PubMed Health⌕ Search

Biomedical subjects

D C Crowley

Publications and source records attributed to D C Crowley.

53 records · Page 3Linked to original sources
PubMed1985

Results of balloon valvuloplasty in the treatment of congenital valvar pulmonary stenosis in children.

Transluminal balloon valvuloplasty was used in the treatment of congenital valvar pulmonary stenosis in 19 children, aged 5 months to 18 years. The right ventricular (RV) systolic pressure and RV outflow tract gradient decreased significantly immediately after the procedure (95 +/- 29 vs 59 +/- 14 mm Hg, p less than 0.01, and 78 +/- 27 vs 38 +/- 13 mm Hg, p less than 0.01). Seven of these patients were evaluated at cardiac catheterization 1 year after balloon valvuloplasty. No significant change occurred in RV systolic pressure or RV outflow tract gradient at follow-up evaluation compared with measurements immediately after balloon valvuloplasty (60 +/- 5 mm Hg vs 56 +/- 12 mm Hg and 39 +/- 5 vs 38 +/- 10 mm Hg). In addition, follow-up evaluation was performed using noninvasive methods and included electrocardiography (n = 13), vectorcardiography (n = 11) and Doppler echocardiography (n = 11) Doppler echocardiography in 11 patients 15 +/- 9 months after balloon valvuloplasty showed a continued beneficial effect with a mild further decrease in RV outflow tract gradient. Thus, balloon valvuloplasty is effective in the relief of pulmonary stenosis.

Adolescent↗
PubMed1985

Hemodynamic determinants of exercise-induced ST-segment depression in children with valvar aortic stenosis.

To evaluate the hemodynamic factors associated with treadmill-induced ST-segment depression in children with valvar aortic stenosis, 12 patients (mean age 13 years) with ST-segment depression during treadmill exercise and 5 patients (mean age 13 years) without ST-segment depression during treadmill exercise underwent exercise testing during cardiac catheterization. The left ventricular (LV) systolic pressure and LV outflow tract gradient at rest (177 +/- 25 vs 138 +/- 8 mm Hg and 59 +/- 18 vs 23 +/- 7 mm Hg, respectively) and corresponding pressures during maximal supine exercise (248 +/- 37 vs 189 +/- 17 mm Hg and 112 +/- 34 vs 52 +/- 14 mm Hg) were significantly greater (p less than 0.01) in the patients with exercise-induced ST-segment depression, although overlap existed. The LV-O2 supply-demand ratio during maximal supine exercise was significantly less (6.4 +/- 2.7 vs 11.8 +/- 0.7; p less than 0.005) in patients with than in those without exercise-induced ST-segment depression. In fact, an LV-O2 supply-demand ratio less than 11.0 was 100% sensitive and specific in predicting treadmill-induced ST-segment depression. These results suggest that although the development of ST-segment depression during treadmill exercise is related to LV systolic pressure and LV outflow gradient, its major hemodynamic determinant is the LV-O2 supply-demand ratio.

Adolescent↗
PubMed1985

Two-dimensional and M-mode echocardiographic evaluation of fetal arrhythmia.

