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R Van Praagh

Publications and source records attributed to R Van Praagh.

At least 37 records · Page 2Linked to original sources
PubMed1997

Causes of death after the modified Norwood procedure: a study of 122 postmortem cases.

BACKGROUND: Although the results of the modified Norwood procedure as palliation for the hypoplastic left heart syndrome have improved considerably, in-hospital mortality remains high (28% to 46%). METHODS: To establish the causes of death and consider their therapeutic applications, we reviewed our pathology experience from 1980 to 1995, inclusive, regarding 122 patients who died after undergoing the Norwood procedure. RESULTS: The most important causes of death were found to be impairment of coronary perfusion (33 patients, 27%), excessive pulmonary blood flow (23 patients, 19%), obstruction of pulmonary arterial blood flow (21 patients, 17%), neoaortic obstruction (17 patients, 14%), right ventricular failure (16 patients, 13%), bleeding (9 patients, 7%), infection (6 patients, 5%), tricuspid or common atrioventricular valve dysfunction (6 patients, 5%), sudden death from presumed arrhythmias (6 patients, 5%), and necrotizing enterocolitis (3 patients, 3%). In 26 patients (21%), more than one factor appeared responsible for death. CONCLUSIONS: The leading causes of death after the Norwood procedure were found to be largely correctable surgical technical problems associated with perfusion of the lungs (36%), of the myocardium (27%), and of the systemic organs (14%).

Aortic Diseases↗
PubMed1997

Multipolar endocardial mapping of the right heart using a basket catheter: acute and chronic animal studies.

The development of catheter-based ablative techniques for primary atrial and ventricular arrhythmias is likely to be assisted by improved techniques for systematic endocardial activation sequence mapping. RA mapping using a multielectrode basket catheter has been shown to be feasible with minimal acute toxicity in a prior study. The objectives of the current study are to investigate: (1) the utility of the basket catheter for mapping RV activation; and (2) the evolution of acute endocardial lesions produced by basket catheter use in both the RA and RV over 4-8 weeks time. A flexible, 5-spoke basket catheter bearing 25 electrode pairs was placed in the RA (n = 9) or the RV (n = 13) in 22 juvenile sheep (22-56 kg). The catheter was deployed for 0.1-4.1 hr (RA) and 0.3-3.9 hr (RV). In 20 of these 22 animals, 32 recordings were made of filtered (30-250 Hz) bipolar electrograms and surface ECG. Electrograms were timed and used to construct activation sequences based on a schematic of catheter geometry. Hearts were examined either acutely (4 RA and 9 RV studies) or 4-8 weeks after the procedure (5 RA and 4 RV studies). One animal undergoing RA placement had an air embolism resulting in cardiac arrest immediately prior to basket placement; all other animals were stable during placement. RA electrograms of sufficient quality to determine activation time were recorded from 82% of pairs in RA maps, and RV electrograms from 89% of pairs in RV maps. Mean activation sequence duration in RV was 16 ms versus 47 ms in RA (P < 0.0001), making construction of RV maps more difficult. Acute postmortem studies of RV placement revealed a silent apical RV puncture in one animal. Superficial abrasion or ecchymosis of RV endocardium and/or tricuspid valve were noted in six animals. Postmortem exams in both RA and RV chronic studies showed healed endocardial lesions, with only superficial scarring. Rapid RV activation mapping using a basket catheter is feasible, but requires precision recording techniques. Endocardial abrasions produced in lambs both by RA and RV placement of the catheter are healed in < 4-8 weeks, with trivial residua. The multielectrode basket catheter may be applicable to the mapping of tachycardias originating in or involving the right ventricle.

Animals↗
PubMed1996

Juxtaposition of the morphologically right atrial appendage in solitus and inversus atria: a study of 35 postmortem cases.

Juxtaposition of the atrial appendages has previously been classified positionally, left sided being more frequent than right sided. In our study of 35 postmortem cases, juxtaposition was analyzed morphologically for the first time. Juxtaposition of the morphologically right atrial appendage (JRAA) was always left sided with solitus atria (34 cases) but was right sided with inversus atria (1 case), the latter patient being the first documented case of JRAA with atrial inversion. Thus in patients with JRAA, the sidedness of the juxtaposition depends on the type of atrial situs that coexists. Frequent associated malformations included tricuspid valve anomalies (21 [60%] of 30), hypoplasia of the right ventricular sinus (26 [74%] of 35), and an abnormal conus (subaortic or bilateral) in 100%. Hypoplasia of the right ventricular sinus, plus malformation of the conus, appears to be important in the morphogenesis of JRAA.

