Progressive obstruction of the foramen ovale in patients with left atrioventricular valve atresia.

Thirteen patients with left atrioventricular (AV) valve atresia and a normal aortic root were studied to evaluate the status of the interatrial communication with advancing age. Six patients had cardiac catheterization within the first 2 weeks of age; of these, five had repeat studies before 7 months of age. The seven other patients initially underwent catheterization after 2 weeks of age. In the group with catheterization before 2 weeks of age, the mean left atrial pressure was 7.8 +/- 5.5 mm Hg and the left atrial-right atrial mean pressure gradient was 1.7 +/- 2.4 mm Hg. In the combined group of patients with catheterization after 2 weeks of age, the mean left atrial pressure was 25.9 +/- 5.6 mm Hg and the mean left atrial-right atrial pressure gradient was 21.1 +/- 5.1 mm Hg. Seven of the 13 patients have survived and have now reached a median age of 6.5 years. Balloon atrial septostomy was adequate for long-term survival in one patient; all of the others have required surgical atrial septectomy. Progressive obstruction of the foramen ovale is part of the natural history of left AV valve atresia, and obstruction develops despite the absence of a left atrial-right atrial gradient during newborn study. Balloon atrial septostomy is recommended during the neonatal period in all patients with left AV valve atresia, even in the absence of an interatrial gradient. Because early surgical atrial septectomy is usually necessary for long-term survival, these patients should have serial noninvasive evaluation of the patency of the interatrial communication.

Arrhythmias after the Mustard operation for transposition of the great arteries: a long-term study.

This study presents follow-up data on 95 patients with transposition of the great arteries who underwent a Mustard intraatrial baffle operation. The patients were followed up serially by means of scalar electrocardiograms and 24 hour Holter monitoring studies. The latter study was effective in documenting abnormal rhythm patterns when the standard electrocardiogram was within normal limits. Twenty percent of the patients had atrial arrhythmias at the time of hospital discharge. new rhythm disturbances were recognized during each year of follow-up; 75% of the patients had atrial rhythm disorders by the sixth year. Slow junctional rhythm was the most common rhythm disturbance found. Complete heart block did not occur. Supraventricular tachycardia occurred within the context of the tachycardia/bradycardia syndrome in 8 of 10 patients, and in all it was documented after hospital discharge. The incidence of sudden death in this series was 3%. Six of the patients have had pacemaker insertions and there have been no deaths among these individuals. It was observed that the slow atrial or junctional rhythms that appeared after intraatrial correction of transposition of the great arteries rarely progressed to life-threatening rhythm disorders in childhood or adolescence, but the prognosis in adult life remains unknown. The three deaths in the series occurred in patients with a history of supraventricular tachyarrhythmias. Elimination of arrhythmias caused by extensive intraatrial surgery is one of the potential advantages of the arterial switch operation for correction of transposition of the great arteries.

"Acquired" discrete subvalvular aortic stenosis: natural history and hemodynamics.

Discrete subvalvular aortic stenosis is a progressive lesion. Most reported cases have had a measurable left ventricular-aortic gradient that progressed in severity. This report describes 35 patients in whom no significant left ventricular-aortic obstruction was noted at initial cardiac catheterization, but who later were shown to have significant subvalvular aortic stenosis. In 24 of the 35 cases, absence of a significant left ventricular-aortic gradient (less than or equal to 10 mm Hg) was documented at initial cardiac catheterization. In 11 patients, a left ventricular-aortic pressure gradient was not obtained or not sought in the absence of clinical evidence of an obstructive lesion. In each case, discrete subaortic stenosis was not noted on angiography. Associated lesions included ventricular septal defect in 7, patent ductus arteriosus in 12, coarctation of the aorta in 8, pulmonary stenosis in 3, atrioventricular canal in 2 and miscellaneous lesions in 3 cases. The 35 patients had documentation of subvalvular aortic stenosis 3 months to 19 years after their initial study based on repeat catheterizations in 26, echocardiography in 6 or discovery at surgery in 3 cases. There were eight children with coarctation and no left ventricular-aortic gradient who developed significant subvalvular stenosis at a median of 2 years 9 months after initial cardiac catheterization. Of 30 patients with associated lesions, 23 had surgical intervention before development of subvalvular aortic stenosis, but only 5 of 17 patients with ventricular septal defect had surgical repair or palliation specifically for the interventricular communication before development of subvalvular aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute pulmonary embolism in pediatric patients awaiting heart transplantation.

