Systemic ventricular function in patients with tetralogy of fallot, ventricular septal defect and transposition of the great arteries repaired during infancy

Normoxic and hyperoxic cardiopulmonary bypass in congenital heart disease

Cyanotic congenital heart disease comprises a diverse spectrum of anatomical pathologies. Common to all, however, is chronic hypoxia before these lesions are operated upon when cardiopulmonary bypass is initiated. A range of functional and structural adaptations take place in the chronically hypoxic heart, which, whilst protective in the hypoxic state, are deleterious when the availability of oxygen to the myocardium is suddenly improved. Conventional cardiopulmonary bypass delivers hyperoxic perfusion to the myocardium and is associated with cardiac injury and systemic stress, whilst a normoxic perfusate protects against these insults.

Long-term assessment and serial evaluation of cardiorespiratory exercise performance and cardiac function in patients with atrial switch operation for complete transposition

BACKGROUND

At present, a considerable number of patients survive who underwent an atrial switch operation for correction of complete transposition. Our study aimed to assess their long-term exercise performance and the serial evolution of cardiac function.

METHODS

We studied 22 patients 5 to 17 years after an atrial switch operation, and followed them serially for 3.5 +/- 2 years after the first evaluation. Cardiorespiratory exercise function was assessed by analysis of gas exhange and by determination of the ventilatory anaerobic threshold. Echocardiography was performed on all evaluations.

RESULTS

All patients were in Class I of the classification of the New York Heart Association at all assessments. Ventilatory anaerobic threshold, however, was significantly lower than normal. It averaged 77.9% +/- 13.7 of the normal mean value at the initial evaluation, and remained stable when re-evaluated later (76.2 +/- 13.7%). At the initial study, the increase in oxygen uptake during graded exercise was below the 95% confidence limit in 6 of the patients, and was below this level in 10 patients at re-assessment. The subnormal values for oxygen uptake during submaximal exercise were associated with moderate to severe haemodynamic dysfunction. At echocardiography, 15 of 17 patients studied twice had mild to moderate right ventricular dilation and tricuspidregurgiation, which remained virtually the same at reasssesment. A stable sinus rhythm was initially present in 17 patients, and persisted in 15 patients during follow-up.

CONCLUSION

At medium term follow-up, cardiorespiratory exercise performance remains stable in patients after atrial switch repair. Serial exercise testing appears useful, because in individual patients in the present study, a decreasing exercise tolerance correlated with development of haemodynamic sequels.

Right ventricular function in congenital heart disease: pressure and volume overload lesions

The right ventricle is often subject to both pressure and volume overload in congenital heart disease. Evaluating right ventricular function in both the native lesion and after surgery in light of these loading conditions, presents a unique challenge for investigators studying these misshapen hearts. The purpose of this article is to briefly delineate what is generally known about right ventricular function in congenital heart disease and to touch on some noninvasive imaging modalities which have helped shed some light on this matter.

Nitric-oxide-induced reoxygenation injury in the cyanotic immature heart is prevented by controlling oxygen content during initial reoxygenation

Reintroduction of high levels of molecular oxygen after a hypoxic period is followed by a burst of nitric oxide (NO), peroxynitrite, and oxygen free radicals (OFR), which are highly cytotoxic. This study indicates that hyperoxic reoxygenation of cyanotic immature hearts on cardiopulmonary bypass (CPB) induces a reoxygenation injury and that, by reducing NO and OFR production during institution of CPB with subsequent reoxygenation under blood cardioplegic arrest, this oxygen-related damage can be avoided and biochemical and functional status improved. Of 25 immature piglets (3-5 kg, two to three weeks old), 6 underwent one hour of CPB including thirty minutes of aortic clamping with substrate-enriched modified blood cardioplegia (hypocalcemic, alkalotic, and hyperosmolar; warm induction-cold replenishment-warm reperfusion) without preceding hypoxia (controls). Nineteen others were made hypoxic (arterial [Po2] 20-30 mmHg) for up to two hours by lowering the fraction of inspired oxygen (FIO2) on ventilator. These hypoxic piglets were then reoxygenated on CPB at different Po2 levels (hyperoxic, normoxic, or hypoxic) for five minutes, followed by the aforementioned blood cardioplegic (BCP) arrest regimen. Myocardial conjugated diene (CD) production as a marker of lipid peroxidation, and NO production, determined as its spontaneous oxidation products, nitrite (NO2-) and nitrate (NO3-), were assessed during blood cardioplegic induction, and antioxidant reserve capacity was determined by incubating myocardium in the oxidant t-butylhydroperoxide (t-BHP). Myocardial function was evaluated from end-systolic elastance (Ees, conductance catheter). Blood cardioplegic arrest caused no functional or biochemical changes in normoxic control immature piglets. In contrast, brief reoxygenation at PO2 > 400 mmHg, followed by BCP-arrest (hyperoxic) resulted in marked CD production (42 +/- 4 vs 3 +/- 1 A233 nm/minute/100 g; P < 0.05), and NO production (4500 +/- 500 vs 450 +/- 32 mmol/minute/100 g; P < 0.05) during blood cardioplegic induction, reduced antioxidant reserve capacity (malondialdehyde [MDA] at 4.0 mM of t-BHP: 1342 +/- 59 vs 958 +/- 50 nM/g protein; P < 0.05), and caused profound myocardial dysfunction; Ees recovered only 21 +/- 2% (vs 104 +/- 7; P < 0.05), despite the blood cardioplegic regimen shown to be cardioprotective in control normoxic piglets. Conversely, controlling initial PO2 to normoxic (100 mmHg) or hypoxic (20-30 mmHg) levels reduced lipid peroxidation (CD production 16 +/- 2, 2 +/- 1 A233nm/minute/100 g) and NO production (1264 +/- 736, 270 +/- 182 mmol/minute/100 g), restored antioxidant reserve capacity (MDA at 4.0 mM of t-BHP: 940 +/- 95, 982 +/- 88 nM/g protein), and allowed significant functional recovery (58 +/- 11% and 83 +/- 8%), in a PO2-dependent fashion. The authors conclude that reoxygenation of hypoxemic immature hearts by initiating hyperoxic CPB causes oxidant-related damage characterized by lipid peroxidation, enhanced NO production, and reduced antioxidants, leading to functional depression that nullifies the cardioprotective effects of blood cardioplegia. These detrimental effects can be reduced in a PO2-dependent fashion by controlling initial PO2 on CPB and subsequent reoxygenation during blood cardioplegic arrest.

