Regulation of human heart contractility by essential myosin light chain isoforms.

Most of the patients with congenital heart diseases express the atrial myosin light chain 1 (ALC-1) in the right ventricle. We investigated the functional consequences of ALC-1 expression on the myosin cycling kinetics in the intact sarcomeric structure using multicellular demembranated fibers ("skinned fibers") from the right ventricular infundibulum of patients with Tetralogy of Fallot (TOF), double outlet right ventricle (DORV), and infundibular pulmonary stenosis (IPS), Force-velocity relation was analyzed by the constant-load technique at maximal Ca2+ activation (pCa 4.5). Half-time of tension development (t1/2) was investigated by monitoring contraction initiation upon photolytic release of ATP from caged-ATP in rigor. The patients investigated here expressed between 0 and 27% ALC-1. There was a statistically significant correlation between ALC-l and maximal shortening velocity (Vmax) which rose 1.87-fold from 1.2 muscle length per second (ML/s) to 2.25 ML/s in a normal (0% ALC-1) and diseased (19.9% ALC-1) ventricle. Half-time of tension development decreased 1.85-fold with increasing ALC-1 expression (t1/2) was 0.252 s and 0.136 s at 2 and 18.4% ALC-1, respectively). We conclude that the expression of ALC-1 in the human heart modulates cross-bridge cycling kinetics accelerating shortening velocity and isometric tension production.

Comparison of modified short axis view and apical four chamber view in evaluating right ventricular function after repair of tetralogy of Fallot.

BACKGROUND: In clinical settings an easy and reliable method for following up right ventricular (RV) function in patients after repair of tetralogy of Fallot (TOF) is needed. It is, however, unclear whether the novel modified short axis view from echocardiography is superior to the apical four chamber view in this aspect. MATERIALS AND METHODS: Thirty postoperative TOF patients with median age 17 years (range 6-45 years) and follow up period of 10 years (range 0.5-40 years) were examined echocardiographically using the apical four chamber view and the novel modified short axis view. RV areas in end-systole (Amin) and end-diastole (Amax) were measured and an area fraction [(Amax - Amin)/Amax * 100%] was calculated from the respective view. RV ejection fraction was assessed through magnetic resonance imaging (MRI). The RV area fractions from echocardiography were compared to the RV ejection fraction. RESULTS: The right ventricular area fraction derived from the modified short axis view was significantly lower than that from the apical four chamber view (34.3+/-9.1% vs. 42.5+/-10.2%, p=0.007). Both the RV area fractions obtained from the modified short axis view (r=0.674, p<0.001) and from the apical four chamber view (r=0.512, p=0.025) correlated significantly with the MRI derived RV ejection fraction. CONCLUSION: The novel modified short axis view from echocardiography may be superior to the apical four chamber view for routine follow up of patients after TOF repair, in whom the right ventricular outflow tract plays an important role in the right ventricular systolic function.

Comparison of results and complications of surgical and Amplatzer device closure of atrial septal defects.

OBJECTIVES: Results and complications of surgical versus transcatheter treatment of atrial septal defect in the current era are compared. METHODS: All consecutive patients with a secundum atrial septal defect and a pulmonary/systemic flow ratio of 1.5:1 or more who presented between May 1997 and June 1998 were enrolled in this study. All patients except those who initially had defects not feasible for interventional occlusion were catheterized to allow interventional closure of the defects. All patients in whom interventional closure could not be performed underwent surgical closure. RESULTS: Sixty-one patients underwent surgery at a median age of 20 years (0.5-74 years) and 61 had the defect closed with an Amplatzer device (AGA Medical Corporation, Golden Valley, Minn) at a median age of 12 years (0.8-77.7 years) (P >.2). Hospital stay in surgically treated patients was 8 days (6-19 days) versus 3 days (3-14 days) in interventionally treated patients (P <.001). Atrial septal defect and shunt sizes were larger in the surgical group ( P <.001). Closure rates in the 2 groups were identical (98%). One patient (68 years) in the surgical group had a perforated duodenal ulcer that necessitated an operation 8 days after closure of the atrial septal defect, and 1 (26 years) had an infected lateral thoracotomy wound necessitating plastic surgery. Embolization of the Amplatzer device to the left ventricle was observed in 1 patient (29 years). The device could be retrieved from the heart, but vascular surgery was required to extract it from the femoral artery. CONCLUSIONS: As complete closure rates and complications are identical, but duration of hospital stay is shorter with less morbidity, we prefer implantation of an Amplatzer septal occluder to surgery wherever possible.