Acute pulmonary embolism with infarction can delay urgently needed heart transplantation and increase the postoperative pulmonary complications. Few data are available concerning pulmonary embolization in the pediatric patient with end-stage congestive heart failure. Sixty-two consecutive pediatric patients awaiting heart transplantation were monitored for evidence of acute pulmonary embolism. Acute pulmonary infarction was documented by ventilation-perfusion scan, pulmonary angiography or pathologic examination in six patients. The prevalence differed by diagnosis; 5 of 36 patients with dilated cardiomyopathy and 1 of 20 patients with congenital heart disease developed acute pulmonary embolism with infarction. No significant difference in age at the time of transplantation evaluation, duration of congestive heart failure, presence of cardiac arrhythmias or degree of cardiac dysfunction was seen between patients with and without pulmonary embolism. Two-dimensional echocardiography failed to detect the presence of an intracardiac thrombus in four of the six patients. Two patients who developed acute pulmonary infarction are alive after successful heart transplantation. The remaining four patients died within 6 weeks of initiation of anticoagulant therapy before transplantation could safely be performed. In summary, pediatric patients with end-stage congestive heart failure are at risk for acute pulmonary embolism. No specific clinical factor identified those patients who developed acute pulmonary infarction. Anticoagulant therapy is strongly recommended in the pediatric patient with poor ventricular function awaiting heart transplantation.

Hypoplastic left heart syndrome: report of a unique survivor.

A remarkable patient is described, a child who has survived until the age of 7 years with hypoplastic left heart syndrome (mitral and aortic atresia) without surgical intervention. The child has led an active, normal life and, aside from minimal cyanosis, has remained asymptomatic. The unique clinical course for this patient is the result of a number of favorable hemodynamic factors that have not been previously reported in an individual patient with hypoplastic left heart syndrome and intact ventricular septum widely patent ductus arteriosus, adequate retrograde coronary flow, unrestricted pulmonary venous return, and absence of significant vascular obstructive disease. This documentation of long-term survival in a child without surgical treatment for mitral and aortic atresia suggests that successful early palliative treatment for infants with this syndrome could also result in a favorable prognosis.

Surgical management of the infant with coarctation of the aorta and ventricular septal defect.

Clinical and cardiac catheterization data were collected from 39 infants with coarctation of the aorta and ventricular septal defect, 31 of whom were initially managed only by surgical repair of coarctation. Data were analyzed to determine mortality, morbidity, outcome and factors that might predict survival or the need for septal defect closure. Of the eight patients who did not require surgical treatment before 3 months of age, seven underwent coarctation repair alone at a mean age of 2.3 years. Of the 23 infants managed with coarctation repair alone, before age 3 months, 9 needed no additional surgical treatment and 6 required early and 8 required late repair of the ventricular septal defect. Seven infants underwent coarctation repair and simultaneous pulmonary artery banding and one eventually required debanding after spontaneous closure of the septal defect. The overall mortality rate in this series was 10.3% (mean follow-up time 5.7 years). Of 39 infants, 16 (41%) never required a second operation for ventricular septal defect closure. For patients who had only coarctation or coarctation repair with pulmonary artery banding at less than 3 months of age, ventricular septal defect size was categorized as small (less than 0.5 cm/m2), moderate (less than 1 cm/m2) or large (greater than 1 cm/m2) on the basis of defect size at operative repair or echocardiographic or angiographic assessment. Defect size did not necessarily correlate with the need for operative repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic correlates of exercise function in patients with primary pulmonary hypertension.