Oxidative insult associated with hyperoxic cardiopulmonary bypass in the infantile heart and lung

Cardiopulmonary bypass (CPB) per se alters many factors simultaneously, including free radical generation, which suggests that conventional hyperoxic CPB may produce oxidative injury in the infantile heart and lung. This study tests the hypothesis that CPB provokes oxidative cardiopulmonary changes and pulmonary endothelial dysfunction in immature piglets that can be prevented by free radical scavengers. We studied 15 2- to 3-week-old piglets. Five served as a control without CPB. Ten piglets underwent 60 min of CPB with a membrane oxygenator (Sarns). In 5 of these 10, the bypass prime was supplemented with N-mercaptopropionylglycine (MPG: 80 mg/kg) plus catalase (50,000 U/kg), whereas the others were not treated. Pre- and post-bypass cardiopulmonary function was measured in terms of left ventricular end-systolic elastance [Ees] by a conductance catheter, the arterial/alveolar pO2 ratio (a/A ratio) and static lung compliance. Conjugated dienes (A233 nm/mg lipid) were measured to detect lipid peroxidation in heart and lung tissue, and myocardial antioxidant reserve capacity [malondialdehyde (MDA) production in cardiac tissue incubated with the oxidant t-butyl hydroperoxide (t-BHP)] was assessed to detect oxidative changes. Pulmonary vascular resistance (PVR) and transpulmonary nitric oxide (NO) production were measured to assess pulmonary endothelial injury. Myocardial antioxidant reserve capacity was significantly reduced after 60 min of CPB, compared to control animals (MDA 779 +/- 100 vs 470 +/- 30 nmol/g protein, p < 0.05 at t-BHP 2.0 mmol/L), without evidence of lipid peroxidation or myocardial dysfunction. Pulmonary vascular resistance after CPB was dramatically increased (83 +/- 12 to 212 +/- 30, p < 0.05) without any change in lung function. In parallel to pulmonary vasoconstriction, NO production was significantly decreased after CPB (from 8.8 +/- 1.4 to 2.5 +/- 0.5 mmol/min/kg, p < 0.05). The addition of antioxidants (MPG+catalase) to the prime significantly improved myocardial antioxidant status (MDA: 604 +/- 30 vs 779 +/- 100 nmol/g protein, p < 0.05) and pulmonary vascular resistance (114 +/- 29 vs 212 +/- 30, p < 0.05 vs no-treatment group). In conclusion, the present study confirms that 1) Cardiopulmonary bypass produces substantial oxidative stress in normal immature myocardium, as assessed by reduced antioxidant reserve capacity; 2) CPB impairs pulmonary endothelial function, characterized by NO production, resulting in pulmonary vasoconstriction; and 3) These deleterious effects can be prevented by the addition of antioxidants (MPG/catalase) to the pump prime.

Studies of hypoxemic/reoxygenation injury: without aortic clamping. VII. Counteraction of oxidant damage by exogenous antioxidants: coenzyme Q10

Coenzyme Q10 (CoQ10) is a natural mitochondrial respiratory chain constituent with antioxidant properties. This study tests the hypothesis that CoQ10 administered before the onset of reoxygenation on cardiopulmonary bypass, can reduce oxygen-mediated myocardial injury and avoid myocardial dysfunction after cardiopulmonary bypass. The antioxidant properties of CoQ10 were confirmed by an in vitro study in which normal myocardial homogenates were incubated with the oxidant, t-butylhydroperoxide. Fifteen immature piglets (< 3 weeks old) were placed on 60 minutes of cardiopulmonary bypass. Five piglets underwent cardiopulmonary bypass without hypoxemia (oxygen tension about 400 mm Hg). Ten others became hypoxemic on cardiopulmonary bypass for 30 minutes by lowering oxygen tension to approximately 25 mm Hg, followed by reoxygenation at oxygen tension about 400 mm Hg for 30 minutes. In five piglets, CoQ10 (45 mg/kg) was added to the cardiopulmonary bypass circuit 15 minutes before reoxygenation, and five others were not treated (no treatment). Myocardial function after cardiopulmonary bypass was evaluated from end-systolic elastance (conductance catheter), oxidant damage (lipid peroxidation) was assessed by measuring conjugated diene levels in coronary sinus blood, and antioxidant reserve capacity was determined by measuring malondialdehyde in myocardium after cardiopulmonary bypass incubated in the oxidant, t-butylhydroperoxide. Cardiopulmonary bypass without hypoxemia caused no oxidant damage and allowed complete functional recovery. Reoxygenated hearts (no treatment) showed a progressive increase in conjugated diene levels in coronary sinus blood after reoxygenation (2.3 +/- 0.6 A233 nm/0.5 ml plasma at 30 minutes after reoxygenation) and reduced antioxidant reserve capacity (malondialdehyde: 1219 +/- 157 nmol/g protein at 4.0 mmol/L t-butylhydroperoxide), resulting in severe postbypass dysfunction (percent end-systolic elastance = 38 +/- 6). Conversely, CoQ10 treatment avoided the increase in conjugated diene levels (2.1 +/- 0.6 vs 1.1 +/- 0.3, p < 0.05 vs no treatment), retained normal antioxidant reserve (896 +/- 76 nmol/g protein, p < 0.05 vs no treatment), and allowed nearly complete recovery of function (94% +/- 7%, p < 0.05 vs no treatment). We conclude that reoxygenation of the hypoxemic immature heart on cardiopulmonary bypass causes oxygen-mediated myocardial injury, which can be limited by CoQ10 treatment before reoxygenation. These findings imply that coenzyme Q10 can be used to surgical advantage in cyanotic patients, because therapeutic blood levels can be achieved by preoperative oral administration of this approved drug.

Studies of hypoxemic/reoxygenation injury: without aortic clamping. V. Role of the L-arginine-nitric oxide pathway: the nitric oxide paradox

This study tests the hypothesis that nitric oxide, which is endothelial-derived relaxing factor, produces reoxygenation injury via the L-arginine-nitric oxide pathway in hypoxemic immature hearts when they are placed on cardiopulmonary bypass. Twenty 3-week-old piglets undergoing 2 hours of hypoxemia (oxygen tension about 25 mm Hg) on a ventilator were reoxygenated by initiating cardiopulmonary bypass (oxygen tension about 400 mm Hg). Five animals were not treated, whereas the pump circuit was primed with the nitric oxide-synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 4 mg/kg) in five piglets. L-Arginine, the substrate for nitric oxide, was administered in a fivefold excess (20 mg/kg), together with L-NAME in five piglets (L-NAME and L-arginine), and given alone in five other piglets (L-arginine). Five normoxemic, instrumented piglets served as a control group, and five others underwent 30 minutes of cardiopulmonary bypass without preceding hypoxemia. Left ventricular contractility was determined as end-systolic elastance by pressure-dimension loops. Myocardial conjugated dienes were measured as a marker of lipid peroxidation, and the antioxidant reserve capacity (malondialdehyde production in tissue incubated with t-butylhydroperoxide) was measured. Nitric oxide level was determined in coronary sinus plasma as its spontaneous oxidation product, nitrite. Cardiopulmonary bypass per se did not alter left ventricular contractility, cause lipid peroxidation, or lower antioxidant capacity. Reoxygenation without treatment depressed cardiac contractility (end-systolic elastance 38% +/- 12% of control*), raised nitric oxide (127% above hypoxemic values), increased conjugated dienes (1.3 +/- 0.2 vs 0.7 +/- 0.1, control*), and reduced antioxidant reserve capacity (910 +/- 59 vs 471 +/- 30, control*). Inhibition of nitric oxide production by L-NAME improved end-systolic elastance to 84% +/- 12%,** limited conjugated diene elution (0.8 +/- 0.1 vs 1.3 +/- 0.2, no treatment**), and improved antioxidant reserve capacity (679 +/- 69 vs 910 +/- 59, no treatment**). Conversely, L-arginine counteracted these beneficial effects of L-NAME, because left ventricular function recovered only 24% +/- 6%,* conjugated dienes were 1.2 +/- 0.1,* and antioxidant reserve capacity was 826 +/- 70.* L-Arginine alone caused the same deleterious biochemical changes as L-NAME/L-arginine and resulted in 60% mortality. The close relationship between postbypass left ventricular dysfunction (percent end-systolic elastance) and myocardial conjugated diene production (r = 0.752) provides in vivo evidence that lipid peroxidation contributes to myocardial dysfunction after reoxygenation.(ABSTRACT TRUNCATED AT 400 WORDS)