Cardiac anatomy and rhythm were evaluated in the fetuses of 18 pregnant women (between 20 and 42 weeks of gestation) referred because of abnormal fetal heart rate or rhythm. Utilizing a 3 MHz two-dimensional scan head with M-mode capability, M-mode recordings were obtained at paper speeds of 50 and 100 mm/s from 16 fetuses. The arrhythmia of two fetuses was diagnosed using two-dimensional echo alone. Semilunar and atrioventricular valve opening and closing points, A waves, plus ventricular wall motion were used for timing purposes; and heart rate and rhythm were determined. Diagnoses made were atrial premature beats n = 3, ventricular premature beats n = 3, congenital heart block n = 4, supraventricular tachycardia n = 3, sinus bradycardia n = 1, and blocked atrial beats n = 1. In three fetuses no arrhythmia was identified. Cardiac anatomy was normal in 16 fetuses, with two (congenital heart block) felt to have univentricular hearts. Fourteen pregnancies went to term, two were delivered prematurely, and two fetuses with congenital heart block were stillborn. In three fetuses arrhythmia was confirmed during labor by fetal scalp electrode. Arrhythmia was absent after birth in 11 of 16 infants, with congenital heart block persistent in two infants, and supraventricular tachycardia, atrial premature beats, and blocked atrial premature beats remaining in one each. Intervention with medical management was attempted in four pregnancies, with successful termination of arrhythmia supraventricular tachycardia) in two fetuses. We conclude that combined two-dimensional M-mode capability is useful in the diagnosis of fetal rhythm disturbances, and perhaps in the selection of timing, and mode of intervention.

Adult↗
PubMed1985

Atrial overdrive pacing for conversion of atrial flutter in children.

Twenty-three successive patients with 27 different episodes of sustained atrial flutter were treated with atrial pacing for conversion of the tachyarrhythmia; 15 patients with 16 episodes of atrial flutter underwent intracardiac right atrial pacing and eight patients with 11 episodes of atrial flutter were treated with transesophageal atrial pacing. Ten of sixteen episodes (63%) and eight of 11 episodes (73%) were successfully converted using intracardiac and transesophageal techniques, respectively. Mean flutter cycle length for all 27 episodes was 219 ms (mean heart rate 274 beats per minute); successful pacing conversion cycle length (n = 15) was 72% of the flutter cycle length. Hemodynamic, electrophysiologic, and roentgenographic data were not predictive of conversion by either technique. Induction of localized atrial fibrillation or failure to meet critical pacing criteria may explain pacing failures. Based on this experience, a trial of transesophageal atrial pacing for acute conversion of any episode of atrial flutter in children prior to direct current cardioversion is recommended.

Adolescent↗
PubMed1984

Chronic verapamil therapy in pediatric and young adult patients with hypertrophic cardiomyopathy.

Oral verapamil, 5.2 +/- 1.1 mg/kg/day (range 2.8 to 7), was administered to 13 pediatric patients with hypertrophic cardiomyopathy for 13 +/- 6 months (range 2 to 20). The patients had significant symptomatic improvement on verapamil therapy. Murmur intensity diminished in 6 patients during therapy and left ventricular (LV) electromotive forces on the electrocardiogram diminished in 4, increased in 5 and did not change in 4. Exercise endurance increased from 8.4 +/- 3.9 to 10.9 +/- 2.8 minutes (p less than 0.01). Seven patients had ST-segment depression (0.38 +/- 0.28 mV) before verapamil therapy, which improved after verapamil therapy in 5 (0.24 +/- 0.17 mV, p less than 0.02). Of 4 patients with exercise-induced ventricular ectopic activity, 3 had diminution or abolishment of ectopy following verapamil. By echocardiography, the patients had an increase in LV end-diastolic dimension from 3.4 +/- 0.7 to 3.9 +/- 0.8 cm (p less than 0.01), with no significant change in shortening fraction (46.1 +/- 8.0% vs 44.6 +/- 8.0%). When adjusted for body size and age there was a significant decrease in LV septal thickness (from 106 +/- 70 to 45 +/- 52% of predicted normal values, p less than 0.05) and LV posterior wall thickness (from 40 +/- 45 to 5 +/- 26% of predicted normal values p = 0.05) after verapamil. Isovolumic relaxation time decreased from 69 +/- 26 to 42 +/- 19 ms after verapamil (p less than 0.01). Systolic anterior motion of the anterior mitral leaflet disappeared in 5 of 8 patients and midsystolic closure of the aortic valve was no longer present in 4 of 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Vasodilator therapy in children: acute and chronic effects in children with left ventricular dysfunction or mitral regurgitation.

