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Biomedical subjects

O G Thilenius

Publications and source records attributed to O G Thilenius.

At least 19 recordsLinked to original sources

Alternative techniques for surgical management of recoarctation.

OBJECTIVE: To evaluate the different surgical options in patients with recoarctation and minimal collaterals. METHODS: Thirty-three cases operated on between January 1980 and January 1995 were reviewed. Initial repair was end-to-end anastomosis in 16 patients, subclavian artery aortoplasty in 10, synthetic patch aortoplasty in 4 and bypass conduit in 3 patients. Age at reoperation was 7.5 +/- 5.2 years (1-17 years). Pressure gradient was 20-48 Torr (33 +/- 9). Upper extremity resting or exercise systemic hypertension was present in all. In 18 patients recoarctation was repaired using subclavian artery aortoplasty (n = 15) or synthetic patch aortoplasty (n = 3); alone in 9, with temporary heparinized bypass in 2, or in addition to placement of ascending aorta to descending aorta conduit as a permanent bypass through a left thoracotomy in 9. In 13 patients a conduit was interposed between ascending aorta and descending aorta through a right thoracotomy. In one patient recoarctation segment was patched on cardiopulmonary bypass through a midsternotomy. RESULTS: There was no mortality or complications. All patients had no echocardiographic pressure gradients across recoarctation on 5 +/- 3.4 years follow-up. Persistent systemic hypertension following recoarctation repair was present in 3/8 patients (37%) operated on at age greater than 10 years, but has been resolved in all 25 patients less than 10 years of age (P = 0.02). CONCLUSIONS: Use of ascending aorta to descending aorta conduit, either alone through a right thoracotomy, or as permanent bypass in combination with patching the recoarctation through a left thoracotomy provides safe and excellent relief of obstruction.

Adolescent↗

AV node reentry tachycardia in infants.

The purpose of this study was to determine the frequency of atrioventricular (AV) node reentry tachycardia in infants undergoing transesophageal electrophysiological study for paroxysmal tachycardia. The records of all 52 infants < 1-year-old with structurally normal hearts who underwent transesophageal study for paroxysmal tachycardia over a 3-year period were reviewed. Those with a diagnosis of AV node reentry tachycardia underwent complete data review, and follow-up of > 12 months was obtained. Six of 52 infants had a diagnosis of the common type of AV node reentry tachycardia. Tachycardia was diagnosed at a mean age of 2.1 months (range 1 day to 10 months), and 3 of 6 underwent transesophageal study within the first month. Although no patient had structural heart disease, three patients had significant noncardiac disease. Follow-up of 15-38 months (mean 24 +/- 7.8) revealed recurrences in 2 of 6 patients. The mean tachycardia cycle length was 240 ms (range 200-310 ms), and the transesophageal ventriculoatrial intervals ranged from < 30 to 55 ms. All patients had a inducible reentrant tachycardia with a ventriculoatrial interval that remained constant even when tachycardia cycle length increased following verapamil or adenosine administration, or decreased following isoproterenol infusion. Five of 6 had evidence for discontinuous AV node conduction curves. In our patients the substrate for AV node reentry tachycardia was present early in life, and AV node reentry tachycardia can be a clinical problem even in the newborn period.

Adenosine↗

Variations in expression and treatment of transient neurocardiogenic instability.

Whereas previous reports describe the head-up tilt test for the diagnosis of neurocardiogenic syncope, this study focuses on the events leading up to syncope. These events are part of a spectrum of neurocardiogenic instability; syncope is the extreme end point. This report is based on tilt studies of 108 patients, aged 4 to 22 years (mean 13), with histories of either unexplained syncope or episodes of visual blackout without loss of consciousness. The tilt study was positive in 74% of the patients. Five stages of neurocardiogenic instability were identified, ranging from excessive fluctuations in heart rate to full syncope. Uncommon reactions during the tilt study include dissociation of hypotension, bradycardia and vagal symptoms and extended asystole (greater than 6 seconds). Therapy with beta 1-selective blockers was highly successful in suppressing symptoms of neurocardiogenic instability. Repeat tilt testing with beta blockade has resulted in either normal or markedly improved stability in heart rate and blood pressure. Neurocardiogenic instability is a common condition occurring between age 10 and 20 years. It appears to be self-limited.

Adolescent↗

Advantages of early relief of subaortic stenosis in single ventricle equivalents.