The purpose of this investigation was to study the hemodynamic correlates of exercise function in patients with primary pulmonary hypertension and to further define the role of exercise testing in the evaluation of these individuals. Data from the progressive exercise tests and subsequent cardiac catheterization in 16 consecutive patients, aged 16.9 +/- 10.4 years (range 6 to 35), with primary pulmonary hypertension were prospectively collected and analyzed. Exercise capacity averaged 40 +/- 36% (range 0 to 117%) of that predicted for age, height and gender. Statistically significant correlations existed between exercise capacity and 10 invasively measured hemodynamic variables. Mean right atrial pressure, a variable previously noted to be one of the best predictors of survival in patients with primary pulmonary hypertension, correlated best with exercise capacity (r = -0.83, p less than 0.0001). Exercise capacity greater than 75% of the predicted value identified the two patients who had a positive response to acute pulmonary vasodilator drug testing. Poor exercise capacity (less than 10% of the predicted value) identified the three patients who died during or soon after cardiac catheterization. The ability of exercise testing to identify patients at high risk for cardiac catheterization was superior to that of other noninvasive variables. Results of exercise testing may help guide decisions regarding the optimal timing of heart-lung or single lung transplantation.

Spontaneous complete closure of a congenital coronary artery fistula.

The first documentation is reported of spontaneous closure of a coronary artery to right ventricle fistula that was demonstrated initially in a 14 month old boy. Over a 4 year period after diagnosis, the characteristic continuous murmur gradually disappeared. When the patient was 5 1/2 years of age, selective coronary arteriography showed normal coronary vessels and circulation. Six other cases of coronary fistula observed during the past 10 years are also reviewed. This study supports the rationale for clinical follow-up rather than obligatory surgical intervention in asymptomatic patients with a small shunt who have no evidence of myocardial dysfunction.

Heart transplantation in children with congenital heart disease.

OBJECTIVES: The aim of this study was to describe heart transplantation in children with congenital heart disease and to compare the results with those in children undergoing transplantation for other cardiac diseases. BACKGROUND: Reports describe decreased survival after heart transplantation in children with congenital heart disease compared with those with cardiomyopathy. However, transplantation is increasingly being considered in the surgical management of children with complex congenital heart disease. Present-day results from this group require reassessment. METHODS: The diagnoses, previous operations and indications for transplantation were characterized in children with congenital heart disease. Pretransplant course, graft ischemia time, post-transplant survival and outcome (rejection frequency, infection rate, length of hospital stay) were compared with those in children undergoing transplantation for other reasons (n = 47). RESULTS: Thirty-seven children (mean [+/- SD] age 9 +/- 6 years) with congenital heart disease underwent transplantation; 86% had undergone one or more previous operations. Repair of extracardiac defects at transplantation was necessary in 23 patients. Causes of death after transplantation were donor failure in two patients, surgical bleeding in two, pulmonary hemorrhage in one, infection in four, rejection in three and graft atherosclerosis in one. No difference in 1- and 5-year survival rates (70% vs. 77% and 64% vs. 65%, respectively), rejection frequency or length of hospital stay was seen between children with and without congenital heart disease. Cardiopulmonary bypass and donor ischemia time were significantly longer in patients with congenital heart disease. Serious infections were more common in children with than without congenital heart disease (13 of 37 vs. 6 of 47, respectively, p = 0.01). CONCLUSIONS: Despite the more complex cardiac surgery required at implantation and longer donor ischemic time, heart transplantation can be performed in children with complex congenital heart disease with success similar to that in patients with other cardiac diseases.

Imaging of cardiac allograft rejection in dogs using indium-111 monoclonal antimyosin Fab.