Adolescent↗
PubMed1996

Juxtaposition of the morphologically left atrial appendage in solitus and inversus atria: a study of 18 postmortem cases.

Juxtaposition of the morphologically left atrial appendage (JLAA) was analyzed for the first time primarily morphologically, rather than primarily positionally. In a series of 18 postmortem cases, JLAA with solitus atria occurred in 16 (89%) cases, and JLAA with inversus atria was found in 2 (11%) cases. JLAA with solitus atria was always right-sided, whereas JLAA with inversus atria was left-sided. Thus the sidedness of the malposed (juxtaposed) LAA depended on the atrial situs, not on the type of ventricular loop (contrary to what was formerly thought). The anatomic features associated with JLAA are essentially the opposite of those with JRAA. JLAA was characterized by left atrial outlet obstruction (69%), left ventricular hypoplasia (67%), and aortic outflow tract obstruction (39%). JLAA usually has a hypoplastic left ventricle and normal conus, whereas JRAA typically has a hypoplastic right ventricle and abnormal conus.

Autopsy↗
PubMed1996

The Holmes heart: historic associations and pathologic anatomy.

In 1824, Andrew F. Holmes, later to become the first Dean of the Medical Faculty of McGill University, published the autopsy findings of a 21-year-old man who had died with chronic cyanosis and congestive heart failure. Autopsy revealed the first documented case of single ventricle. Reinspection and detailed photographs published for the first time show absence of the sinus (body or inflow tract) of the morphologically right ventricle (RV) and hence a single (unpaired) morphologically left ventricle (LV), double-inlet LV, infundibular outlet chamber (IOC), and normally related great arteries, with the pulmonary artery arising from the IOC and the aorta from the single LV. In view of its rarity, William Osler urged Maude Abbott to republish this case, which she did in 1901. Republication of the Holmes heart catalyzed the career of Maude Abbott, who then proceeded to become the world's authority on congenital heart disease until her death in 1940.

Canada↗
PubMed1995

Tetralogy of Fallot [S,D,I]: successful repair without a conduit.

Tetralogy of Fallot [S,D,I] is a recently discovered form of tetralogy with solitus atria (S) and D-loop ventricles (D), but with inverted normally related great arteries (I). Because of infundibuloarterial inversion, the right coronary artery must traverse the stenotic pulmonary outflow tract, increasing the risk of surgical trauma to the right coronary artery. Here we report a case of successful surgical repair of tetralogy of Fallot [S,D,I] without the use of an extracardiac conduit.

Cardiac Surgical Procedures↗
PubMed1995

Transposition of the great arteries [S,D,L]. Pathologic anatomy, diagnosis, and surgical management of a newly recognized complex.

The transposition of the great arteries [S,D,L] complex is delineated for the first time from the anatomic, diagnostic, and surgical standpoints in this study of 26 cases: 16 surgical and 10 postmortem. Transposition of the great arteries with situs solitus of the viscera and atria (S), D-loop ventricles (D), and L-transposition (L) was characterized by six additional interrelated anomalies that largely determined surgical management: (1) ventricular septal defect, usually conoventricular, in 96%; (2) malalignment of the conal septum, typically leftward and posteriorly, in 80%; (3) right ventricular hypoplasia in 50%; (4) pulmonary outflow tract stenosis in 27%; (5) ventricular malposition, such as superoinferior ventricles, in 23%; and (6) absent left coronary ostium resulting in "single" right coronary artery in 23%. Complete surgical repair was done in 81% of the surgical patients with a 12.5% hospital mortality rate and no late deaths. When there was no pulmonary outflow tract stenosis and intracardiac anatomy was uncomplicated, we undertook anatomic repair before 1 month of age. However, when pulmonary outflow tract stenosis coexisted, complete repair was deferred until after age 1 year, our currently preferred operation being the REV procedure (réparation a l'etage ventriculaire). When complex intracardiac anatomy precluded biventricular repair, a palliative procedure was performed in 19% without mortality. Hence, this experience indicates that surgical management of patients with the transposition of the great arteries [S,D,L] complex is feasible.