Studies of hypoxemic/reoxygenation injury: with aortic clamping. X. Exogenous antioxidants to avoid nullification of the cardioprotective effects of blood cardioplegia

This study tests the hypothesis that reoxygenation of cyanotic immature hearts when starting cardiopulmonary bypass produces an "unintended" reoxygenation injury that (1) nullifies the cardioprotective effects of blood cardioplegia and (2) is avoidable by adding antioxidants N-(2-mercaptopropionyl)-glycine plus catalase to the cardiopulmonary bypass prime. Twenty immature piglets (2 to 3 weeks) underwent 30 minutes of aortic clamping with a blood cardioplegic solution that was hypocalcemic, alkalotic, hyperosmolar, and enriched with glutamate and aspartate during 1 hour of cardiopulmonary bypass. Of these, six piglets did not undergo hypoxemia (blood cardioplegic control) and 14 others remained hypoxemic (oxygen tension about 25 mm Hg) for up to 2 hours by lowering ventilator fraction of inspired oxygen before reoxygenation on cardiopulmonary bypass. The primary solution of the cardiopulmonary bypass circuit was unchanged in eight piglets (no treatment) and supplemented with the antioxidants N-(2-mercaptopropionyl)-glycine (80 mg/kg) and catalase (5 mg/kg) in six others (N-(2-mercaptopropionyl)-glycine and catalase). Myocardial function (end-systolic elastance), lipid peroxidation (myocardial conjugated diene production), and antioxidant reserve capacity were evaluated. Blood cardioplegic arrest produced no biochemical or functional changes in nonhypoxemic control piglets. Reoxygenation caused an approximate 10-fold increase in conjugated production that persisted throughout cardiopulmonary bypass, lowered antioxidant reserve capacity 86% +/- 12%, and produced profound myocardial dysfunction, because end-systolic elastance recovered only 21% +/- 2%. Supplementation of the cardiopulmonary bypass prime with N-(2-mercaptopropionyl)-glycine and catalase reduced lipid peroxidation, restored antioxidant reserve capacity, and allowed near complete functional recovery (80% +/- 8%).** Lipid peroxidation (conjugated diene) production was lower during warm blood cardioplegic reperfusion than during induction in all reoxygenated hearts, which suggests that blood cardioplegia did not injure reoxygenated myocardium. We conclude that reoxygenation of the hypoxemic immature heart causes cardiac functional and antioxidant damage that nullifies the cardioprotective effects of blood cardioplegia that can be avoided by supplementation of the cardiopulmonary bypass prime with antioxidants (*p < 0.05 vs blood cardioplegic control; **p < 0.05 vs reoxygenation).

Studies of hypoxemic/reoxygenation injury: with aortic clamping. XII. Delay of cardiac reoxygenation damage in the presence of cyanosis: a new concept of controlled cardiac reoxygenation

Twenty-one immature piglets (< 3 weeks old) underwent 30 minutes of aortic clamping with hypocalcemic glutamate/aspartate blood cardioplegia. Six piglets underwent hyperoxemic cardiopulmonary bypass and blood cardioplegia without preceding hypoxemia (control). Fifteen piglets became hypoxemic (oxygen tension about 25 mm Hg) for up to 2 hours by decreasing ventilator fraction of inspired oxygen to 6% to 7% before cardiopulmonary bypass. Of these, six piglets underwent 5 minutes of abrupt hyperoxemic uncontrolled reoxygenation by starting cardiopulmonary bypass at oxygen tension of about 400 mm Hg before they received oxygen tension of about 400 mm Hg blood cardioplegia. Nine others underwent controlled cardiac reoxygenation by starting cardiopulmonary bypass at ambient oxygen tension (about 25 mm Hg) followed 5 minutes later by 30 minutes of cardiopulmonary bypass at normoxemic oxygen tension (about 100 mm Hg) before raising oxygen tension to about 400 mm Hg. Myocardial function after cardiopulmonary bypass was evaluated from end-systolic elastance by conductance catheter, oxidant damage was estimated by measuring transcoronary conjugated diene levels to detect lipid peroxidation, and antioxidant reserve capacity was determined by measuring malondialdehyde produced from myocardium incubated with the oxidant t-butylhydroperoxide. Hyperoxemic cardiopulmonary bypass and blood cardioplegia preserved myocardial function and produced no oxidant damage in nonhypoxemic piglets. In contrast, uncontrolled reoxygenation at oxygen tension about 400 mm Hg, followed by blood cardioplegia, resulted in marked conjugated dienes production (42 +/- 4* vs 3 +/- 1) A233 nm/min/100 g during blood cardioplegic induction, reduced antioxidant reserve capacity malondialdehyde at 4 mmol/L t-butylhydroperoxide; 1342 +/- 59* vs 958 +/- 50 nmol/g protein) and caused profound myocardial dysfunction; end-systolic elastance recovered only 21% +/- 2%* despite a blood cardioplegic regimen that was cardioprotective in nonhypoxemic piglets. Conversely, controlled cardiac reoxygenation reduced lipid peroxidation (conjugated dienes production was 2 +/- 1**), restored antioxidant reserve capacity (malondialdehyde at 4 mmol/L t-butylhydroperoxide; 982 +/- 88**), and allowed near-complete (83 +/- 8%**) functional recovery. We conclude that reoxygenation of the hypoxemic immature heart by initiating conventional hyperoxemic cardiopulmonary bypass causes oxidant damage characterized by lipid peroxidation, reduced antioxidant reserve capacity, and results in functional depression that nullifies the cardioprotective effects of blood cardioplegia. These changes can be reduced by starting cardiopulmonary bypass at the ambient oxygen tension of the hypoxemic subject and delaying subsequent reoxygenation until blood cardioplegic induction by controlled cardiac reoxygenation (*p < 0.05 vs control; **p < 0.05 vs uncontrol reoxygenation) and analysis of variance.