Thirteen patients with single ventricle equivalents and subaortic stenosis underwent relief of the stenosis and subsequent Fontan operation. Nine patients, group 1, had the obstruction relieved at 3.6 +/- 1.6 years of age whenever the pressure gradient became apparent. Four patients, group 2, had the subaortic stenosis operated on at the neonatal period, 10.5 +/- 10 days old, before hemodynamic evidence of obstruction. Preoperative pressure gradient across the outflow tract was 44.2 +/- 4.7 mm Hg in group 1 versus 4.7 +/- 5 mm Hg in group 2 (p = 0.002). Ventricular muscle mass was 186% +/- 18% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.0001), and mass/volume ratio was 1.12 +/- 0.62 in group 1 versus 0.62 +/- 0.16 in group 2 (p = 0.003). Relief of subaortic stenosis was achieved by proximal pulmonary artery to ascending aorta or aortic arch anastomosis and by systemic to distal pulmonary artery shunt. There was no hospital mortality or complication related to the procedure. At evaluation before Fontan operation, 4.3 +/- 1.6 years after relief of subaortic stenosis in group 1 and 3.2 +/- 0.9 years in group 2, the pressure gradient across the ventricular outflow tract was 4 +/- 3 mm Hg in group 1 versus 3 +/- 2 mm Hg in group 2 (p = not significant), ventricular muscle mass was 184% +/- 31% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.003), and the mass/volume ratio was 1.17 +/- 0.2 in group 1 versus 0.62 +/- 0.2 in group 2 (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗

Surgical options in subaortic stenosis associated with endocardial cushion defects.

Over a 15-year period, 12 patients with endocardial cushion defects undergoing correction had subaortic stenosis requiring operative intervention. Ages ranged from 4 months to 17 years (mean, 7 +/- 6 years) and subaortic gradients from 15 to 100 mm Hg (mean, 60 +/- 25 mm Hg). Subaortic stenosis was due to discrete fibromuscular tissues in 7 patients, mitral valve malattachment in 3, and tunnel outflow in 2. In 2, the subaortic stenosis was clinically significant at the time of endocardial cushion defects repair, whereas in 10 it was noted 2 to 14 years postoperatively (mean, 6.3 +/- 5 years). Surgical relief of subaortic stenosis was accomplished by resection of muscle tissues in 7, apicoaortic conduit insertion in 2, modified Konno procedure (aortic valve preserved) in 2, and lifting of malattached mitral valve from the outflow in 1. There was no early death and one late death (infected conduit). Severe mitral insufficiency developed in the patient who had the mitral valve lifted and necessitated valve replacement. Postoperative echocardiographic gradient in 9 patients ranged from 0 to 36 mm Hg (mean, 10.5 +/- 14 mm Hg). Clinically significant subaortic stenosis has not developed in any patient in 15 years of follow-up (mean, 5 +/- 4 years). We conclude that in subaortic stenosis associated with endocardial cushion defects, resection is effective for discrete obstruction, whereas a modified Konno procedure is preferable for obstruction due to tunnel outflow or mitral valve malattachment.

Aortic Valve Stenosis↗

Conal enlargement for diffuse subaortic stenosis.

Twelve patients underwent conal enlargement for diffuse subaortic stenosis over a 3 1/2-year period. The subaortic stenosis was due to tunnel outflow in 11 and malattached mitral valve in one. Mean age was 4.4 +/- 4 years and mean subaortic gradient was 50 +/- 21 mm Hg. Three infants had a malalignment ventricular septal defect. In eight patients significant obstruction occurred 2 to 7 years (mean 4 +/- 2) after simple resection of subaortic stenosis (n = 2), ventricular septal defect closure (n = 2), ventricular septal defect closure and subaortic stenosis resection (n = 2), and canal repair (n = 2). In three infants the tunnel outflow distal to a malalignment ventricular septal defect was enlarged and closed with the defect. In three patients with subaortic stenosis proximal to a previously repaired ventricular septal defect, transatrial conal enlargement through the ventricular septal defect was performed. Another patient without a ventricular septal defect had transatrial conal enlargement. The remaining five patients had the modified Konno procedure. Two patients had postoperative complete heart block and one infant had insertion of an apicoaortic conduit for aortic anulus hypoplasia 9 months later. One patient died of pneumonia during the follow-up period. Postoperative echographic outflow gradients up to 3 1/2 years (mean 1.2 +/- 1) ranged up to 25 mm Hg (mean 7 +/- 11) and were mainly at the aortic level. The 11 surviving patients are doing well up to 3 1/2 years of follow-up (mean 1.5 +/- 1). We conclude that conal enlargement procedures with aortic valve preservation are preferable, effective, and can be safely performed for diffuse subaortic stenosis in infants and children.