To determine the acute and chronic effects of vasodilator therapy in children, vasodilator therapy was evaluated in 13 children (aged 0.2 to 14.5 years) with severe left ventricular dysfunction or mitral regurgitation. In seven children, nitroprusside increased cardiac index by an average of 33% (P less than .01) and increased stroke index by 29% (P less than .01). In eight children, hydralazine caused a 31% increase in cardiac index (P less than .01) and a 27% increase in stroke index (P less than .02). Ten children received chronic oral vasodilator therapy and were followed for 5.7 +/- 1.4 (SEM) months. Early clinical improvement was observed in every child. Symptoms of heart failure diminished in all, and five children became entirely asymptomatic. A significant (P less than .05) improvement was noted in growth velocity, respiratory rate, heart size, and incidence of gallop rhythm after 1 month of therapy. The duration of the beneficial response to vasodilator therapy varied considerably, however, and significant improvement for the group was not found after 1 month. Four children had sustained clinical improvement for 6 months or longer, but the others experienced recurrent heart failure within 1 to 4 months.

Adolescent↗
PubMed1984

Repair of truncus arteriosus in neonates with the use of a valveless conduit.

Each of seven infants 1 to 9 days old and weighing 2.1 to 3.3 kg with truncus arteriosus underwent repair of their defects with a right ventricular-to-pulmonary artery valveless conduit. Congestive heart failure and cyanosis were present before surgery in each. Five patients survived surgery and one of these subsequently died. Comparison between preoperative hemodynamics of the survivors and nonsurvivors disclosed similar peak systolic pulmonary arterial and aortic pressures, and pulmonary (Rp) or systemic resistance (Rs) in the groups. However, the mean Rp/Rs ratio in survivors (0.15) was significantly less than in nonsurvivors (0.63) (p = .001). The four remaining survivors are asymptomatic 7 months to 5.5 years after operation. Postoperative cardiac catheterization in three patients disclosed proximal conduit obstruction of 10 to 20 mm Hg in each, distal conduit obstruction of 35 mm Hg in two, and mild truncal valve stenosis and moderate truncal regurgitation in one each. We recommend the use of a valveless conduit for the symptomatic neonate with truncus arteriosus and a low Rp/Rs ratio (less than or equal to 0.03).

Blood Vessel Prosthesis↗
PubMed1983

Clinical and hemodynamic follow-up of left ventricular to aortic conduits in patients with aortic stenosis.

To assess the long-term results of left ventricular outflow tract reconstruction utilizing an apical left ventricular to aortic valved (porcine) conduit the clinical and hemodynamic data were reviewed from 24 patients who had placement of an apico-aortic conduit. Eighteen of the patients are asymptomatic and taking no cardiac medications. Three patients were reoperated on, one patient 1.5 years after his original operation for subacute bacterial endocarditis and two patients 3 to 4 years after their original operation for severe conduit valve insufficiency. None of the patients is taking anticoagulants and no thromboembolic events have occurred. Postoperative catheterization has been performed 1 to 1.5 years (mean 1.2) after repair in 15 of 21 patients. The rest left ventricular outflow tract gradient has decreased from 102.5 +/- 20 mm Hg preoperatively to 14.8 +/- 9.9 mm Hg postoperatively (probability [p] less than 0.001). Some degree of conduit obstruction was demonstrated by catheter passage in 11 of the 15 patients. In these 11 patients, the obstruction occurred at three distant sites: at the egress of the left ventricle in 9, at the porcine valve in 5 and at the aortic to conduit junction in 1. Isometric exercise in five and supine bicycle exercise in six patients increased the left ventricular outflow tract gradient by 2.5 +/- 1.1 and 20.8 +/- 11.8 mm Hg, respectively, despite an increase in cardiac index of 1 +/- 0.3 and 3.7 +/- 0.4 liters/min per m2, respectively. The data suggest that a left ventricular to aortic conduit is an effective form of therapy for severe left ventricular outflow tract obstruction.