The acute rejection of cardiac allografts is currently diagnosed by the presence of myocyte necrosis on endomyocardial biopsy. We evaluated the efficacy of noninvasive scintigraphic imaging with indium-111-labeled anticardiac myosin Fab fragments (indium-111 antimyosin) to detect and quantify cardiac allograft rejection. Six dogs that had intrathoracic heterotopic cardiac allograft transplantation were injected with indium-111 antimyosin and planar and single photon emission computed tomographic (SPECT) images were obtained in various stages of acute and subacute rejection. Four dogs had an allograft older than 8 months and had been on long-term immunosuppressive therapy; two dogs had an allograft less than 2 weeks old and were not on immunosuppressive therapy. Count ratios comparing heterotopic with native hearts were calculated from both SPECT images and in vitro scans of excised and sectioned hearts and were compared with the degree of rejection scored by an independent histopathologic review. Indium-111 antimyosin uptake was not visible in planar or SPECT images of native hearts. Faint diffuse uptake was apparent in cardiac allografts during long-term immunosuppression and intense radioactivity was present in hearts with electrocardiographic evidence of rejection. The heterotopic to native heart count ratios in SPECT images correlated significantly with the count ratios in the excised hearts (r = 0.93) and with the histopathologic rejection score (r = 0.97). The distribution of indium-111 antimyosin activity in right and left ventricles corresponded to areas of histopathologic abnormalities. Immunoperoxidase studies showed deposition of indium-111 antimyosin only in areas of myocyte necrosis. The results demonstrate that indium-111 antimyosin imaging can noninvasively detect the presence, location and severity of canine cardiac allograft rejection.

Long-term outcome in congenitally corrected transposition of the great arteries: a multi-institutional study.

OBJECTIVES: The purpose of this study was to determine long-term outcome in adults with congenitally corrected transposition of the great arteries (CCTGA), with particular emphasis on systemic ventricular dysfunction and congestive heart failure (CHF). BACKGROUND: Patients with CCTGA have the anatomical right ventricle as their systemic pumping chamber, with ventricular dysfunction and CHF being relatively common in older adults. METHODS: Retrospective analysis of records of 182 patients from 19 institutions were reviewed to determine current status and possible risk factors for systemic ventricular dysfunction and CHF. Factors considered included age, gender, associated cardiac defects, operative history, heart block, arrhythmias and tricuspid (i.e., systemic atrioventricular) regurgitation (TR). RESULTS: Both CHF and systemic ventricular dysfunction were common in groups with or without associated cardiac lesions. By age 45, 67% of patients with associated lesions had CHF, and 25% of patients without associated lesions had this complication. The rates of systemic ventricular dysfunction and CHF were higher with increasing age, the presence of significant associated cardiac lesions, history of arrhythmia, pacemaker implantation, prior surgery of any type, and particularly with tricuspid valvuloplasty or replacement. Aortic regurgitation (a previously unreported problem) was also relatively common in this patient population. CONCLUSIONS: Patients with CCTGA are increasingly subject to CHF with advancing age; this complication is extremely common by the fourth and fifth decades. Tricuspid (systemic atrioventricular) valvular regurgitation is strongly associated with RV (anatomical right ventricle connected to aorta in CCTGA patients; systemic ventricle in CCTGA) dysfunction and CHF; whether it is causative or a secondary complication remains speculative.

Greater dietary intake of simple carbohydrate is associated with lower concentrations of high-density-lipoprotein cholesterol in hypercholesterolemic children.

Hypercholesterolemic children are increasingly being treated with lipid-lowering diets, but little research has focused on the effects of specific dietary substitutions on HDL cholesterol. We examined the relation between carbohydrate intake and HDL cholesterol in hypercholesterolemic children consuming fat-restricted diets. We obtained 3-d food records for 67 children (mean age: 5.8 +/- 2.5 y) referred for the treatment of hypercholesterolemia. Mean plasma HDL cholesterol was 1.12 +/- 0.21 mmol/L and total cholesterol was 5.99 +/- 1.39 mmol/L. Dietary intake comprised (percentage of total energy) 24.9 +/- 5.1% fat, 59.9 +/- 6.5% carbohydrate, and 16.5 +/- 3.4% protein. Carbohydrate intake included 30.7 +/- 7.4% from simple and 22.6 +/- 6.2% from complex carbohydrates. HDL cholesterol was positively correlated with intake of total fat (r = 0.44, P < 0.001) and saturated fatty acids (r = 0.43, P < 0.001) and inversely correlated with intake of total carbohydrate (r = -0.55, P < 0.001) and simple carbohydrate (r = -0.40, P < 0.001), but not with complex carbohydrate (r = -0.02). The significant inverse relation between simple carbohydrate intake and HDL cholesterol remained after intakes of saturated, monounsaturated, and polyunsaturated fatty acids; intake of complex carbohydrates; dietary cholesterol; plasma triacylglycerol; and age were adjusted for with multivariate techniques. In summary, higher dietary intake of simple carbohydrates was associated with lower HDL-cholesterol concentrations in hypercholesterolemic children consuming reduced-fat diets.

