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Biomedical subjects

R M Freedom

Publications and source records attributed to R M Freedom.

At least 55 records · Page 3Linked to original sources
PubMed1999

'You didn't see them, but now you do!': use of balloon occlusion angiography in the identification of systemic venous anomalies before and after cavopulmonary procedures.

We describe the importance of angiographic identification of collateral venous channels by balloon occlusion venography after bidirectional cavopulmonary connections. Use of the balloon occlusion technique is essential for identification of these vessels, as they can easily be missed by standard venous angiography, with possible clinical consequences for postoperative management.

Cardiac Surgical Procedures↗
PubMed1999

The Paediatric Cardiology Hall of Fame: Richard Desmond Rowe MD, MB, ChB. February 10, 1923 to January 18, 1988.

Dick Rowe (Fig.) would be embarrassed by this attention, as he was such a very modest man. Yet it is appropriate that the late Richard Desmond Rowe be included in Cardiology in the Young's Paediatric Cardiology Hall of Fame. As I consider the life and contributions of Dick Rowe, I am at first troubled, indeed saddened, by the realization that more than a decade has passed since his untimely and premature death just weeks before his planned retirement. I have his picture on the mantle of my office. Not a day goes by that I don't look at his countenance, however fleeting, reflecting on my good fortune to have worked with and considered Dick Rowe as mentor, colleague, teacher and friend. This sense of good fortune is shared by virtually all those touched by his warmth and generosity.

Cardiology↗
PubMed1999

Clinical outcomes of acute myocarditis in childhood.

OBJECTIVE: To describe clinical outcomes of a paediatric population with histologically confirmed lymphocytic myocarditis. DESIGN: A retrospective review between November 1984 and February 1998. SETTING: A major paediatric tertiary care hospital. PATIENTS: 36 patients with histologically confirmed lymphocytic myocarditis. MAIN OUTCOME MEASURES: Survival, cardiac transplantation, recovery of ventricular function, and persistence of dysrhythmias. RESULTS: Freedom from death or cardiac transplantation was 86% at one month and 79% after two years. Five deaths occurred within 72 hours of admission, and one late death at 1.9 years. Extracorporeal membrane oxygenation support was used in four patients, and three patients underwent heart replacement. 34 patients were treated with intravenous corticosteroids. In the survivor/non-cardiac transplantation group (n = 29), the median follow up was 19 months (range 1.2-131.6 months), and the median period for recovery of a left ventricular ejection fraction to > 55% was 2.8 months (range 0-28 months). The mean (SD) final left ventricular ejection and shortening fractions were 66 (9)% and 34 (8)%, respectively. Two patients had residual ventricular dysfunction. No patient required antiarrhythmic treatment. All survivors reported no cardiac symptoms or restrictions in physical activity. CONCLUSIONS: Our experience documents good outcomes in paediatric patients presenting with acute heart failure secondary to acute lymphocytic myocarditis treated with immunosuppression. Excellent survival and recovery of ventricular function, with the absence of significant arrhythmias, continued cardiac medications, or restrictions in physical activity were the normal outcomes.

Acute Disease↗
PubMed1998

Myocardial bridging in children with hypertrophic cardiomyopathy--a risk factor for sudden death.