Child↗
PubMed1995

Systemic and pulmonary venous connections in visceral heterotaxy with asplenia. Diagnostic and surgical considerations based on seventy-two autopsied cases.

To facilitate the preoperative diagnosis and surgical management of visceral heterotaxy and asplenia, 72 postmortem cases were reviewed with particular attention focused on the systemic and pulmonary venous connections. The superior vena cava was bilateral in 51 cases (71%), but in 9 cases one of the superior venae cavae was partly or totally atretic. Patent bilateral superior venae cavae were found in 42 cases (58%) and the superior vena cava was unilateral in 21 (29%). Although the inferior vena cava was never interrupted, a prominent azygos vein was found in 6 cases (8%). Some hepatic veins drained separately from the inferior vena cava in 20 cases (28%). An intact coronary sinus was rare (2 cases, 3%). Anomalous pulmonary venous connection to a systemic vein was total in 42 (58%) of 72 and partial in 2 (3%) of 72, with obstruction in 24 (55%) of 44. Abnormal pulmonary artery branches (severe hypoplasia, localized stenosis, or discontinuity) were present in 21 (29%), and these obstructive arterial anomalies were associated with a significantly higher prevalence of anomalous pulmonary venous connection (p < 0.01) and of pulmonary venous obstruction (p < 0.01). Cardiac pulmonary venous connections were found in 28 (39%), with the pulmonary veins and the inferior vena cava entering the same atrium in 10 (36%) of 28.

Adolescent↗
PubMed1995

Partial or total direct pulmonary venous drainage to right atrium due to malposition of septum primum. Anatomic and echocardiographic findings and surgical treatment: a study based on 36 cases.

The clinical and anatomic findings in 36 patients (21 postmortem cases and 15 living patients) with partially anomalous (16 [44%]) or totally anomalous (20 [56%]) pulmonary venous drainage directly to the right atrium constitute the material basis of this report. Displacement of septum primum--leftward in atrial situs solitus or rightward in atrial situs inversus--was present in all and appeared responsible for the anomalous pulmonary venous drainage. The pulmonary veins were connected with what normally constitutes the posterior wall of the left atrium, which became incorporated into the right atrium because of atrial septal displacement. This abnormality occurred predominantly in patients with visceral heterotaxy, usually with polysplenia, or rarely with asplenia or a normally formed spleen. Poor development or absence of septum secundum appeared responsible for the malposition of septum primum. Echocardiographic recognition of the displacement of septum primum facilitated surgical management.

Abnormalities, Multiple↗
PubMed1994

Sinus venosus defects: unroofing of the right pulmonary veins--anatomic and echocardiographic findings and surgical treatment.

To clarify the nature of so-called sinus venosus atrial septal defects, the echocardiographic findings in 41 patients undergoing surgery at Children's Hospital, Boston, from March 1986 to October 1992 were reviewed, and four heart specimens with this anomaly were reassessed. Our conclusion, clearly demonstrated echocardiographically, is that sinus venosus defects result from a deficiency in the wall that normally separates the right pulmonary veins from the SVC and the RA. This deficiency unroofs the right pulmonary veins, permitting them to drain into the SVC or into the RA. An interatrial communication is almost always present and is posterior or posterosuperior to the fossa ovalis. This interatrial communication is the orifice of the unroofed right pulmonary veins rather than a defect in the atrial septum.

Adolescent↗
PubMed1994

Late enlargement of radiofrequency lesions in infant lambs. Implications for ablation procedures in small children.