Coarctation of the aorta: a study in delayed detection.

The findings and presentations of 65 consecutive patients in whom uncomplicated coarctation of the aorta was diagnosed after 1 year of age were reviewed. Significant delays in diagnosis occurred in the great majority of patients. The median age at diagnosis was 10 years (range 1 to 36 years). Pediatricians made 75% of the referrals. However, the diagnosis of coarctation of the aorta was made before referral in only 14% of these cases. The remaining referrals were made after the incidental notation of hypertension or a heart murmur out of the context of routine medial care (eg, emergency room, school nurses, working paper and insurance physicals, pregnancy, etc). Cardiac murmurs (median age at diagnosis 6 years) and hypertension (median age at diagnosis 18 years) accounted for referrals in whom the condition was not diagnosed. Prompt referral to a cardiologist after the detection of an abnormal finding did not always occur. Additional delays in referral occurred in 29 patients. All of the patients had cardiac murmurs and differential blood pressure between upper and lower extremities. Elevated systolic blood pressure in the upper extremities was found in 89%; femoral pulses were absent in 40%; and pedal pulses were absent in 77%. It is concluded that coarctation of the aorta is a diagnosis that is often overlooked despite specific physical findings. The importance of upper and lower extremity blood pressure determination as part of an initial routine physical examination is emphasized. The impact of delayed diagnosis has yet to be fully defined, but may well be significant in terms of cardiovascular sequelae of prolonged hypertension.

Early diagnosis of coarctation of the aorta in children: a continuing dilemma.

UNLABELLED: Because late repair of coarctation of the aorta (COA) is associated with premature cardiovascular disease in adult life, early detection and treatment is important. OBJECTIVES: To determine the timing of referral to see whether early detection of COA has improved in the past decade, to evaluate the pattern of and reasons for medical center referral, and to assess the clinical signs relating to the diagnosis of COA. METHODS: The records of 50 consecutive patients older than 1 year who had surgical repair of COA from 1980 to 1990 were reviewed. The age of referral, pattern of referral, and presence of standard clinical signs of COA were analyzed, and data were compared with those from the previous decade. RESULTS: The mean and median ages at referral were 8.4 and 5.8 years, respectively. Pediatricians accounted for 64% of the referrals. A specific diagnosis of COA was made in 2 (4%) of 50 patients before referral to a pediatric cardiologist. The most consistent clinical findings were a cardiac murmur and a systolic blood pressure gradient between the arms and legs of greater than 10 mm Hg, which were both present in all patients. Lower-extremity pulses were decreased in 37 (74%) and absent in 9 (18%). Forty-seven children (94%) had upper-extremity hypertension (> 95th percentile for age); 25 (50%) had systolic blood pressure higher than 140 mm Hg. COA would have been missed in 82% of children if absent lower-extremity pulses were required as a diagnostic feature. These findings were similar to those reported by our institution in the previous decade, suggesting that early detection has not improved. CONCLUSIONS: The timing of, reasons for, and sources of referral for COA in this study, compared with data from the previous decade, indicate no improvement in early detection of COA by pediatricians. Screening all children for COA by routinely measuring upper- and lower-extremity blood pressures during at least one physical examination after the newborn period is mandatory.

Predicting coronary aneurysms in Kawasaki disease.

Intravenous immunoglobulin is used to prevent coronary artery involvement in patients with acute Kawasaki disease. In this issue of the journal, Beiser et al provide a scoring system that is invoked 24 hours after gamma globulin therapy to predict risk for coronary involvement. This instrument would be useful for pediatric cardiologists and pediatricians in planning later management of patients with Kawasaki disease and counseling parents regarding long-term outcome.

Progressive atrioventricular valvular regurgitation in single ventricle.