BACKGROUND: Myocardial bridging may cause compression of a coronary artery, and it has been suggested that myocardial ischemia may result. The clinical significance and prognostic value of myocardial bridging of the left anterior descending coronary artery in children with hypertrophic cardiomyopathy are unknown. We sought to determine the prevalence and clinical effects of myocardial bridging in children with hypertrophic cardiomyopathy who underwent cardiac catheterization. METHODS: Angiograms from 36 children with hypertrophic cardiomyopathy were reviewed to determine whether myocardial bridging was present and, if so, to assess the characteristics of systolic narrowing of the left anterior descending coronary artery caused by myocardial bridging and the duration of residual diastolic compression. We also reviewed clinical data on these patients. RESULTS: Myocardial bridging was present in 10 (28 percent) of the patients. Compression of the left anterior descending coronary artery persisted for a mean (+/-SD) of 50+/-17 percent of diastole. As compared with patients without bridging, patients with bridging had a greater incidence of chest pain (60 percent vs. 19 percent, P=0.04), cardiac arrest with subsequent resuscitation (50 percent vs. 4 percent, P=0.004), and ventricular tachycardia (80 percent vs. 8 percent, P<0.001). On average, the patients with bridging had a reduction in systolic blood pressure with exercise of 17+/-27 mm Hg, as compared with an elevation of 43+/-31 mm Hg in those without bridging (P<0.001). The patients with bridging also had greater ST-segment depression with exercise (median, 5 vs. 0 mm, P=0.004) and a shorter duration of exercise (mean, 6.6+/-2.4 vs. 9.1+/-1.4 minutes, P=0.008). The degree of dispersion of the QT interval corrected for heart rate on the electrocardiogram was greater in patients with bridging than in those without bridging (104+/-46 vs. 48+/-31 msec, P=0.002). Kaplan-Meier estimates of the proportions of patients who had not died or had cardiac arrest with subsequent resuscitation five years after the diagnosis of hypertrophic cardiomyopathy were 67 percent among patients with bridging and 94 percent among those without bridging (P=0.004). CONCLUSIONS: Myocardial bridging is associated with a poor outcome in children with hypertrophic cardiomyopathy. Our observations suggest that bridging is associated with myocardial ischemia

Adolescent↗
PubMed1998

Outcome in cyanotic neonates with Ebstein's anomaly.

Clinical, angiographic, radiographic, and echocardiographic data on 46 neonates with Ebstein's anomaly presenting with cyanosis between 1954 and 1996 were reviewed to determine possible risk factors for mortality. Most patients (67%) presented at birth with 3 cases diagnosed in utero. Mean systemic oxygen saturation was 62+/-12%. An atrial septal defect > or = 4 mm was noted in 20 patients (44%). The patent right ventricle to pulmonary artery connection was present in 10 (22%), and pulmonary atresia was functional in 25 (54%) and anatomic in 11 patients (24%). Fifteen patients (35%) underwent surgical interventions. Total mortality was 70% (vs 14% in acyanotic patients diagnosed during the same time period; p <0.0001) and was related to low cardiac output and hypoxia in 20 patients (62%), postoperative complications in 8 (25%), and sudden death in 4 (13%). Kaplan-Meier survival estimates were 61% at age 1 week (95% confidence interval [CI], 47% to 75%), 48% at age 1 month (95% CI, 34% to 62%), and 36% at both 1 and 5 years of age (95% CI, 22% to 50%). Mortality improved from 81% in 1954 to 1985 to 47% in 1986 to 1996 (p = 0.04). Significant independent predictors of mortality included an atrial septal defect > or = 4 mm (odds ratio [OR] 2.39; p = 0.04), reduced left ventricular function (OR 4.10; p = 0.002), and functional or anatomic pulmonary atresia (OR 2.44, p = 0.003; and OR 5.97, p = 0.004, respectively). An echocardiographic ratio of the combined right atrial and atrialized right ventricular area to the area of the functional right ventricle and left heart >1.0 was 100% predictive of mortality.

Cyanosis↗
PubMed1998

Should we address the course as well as the origin of a translocated anomalous coronary artery?

The identification of an anomalous left coronary artery arising from the pulmonary artery demands urgent surgical attention. Myocardial infarction and ongoing myocardial ischemia are a direct consequence with subsequent left ventricular dysfunction. A modification using a combination of autogenous aortic and pulmonary artery flaps is described, which addresses both the origin and the course of the anomalous coronary artery--until now, a feature not generally considered necessary of repairs involving anomalous left coronary artery arising from the left facing pulmonary sinus.

Coronary Vessel Anomalies↗
PubMed1998

Obstructive rhabdomyoma and univentricular physiology: a rare combination.

We report the successful excision of a large left atrial rhabdomyoma producing complete obstruction of both inflow and outflow to the left ventricle. Systemic perfusion was dependent on anterograde ductual flow. The resultant univentricular physiology was initially managed medically, with spontaneous tumor regression contemplated as a means of possible long-term "cure." Failure to achieve hemodynamic stability compelled urgent surgical excision. This neonate was successfully discharged home with an in-series biventricular circulation.

Heart Neoplasms↗
PubMed1998

Truncal valve repair: initial experience in neonates.

