of obligatory pulmonary insufficiency caused by transannular patch is similar in both groups, these results cannot be directly attributed to the presence of pulmonary insufficiency alone. With ambulatory electrocardiographic monitoring, no patient in Group 1 had any ventricular premature contractions whatsoever, whereas six of 22 patients in Group 2 had demonstrable ventricular premature contractions. These results suggest that in children with tetralogy of Fallot, right ventricular outflow tract obstruction can be effectively relieved with this modified approach with improved early preservation of right ventricular function.

Ambulatory Care↗

Hemodynamic and electrophysiologic results of the Senning procedure for transposition of the great arteries.

Of 24 patients, aged 6 days to 24 months, undergoing the Senning procedure for transposition of the great arteries, 2 patients died perioperatively (8% operative mortality): 1 patient, a neonate, from sepsis and 1 patient, born prematurely and with multiple anomalies, from congestive heart failure. One patient died late postoperatively from noncardiac causes. The 21 survivors are clinically well, and in 20 complete hemodynamic and electrophysiologic data were obtained by cardiac catheterization a mean of 13 months after repair. All patients have normal systemic arterial oxygen saturation. Left ventricular function and pulmonary artery pressures are normal in all. None had pulmonary venous obstruction. Narrowing at the junction of the superior vena cava and systemic venous atrium with mean pressure differences of 5 mm Hg or more was found in 4 of the 20 patients, but was clinically manifest in only 1 patient. No abnormality of atrioventricular conduction was seen in response to programmed electrical stimulation. Sinus node dysfunction was present in 6 patients, with abnormalities of both automaticity and sinoatrial conduction. Among these 6 patients were the 5 who were younger than 5 months at operation. The Senning procedure generally results in excellent hemodynamic and electrophysiologic status in patients who undergo operation after the newborn period. Identification of sinus node dysfunction, seen in patients in whom the procedure is performed in the first few months of life, is of concern and identifies a need for close follow-up of sinus node function in this cohort of patients.

Cardiac Pacing, Artificial↗

Childhood mitral valve prolapse.

Mitral valve prolapse is now the most common cardiac diagnosis of childhood. The auscultatory findings of a non-ejection click with or without an associated murmur of mitral insufficiency are reviewed and related to the pathologic and histologic abnormalities. Findings at presentation in a large series of patients are given. Potential problems with progressive mitral insufficiency, arrhythmias and bacterial endocarditis are reviewed. This overview attempts to establish the essentially benign nature of mitral valve prolapse in childhood while indicating areas where continued observation is necessary.

Arrhythmias, Cardiac↗

Improved right ventricular function following late pulmonary valve replacement for residual pulmonary insufficiency or stenosis.

Residual severe pulmonary insufficiency or stenosis may result in significant myocardial dysfunction late after repair of tetralogy of Fallot. Although pulmonary valve replacement has been advocated for selected patients, objective improvement in right ventricular function has been difficult to demonstrate. We undertook pulmonary valve replacement in 11 patients to treat residual insufficiency (n = 8) or stenosis (n = 3) and evaluated them before and after operation by radionuclide ventriculography and M-mode echocardiography. Patients' age at the original repair was 6.6 +/- 0.6 years (range 2 to 8 years) and at subsequent valve replacement was 14.6 +/- 1.5 years (range 5 to 20 years). Indications for pulmonary valve replacement were conduit stenosis indicated by a gradient greater than or equal to 75 mm Hg (n = 3), symptoms (n = 2), progressive cardiomegaly (n = 3), and new onset of tricuspid insufficiency (n = 3). Prior to pulmonary valve replacement, right ventricular ejection fraction was 0.29 +/- 0.12 (range 0.12 to 0.48) and rose to 0.35 +/- 0.10 (range 0.19 to 0.48) at a mean of 10.5 +/- 2.3 months after operation (p less than 0.05). Improvement (defined as an increase in ejection fraction greater than 0.05) was noted in seven patients whereas four demonstrated no change. Left ventricular ejection fraction before operation (0.55 +/- 0.12) was unchanged after pulmonary valve replacement (0.54 +/- 0.06). M-mode echocardiography demonstrated significant reduction in right ventricular dilatation. Right ventricular/left ventricular end-diastolic dimension fell from 1.03 +/- 0.30 to 0.73 +/- 0.13 after operation (p less than 0.01). Cardiothoracic ratio fell from 0.59 +/- 0.02 to 0.55 +/- 0.02 at a mean of 12 months after pulmonary valve replacement (p less than 0.01). Subjective improvement in exercise tolerance was noted in all seven patients who showed an increase in right ventricular ejection fraction. Of the remaining four patients, two had no improvement, one felt symptomatically improved, and one was too young for evaluation. These data demonstrate objective improvement in right ventricular function following pulmonary valve replacement and confirm the usefulness of this procedure in patients with significant right ventricular dysfunction secondary to residual pulmonary insufficiency and stenosis.