The effects of cyanosis on myocardial blood flow, oxygen utilization, and lactate production in dogs

To elucidate differences in myocardial blood flow and metabolism between cyanotic and normal hearts, a model of chronic cyanosis was created in five adult mongrel dogs by anastomosing the inferior vena cava to the left atrium. After 6 to 9 months, myocardial blood flow, the ratio of subendocardial to subepicardial flow, oxygen consumption, oxygen extraction ratio, and lactate consumption in these cyanotic dogs and five control dogs were determined under baseline conditions and during pharmacologic stress with isoproterenol (0.2 micrograms/kg/min). Radioactive microspheres were used to determine left and right ventricular blood flow rates, and arterial and coronary sinus differences in oxygen and lactate levels were measured. At baseline and during stress, oxygen consumption and oxygen extraction ratios were identical in control and cyanotic hearts. Total myocardial blood flow was increased with stress and did not differ between cyanotic and control hearts. Left ventricular muscle from cyanotic hearts did exhibit lower endocardial/epicardial blood flow ratios than those of control hearts at rest, and the relative subendocardial flow decreased further with stress. During isoproterenol infusion, myocardial lactate production, indicative of anaerobic metabolism, was evident in two of five cyanotic animals and none of the control dogs. The relative subendocardial ischemia and its further aggravation by stress in cyanotic hearts may contribute to the pathophysiologic basis of myocardial dysfunction in cyanotic heart disease.

Staged conversion to arterial switch for late failure of the systemic right ventricle

Late failure of the systemic right ventricle is seen in up to 10% of patients after atrial switch for transposition of the great arteries and in patients with atrioventricular and ventriculoarterial discordance. Since 1981, 24 such patients have entered a program to achieve conversion to arterial switch. The primary diagnoses were transposition of the great arteries with ventricular septal defect (n = 10), transposition of the great arteries with intact ventricular septum (n = 5), Taussig-Bing anomaly (n = 4), and atrioventricular and ventriculoarterial discordance (n = 5). The mean interval from atrial switch to right ventricular failure was 7 years. Four patients underwent direct conversion to arterial switch, with one operative death. In 3 of these patients the initial left ventricular pressure was high. The fourth patient was too sick to undergo banding, and he required left ventricular assist device support after switch conversion. The other 20 patients underwent 34 procedures to place or tighten a pulmonary artery band to prepare the left ventricle to tolerate systemic pressure. There was one band-related operative death. Twelve patients have thus far gone on to switch conversion 13 days to 5 years (mean, 26 months) after banding. In total, therefore, 16 patients have had an arterial switch with atrial reconstruction. The early mortality for switch conversion was 2 of 16 (12.5%; 70% confidence limits, 4% and 27%), with one late death 12 months after operation. Including operative mortality, the 1-year actuarial survival probability after conversion was 80% (70% confidence limits, 62% and 92%). All survivors are asymptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiorespiratory exercise capacity after surgical closure of atrial septal defect is influenced by the age at surgery

To study the influence of age at the time of the operation on long-term functional performance in children undergoing surgery for atrial septal defect (ASD) of the secundum type, exercise tolerance was assessed in 24 patients and values were compared with those of normal subjects. Patients were divided into two groups: 11 patients had surgery before the age of 5 years (group 1) and 13 patients had surgery at a later age (group 2). There were no significant differences between groups 1 and 2 with regard to the pulmonary-to-systemic flow ratio, pulmonary artery pressure, and the interval between surgery and exercise testing. Performance capacity was assessed by determination of the ventilatory threshold during submaximal exercise. The mean value for the ventilatory threshold in group 1 was normal (99.4 +/- 15.1% of the age-predicted normal value). In the children who were more than 5 years of age at the time of the operation, the ventilatory threshold was below normal (84.5 +/- 10.9% of the age-predicted normal value). Furthermore, in group 2 more patients (77%) had values that were below normal (below the 95% confidence limit of the age-predicted normal value) compared with group 1 (27%). It is concluded that functional performance capacity is better when surgical closure of ASD is performed in early childhood and before the age of 5 years rather than at a later age.

Anesthesia for Cardiac Surgery in Newborns with Congenital Heart Disease

The repair of complex congenital heart disease in the neonatal period is an evolving practice that began a decade ago and has resulted in improved survival and reduced long term morbidity. Surgical techniques and anesthetic, management hare evolved to care for these uniquely challenging infants. Optimal anesthetic care requires a sound basis in normal and pathologic neonatal and dedopmental physiology, cardiac and pediatric anesthesia, and cardiopulmonary bypass management. Typical concerns in neonatal congenital heart patients include a reduced myocardial compliance and poorly

developed calcium transport systems. This limits stroke volume and increases calcium requirements in the post-bypass patient. Additionally, abnormal blood flow patterns are common and may be adversely affected by inotropes, inspired oxygen concentration, carbon dioxide tension, and mechanical ventilation. The impact of cardiopulmonary bypass on the neonate is extreme. Infants are commonly cooled to 15°C, their blood volume is hemodiluted by 3-4 fold, and periods of total circulatory arrest for up to 60 min are routine. The physiologic impact of these biologic extremes on organ function must be anticipated. Bypass management must assure optimal distribution of pump flow to minimize any impediment to organ protection. High dose narcotics combined with a benzodiazepine have become an integral part of anesthetic management for the neonate with congenital heart disease. Combined intravenous drug therapy provides a complete anesthetic (sedation amnesia and analgesia), hemodgnamic stability, reduced stress hormone release, and control of pulmonary vascular reactivity. Thii reduces the need for multiple inotropic therapy aimed at decreasing pulmonary vascular resistance and improving myocardial contractility. This manuscript provides an in-depth understanding of the anesthetic management of the neonate with complex congenital heart disease. The overall goal of anesthetic management is to deliver a patient to the ICU with stable hemodynamics and a clear management plan based on intraoperative observations and interventions.