BACKGROUND: The identification of moderate to severe preoperative truncal valve regurgitation has been synonymous with significant postoperative mortality after neonatal repair of truncus arteriosus. Spurned by the deficiencies of current truncal valve substitutes surgeons are once again reexamining the option of truncal valve reparative techniques. METHODS: From May 1996 until June 1997, 8 children underwent correction of truncus arteriosus. A retrospective analysis was conducted. RESULTS: There was one in-hospital death secondary to a postoperative massive coronary air embolism. Moderate-to-severe truncal valve regurgitation was identified clinically and confirmed with cardiac ultrasound in 3 neonates with a mean age of 7 days (range, 4 to 12 days) all with quadracusp truncal valves. Successful truncal valve repair was accomplished in 2 infants, with a third neonate requiring homograft replacement with coronary reimplantation for failure in achieving valvular competence after attempted valvuloplasty. Postoperative echocardiograms in those neonates who underwent truncal valve repair confirmed a functional "tricuspid" valve with only mild to mild-plus regurgitation. CONCLUSIONS: We give further credence to the hypothesis that primary neonatal truncal valve repair is feasible and may be successful in the avoidance and delay of serial truncal valve replacements using either mechanical or allograft substitutes.

Aortic Valve↗
PubMed1998

Cardiac rhabdomyomas and obstructive left heart disease: histologically but not functionally benign.

BACKGROUND: Cardiac rhabdomyoma is the most common primary heart tumor in infants. Spontaneous regression of such tumors is common, particularly with smaller lesions, followed by resolution of symptoms. Based on our data on spontaneous involution, our institutional philosophy has been one of expectant management in the absence of life-threatening symptoms. However, surgical intervention sometimes is required for the extirpation of a rhabdomyoma from the left ventricular outflow tract. METHODS: A retrospective review was conducted of 30 children in whom a rhabdomyoma was diagnosed over a 27-year period. RESULTS: Twenty-three percent (7/30) of the children required surgical extirpation of the tumor from within their left ventricular outflow tract, although a total of 94% had left ventricular involvement. There were no deaths. To date, no child has required reexcision of tumor. CONCLUSIONS: The natural history of rhabdomyoma is one of spontaneous regression (the 23 children who did not undergo surgical intervention are alive and continue to be followed up medically). We recommend surgical excision to alleviate acute outflow tract obstruction with reliance on the tumor's natural history of regression to achieve long-term freedom from reoperation. Although operation has been recognized as lifesaving, we were somewhat surprised to find that greater than 20% of our pediatric population required operative intervention.

Female↗
PubMed1998

Total cavopulmonary anastomosis (Fontan) in children with Down's syndrome.

BACKGROUND: There is a paucity of information to guide the management of the child with Down's syndrome and congenital heart disease in whom biventricular repair is precluded. METHODS: Through the cardiology and cardiovascular surgery databases of The Hospital for Sick Children and Toronto Congenital Cardiac Centre for Adults, we identified patients with trisomy 21 and ventricular hypoplasia who had undergone a Fontan procedure (or modification). RESULTS: Of 533 patients who had undergone a Fontan operation between 1976 and 1997, 4 had trisomy 21. All 4 patients had unbalanced complete atrioventricular septal defect with right ventricular hypoplasia in 3 and left ventricular hypoplasia in 1. Three patients survived, and 1 died of endocarditis. The 3 survivors have done well in the short term and medium term without complications related to the pulmonary vasculature. CONCLUSIONS: We suggest that in appropriately selected patients with trisomy 21 and ventricular hypoplasia who are unsuitable for two or one and a half ventricle repair, the Fontan procedure is not contraindicated and provides short-term and medium-term benefit.

Down Syndrome↗
PubMed1998

A practical approach to 1 1/2 ventricle repairs.

BACKGROUND: Perioperative and long-term problems associated with the Fontan circulation are substantial. There has been an exploration of extending the limits of a biventricular ventricular repair by using a superior vena cava-to-pulmonary artery anastomosis. This type of repair is known as a 1 1/2 ventricle repair. METHODS: Patients having defects of the pulmonary ventricle in size or function have undergone 1 1/2 ventricle repairs with or without creation of an atrial septal defect. Repairs with tricuspid z values as small as -10 and predicted pulmonary ventricular volumes as low as 30% have been reported. The 1 1/2 ventricle repair technique has also been used in special situations associated with an arterial switch or double switch procedure. RESULTS: Mortality has ranged from 0% to 12%. Complications have included persistent elevation of superior vena cava pressure, intermittent periorbital edema, and 1 superior vena caval aneurysm requiring takedown. There appears to be an increased risk of perioperative pleural effusions and chylothorax. Protein-losing enteropathy and chronic atrial arrhythmias have not been present. CONCLUSIONS: Successful 1 1/2 ventricle repairs have been reported for morphologically small or poorly functioning pulmonary ventricles and special situations. Intermediate-term follow-up is favorable when compared with reported outcomes for the Fontan circulation.