Adolescent↗

Cardiac rhythm after the Mustard operation for complete transposition of the great arteries.

The Mustard operation corrects the effects of congenital transposition of the great arteries by creating an intraarterial baffle to direct pulmonary venous blood to the tricuspid orifice and systemic venous blood to the mitral orifice. To identify the long-term effects of this procedure, we followed 372 patients with complete transposition of the great arteries who survived the Mustard operation for at least three months. The mean follow-up period was 4.5 years (range, 0.4 to 15.9); the mean age at operation was 2.0 years. Mean resting heart rates were consistently lower than those for age-matched normal children. Seventy-six per cent of the patients had sinus rhythm during the year of operation--a figure that decreased to 57 per cent by the end of the eighth postoperative year. Twenty-five patients died during the follow-up period, nine suddenly. Life-table analysis revealed a cumulative survival rate of 91 per cent for 11 years and 71 per cent for 15 years after the operation. No strong risk factor for sudden unexpected death identified. This study demonstrates that extended survival among patients with transposition can be expected after the Mustard operation. However, over time there is a decreasing prevalence of normal sinus rhythm in survivors, as well as a small risk of sudden death.

Actuarial Analysis↗

Pulmonary hemodynamics and maintenance of palliation following polytetrafluoroethylene shunts for cyanotic congenital heart disease.

Subclavian-to-pulmonary artery anastomoses with interposition polytetrafluoroethylene (PTFE) conduits provide excellent early palliation for many forms of cyanotic heart disease. It is important to assess whether patients with this condition maintain adequate arterial oxygenation without developing pulmonary artery distortion or hypertension. From October, 1980, to December, 1982, 29 PTFE shunts were performed. There were no hospital deaths or shunt failures. Catheterization was performed in 14 patients from 2 months to 2.5 years (mean 13.4 months) following operation. All shunts were patent. Arterial Po2 at the late study ranged from 33 to 96 torr (mean 57.1 +/- 17.3 torr) and was not significantly different from values obtained before hospital discharge at the time of the shunt procedure (mean 47.6 +/- 5.9 torr). Only one patient demonstrated moderate pulmonary hypertension (44/25 mm Hg), believed to be secondary to ventricular dysfunction. No patient demonstrated pulmonary artery distortion or kinking, and none required a second shunt because of inadequacy of the original procedure. The results in these patients, as well as the continued excellent clinical course of the patients not as yet recatheterized, have prompted us to use this shunt as our procedure of choice in neonates.

Blood Pressure↗

Subclavian-pulmonary artery shunts with polytetrafluorethylene interposition grafts.

Systemic-pulmonary artery shunts remain an important treatment in cyanotic patients. Central shunts continue to pose early and late problems when standard Blalock-Taussig shunts are not possible. Twenty patients underwent subclavian-pulmonary artery shunt procedures with polytetrafluoroethylene (PTFE) prostheses between October, 1980, and August, 1982. Their ages ranged from 1 day to 15 years; 11 patients were less than 14 days old. The arterial oxygen tension rose from 30.7 +/- 11.9 mm Hg to 51.3 +/- 9.1 mm Hg (standard deviation; p less than 0.001) and from 26.4 +/- 7.5 mm Hg to 50.5 +/- 9.3 mm Hg (p less than 0.001) among the 11 neonates. There were no hospital deaths and only 2 late deaths (not shunt related). All patients have patent shunts and excellent relief of cyanosis. The 18 survivors have been followed for an average of 19 months (range, 7 to 29 months). No patient has required reoperation for shunt inadequacy or thrombosis. Recatheterization in 11 patients has demonstrated normal pulmonary pressures and good pulmonary artery growth without vessel distortion. Subclavian-pulmonary shunts using PTFE provide long-term palliation in cyanotic patients. This type of shunt appears to offer important advantages over other shunt procedures, including the classic Blalock-Taussig operation, in newborns.

Adolescent↗

Results with the two-patch technique for repair of complete atrioventricular septal defect.