Adolescent↗
PubMed1983

Hemodynamic effects of verapamil in children and adolescents with hypertrophic cardiomyopathy.

The acute hemodynamic effects of verapamil were evaluated in nine children with hypertrophic cardiomyopathy. Verapamil, 0.1 mg/kg, was administered as an i.v. bolus over 2 minutes, followed by a 20-minute continuous infusion of 0.007 mg/kg/min. Hemodynamic measurements were obtained at rest in nine patients and at maximal supine bicycle exercise in seven before and 15 minutes after verapamil. At rest, verapamil increased the mean cardiac output from 3.3 +/- 0.9 to 3.7 +/- 0.9 l/min/m2 (+/- SD) (p less than 0.02) and decreased left ventricular end-diastolic pressure from 19.3 +/- 8.1 to 14.5 +/- 6.9 mm Hg (p less than 0.006). In six patients with resting left ventricular outflow tract obstruction, the systolic pressure gradient decreased from 17.5 +/- 7.2 to 5.2 +/- 4.5 mm Hg (p less than 0.04). Repeat supine bicycle exercise testing after verapamil showed increases in total work performed (1743 +/- 1284 to 3168 +/- 1643 kg-m, p less than 0.006) and maximal cardiac index during exercise (6.5 +/- 1.3 to 7.8 +/- 1.8 l/min/m2, p less than 0.05), and decreases in maximal exercise left ventricular end-diastolic pressure (29.1 +/- 10.1 to 19.3 +/- 10.4 mm Hg, p less than 0.002) and left ventricular systolic outflow tract gradient (31.2 +/- 10.5 to 1.75 +/- 1.7 mm Hg, p less than 0.04). These results suggest that verapamil may be an effective therapeutic agent for the treatment of hypertrophic cardiomyopathy in children.

Adolescent↗
PubMed1982

Correction of truncus arteriosus in the neonate using a nonvalved conduit.

Successful correction of truncus arteriosus in two neonates, both 4 days of age, is described. Nonvalved polytetrafluoroethylene (PTFE) conduits were used because of the small size of the infants. Both recovered from operation with no signs right ventricular failure and remain well. Catheterization data on one patient show satisfactory hemodynamics 1 year after operation with only residual branch pulmonary artery stenosis. These data suggest that a conduit valve is not essential in the correction of truncus arteriosus even in the neonate.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Pressure-regulated volume control vs volume control ventilation in infants after surgery for congenital heart disease.

The objective of this investigation was to compare how two modes of positive pressure ventilation affect cardiac output, airway pressures, oxygenation, and carbon dioxide removal in children with congenital heart disease in the immediate postoperative period. The investigation used a one group pretest-post-test study design and was performed in the pediatric cardiac intensive care unit in a university-affiliated children's hospital. Nine infants were enrolled immediately after repair of tetralogy of Fallot (2) or atrioventricular septal defects (7) with mean weight = 5.5 kg (4.2-7.3 kg). Children were admitted to the pediatric cardiothoracic intensive care unit after complete surgical repair of their cardiac defect and stabilized on a Siemen's Servo 300 ventilator in volume control mode (VCV1) (volume-targeted ventilation with a square flow wave pattern). Tidal volume was set at 15 cc/kg (total). Hemodynamic parameters, airway pressures and ventilator settings, and an arterial blood gas were measured. Patients were then changed to pressure-regulated volume control mode (PRVC) (volume-targeted ventilation with decelerating flow wave pattern) with the tidal volume set as before. Measurements were repeated after 30 minutes. Patients were then returned to volume control mode (VCV2) and final measurements made after 30 minutes. The measurements and results are as follows: After correction of congenital heart defects in infants, mechanical ventilation using a decelerating flow wave pattern resulted in a 19% decrease in peak inspiratory pressure without affecting hemodynamics, arterial oxygenation, or carbon dioxide removal.