BACKGROUND: Despite the current clinical use of radiofrequency (RF) catheter ablation in infants, the acute and late effects of RF lesion production in immature myocardium remain unknown. This study was specifically designed to investigate the pathology of RF lesions in developing sheep myocardium. METHODS AND RESULTS: In study 1, RF lesions were made on the epicardial left ventricular surface of the beating heart in 15 sheep, 5 approximately 4 weeks of age (11.0 +/- 1.0 kg) and 10 approximately 8 weeks of age (23.8 +/- 3.4 kg), to assess the effects of RF application duration (10 to 90 seconds) and electrode tip temperature (45 degrees to 90 degrees C) on lesion size in immature myocardium. Lesion width and depth increased asymptotically with RF duration, to 7.0 +/- 0.7 and 4.8 +/- 1.0 mm at 90 seconds, respectively. The time to reach one-half lesion size was 6.5 seconds for width and 12.0 seconds for depth. Lesion width increased nearly linearly with tip temperature above 50 degrees C, but depth followed a sigmoid relation, with no increase above 80 degrees C. In study 2, RF lesions were made in all four cardiac chambers under fluoroscopic guidance in 19 infant sheep (10.9 +/- 1.4 kg). Lesion sizes and histological characteristics were assessed acutely (acute, n = 5), at 1.07 +/- 0.02 months (1 month, n = 5), and at 8.5 +/- 0.5 months (late, n = 9). Atrial and ventricular lesions but not atrioventricular groove lesions apparently increased in size during the follow-up period. Atrial lesions width increased from 5.3 +/- 0.5 to 8.7 +/- 0.7 mm at 1 month (164%) but did not increase further at late follow-up, while ventricular lesion width increased from 5.9 +/- 0.8 to 10.1 +/- 0.7 mm (171%) at late follow-up but was not significantly changed at 1 month. Histological evaluation revealed replacement of normal myocytes with fibrous and elastic tissue at 1 month and late follow-up in all locations but also demonstrated a poorly delineated border with multiple extensions of fibrous and elastic tissue into surrounding normal myocardium in late ventricular lesions. CONCLUSIONS: RF lesion formation in immature sheep myocardium is similar to that in adult myocardium acutely but is associated with late lesion enlargement and fibrous tissue invasion of normal myocardium. These findings may have implications for clinical RF ablation procedures in infants.

Animals↗
PubMed1993

Conal anatomy in 119 patients with d-loop transposition of the great arteries and ventricular septal defect: an echocardiographic and pathologic study.

OBJECTIVES: We sought to study the range of conal morphology in transposition of the great arteries with ventricular septal defect and their embryologic and surgical implications. BACKGROUND: Conal anatomy in transposition of the great arteries and ventricular septal defect is variable and might affect surgical repair. METHODS: Conal anatomy was explored using two-dimensional echocardiography in 119 patients with transposition of the great arteries and a large ventricular septal defect who presented between 1984 and 1991. The influence of conal anatomy on surgical technique was determined by review of the operative reports. Specimens of transposition of the great arteries with unusual conal anatomy were selected from the Cardiac Registry for comparison with the echocardiograms. RESULTS: One hundred five patients (88.2%) had subaortic conus only with no subpulmonary conus (Group 1). Subarterial conus was present bilaterally in eight patients (6.7%) (Group 2). Four patients (3.4%) had only subpulmonary conus with no (or minimal) subaortic conus (Group 3). Among these four patients, the aorta was posterior to the pulmonary artery in one patient, side by side relative to the pulmonary artery in two patients and slightly anterior in the fourth patient. Subarterial conus was absent bilaterally in two patients (1.7%) (Group 4); the aorta was slightly posterior in one and side by side with the pulmonary artery in the other. CONCLUSIONS: This variability of conal anatomy in transposition of the great arteries with ventricular septal defect implies four mechanisms by which transposition can occur. The conal anatomy appeared to affect surgical repair in Groups 1 and 2 insofar as it influenced ventricular outflow tract obstruction. In Groups 3 and 4, an arterial switch operation was performed in four of the six patients. The posterior location of the aorta obviated the need for the Lecompte maneuver in two of these four patients. In the remaining two cases in Groups 3 and 4, the condition was repaired by directing the left ventricular outflow across the ventricular septal defect to the aorta using a patch, with or without placement of a conduit from the right ventricle to the pulmonary artery.

Abnormalities, Multiple↗
PubMed1992

Morphometry of human coronary capillaries during normal growth and the effect of age in left ventricular pressure-overload hypertrophy.