The hemodynamic status of the patient with single ventricle is not static. This study describes the rapid development of mechanical malfunction of the atrioventricular (AV) valve in a subset of patients with single ventricle. Eighty patients with single ventricle were reviewed. Eight patients with single ventricle and single AV valve were observed to have moderate to severe AV valvular regurgitation. Patient age when AV regurgitation was first detected was 22 months to 35 years (median 15 years). Clinically, all patients were symptomatic and had severe congestive heart failure. All patients underwent cardiac catheterization, which revealed moderate to severe AV regurgitation; 7 of 8 patients had well preserved ventricular function. Earlier catheterization revealed no significant AV regurgitation. Four patients underwent surgery: 2 had AV valve replacement with the Fontan procedure and 2 had Carpentier ring placement (1 with the Fontan procedure). The 3 survivors were in improved clinical condition. At surgery 1 patient had an abnormal AV valve with 4 leaflets, and the other 3 had myxomatous degeneration of the AV valve. Thus, AV regurgitation is a significant and specific complication that occurs in patients with single ventricle and single AV valve. If recognized before development of eventual myocardial dysfunction, surgical management should be considered.

Cardiovascular adaptations to transfusion/chelation therapy of homozygote sickle cell anemia.

The effect of transfusion/chelation therapy on the cardiovascular adaptations to chronic anemia in pediatric and young adult patients with homozygous sickle cell disease is uncertain. This study compares left ventricular (LV) function indexes and thoracoabdominal aortic systolic and diastolic blood flow in nontransfused and transfused patients with homozygous sickle cell disease. The study population consisted of 29 nontransfused patients with homozygous sickle cell disease, ages 0.4 to 20.9 years (group 1) and 11 chronically transfused/chelated patients, ages 4.0 to 21.8 years (group 2). The mean total hemoglobin concentration in group 2 was 28% greater than that in group 1. The mean duration of transfusion/chelation therapy in group 2 was 3.7 years. The percent of predicted LV end-diastolic and end-systolic dimensions were significantly greater than the respective controls in both groups. There was no significant difference in percent of predicted LV end-diastolic dimension (group 1, 120 +/- 12%; group 2, 120 +/- 12%) or percent of predicted LV end-systolic dimension (group 1, 120 +/- 12%; group 2, 117 +/- 8) between the groups. The percent of LV shortening fraction was similar in study groups and control subjects. Aortic systolic blood flow (cc/min/m2) for group 1 (2,426 +/- 841) and 2 (2,374 +/- 1.004) were significantly greater than corresponding control values (1,683 +/- 442, 1,736 +/- 430, respectively). Aortic diastolic blood flow was significantly greater than corresponding control values for both group 1 (699 +/- 313 vs 488 +/- 212) and group 2 (1,080 +/- 607 vs 588 +/- 219).(ABSTRACT TRUNCATED AT 250 WORDS)

Survival and risk factor analysis for the Norwood procedure for hypoplastic left heart syndrome.

The optimal approach to hypoplastic left heart syndrome (HLHS) is controversial. The palliative Norwood operation, cardiac transplantation, and no surgical intervention have all been advocated. Centers that perform the Norwood operation have met with varied results, and conflicting reports exist regarding factors predictive of stage I outcome. From January 1990 to January 1996, 67 patients with HLHS were admitted with intent to perform the staged Norwood procedure. Fourteen patients did not undergo surgery. In the 53 patients treated surgically, outcome was reviewed, and 10 potential risk factors for first stage mortality were analyzed. Forty-one infants survived the Norwood I operation to hospital discharge (77% of the surgically treated patients and 61% of the entire group, including those who did not undergo operation) with 6 additional deaths 3 to 5 months after operation. Univariate analysis showed cardiopulmonary bypass time and circulatory arrest time to be significant risk factors for hospital mortality. Multivariate analysis revealed only cardiopulmonary bypass time as significant (p <0.01). Of the 15 prenatally diagnosed newborns who underwent surgery, 11 survived (p = 0.72). Ten of 11 patients with preoperative organ damage survived (p = 0.42). Among the 35 bidirectional Glenn (Norwood II) and Fontan (Norwood III) procedures performed, there were 2 deaths. The 5-year actuarial survival for patients who underwent operations was 61%. The Norwood procedure is a favorable option for the infant with HLHS. Surgical survival may be affected by a prolonged cardiopulmonary bypass time, but is not affected by other factors analyzed, including prenatal diagnosis and preoperative organ damage.

