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Biomedical subjects

D A Fyfe

Publications and source records attributed to D A Fyfe.

At least 37 records · Page 2Linked to original sources
PubMed1993

Randomized trial of oral indomethacin and terbutaline sulfate for the long-term suppression of preterm labor.

OBJECTIVE: Our purpose was to determine the efficacy and safety of long-term oral tocolysis with indomethacin or terbutaline sulfate. STUDY DESIGN: Seventy-one patients at 26 to 32 weeks' gestation admitted for preterm labor were prospectively randomized to receive oral indomethacin or terbutaline sulfate after successful intravenous tocolysis. Patients were monitored weekly for cervical change, maternal side effects, amniotic fluid volume, and constriction of the fetal ductus arteriosus. Patients receiving indomethacin were converted to terbutaline at 34 weeks or with the occurrence of fetal ductal constriction or oligohydramnios. RESULTS: Of 71 patients randomized six were excluded after randomization. Thirty-three patients were randomized to indomethacin and thirty-two to terbutaline. There were no differences in the percentage of patients achieving 34 weeks of gestation. No differences in neonatal outcome were noted. Nine (27%) fetuses receiving indomethacin had constriction of the fetal ductus arteriosus, and 13 (38%) had oligohydramnios. Most patients on terbutaline reported beta-mimetic side effects (53%), but only one required discontinuation of therapy. CONCLUSION: Both indomethacin and terbutaline sulfate are effective tocolytics, but major fetal side effects are common with long-term indomethacin use.

Adult↗
PubMed1993

Sonographic assessment of fetal cardiac arrhythmias.

The fetus with an arrhythmia may be at high risk both from the arrhythmia itself and from the condition that provoked it. Incorrect diagnosis and inappropriate or delayed treatment may further compound the hazard. Although echocardiography can specifically identify the arrhythmia, this technique requires very skilled and careful examination by a physician who fully understands how to differentiate optimally between similar-appearing but mechanistically different arrhythmias. Congenital heart disease may also be present and must be evaluated specifically. This report describes ultrasound recording techniques used to diagnose arrhythmias and includes a discussion of M-mode echocardiography, two-dimensional imaging, pulsed Doppler, and color-flow Doppler. It also differentiates specific arrhythmias--premature atrial contractions, ventricular tachycardia, atrial flutter, complete heart block, and supraventricular tachycardia--and presents the optimal diagnostic tools for each.

Arrhythmias, Cardiac↗
PubMed1991

Prognostic features of children with idiopathic dilated cardiomyopathy.

The presenting features and long-term outcome of 39 children (median age 6.5 months, range 1 day to 16 years) with idiopathic dilated cardiomyopathy (IDC) were reviewed to help determine the appropriate management of these patients. Four outcome groups were identified: those who died, improved, had IDC resolved or received transplants. Presenting clinical features of age, sex, race, congestive heart failure, cardiomegaly, and degree of systolic ventricular dysfunction did not predict final outcome. Left ventricular hypertrophy on the electrocardiogram was seen significantly more often in children who improved than in those who died or in whom IDC resolved (p = 0.002). A rhythm disturbance was also seen more often in those who died than in those who survived (p = 0.025). Of 36 patients treated medically, 12 (33%) died, 15 (42%) improved and 9 (25%) resolved. Eighteen of 26 (69%) patients presenting at age less than or equal to 2 years survived, whereas 6 of 10 patients greater than 2 years survived. There were no differences based on age at presentation, in the time to death or time of follow-up. Three patients received orthotopic heart transplants, 1 of whom died from graft failure. Thus, no clinical feature including age at presentation consistently predicts ultimate outcome in children with IDC.

Arrhythmias, Cardiac↗
PubMed1991

The utility of transesophageal echocardiography during and after Fontan operations in small children.

Transesophageal echocardiography with Doppler examination was performed intraoperatively in 19 children undergoing modified Fontan operations and in 10 patients postoperatively. Comparisons were made with results of intraoperative epicardial imaging (9 patients) and with postoperative transthoracic imaging (10 patients). Transesophageal echocardiography optimally visualized atriopulmonary and cavopulmonary anastomoses. Epicardial echocardiography was successful in only three of nine patients. Intraoperative transesophageal echocardiography showed residua in 8 of 19 studies and led directly to surgical revision or medical therapy. These residua included stenosis of the cavopulmonary anastomosis (1 patient), unsatisfactory atrial fenestration (2 patients), patent ductus arteriosus (1 patient), residual cavoatrial shunting (1 patient), atrial thrombi (1 patient), and poor ventricular function (2 patients). Results of examination in the postoperative intensive care unit showed significant abnormalities in 4 of 10 patients. This study demonstrates that transesophageal echocardiography provides unique anatomic and physiologic information during and after modified Fontan operations in small children and therefore may have significant impact on patient management.

Child↗
PubMed1991

Doppler echocardiographic evaluation of streptokinase lysis of thrombosed right-sided St. Jude Medical valves in patients with congenital heart defects.