BACKGROUND: In adults, acquired pressure-overload left ventricular hypertrophy can result in myocardial ischemia, which may be due in part to insufficient capillary growth during development of hypertrophy. The coronary microvascular response to congenital pressure-overload hypertrophy in children has not been previously characterized. METHODS AND RESULTS: Average capillary density and heterogeneity of capillary spacing were measured in 63 postmortem human hearts with left ventricular hypertrophy and control hearts without heart disease. Pathology specimens were chosen that had left ventricular hypertrophy caused by 1) congenital isolated aortic valve stenosis in infants less than 1 year old at death, children 9-14 years old, and adults 15-30 years old; 2) congenital isolated coarctation of the aorta in adults 15-39 years old; and 3) acquired aortic stenosis in adults 51-86 years old. Major findings of the study were: 1) Human left ventricular capillary density and heterogeneity of capillary spacing are similar to other mammalian species. 2) Capillary density is higher in infants (3,315 +/- 85 capillaries per square millimeter), decreases with increasing heart weight during normal growth in early childhood (children, 2,388 +/- 75 capillaries per square millimeter, p less than 0.05), and thereafter remains relatively constant. 3) Capillary density with left ventricular hypertrophy is dependent on the age of onset. Congenital aortic stenosis and coarctation are characterized by an increase in capillary supply proportional to myocyte volume, maintaining capillary density similar to control hearts. Adults with acquired aortic stenosis have decreased capillary density (1,671 +/- 66 capillaries per square millimeter, p less than 0.01 versus control). CONCLUSIONS: Pressure-overload left ventricular hypertrophy in children demonstrates proportional capillary angiogenesis, whereas in adults, hypertrophy appears to be associated with failure of compensatory angiogenesis.

Adolescent↗
PubMed1992

Surgical management of late right ventricular failure after Mustard or Senning repair.

BACKGROUND: Information on surgical management and outcome in patients who develop symptomatic right ventricular failure after prior Mustard or Senning operations is limited. METHODS AND RESULTS: From March 1987 to March 1991, 10 patients 3.6-23.5 years old (median, 7.0 years) with transposition of the great arteries and prior Mustard (six patients) or Senning (four patients) repairs (performed at ages 2 months to 5 years; median, 6 months) underwent surgical intervention for symptomatic right ventricular failure. In five of 10 patients, anatomic correction with either an arterial switch operation (three patients) or a pulmonary artery-to-aorta anastomosis and right ventricle-to-pulmonary artery conduit (two patients) was performed. Before anatomic correction in these five patients, four of five patients had a pulmonary artery band to prepare the left ventricle. The interval between preparation and correction ranged from 8 days to 12 months (median, 2 months). One patient died after an arterial switch operation. In the remaining five patients, coexisting left ventricular dysfunction precluded anatomic correction; all five patients survived cardiac transplantation. Survival for the entire group of 10 patients is 90%, and the median postoperative hospital stay was 17 days. During follow-up (12-62 months; median, 27 months), there were no deaths. Neoaortic insufficiency after anatomic correction was common (mild in one patient, moderate in two patients, and severe in one patient who required aortic valve replacement 4 months after surgery). In the transplantation group, one patient developed lymphoma 3 months after transplantation but is currently in remission after reduction of immunosuppression. CONCLUSIONS: In patients who develop late right ventricular failure after Mustard or Senning repair, surgical intervention with either anatomic correction or cardiac transplantation can be done with acceptable morbidity and low mortality. Neoaortic valve insufficiency demands close follow-up after anatomic correction.

Aorta, Thoracic↗
PubMed1991

Pulmonary valve-moderator band distance and association with development of double-chambered right ventricle.

Double-chambered right ventricle (DCRV), a form of right ventricular outflow obstruction that sometimes accompanies a ventricular septal defect (VSD), is associated with superior and rightward displacement of the septal insertion of the moderator band. It was hypothesized that this superior displacement is present and identifiable by echocardiography in patients with a VSD even before right ventricular outflow tract obstruction develops. Eight patients who had a previous echocardiographic study showing a VSD alone were echocardiographically diagnosed as having DCRV. Their initial echocardiographic studies were reviewed, and superior displacement of the moderator band was quantified by measuring the distance between the pulmonary valve and moderator band, normalized to tricuspid anulus diameter. These measurements were compared with those from the initial studies of the following 3 other groups: (1) an age-matched group of 10 patients with no structural heart disease; (2) an age-matched group of 10 patients with a VSD who did not develop DCRV; and (3) a group (not age-matched) of 10 patients with VSD and DCRV in whom subpulmonary obstruction was present on the initial study. The 8 patients who eventually developed subpulmonary obstruction had significant superior displacement of the moderator band at the time of their initial echocardiogram compared with that of the 2 age-matched control groups (p less than 0.01). In contrast, there was no significant difference in moderator band displacement between these patients and the 10 with DCRV who already had right ventricular outflow obstruction at their initial study (p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