The Senning operation for complete transposition: mid-term physiologic, electrophysiologic, and functional results

SummaryWe report analysis of surgical results in 110 consecutive infants and children who underwent atrial repair of simple complete transposition using the Senning operation between February 1978 and May 1990. Mean age at operation was 5.4 months ± 6.1 (range 1 week to 4 years); 75 were less than 6 months old. There were 72 males and 38 females. Operative mortality rate was 5.5%, with one late death. Average follow-up is 48.1 months with 44 followed greater than 3 years, and 27 greater than 5 years. Postoperative cardiac catheterization was performed in 48 patients. Right ventricular ejection fraction averaged 0.52 ± 0.08 and was normal in 28 patients. Response of right ventricular ejection fraction to afrerload stress was abnormal in 12 of 14 patients tested. Right ventricular ejection fraction increased normally during exercise in 6 patients, but was abnormal in 15. Mild tricuspid regurgitation was noted in 12 patients. Mild obstruction of the superior caval vein was noted in 4 patients. Baffle leak requiring reoperation occurred in one patient. Fifty-seven of 90 patients are in sinus rhythm by latest electrocardiogram. Postoperative electrophysiologic studies were performed in 34 patients, and Holter monitoring in 25. Significant arrhythmia occurred in 26 patients: 6 patients required pacemakers for slow junctional rhythm or complete heart block; 20 additional patients have a junctional rhythm. Six patients have delayed sinus nodal recovery time. At last follow-up, 88 children (98%) are in New York Heart Association functional Class I, and 2 (2%) are in Class II. The Senning operation for compete transposition can be accomplished with a low operative and late mortality. Serious baffle complications requiring reoperation are rare. Surviving patients are clinically well, but arrhythmias and depressed right ventricular function may limit their long-term functional status.

Functional assessment of the heart after corrective surgery for complete transposition

SummaryThe justification for the introduction of the arterial switch procedure was based, primarily, on concern regarding the long-term ability of the right ventricle to perform as the systemic pumping chamber. In this article, the functional performance of both the systemic and pulmonary ventricles after atrial redirection procedures and the arterial switch operation will be discussed.

Results of the arterial switch operation for transposition of the great arteries with ventricular septal defect. Surgical considerations and midterm follow-up data

Between January 1983 and December 1987, 62 patients underwent an arterial switch operation for transposition of the great arteries with ventricular septal defect or double outlet right or left ventricle. There were three hospital deaths (4.8%), and no deaths occurred in neonates (less than 1 month of age, n = 18). There were three late deaths, one due to coronary obstruction and two due to pulmonary vascular obstructive disease. One child has been lost to follow-up. We have prospectively evaluated the remaining 55 survivors by clinical evaluation, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and limited electrophysiologic studies. The mean length of follow-up has been 27 +/- 16 months since surgery. One child has required reoperation for a residual ventricular septal defect; no child has undergone reoperation for supravalvar pulmonary or aortic stenosis. Aortic regurgitation was identified in 12 children (22%), which was mild in 11 and moderate in one. One child has asymptomatic occlusion of the left main coronary artery, one child has a tiny right coronary artery-to-pulmonary artery fistula, and one child has abnormal left ventricular wall motion according to follow-up angiography. No other abnormalities of systemic (left) ventricular function have been identified at late follow-up. In addition to the two late deaths due to pulmonary vascular obstructive disease, three children, all of whom were repaired at more than 6 months of age, have elevated pulmonary vascular resistance. Notable postoperative arrhythmias include complete heart block in four patients and nonsustained supraventricular or ventricular tachycardia early after surgery in eight patients (all resolved without medication at later follow-up). Only two patients have evidence of sinus node dysfunction and have not required treatment. The low hospital mortality and encouraging early follow-up data represent a significant improvement over atrial level repairs, supporting the arterial switch operation as the procedure of choice for children who have transposition of the great arteries with ventricular septal defect or double outlet ventricle. Because of the potential for the development of early pulmonary vascular obstructive disease in these patients, repair is recommended within the first 2 months of life.

Comparison of cardiovascular adjustments to exercise in adolescents 8 to 15 years of age after correction of tetralogy of fallot, ventricular septal defect or atrial septal defect

Surgical correction of tetralogy of Fallot (TF) has generally been associated with a reduced maximal exercise tolerance, possibly related to the ventriculotomy inherent to the intracardiac repair procedure. This study documents the exercise hemodynamics of a group of patients operated on for TF who showed similar clinical and functional characteristics, and compares these responses to those of age-matched patients operated on for an isolated ventricular septal defect (VSD) or atrial septal defect (ASD) in an attempt to better understand the role of the ventriculotomy in the exercise limitation. Thirty patients, ages 12 to 19 years, operated on before 5 years of age for complete repair of TF (n = 13), VSD (n = 7) or ASD (n = 10) and 10 age-matched control subjects underwent a progressive maximal cycling test to determine the maximal oxygen uptake (VO2 max), and completed submaximal cycling at intensities of 33 and 66% VO2 max, respectively, to determine the cardiac output (CO2-rebreathing). No significant differences in VO2 max were observed (TF = 37.6 +/- 10; VDS = 34.0 +/- 9.2; ASD = 36.5 +/- 7; controls = 41.3 +/- 6.0 ml/kg/min). The maximal heart rate, however, remained lower in all patient groups in comparison with control subjects (p less than or equal to 0.05) (TF = 178 +/- 14; VSD = 172 +/- 17; ASD = 179 +/- 16; controls = 191 +/- 12 beats/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of right ventricular performance by pulsed Doppler echocardiography in patients after intraatrial repair of aortopulmonary transposition in infancy or childhood

The purpose of this study was to determine whether measurement of aortic blood flow velocity and acceleration by pulsed Doppler ultrasound can be used to assess the global performance of the systemic right ventricle noninvasively in young patients who have undergone intraatrial repair of aortopulmonary transposition. The effect of age at surgery on right ventricular performance in these patients was also studied. Pulsed Doppler velocity profiles of aortic blood flow were analyzed at a mean age of 5.5 years in 24 patients who had undergone intraatrial repair of aortopulmonary transposition either in early infancy (mean age 3.4 +/- 1.3 weeks) or later (mean age 8.5 +/- 6.5 months). Velocity and acceleration variables in these patients were compared with the same variables in 24 age-matched normal subjects and with the performance of their own right ventricle as assessed by two-dimensional echocardiographic measurement of ejection fraction. The 12 patients who underwent early repair had a higher ejection fraction than did the 12 who underwent later repair (mean +/- SD 0.60 +/- 0.07 versus 0.42 +/- 0.10; p less than 0.001). Aortic flow velocity was similar in all patients. Aortic acceleration was normal in patients after early intraatrial repair of aortopulmonary transposition (20.8 +/- 2.3 m/s2), but was abnormally slow in patients after late repair (11.1 +/- 1.8 m/s2; p less than 0.001), thus suggesting that the latter group had diminished right ventricular performance. Concomitantly, acceleration time and ratio of acceleration time to ejection time were increased in patients after late repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Ten years' experience with the Senning operation for transposition of the great arteries: physiological results and late follow-up