Analysis of Variance↗
PubMedDate not supplied

Neonatal cardiac catheterization: A 10-year transition from diagnosis to therapy.

To assess the changing role of cardiac catheterization in the care of the neonate, a retrospective review of all catheterizations between January 1984 to December 1985 (group I) and January 1994 to December 1995 (group II) at C.S. Mott Children's Hospital was performed. Neonatal cardiac catheterization was performed more frequently (p = 0.02) in group I, comprising 14% (110 of 772) of all catheterizations versus 11% (93 of 880) in group II. Access was performed by cutdown in 15 patients (13 venous and 2 arterial), all in group I. In group I, 20 of 110 patients (18%) had balloon atrial septostomies; no other catheter interventions were performed. Interventions were more frequent (p = 0.003) and varied in group II, including 15 septostomies, 17 balloon valvuloplasties (13 pulmonary and 4 aortic), 2 coil embolizations of collaterals, and 1 cardiac biopsy. Despite the higher prevalence and complexity of interventions in group II, fluoroscopy times (median; range: 16 min; 2-55 vs 16 min; 1-107) were similar in both groups (p = not significant) as well as the prevalence of complications. Neonatal cardiac catheterizations are performed less frequently than they were a decade ago at our institution, and therapeutic interventions have become more common. Despite these changes, fluoroscopy time and the rate of complications have not increased.

Cardiac Catheterization↗
PubMedDate not supplied

Echocardiographic indexes of allograft rejection in pediatric cardiac transplant recipients.

To determine the usefulness of echocardiographic indexes of left ventricular (LV) function as possible predictors of cardiac rejection, 12 transplant recipients (ages 3 to 17 years) underwent a total of 52 serial echocardiographic examinations and cardiac biopsies. The results were compared to those of 12 normal children (ages 2 to 17 years). Biopsies were graded as no rejection (n = 23), mild rejection (cellular infiltrate, n = 13), and moderate rejection (myocyte necrosis, n = 16). LV dimensions, percent shortening fraction, indexed LV mass, and ejection fraction were measured from M-mode and two-dimensional echocardiography. From the mitral valve Doppler tracing, the following measurements were made: isovolumic relaxation time, peak E and peak A velocities, and the fraction of filling under the E and A waves as well as in the first third of diastole. Compared with normal subjects, transplant recipients with no rejection had higher heart rates (95 +/- 15 vs 80 +/- 17 beats/min), longer isovolumic relaxation time (68.8 +/- 11.2 vs 51.5 +/- 13.6 msec), decreased first third area fraction (0.48 +/- 0.10 vs 0.57 +/- 0.10), and similar shortening fraction, LV mass, and peak E and A velocities (p less than 0.03). Compared with transplant recipients with no rejection, patients in whom mild rejection developed also had decreased shortening fraction (31% +/- 10% vs 37% +/- 8%) and decreased peak E velocity (0.68 +/- 0.19 vs 0.88 +/- 0.15 m/s) (p less than 0.03). From mild to moderate rejection, no further changes were noted in any echocardiographic indexes measured.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

The psychosocial impact of pediatric heart transplantation.

Children with terminal heart disease experience a dramatic improvement in functional status after heart transplantation but may be at increased risk for problems in psychosocial adaptation. Selected psychosocial outcomes were assessed in 49 pediatric heart transplant recipients and their families from five heart transplantation centers. Heart transplant recipients did not appear significantly different from their peers on self-report measures of self-concept and anxiety, but they showed significantly less social competence and more behavior problems than a normative population. Behavior problems observed were most frequently suggestive of depression and were significantly associated with greater family stress and diminished family resources for managing stress. The study findings further suggest that the heart transplant recipients' ability to verbalize or ventilate their feelings and concerns to others seems to facilitate psychosocial adaptation. Assessment of stress, resources, and coping is imperative to enable health professionals to promote the psychosocial adaptation of pediatric heart transplant recipients and their families.

Adaptation, Psychological↗