Aortic Valve↗

Tilt test for diagnosis of unexplained syncope in pediatric patients.

Thirty-five teenage patients with a history of presyncope or syncope underwent a passive head-up tilting to reproduce symptoms of syncope. If tilting alone did not induce syncope, isoproterenol infusion was given to increase heart rate to 150 to 160 beats per minute. In 80% of patients with a history of syncope, identical symptoms could be reproduced during tilting: an abrupt fall in blood pressure combined with profound nodal bradycardia, ranging from 32 to 86 beats per minute. These symptoms were quickly reversed by returning the patient to the supine position. For patients with frequent occurrences of syncope, especially when there was a history of trauma sustained during these episodes, a therapeutic regimen of either beta blockers or 9 alpha-fluorocortisol was begun. The mechanisms of this common cause of syncope in childhood is neurocardiogenic in response to venous pooling and catecholamine-induced tachycardia. The tilt test is an excellent and cost-effective test for the workup of unexplained syncope in childhood.

Adolescent↗

Transatrial relief of diffuse subaortic stenosis after ventricular septal defect closure.

Transatrial enlargement of the left ventricular outflow tract for serious obstruction was performed in 3 patients with previous ventricular septal defect closure. Two patients had recurrent subaortic stenosis as resection had already been performed at initial operation. In all patients, the obstruction was located below the ventricular septal defect patch. Patch enlargement of the left ventricular outflow tract was carried out by opening the ventricular septal defect patch through the tricuspid valve and extending the incision downward through the area of obstruction and the left ventricular body. All patients had uneventful postoperative course and effective relief of left ventricular outflow tract obstruction. We feel that the approach is simple and effective; it avoids a right ventriculotomy and provides a viable option in certain patients with left ventricular outflow tract obstruction.

Aorta↗

Small aortic valve annulus in children with fixed subaortic stenosis.

Twenty-one hearts with fixed subaortic stenosis (FSAS) were examined pathologically. Thirty children with no hemodynamically significant heart disease, 31 children with valvar aortic stenosis, and 25 children with FSAS were studied by echo- and angiocardiography. The following conclusions were drawn: (1) Patients with FSAS often have abnormal aortic valve leaflets as well as small aortic valve annulus. (2) A small aortic annulus/descending aorta ratio is probably present at birth, and may decrease with increasing age. (3) In some patients with FSAS the aortic valve annulus is too small for simple resection of the fibroelastic tissue. A Konno operation is needed for these patients. (4) M-mode echocardiography has not been useful in identifying abnormally small aortic valve annulus in FSAS patients.

Adolescent↗

Horizontal ventricular septum with dextroversion: hearts with and without aortic atresia.

Two hearts with horizontal ventricular septum, dextroversion (situs solitus), ventricular septal defects, and malaligned great vessels are reported. One of the hearts had aortic atresia and the infant died; the other patient had a Fontan-type physiologic correction. Reviewing the literature, the following conclusions are drawn: (a) Hearts with horizontal ventricular septum and those with criss-cross atrioventricular connections may be the result of different degrees of rotation of the ventricular muscle mass. This rotation is not likely to be postseptational but preseptational. (b) Only those hearts with a complete 180 degrees rotation should be called criss-cross hearts. (c) Partial rotation results in a horizontal septum such that the right ventricle is invariably superior, regardless of atrioventricular concordance or discordance, situs solitus or inversus, or dextroversion. (d) Physiologic surgical correction is often possible but has to be tailored to the details of each heart.

Aorta↗

Electrophysiologic abnormalities of children with ostium secundum atrial septal defect.

Sinus node (SN) and atrioventricular node (AVN) function were evaluated in 49 patients with secundum type atrial septal defect (ASD). Automaticity and conduction system function were assessed by intracardiac recording of the AH and HV intervals at rest, corrected SN recovery time, sinoatrial conduction time, AVN refractory period and the ability of the AVN to conduct rapidly paced atrial beats to the ventricles. Electrophysiologic abnormalities were found in 41% of the 34 patients who were studied before surgery. However, no preoperative abnormalities were present in children younger than 2.5 years. If only children older than 2.5 years were analyzed, the incidence of conduction abnormalities was similar for the patients studied before operation (62%) and those studied after operation (71%). The size and ejection fractions of the right and left ventricles, the magnitude of shunt flow and the size of the ASD did not differ between the patients with and those without electrophysiologic abnormalities. AVN dysfunction was present in 40% of the patients who were studied after surgical repair. While this frequency was more than twice the preoperative incidence of AVN dysfunction, it was not statistically significant. The data suggest that patient age is the major factor that influences the presence of conduction system dysfunction in patients with ASD.