From May, 1982, to September, 1983, 9 patients underwent repair of complete AV septal defect. They ranged in age from 11 months to 48 months and in weight from 5.3 kg to 16.5 kg. Seven patients were 24 months old or less. Previous operations included pulmonary artery banding in 1 patient and ligation of a patent ductus arteriosus with repair of coarctation in another. All patients had large left-to-right shunts (mean pulmonary to systemic flow ratio, 3.1), and the 7 young infants had marked pulmonary hypertension. Mitral regurgitation was absent in 2 patients, mild in 3, moderate in 2, and severe in 2. One patient had the right ventricular dominant form of complete AV septal defect. In all instances, repair was done using separate ventricular and atrial patches. Leaflet tissue was not divided, and a trileaflet mitral valve was left in each patient. Eight patients survived operation and are well 3 to 17 months after repair. The single operative death occurred in the patient with right ventricular dominance. Only 1 patient has mild residual heart failure 4 months after operation. Clinically, mitral regurgitation is absent in 4 patients and, at most, mild in the other 4. No patient has a conduction disturbance. Repair of complete AV septal defect is facilitated by using separate patches for the ventricular and atrial components of the defect. Less distortion is created, and a more accurate reconstruction of a competent trileaflet mitral valve can be done.

Bioprosthesis↗

Ventricular arrhythmias and mitral valve prolapse in childhood.

Although ventricular arrhythmias are well described in adults with mitral valve prolapse, this association remains controversial in children. To assess the incidence of ventricular premature complexes (VPCs), 103 consecutive children with mitral valve (MV) prolapse confirmed by echocardiography were evaluated prospectively by treadmill exercise and ambulatory ECG. A group of 50 normal children with clinical, ECG, or echocardiographic evidence of heart disease who had undergone treadmill exercise and ambulatory ECG served as controls. In the group with MV prolapse, 16 patients had VPCs with treadmill exercise and 39 had VPCs on ambulatory ECG. High-grade ventricular ectopy (multiform VPCs, couplets, or ventricular tachycardia) was recorded in four patients with MV prolapse during treadmill exercise and in eight during ambulatory ECG. In contrast, no control patient had a single VPC in response to treadmill exercise and only four control patients had rare uniform VPCs on ambulatory ECG. Neither physical examination findings, standard ECG results, nor symptoms could be correlated with VPCs in the patients with MV prolapse. Although the prognostic implications of these findings are uncertain, this study demonstrates that potentially serious ventricular arrhythmias are frequently observed in children with MV prolapse.

Adolescent↗

Anemia of prematurity: determinants of the erythropoietin response.

This study was undertaken to determine the factors that are important in determining the erythropoietin response in low-birth-weight infants during the period of so-called anemia of prematurity. In the first weeks of life oxygen consumption in a group of 21 infants gradually increased as hemoglobin level fell. The magnitude of the erythropoietin response inversely varied with the central venous oxygen tension (P-vO2) (r = -0.55, P less than 0.001). When the P-vO2 declined to less than 30 torr, erythropoietin values were uniformly increased above the "normal" range (defined as the values associated with P-vO2 greater than 38 torr). Erythropoietin values varied inversely with hemoglobin but in general did not exceed the values observed for normal adult men. The erythropoietin values in the infants were remarkably lower at any given hemoglobin level when compared with those of older children with anemia resulting from bone marrow failure. In general, elevations of erythropoietin were seen when the hemoglobin concentration declined to less than 10.0 gm/dl. Change in heart rate did not appear to be a reliable indicator of the presence of anemia; rather, it correlated best with oxygen consumption.

Adult↗

Ventricular arrhythmias and biventricular dysfunction after repair of tetralogy of Fallot.

To test the hypothesis that subclinical levels of ventricular dysfunction contribute to the development of ventricular arrhythmias after repair of tetralogy of Fallot, 38 postoperative patients were studied by radionuclide ventriculography and M-mode echocardiography. Eighteen patients (group I) had Lown grade 2 or greater ventricular arrhythmias on ambulatory electrocardiography or treadmill exercise, or both; 20 patients (group II) had no documented ventricular arrhythmias. Radionuclide ventriculograms were performed using technetium -99m-labeled red cells; ejection fractions were derived by computer from multigated images, with normal values being 45% for the right ventricle and 55% for the left ventricle. From M-mode echocardiography, right and left ventricular end-diastolic dimensions were expressed as a ratio, the highest normal value being 0.45. By radionuclide ventriculography, right ventricular ejection fraction was lower for group I (28 +/- 3%) than for group II (31 +/- 2%), but the difference was not significant (p less than 0.10). Left ventricular ejection fraction was significantly lower for group I than for group II (45 +/- 5% versus 55 +/- 3%, p less than 0.05). The echocardiographic right and left ventricular diastolic dimension ratio was elevated in all patients except two in group II; it was significantly greater in group I than in group II (0.84 +/- 0.06 versus 0.63 +/- 0.04, p less than 0.005). This study provides evidence for right ventricular dilation by M-mode echocardiography and for biventricular dysfunction by radionuclide ventriculography in patients who have undergone repair of tetralogy of Fallot.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