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Biomedical subjects

R M Sade

Publications and source records attributed to R M Sade.

At least 19 recordsLinked to original sources

Life-threatening postoperative junctional ectopic tachycardia.

Junctional ectopic tachycardia developed in an infant after intraatrial repair of transposition of the great arteries. He failed to respond to medical management and, in moribund condition, underwent His bundle cryoablation. He survived and ultimately did well. Junctional ectopic tachycardia is not uncommon after open heart operations in children and may be lethal. Its genesis, diagnosis, and treatment are now well enough understood to allow successful treatment of nearly all patients.

Atrioventricular Node

Atrioventricular pacing in congenital heart disease.

We have attempted to optimize cardiac performance in patients with congenital heart disease requiring artificial pacing by using pacemakers capable of both sensing and pacing both the atrium and the ventricle (DDD). We reviewed our results with 88 patients receiving DDD devices to determine the safety and dependability of these devices in children. Age ranged from 1 hour to 25 years. Endocardial leads were used in 68 patients, whereas epicardial leads were used in 20 patients. Previous cardiac procedures had been done in 30 patients. There were nine deaths but none due to pacemaker malfunction. Endocardial leads functioned better than epicardial leads. Ninety-eight percent of patients with endocardial leads and 62% of patients with epicardial leads were maintained in the DDD mode. Complications were infrequent and all were corrected without long-term sequelae. The DDD mode may offer considerable benefits to children who require artificial pacing. Our data allow us to conclude that most children can be paced safely and dependably in the DDD mode.

Adolescent

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

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

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

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

Subvalvar aortic stenosis: timing of operation.

Subvalvar aortic stenosis can be associated with progressive left ventricular outflow tract obstruction, aortic insufficiency, and infective endocarditis. We reviewed the records of 36 surgical patients who underwent 39 operations for subaortic stenosis. Seventeen patients had associated congenital cardiac anomalies. One perioperative death occurred in a patient with tetralogy of Fallot. The mean preoperative left ventricular outflow tract systolic pressure gradient was 64 +/- 5 mm Hg (+/- standard error of the mean) and decreased to 9 +/- 2 mm Hg postoperatively (p less than 0.001). Reliable preoperative and postoperative information regarding aortic valve function was available for 27 patients. Aortic insufficiency was found in 17 (63%) of those patients preoperatively. Postoperatively, insufficiency increased in 3 patients and decreased in 4; none of these changes was major. Severity of preoperative aortic insufficiency increased significantly with age (p less than 0.05), but did not correlate with left ventricular outflow tract gradient. The information from this study and previous studies suggests that resection of subaortic stenosis is safe and effective, and operation at the time of diagnosis, regardless of left ventricular outflow tract gradient or symptomatic status, is a reasonable therapeutic alternative.

Adolescent

Repair of supravalvar aortic stenosis: cardiovascular morphometric and hemodynamic results.

Supravalvar aortic stenosis is associated with normal systolic pressure in the aorta and its branches with the singular exception of the coronary arteries, which are hypertensive. This uncommon lesion has been treated by patch aortoplasty of several types. We examined hemodynamics and morphometrics in 13 patients who underwent operation for supravalvar aortic stenosis from 1979 through 1988. They ranged in age from 2 to 43 years (mean age, 14.5 +/- 3.8 years [+/- standard error of the mean]). There were no operative deaths. Preoperative and postoperative (1 to 5 years) catheterization or echocardiography or a combination of these was done in all but 3 patients (1 died late suddenly without a postmortem examination; 1 was lost to follow-up; and 1 has not yet been restudied). Pressure gradients across the stenosis in patients treated with a single-sinus patch (n = 4) were 65 +/- 18 mm Hg preoperatively and 5 +/- 3 mm Hg postoperatively (p less than 0.05) and in patients with a bisinus patch (n = 6), 83 +/- 15 mm Hg preoperatively and 6 +/- 2 mm Hg postoperatively (p less than 0.05); the two groups were not significantly different. Measurements of the diameters of the coronary arteries, aortic annulus, and descending aorta were made, and calculation of the ratio of the coronary artery and annulus diameters to the descending aortic diameters both preoperatively and postoperatively was possible in 5 patients. The left coronary artery was larger than normal before and after operation. Preoperatively there was a disproportionate increase in left coronary artery and annulus size during systole. Left ventricular wall thickness decreased significantly postoperatively (p less than 0.05). Repair of supravalvar aortic stenosis (localized and diffuse) by both single sinus and bisinus patch repair is safe and hemodynamic results are good.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

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

Problems with permanent atrial pacing in the Fontan patient.

Transvenous atrial pacing is the preferred method for control of both brady and tachyarrhythmias in the postoperative pediatric patient with normal atrioventricular conduction. We reviewed our experience with the use of permanent atrial pacing for the control of bradycardia and tachycardia in the Fontan patient. We then compared this pacing experience to atrial pacing data compiled for postop Transposition of the Great Arteries (TGA) patients. Out of twenty-five Fontan patients followed at the Medical University of South Carolina, six patients have had atrial arrhythmias necessitating pacing (24%). Underlying congenital heart disease included tricuspid atresia physiology in three and single ventricle in three. The indications for atrial pacing was brady-tachy syndrome in four patients and sick sinus syndrome in two. Pacers were inserted immediately post-op in three patients and 1.5 years, 2 years, and 8 years post Fontan in the other three. These six patients have required a total of nine pulse generator implantations. Five of the nine pacers were inserted transvenously and four via thoracotomy. In contrast to our experience with permanent atrial pacing in post TGA patients, dysrhythmia control with atrial pacing in the Fontan patient has been more difficult to achieve. The Fontan patients have a higher incidence of symptomatic dysrhythmias, hospitalizations, and antidysrhythmic medication requirements after pacer insertion. Implantation thresholds of the Fontan patients are higher than those of the transposition group. While successful atrial demand pacing is attainable in both groups, antitachycardia pacing is more reliable in the post-op TGA patient. The Fontan procedure seems to present a new set of obstacles for successful atrial pacing in the pediatric post-op patient.

Arrhythmias, Cardiac

Valve prostheses in children: a reassessment of anticoagulation.

We have previously published evidence that children with St. Jude Medical prostheses on the left side of the heart may not require anticoagulation. Between March 1979 and September 1986, we followed up 48 patients who had no anticoagulant therapy for up to 7 years after valve replacement, an aggregate of 122 patient-years. The 25 male and 23 female patients ranged in age at implantation from 5 months to 21 years (12 +/- 6 years, mean +/- standard deviation). Five patients (all with complex associated malformation) died in the hospital (10%), and nine died late (22%). None of the early and one of the late deaths was associated with a thrombosed prosthesis. During follow-up, seven thrombotic (one mitral, one aortic) or thromboembolic (two mitral, three aortic) events occurred (5.7 +/- 2.1 per 100 patient-years). Of these seven events, five occurred within the last 14 months of the study. There was no relation of these events to age of patient at implantation, age at the time of even, gender, or site of implantation. Concurrently, we have followed up 340 adult patients with St. Jude Medical prostheses who had warfarin sodium (Coumadin) anticoagulation for 875 patient-years. By the end of this study, the children who did not receive anticoagulants were significantly less free of thrombotic and thromboembolic events than the adults who did receive anticoagulants (p less than 0.01).

Anticoagulants