Two-dimensional echocardiographic assessment of right ventricular function as a predictor of outcome in hypoplastic left heart syndrome.

This study was undertaken to assess the importance of right ventricular function at the time of initial presentation on early and intermediate outcome in patients with hypoplastic left heart syndrome (HLHS). Several studies have attempted to define physiologic risk factors for poor early outcome following the Norwood palliation for HLHS. No clinical or hemodynamic factors including right ventricular function have been found to reliably predict Norwood I operative survival. The relation between initial ventricular function and later survival has not been investigated. To assess the importance of right ventricular (RV) function at the time of initial presentation on outcome in patients with HLHS, systolic function was determined by qualitative and quantitative methods in 60 consecutive patients before surgical intervention. The effects on stage I operative survival, survival to stage II, and overall survival were analyzed. Initial RV function did not impact on stage I survival. However, analysis of later outcome of the stage I survivors showed that those with prestage I RV dysfunction had significantly greater mortality before stage II. Actuarial survival 18 months after Norwood surgery was 93% for patients with initially normal RV function compared with 47% for those with abnormal function (p = <0.005). The relative risk for later mortality was approximately 11 times greater for patients with initial RV dysfunction. Thus, RV dysfunction identifiable soon after initial presentation does not impact on early survival after Norwood I operation for HLHS. Intermediate and overall survival, however, is significantly decreased in patients with initially diminished RV function.

Synergy of amlodipine and angiotensin-converting enzyme inhibitors in regulating myocardial oxygen consumption in normal canine and failing human hearts.

The production of endogenous nitric oxide, which regulates myocardial oxygen consumption, is decreased in heart failure. As with angiotensin-converting enzyme (ACE) inhibitors, amlodipine, a calcium antagonist, increases kinin-mediated nitric oxide production in coronary microvessels. We investigated the possibility of synergy between ACE inhibitors and amlodipine in regulating myocardial oxygen consumption. Left ventricular myocardium was isolated from 6 healthy dog hearts and 5 human hearts with end-stage heart failure at the time of orthotopic heart transplantation. Myocardial oxygen consumption was measured before and after administration of bradykinin, S-nitroso N-acetyl penicillamine (SNAP, a nitric oxide donor), ramiprilat (an ACE inhibitor), amlodipine, and the combination of a sub-threshold dose of ramiprilat (10(-8) md/L) + amlodipine. These experiments were repeated with L-nitro-arginine methyl ester (L-NAME, an inhibitor of nitric oxide synthesis), dichloroisocoumarin (an inhibitor of kinin synthesis), and HOE 140 (a B2 kinin-receptor antagonist). Baseline myocardial oxygen consumption in canine hearts was 182 +/- 21 nmol/g/min. Bradykinin and SNAP caused dose-dependent reductions in myocardial oxygen consumption (p <0.05). Ramiprilat and amlodipine caused a 10 +/- 3.2% and 11 +/- 0.8% reduction in myocardial oxygen consumption, respectively, when used alone (p <0.05). In the presence of a subthreshold dose of ramiprilat, amlodipine caused a larger (15 +/- 1.7%) reduction in myocardial oxygen consumption compared with either drug used alone (p <0.05). In human hearts, baseline myocardial oxygen consumption was 248 +/- 57 nmol/g/min. Amlodipine caused a larger reduction in myocardial oxygen consumption when used with ramiprilat (22 +/- 3.2%) as compared with amlodipine alone (15 +/- 2.6%). The effect of both drugs was attenuated by L-NAME, dichloroisocoumarin, and HOE 140 (p <0.05). In conclusion, ACE inhibitors and amlodipine act synergistically to regulate myocardial oxygen consumption by modulating kinin-mediated nitric oxide release, and this combination of drugs may be useful in the treatment of heart failure.