Anastomosis, Surgical↗
PubMed1998

Primum atrial septal defect in children: early results, risk factors, and freedom from reoperation.

BACKGROUND: Repair of primum atrial septal defect in children usually is associated with a low operative mortality, except for a subgroup of children with congestive heart failure. To determine the early mortality and incidence of reoperation in children with primum atrial septal defect, we analyzed retrospectively the results of patients who underwent repair of this defect. METHODS: Between July 1982 and December 1996, 180 children underwent repair of primum atrial septal defect. The mean age at repair was 4.6 years (median, 3.6 years; range, 1 month to 16.4 years); of the 180 children, 23 were infants less than 1 year of age. Absent or mild symptoms were present in 145 (80%), whereas 34 (20%) of children presented with severe symptoms or congestive heart failure. RESULTS: Early mortality occurred in 3 (1.6%); 2 were less than 1 year of age. Follow-up ranged from 2 months to 14.5 years (mean, 6 +/- 4.2 years). Actuarial survival is 98% at 10 years with no late deaths. Age less than 1 year is a predictor of death. During follow-up, 17 (9%) of the 180 patients underwent reoperation, 5 of whom were in the infant group. Five underwent reoperation for subaortic obstruction, and 12 for left atrioventricular valve regurgitation of whom 11 were repaired; and 1 required valve replacement. Age and preoperative moderate-to-severe left atrioventricular valve regurgitation were predictors of reoperation. CONCLUSIONS: Results of the repair of primum atrial septal defect during childhood are favorable. Infants have a higher risk for death and reoperation. Left atrioventricular valve insufficiency and subaortic stenosis are important late complications and can be repaired safely at reoperation.

Adolescent↗
PubMed1998

Total anomalous pulmonary venous connections and consideration of the Fontan or one-ventricle repair.

There is now a considerable literature that babies with right atrial isomerism have a poor outcome. The reasons for this are complex and multifactorial, but may be related at least in part to intrinsically small and abnormal pulmonary veins. We reviewed a series of consecutive patients seen at a single institution and found that babies with right atrial isomerism, severe pulmonary outflow tract obstruction or atresia, and total anomalous obstructed pulmonary veins had a grim outlook, especially those requiring operation in the neonatal period. Others have reported a similarly concerning outcome.

Fontan Procedure↗
PubMed1998

The physiology of the bidirectional cavopulmonary connection.

This article reviews the indications for the bidirectional cavopulmonary connection and demonstrates its efficacy in reducing mortality for the Fontan procedure. The indications for adding an additional source of pulmonary blood flow to the bidirectional cavopulmonary connection are discussed, but this issue remains controversial. Also unclear is whether the bidirectional cavopulmonary connection promotes symmetric growth of the pulmonary arteries, or whether growth of the left pulmonary artery is disadvantaged. Finally, systemic venous collateralization is a well-recognized sequel after cavopulmonary connection. The clinical implications of this collateralization are reviewed.

Anastomosis, Surgical↗
PubMed1998

Subaortic obstruction and the Fontan operation.

Systemic outflow tract obstruction in the heart with a functional single ventricle promotes myocardial hypertrophy, and this has been shown to be an unequivocal risk factor for poor outcome at Fontan procedure. Such systemic outflow tract obstruction may be congenital or acquired. Those factors contributing to acquired systemic outflow tract obstruction in those patients with a double-inlet left ventricle, a rudimentary right ventricle, and a discordant ventriculoarterial connection include the size of the ventricular septal defect, previous pulmonary artery banding, and other volume unloading surgical procedures. Staging with a bidirectional cavopulmonary connection and construction of a proximal pulmonary artery-aortic connection or ventricular septal defect enlargement has neutralized this factor.

Fontan Procedure↗