We report our results in 93 consecutive infants and children who underwent atrial repair of simple transposition of the great arteries using the Senning operation between February 1978 and February 1988. Mean age at operation was 5.6 +/- 6.3 months (range, 1 week to 4 years); 60 were less than 6 months old. There were 65 boys and 28 girls. Operative mortality was 5.4%, and there has been 1 late death. Average follow-up is 45.1 months with 39 followed more than 3 years and 25 followed more than 5 years. Postoperative cardiac catheterization was performed in 43 patients. Right ventricular ejection fraction at rest averaged 0.50 +/- 0.09 and was normal in 26 patients. Response of right ventricular ejection fraction to afterload stress was abnormal in 12 of 14 patients tested. Right ventricular ejection fraction increased normally during exercise in 6 patients, but was abnormal in 15. Mild tricuspid regurgitation was noted in 10 patients. Mild obstruction of the superior vena cava was noted in 4 patients. Baffle leak requiring reoperation occurred in 1 patient. Seventy-two of 80 patients are in sinus rhythm by latest electrocardiogram. Postoperative electrophysiological studies were performed in 34 patients and Holter monitoring was performed in 22. A major arrhythmia occurred in 8 patients: 3 required a pacemaker for junctional rhythm or sinus node dysfunction, 2 have symptomatic or inducible supraventricular tachycardia, 2 have junctional rhythm, and 1 has sick sinus syndrome. Eight additional patients have delayed sinus node recovery time. At last follow-up, 78 children (97.5%) are in New York Heart Association functional class I, and 2 (2.5%) are in class II.(ABSTRACT TRUNCATED AT 250 WORDS)

Right ventricular myocardial function after atrial switch operation for transposition of the great arteries

Postoperative right ventricular (RV) myocardial function was evaluated in 6 patients who underwent atrial switching for simple transposition of the great arteries (TGA). The average age at study was 5.5 years. RV function was evaluated at rest and during administration of methoxamine by cardiac catheterization and RV angiography. The data were compared with left ventricular function in a control group, which consisted of 6 patients, 3 with functional murmur and 3 with pulmonary valvar stenosis. During stress, the TGA group showed a significant increase in end-diastolic pressure, minute work index and end-diastolic and end-systolic volume indexes, along with a significant decrease in ejection fraction. The control group also showed an increase in these variables except for ejection fraction during stress, which did not change. The slope of the work-function curve for the TGA group was lower than that for the control group (p = 0.02). The TGA group had a lower slope of the peak systolic pressure-volume relation than the control group (p = 0.005). There was no significant correlation between the slope of the peak systolic pressure-volume relation and age at repair or study. This study shows that RV pump dysfunction observed in postoperative TGA patients may be caused by depressed myocardial function.

Mechanism of decreased forward stroke volume in children and swine with ventricular septal defect and failure to thrive

Children with ventricular septal defect (VSD) often demonstrate failure to thrive (FTT). Such patients usually have reduced systemic cardiac output which has been postulated as a cause for their growth retardation. This study was conducted to ascertain the mechanism of the reduced cardiac output in children with VSD and FTT and also in a porcine model of VSD. Forward stroke volume was reduced in VSD-FTT children, 31 +/- 8 ml/m2, compared to normal children, 49 +/- 15 ml/m2 (P less than 0.05), but was not reduced in children with VSD and normal growth and development (41 +/- 16 ml/m2). Forward stroke volume was also reduced in swine with VSD compared to controls. Contractility assessed by mean velocity of circumferential shortening (Vcf) corrected for afterload was similar in normals and VSD-FTT children. Contractile performance was also similar in normal and VSD swine. Afterload assessed as systolic stress was similar in FTT-VSD children and normal subjects. Preload assessed as end-diastolic stress was increased in the VSD-FTT group. End-diastolic volume was not larger in the VSD-FTT group. We conclude that the reduced stroke volume seen in VSD-FTT children and VSD-swine was not due to reduced contractility, increased afterload or reduced preload. The reduced stroke volume may have been due to failure of end-diastolic volume to increase adequately.

Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiologic data

Although the short-term results of atrial level repair of transposition of the great arteries (TGA) are satisfactory, longer follow-up has disclosed a significant incidence of systemic right ventricular dysfunction and rhythm disturbances. The arterial switch operation (ASO) may represent a major improvement by restoring the left ventricle as the systemic ventricle and avoiding extensive atrial surgery. We have prospectively evaluated 49 consecutive survivors of ASO for TGA with intact ventricular septum (IVS) by clinical examination, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and invasive electrophysiologic studies. The mean length of follow-up has been 29 +/- 14 (SD) months after surgery. All children are currently asymptomatic and on no medications. Severe supravalvular pulmonary stenosis (greater than 60 mm Hg) was present in five children, all of whom have undergone reoperation. No patient has severe supravalvular aortic obstruction. Mild degrees of supravalvular pulmonary or aortic obstruction have not progressed. Seven children (14%) have trivial or mild aortic regurgitation. Two children have proximal occlusion of the left anterior descending coronary artery with adequate retrograde collateral perfusion. One child had an electrocardiographic pattern of inferior myocardial infarction without evidence of ventricular dysfunction. Systemic (left) ventricular function is normal as measured by end-diastolic pressure (mean 7 +/- 6 mm Hg), ejection fraction (mean 68 +/- 6%), end-diastolic volume (mean 101 +/- 22% of predicted normal), and cardiac index (mean 4.7 +/- 1.3 liters/min/m2). Only one patient has sinus node dysfunction. There have been no late deaths. These early results are encouraging. We conclude that the arterial switch operation is currently the procedure of choice for neonates with TGA and IVS.

Cardiorespiratory exercise testing after venous switch operation in children with complete transposition of the great arteries

In 14 children who underwent a venous switch operation for complete transposition of the great arteries, exercise testing was performed 3 to 15 years (mean 8) after the operation. Exercise performance capacity was assessed by the determination of the ventilatory threshold during exercise and by the oxygen uptake (VO2) reached at a heart rate of 170 beats/min (VO2,170). The ventilatory threshold was defined as the highest oxygen uptake (VO2) at which the pulmonary ventilation (VE) stops to increase linearly when related to VO2. During exercise above this threshold a disproportionate increase in VE relative to VO2 is observed. The mean ventilatory threshold was significantly lower (p less than 0.01) than the normal mean value and averaged 72 +/- 15%, 67 +/- 15% and 70 +/- 13% of the predicted normal value for children of comparable age, weight and height, respectively. The mean value for VO2,170 also was significantly lower (p less than 0.05) than the normal mean value for children of comparable age, weight and height, and averaged 81 +/- 20%, 81 +/- 18% and 80 +/- 18%, respectively. Compared with normal control subjects of the same sex and age, the ventilatory threshold was surpassed sooner (p less than 0.001) and reached after 2 +/- 1 min instead of the 4 +/- 1 min required by the controls. In nearly half of the patients, a lower than normal (i.e. below the 95% confidence limit) heart rate response to exercise was observed. Theoretically, this could be interpreted as indicating a normal or high physical performance capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular systolic and diastolic function after total correction of tetralogy of Fallot

Left ventricular (LV) systolic and diastolic function was assessed in 12 patients after total correction of tetralogy of Fallot (age range 5 to 18 years, mean 10) and compared with 10 control patients. Only 1 patient had a shunt before total correction that was performed at a mean age of 3.5 years, (range 0.3 to 8). At cardiac catheterization the following indexed LV parameters were measured: end-diastolic and end-systolic volumes, wall mass, ejection fraction, stroke volume and end-diastolic and end-systolic pressures and stresses. The rate-corrected mean velocity of fiber shortening was calculated. LV diastolic operant chamber stiffness and myocardial stiffness were calculated from simultaneous diastolic pressures and volumes in mid- and late diastole using monoexponential formulas. The 2 groups were compared by unpaired t tests. The tetralogy group had higher mean end-diastolic (93 vs 74 ml/m2), end-systolic (29 vs 19 ml/m2) and stroke (64 vs 55 ml/m2) volumes than controls. Rate-corrected mean velocity of fiber shortening was lower in the tetralogy group (1.07 vs 1.24). Myocardial stiffness was higher in the tetralogy group (16 vs 11). Other indexes were not significantly different. Thus, LV function after total correction of tetralogy of Fallot may be abnormal with larger than normal LV size, decreased contractile function and increased myocardial stiffness.