Four episodes of St. Jude Medical prosthesis leaflet thrombosis were serially evaluated by two-dimensional and Doppler echocardiography during treatment with streptokinase. Three patients aged 4, 11, and 24 years with congenital heart disease had St. Jude Medical valves in pulmonary positions (two cases) for tetralogy of Fallot and in the tricuspid position (one case). The duration of thrombosis was not known in any patient. Leaflet immobility and its resolution were demonstrated by echocardiography and were confirmed fluoroscopically. Continuous wave Doppler echocardiography showed abnormal stenotic gradients in thrombosed valves that were reduced after thrombolysis. These studies demonstrate the utility of two-dimensional and Doppler echocardiography in serial evaluation of prosthetic pulmonary and tricuspid valve thrombosis during thrombolysis.

Adult↗
PubMed1991

Hemi-Fontan operation in surgery for single ventricle: a preliminary report.

Mortality after Fontan operation is related to risk factors like ventricular hypertrophy, pulmonary artery deformity, and young age (infancy). Preliminary procedures may improve Fontan results. The hemi-Fontan operation includes atriopulmonary anastomosis and correction of all anatomical risk factors, but an atriopulmonary patch directs superior vena caval flow into both pulmonary arteries and inferior vena caval flow into the ventricle, thus maintaining cardiac output (modified Glenn physiology). We performed 17 hemi-Fontan procedures in 16 patients, 14 primarily (median age, 9 months) and 3 for takedown of a Fontan operation. The 14 primary operations were for hypoplastic left heart syndrome (5), pulmonary atresia with intact ventricular septum (4), and other (5). All patients had multiple risk factors. Extubation was at 18 hours (median), chest tube removal was at 3 days, and hospital discharge was at 8 days postoperatively. Important complications included subglottic stenosis, transient diaphragmatic paralysis, pulmonary artery stenosis and thrombosis requiring reoperation, and transient ventricular fibrillation. One patient required hemi-Fontan takedown, and this patient later (3 months postoperatively) became the only death. Fontan take-downs have had a high mortality rate. In 3 patients who tolerated Fontan operation poorly, converting Fontan to hemi-Fontan abruptly reversed the downhill course. For these patients, the operation was life-saving. Hemi-Fontan operation is safe and well-tolerated, even in infants, provides the advantages of modified Glenn physiology before Fontan operation, and may be especially useful for Fontan takedown after failed Fontan.

Cardiac Surgical Procedures↗
PubMed1991

Transesophageal echocardiography detects thrombus formation not identified by transthoracic echocardiography after the Fontan operation.

Transesophageal echocardiography demonstrated six instances of venous thrombus formation in the inferior vena cava, right atrium and caval-pulmonary anastomosis region in four children after a modified Fontan operation. Transthoracic surface echocardiography failed to identify these thrombi in five of the six cases because of the posterior location of the thrombus or imaging interference from surgical hardware. These thrombotic episodes occurred 2 days to 5 years after the Fontan operation in children 25 to 168 months of age. Clinical features of compromised cardiac performance with cyanosis or inadequate perfusion were present during four of the six episodes. In two patients, thrombi occurred around transvenous permanent atrial pacing leads. Therapy to eliminate thrombus included surgery (two cases), anticoagulation with warfarin (three cases) and streptokinase thrombolysis (one case). Disappearance of the thrombus was confirmed by transesophageal study in three of the four cases with follow-up echocardiography. Transesophageal echocardiographic demonstration of atrial and pulmonary thrombi that could not be seen by transthoracic imaging suggests that these thrombi occur with greater frequency in patients who have undergone the Fontan operation than was previously suspected.

Adolescent↗
PubMed1991

Transesophageal echocardiography for congenital heart disease.

Surface echocardiographic imaging of small children is routinely successful in defining anatomical details and Doppler flow patterns with even the most complex congenital cardiac malformations. However, in larger children or adults, imaging is frequently limited. A recent expansion of the role of echocardiography is intraoperative epicardial imaging. Epicardial and postoperative imaging, however, have significant limitations. To avoid some of these limitations, transesophageal echocardiography has increasingly been used in the arena of congenital heart disease. The more recent development of small sized gastroscopic probes has allowed transesophageal echocardiographic assessment of congenital heart disease in children down to newborn size. As detailed studies of individual lesions are reported, it has become clear that the mere presence of a congenital heart defect is not an indication for transesophageal echocardiography in most children if imaging can be accomplished by surface examination. However, transesophageal echocardiography may be indicated for the intraoperative or postoperative assessment of that defect, particularly when repair has been difficult or is known to be associated with significant residual abnormalities. Cardiac structures encountered with horizontal and vertical imaging plane transducers have been described and should be completely familiar to the examining echocardiographer.

Child↗
PubMed1991

Preoperative prediction of postoperative pulmonary arteriolar resistance after surgical repair of complete atrioventricular canal defect.