Adolescent↗

Drainage of right superior vena cava into both atria. Review of the literature and description of a case presenting with polycythemia and paradoxical embolization.

An unusual cause of polycythemia, cyanosis and paradoxical embolus is described in a 37-year-old man, consisting of a rare congenital anomaly of the superior vena cava (SVC). The right-sided SVC received pulmonary venous drainage from the right lung and drained, through two channels, into both atria with the left atrium receiving the larger of the two channels. The atrial septum was intact. Corrective surgery and postoperative cardiac catheterization are described and the literature concerning anomalies of the right superior vena cava is reviewed.

Adult↗

Cardiac pathology of Marfan's syndrome. Can dissection and rupture of aortic aneurysms be prevented?

A 10-year-old boy with Marfan's disease suffered an acute dissection of an aortic aneurysm. A dacron sleeve (extending from 3 cm above the sinuses of Valsalva to just distal to the left subclavian artery) was placed around the aorta. 2 years later the child succumbed to aortic dissection and rupture distal to the sleeve. Autopsy showed (1) complete healing of the earlier dissection, and (2) lack of aneurysmal progression within the sleeve. Although the sleeve had provided effective support to the diseased aorta, it did not have sufficient length and should have been extended to include the region of the first and second intercostal arteries. The use of an extensive dacron sleeve is potentially useful as treatment prior to dissection.

Aortic Dissection↗

Endocardial cushion defect associated with cor triatriatum sinistrum or supravalve mitral ring.

Clinical and angiographic or autopsy data, or both, on three children with a subdivided left atrium (cor triatriatum) and an associated endocardial cushion defect are reviewed. (One child had ostium primum defect, and two had complete atrioventricular [A-V] canal.) A fourth patient demonstrates the difficulties in differentiating subdivided left atrium from supravalve mitral stenosis in the presence of an endocardial cushion defect. The clinical findings are greatly influenced by the endocardial cushion defect. A pressure gradient between the pulmonary wedge and (left or right) ventricular end-diastolic pressures in patients with an endocardial cushion defect indicates pulmonary venous obstruction and should alert one to the possibility of these combined lesions. The exact diagnosis is made with injections of angiographic contrast medium into the proximal and distal left atrial chambers, to documented the respective relations of the pulmonary veins, left atrial appendage and A-V valves to these atrial chambers. All three patients with an endocardial cushion defect and a subdivided left atrium had an associated patent ductus arteriosus. The common association of subdivided left atrium with intracardiac, pulmonary venous and aortic anomalies is again demonstrated.

Cardiac Catheterization↗

Cardiac function in total anomalous pulmonary venous return before and after surgery.

Cardiac performance was evaluated in 12 infants with isolated total anomalous pulmonary venous return. Four had significant pulmonary venous obstruction and severe pulmonary hypertension (group A). Eight had no obvious venous obstruction, and the pulmonary pressures were lower (group B). In all subjects, right ventricular end-diastolic volume was increased (197% of predicted normal) and its ejection fraction was normal. Left ventricular volume was, generally speaking, still in the normal range (87% of predicted normal); however, its ejection fraction was reduced (0.57 vs normal of 0.73) and left ventricular output was low (3.08 L/min/m2 vs normal of 3.98). Left atrial volume was consistently small (53% of predicted normal) with an appendage of normal size. The infants in group A had smaller chamber volumes/m2 BSA than those in group B. Left atrial function was abnormal, characterized by reduced reservoir function and a greater role as "conduit" from right atrium to left ventricle. Left atrial size was not found to be critical in the surgical repair of TAPVR. Cardiac function is restored to normal following surgery.

Angiocardiography↗

Right ventricular mass estimation by angioechocardiography.

A combined angiocardiographic-echocardiographic method for estimating right ventricular wall mass is described. Biplane cineangiocardiograms are analyzed for ventricular volume in end-diastole, and wall thickness is determined from echocardiograms obtained with a high frequency transducer and strip chart recorder, The intracavitary and the external surface volumes of the ventricle are derived, and the difference multiplied by 1.050, the specific gravity of myocardium. Excellent correlation was observed between right ventricular wall mass and body surface area in normal children (r = 0.93). The mean right ventricular mass was 44.5 g/M2 as compared to 78.1 g/M2 for the left ventricle, corresponding mass/EDV values were 0.48 g/cm3 and 1.26 g/cm3, respectively. In isolated right ventricular pressure overload, the increase in right ventricular mass is chiefly due to the increase in wall thickness; in volume overload, it is due mostly to the increase in chamber volume,

Adolescent↗