Correlation of NYHA classification, bicycle ergometry and right heart haemodynamics after total correction of tetralogy of Fallot in adults

Thirty-two patients who had undergone correction of Fallot's tetralogy in adult life were examined on average 6.3 years postoperatively, at mean age 25.8 years. Palliative shunt operation had been performed in childhood in 28 cases. The clinical condition was good in 25 patients (78%). 13 of whom had mean gradient between right ventricle and pulmonary artery 16.0 +/- 4.2 mmHg and systolic right ventricular pressure 39.0 +/- 10.0 mmHg, while 12 had right ventricular pressure 62.6 +/- 16.3 mmHg. In these groups the maximum exercise capacity was, respectively, 136.7 +/- 36.1 and 106.1 +/- 30.8 W/min. Three other patients were in satisfactory, and four in poor clinical condition, with right ventricular systolic pressure, respectively, 74.3 +/- 10.9 and 91.5 +/- 60.0 mmHg. The gradient from right ventricle to pulmonary artery averaged 58.5 +/- 10.4 mmHg in the latter group but, despite the obstructed pulmonary outflow tract, the exercise capacity (116.7 +/- 28.9 W/min) was similar to that in the groups with better clinical results. It is concluded that in most patients with palliative surgery in childhood, tetralogy of Fallot can be successfully corrected in adult life. The causes of right ventricular impairment do not significantly reduce the exercise capacity.

Recent advances in cardiac surgery

Virtually all forms of congenital heart disease can be repaired or significantly palliated. The risk of surgery in infancy continues to decline, and many lesions are being routinely repaired at an early age. This may permit an improved functional result later in life. Other recent advances include the arterial switch procedure for transposition of the great arteries, the palliative repair of hypoplastic left heart syndrome, and the increased application of the Fontan procedure in patients with only one effective ventricle. Combined with an ever-growing understanding of cardiopulmonary physiology, anatomy, and biochemistry, the future of congenital cardiac surgery is bright and exciting.

Ventricular function in transposition of the great arteries: evaluation by radionuclide angiocardiography

Right ventricular ejection fraction and tricuspid regurgitation were estimated by radionuclide angiocardiography to quantitate systemic ventricular function in "simple" transposition of the great arteries. Mean right ventricular ejection fraction was 0.52 +/- 0.07 for 18 pre Mustard operation infants, 0.54 +/- 0.07 for 23 patients operated upon less than a 1 year before, and 0.57 +/- 0.08 for 14 patients operated upon more than 3 years earlier. Eight patients were evaluated before and following the Mustard operation; ejection fraction rose in three, fell in three, and remained constant in two. Mean right ventricular ejection fraction was not different between groups nor when compared to our "normal." The left ventricle:right ventricle stroke volume ratio of the postoperative patients was compatible with tricuspid regurgitation in four patients. This radionuclide study suggests that following surgery for transposition of the great arteries: mean right ventricular systolic ejection fraction remains at levels consistent with values usually found for the "normal" right ventricle; group right ventricular function does not deteriorate in the years following surgery; and tricuspid regurgitation may be detected in the early postoperative years.

Comparison of ventricular function after Senning and Jatene procedures for complete transposition of the great arteries

Postoperative right (RV) and left ventricular (LV) volume characteristics in patients with complete transposition of the great arteries were studied to compare ventricular function after Senning and Jatene procedures and to analyze RV dimensional change during systole in patients after the Senning procedures. RV end-diastolic volume (EDV) was 181 +/- 74% of normal (mean +/- standard deviation) and RV ejection fraction (EF) was 0.48 +/- 0.09 in 15 patients who underwent the Senning procedure. In 9 patients who underwent the Jatene procedure, LVEDV was 152 +/- 27% of normal and LVEF was 0.61 +/- 0.09. One patient with aortic regurgitation, 1 with aortic regurgitation and residual ventricular septal defect, and 1 with aortic regurgitation and generalized LV wall hypokinesia of unknown cause had large LVEDVs. Pulmonary ventricular EDV and EF were within normal ranges except in the patients with persistent pulmonary hypertension, who had large EDVs and low EFs regardless of the anatomic type of ventricle, either the left or right. The study of RV dimensional change in the Senning group showed a reduced systolic shortening of the anteroposterior diameter compared with the preoperative transposition of the great arteries and normal. This reduced shortening may be related to postoperative adhesion of the RV free wall to the anterior chest wall and fixation of the atrium secondary to the intraatrial repair. In conclusion, systemic ventricular function after intraatrial repair for complete transposition of the great arteries is depressed by unavoidable residua and sequelae: persistent RV hypertension, anatomy of the right ventricle and, possibly, postoperative adhesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Two-dimensional echocardiography in the older child

The role of two-dimensional echocardiography in the management of any congenital cardiovascular anomaly depends on the lesion's natural history and surgical alternatives. Diagnostic assessment of subaortic stenosis and postoperative follow-up of Fontan and Mustard/Senning procedures and tetralogy of Fallot reconstruction illustrate the application of two-dimensional echocardiography to the management of these problems in the older child. Two-dimensional echocardiography displays the static anatomic as well as dynamic functional sequels of left ventricular outflow obstruction. Detailed anatomic display of Fontan reconstruction is compromised by its somewhat unpredictable spatial organization. Combining two-dimensional imaging with gated pulsed Doppler techniques, however, supplements limited anatomic definition with flow profile data specific to the varied surgical interpretations of the Fontan principle. In a similar manner, combined imaging after Senning/Mustard procedures permits detailed anatomic and hemodynamic interrogation of pulmonary and systemic venous return to the neo-left and neo-right atria. The limitations of cardiac ultrasound imaging of the older child after tetralogy of Fallot reconstruction offer some insight into the future directions that are necessary in the application of this imaging technique. Imaging of these patients is compromised by the prosthetic material, which compromises the assessment of right ventricular outflow pulmonary artery reconstruction and ventricular septal closure. Although gated pulsed Doppler echocardiography overcomes some of these limitations, better tissue characterization in the presence of bioprosthetic material is necessary.