The natural history of patients with complete atrioventricular canal defect is one of unrelenting development of pulmonary vascular obstructive disease. Corrective surgery, which can be performed with low mortality during infancy, reduces the time that the pulmonary vascular bed is exposed to excessively high pressure and blood flow. In some patients, however, advanced vascular disease may already be established at operation. Surgical intervention in these patients may not prevent the progression of obliterative pulmonary vascular disease and may in time even result in right ventricular failure, since after the corrective operation there is no ventricular septal defect to shunt away the right ventricular pressure overload. This article outlines a numeric method for predicting pulmonary vascular resistance after surgical correction; the method is based on age and hemodynamic data available from preoperative cardiac catheterization. Retrospective analysis of preoperative and postoperative data from 20 patients produced a regression equation in which a linear combination of inverse pulmonary/systemic blood flow ratio and age at operation predicted pulmonary vascular resistance after operation, with a multiple correlation coefficient of 0.85. This newly discovered relationship may provide valuable insight into the probable outcome of surgical intervention in cases in which pulmonary vascular obstructive disease is suspected as significant.

Arterial Occlusive Diseases↗
PubMed1990

New approaches to treatment of incessant ventricular tachycardia in the very young.

It was assumed that the availability of new antiarrhythmic drugs and new surgical techniques might allow medical or nonexcisional surgical treatment in many young children with incessant ventricular tachycardia. Fourteen infants and young children less than 5 years of age were evaluated and treated for incessant ventricular tachycardia. Medical treatment was pursued up to the use of amiodarone with a type Ib or Ic antiarrhythmic drug unless the patient became hemodynamically unstable. Patients underwent surgery when these drug regimens failed or when moderate congestive heart failure was present. Seven patients were successfully treated medically and seven underwent surgical treatment. Of those treated surgically, five had cryothermic lesions and two had excisions. Five of the surgically treated patients required temporary additional medical treatment. Follow-up ranged from 12 to 53 months (mean 28). Eleven of the 14 patients are currently not taking any antiarrhythmic medication. No patient required a pacemaker, none received anticongestive medications and none died.

Anti-Arrhythmia Agents↗
PubMed1990

Fetal echocardiographic diagnosis of congenital heart disease.

The delineation of the structural and functional abnormalities of the fetal heart by echocardiography has led to the emergence of a new and vital subspecialty, that of fetal cardiology. Its practitioners are from disciplines such as genetics, obstetrics, and pediatrics, the common interests of which in the well-being of the unborn child have converged as technologic advances in ultrasound have enabled detailed evaluation and sometimes treatment of fetal hemodynamic abnormalities. Each discipline forms an entry point for the identification and referral of the high-risk patient or fetus with a suspected abnormality. As has been shown obstetric cardiac screening of the general population with ultrasound provides the highest yield of cardiac malformations when suspicious findings are referred to a subspecialist in fetal cardiac sonography. As we study the pathogenesis of congenital defects, it is likely that hitherto unidentified high risk populations will be found. The future holds the possibility of meaningful surgical interventions that may change the dismal outcome of fetuses with certain, now lethal cardiac malformations. Patients with hydrops fetalis due to congenital complete heart block are almost certain to die. Intrauterine cardiac pacing has been attempted and is a potentially life-saving procedure. Patients in whom pulmonary underdevelopment occurs because of the cardiac enlargement associated with some types of pulmonary atresia could potentially benefit from intrauterine surgery such as valvotomy. Serial fetal echocardiographic examination of the developing heart with higher resolution equipment during the first trimester may one day pinpoint the exact moment of teratogenesis and lead to more specific treatments designed to restore normal embryogenesis. Such examinations will, when known to be safe themselves, at the very least significantly advance our knowledge of normal cardiac embryogenesis and pathogenesis.

Arrhythmias, Cardiac↗
PubMed1990

Tricuspid atresia: current concepts in diagnosis and treatment.

Tricuspid atresia is the third most common cyanotic cardiac malformation, seen in 1 per cent of children with congenital heart disease. Anatomic details in each patient can be elucidated by echocardiography. Surgical treatment initially is palliation, usually with aortopulmonary shunt. Definitive treatment is with a Fontan operation, in which the systemic venous return is connected directly to the pulmonary arterial tree. Long-term results of the corrective procedure have been very good.

Cardiac Catheterization↗
PubMed1990

Real-time, automated, interactive cardiac electrophysiology testing.

We describe a new automated interactive system that performs all of the functions required for complete evaluation of the intracardiac conduction system, for inducing, terminating and analyzing tachydysrhythmias, and for locating and characterizing accessory atrioventricular (AV) connections and ectopic foci. In the first year of operation, the system was used to conduct 210 electrophysiology studies. These ranged from simple postoperative evaluation of the conduction system to complete tachycardia studies during pharmacological manipulation of the patient. Patient age at time of catheterization ranged from 6 days to 70 years, with median age of 8 years and 7 months. Advantages accruing from automated electrophysiology testing with this system included great precision and accuracy of timing measurements, flexibility in designing and implementing pacing protocols, and rapid management of induced or spontaneous dysrhythmias. Significant savings of time and labor were achieved by computer generation of reports and graphs as opposed to manual data extraction and plotting. The single most significant advantage is the ability of the system to provide information on a real-time basis, permitting the electrophysiologist to analyze, modify, extend or curtail the procedure.

Adolescent↗