Transposition of the great arteries and intact ventricular septum: anatomical repair in the neonate

Fourteen neonates 18 hours to 32 days old with transposition of the great arteries (TGA) and virtually intact ventricular septum (IVS) underwent arterial switch operations under deep hypothermic circulatory arrest. Preoperative left ventricular to right ventricular peak systolic pressure ratios ranged from 0.7 to 1.0 (mean, 0.92), and the echocardiogram showed a centrally positioned ventricular septum in 10 patients and a rightward displaced ventricular septum in 4. One patient died twelve hours after operation. Postoperative complications included bleeding from the left coronary artery-pulmonary artery anastomosis (1 patient), stenosis of the pulmonary artery-aorta anastomosis requiring reoperation (2 patients), transient ST segment and T wave abnormalities consistent with ischemia (3), and development of pathological Q waves suggestive of clinically silent infarction (2). The capacity of the left ventricle in a neonate to effectively take over the systemic circulation was clearly demonstrated. A longer follow-up period is needed to assess late ventricular function, coronary ostial growth, growth of the aorta-pulmonary artery anastomosis, late aortic valve (anatomical pulmonary valve) function before definitive recommendations about the superiority of the arterial switch operation in neonates with TGA plus IVS can be formulated.

Assessment of left ventricular contractile state after anatomic correction of transposition of the great arteries

When compared with intra-atrial baffle repairs for D-transposition of the great arteries (TGA), anatomic correction offers the theoretic advantage that it results in the use of the left ventricle (LV) as the systemic ventricle. Although the long-term success of this procedure depends on the function of the LV, little is known regarding LV postoperative contractile state. The LV end-systolic pressure-dimension and wall stress-shortening (% delta D) relationships, sensitive indexes of contractility, were studied during methoxamine-induced increases in afterload in eight patients with TGA and intact ventricular septa and in four patients with TGA and associated lesions. The patients with TGA and intact ventricular septa underwent pulmonary artery banding when they were between the ages 0.1 and 1.1 years (mean 0.4) to prepare the LV for anatomic correction. Age at repair ranged from 0.3 to 1.8 years (mean 1.0) and that at study from 1.7 to 6.7 years (mean 3.3). The interval from correction to study was 0.4 to 4.8 years (mean 2.3). End-systolic pressure was estimated from a calibrated suprasternal notch tracing. End-systolic dimension, wall thickness, and % delta D were determined by M mode and two-dimensional echocardiography, and end-systolic wall stress was then calculated. Results were compared with previously reported normal values. The pressure-dimension and wall stress-% delta D relationships were normal in 10 of 12 TGA patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Transposition of the great arteries and ventricular septal defect: results with the Senning operation and closure of the ventricular septal defect in infants

From May, 1978, to July, 1982, 46 infants ranging in age from 12 days to 12 months and in weight from 2.1 to 8.4 kg underwent repair of dextrotransposition of the great arteries (D-TGA) and ventricular septal defect (VSD) using a Senning repair and closure of the VSD. Ventricular septal defects were classified as membranous (47.8%), malaligned (28.3%), atrioventricular (AV) canal type (13.0%), subarterial (2.2%), muscular (2.2%), and multiple (6.5%). Hospital mortality was 15.2% and late mortality, 5.1%. Postoperative complications included tricuspid regurgitation (mild in 3 and severe, requiring tricuspid valve replacement, in 3), residual VSD (pulmonary/systemic flow ratio of greater than 2:1) in 3 patients (2, AV canal type and 1, multiple VSDs), pulmonary venous obstruction in 3 patients, and permanent complete heart block in 4 patients (2, AV canal type of VSD also requiring tricuspid valve replacement). Lung biopsy studies showed reversible Heath-Edwards and morphometric changes. No patient was seen with Heath-Edwards III or greater changes. In 10 patients, right ventricular end-diastolic pressures and pulmonary artery pressures at rest were within normal limits one year after operation. As the operative mortality of atrial inversion and arterial switch operations for D-TGA with VSD tends to become comparable, more extensive follow-up data, including cardiac catheterization and coronary arteriography in a large number of patients, will be necessary to establish the superiority of one approach over the other.

Clinical and morphologic cardiac findings after anthracycline chemotherapy. Analysis of 64 patients studied at necropsy

The relation between clinical evidence of and histologic signs of anthracycline cardiotoxicity was evaluated by reviewing the clinical and morphologic findings in 64 patients studied at necropsy, all of whom had received doxorubicin or daunorubicin chemotherapy during life. Of the 64 patients, 20 (31%) had documented clinical toxicity consisting of impaired left ventricular systolic performance; in 7 (35%) of these 20 patients, histologic signs of toxicity were absent. In the remaining 13 patients with clinical toxicity, histologic signs of toxicity ranged from mild to severe. Of the 44 (69%) patients without clinical signs of drug toxicity, 21 (48%) had no histologic sign of cardiotoxicity; in 23 (52%) of the patients without clinical toxicity, however, morphologic signs of cardiotoxicity were nevertheless present--mild in most patients, but extensive in 4. Signs of extensive histologic toxicity (19 [30%] of 64 patients) were associated with large doses (greater than 450 mg/m2) of the drug, mediastinal irradiation, and age greater than 70 years. This study suggests that attempts to monitor cardiotoxicity by serial evaluation of cardiac histology in patients undergoing anthracycline chemotherapy may be seriously limited by the fact that clinical evidence of toxicity may be present without histologic signs of toxicity; likewise, histologic signs of anthracycline toxicity may be present without clinical evidence of toxicity.

Radionuclide angiographic evaluation of right and left ventricular function during exercise after repair of transposition of the great arteries. Comparison with normal subjects and patients with congenitally corrected transposition

We assessed the incidence, clinical significance and etiology of ventricular dysfunction after intraatrial repair of d-transposition of the great arteries in 11 patients, mean age 9 +/- 3 years, who had had Mustard operations. We compared the results to 15 patients who were considered to have normal ventricular function, two patients who had Rastelli operations and five patients with congenitally corrected transposition. Gated equilibrium radionuclide angiography with supine exercise stress testing was used to assess these children. We found no significant difference between our patient groups in exercise capacity, heart rate, or blood pressure response to exercise. However, we found a high incidence of right ventricular dysfunction in the patient groups, manifested by an abnormal right ventricular ejection fraction response to dysfunction in the patient groups, manifested by an abnormal right ventricular ejection fraction response to exercise in six of 11 patients with a Mustard repair, both patients with a Rastelli repair and all five with congenitally corrected transposition. In addition, the left ventricular response to exercise was abnormal in 10 of 11 patients who had undergone a Mustard repair, both patients with a Rastelli repair, and two of five patients with congenitally corrected transposition. We conclude that biventricular dysfunction is frequently present after intraatrial repair of d-transposition of the great arteries. Despite this dysfunction, no significant decrease in exercise tolerance is found in childhood.