Anomalous origin of the left coronary artery from the pulmonary artery. Early results with direct aortic reimplantation.

Between January 1991 and June 1993, eleven children with anomalous origin of the left coronary artery from the pulmonary artery underwent direct aortic reimplantation of the left coronary artery at the German Heart Institute Berlin. The patients' ages ranged from 2.5 months to 10.5 years; six were infants. Three infants were intubated and their lungs ventilated before the operation, and one was resuscitated 2 days before the operation. The electrocardiograms of eight patients indicated deep Q waves. All but three of these patients had insufficient collaterals between the right and left coronary arteries. The entire group exhibited reduced left ventricular ejection fraction (minimum 15%) including mitral valve incompetence, which was moderate in six patients and severe in three. All six infants underwent emergency operations, and the remaining children, who were older, underwent elective operations involving moderate hypothermic perfusion and cold crystalloid cardioplegia. Aortic cross-clamping time ranged from 22 to 79 minutes (mean 54 minutes). A two-coronary artery system was established in all patients by direct reimplantation of the anomalous left coronary artery into the ascending aorta. Three patients who also exhibited severe mitral valve incompetence underwent modified Kay mitral valve annuloplasty. A delayed sternal closure procedure (closure performed 1 to 10 days after the operation) was used on eight patients. A 10-month-old patient was successfully treated after the operation with a centrifugal left heart assist device and a 9-year-old patient received extracorporeal membrane oxygenation because of severe heart failure. No postoperative deaths occurred. Left ventricular end-diastolic volume decreased dramatically after the operation and returned to near normal values 1 to 9 months postoperatively. At the same time, the preoperatively depressed left ventricular ejection fraction returned to normal and mitral valve incompetence decreased or vanished in eight patients. Color Doppler echocardiograms (eleven patients) and coronary angiograms (three patients) indicated that the reimplanted left coronary artery was patent in all eleven patients during the follow-up period. Reimplantation of the left coronary artery into the ascending aorta is an effective method of establishing a two-coronary artery system in children with anomalous origin of the left coronary artery from the pulmonary artery. Mitral valve annuloplasty is recommended for patients who also have severe mitral valve incompetence. Prolonged assisted circulation must be used in cases of severe postoperative heart failure.

Acute hemodynamic effects of post cardiotomy peritoneal dialysis in neonates and infants.

OBJECTIVE: Evaluation of the acute hemodynamic changes during peritoneal dialysis in patients with low cardiac output syndrome and acute renal failure after open heart surgery. PATIENTS: Three newborns and three infants after corrective surgery of congenital heart disease with post cardiotomy dialysis. Five of these had an open thorax during dialysis. METHODS: Cardiac output measurements using the thermodilution technique on two consecutive days at four different times during the peritoneal dialysis cycle. RESULTS: We did not find a deterioration of the cardiac index or systemic vascular resistance measured over two cycles in each of the six patients. Pulmonary artery pressure rose slightly after instillation of the dialysate solution in all patients. Changes in central venous pressure and left atrial pressure were not clinically meaningful. In all patients fluid removal by peritoneal dialysis was effective. All five surviving patients recovered renal function. CONCLUSIONS: Peritoneal dialysis can be performed in newborns and infants following cardiac surgery without causing acute hemodynamic imbalances. An open chest may have a significant impact on hemodynamic stability during peritoneal dialysis by blunting any possible negative alterations of increased intraabdominal pressure.

Soluble L-selectin plasma concentrations in infants undergoing heart surgery: no association with capillary leak syndrome or need for respiratory support.

OBJECTIVE: In critical care patients at risk of developing the acute respiratory distress syndrome (ARDS), low soluble L-selectin (sCD62L) plasma concentrations have been shown to be associated with progression to ARDS and prolonged subsequent mechanical ventilation. This study aimed to determine the usefulness of sCD62L plasma concentrations to identify infants undergoing cardiovascular surgery who are at risk for postoperative pulmonary dysfunction and capillary leaks. DESIGN: Serial measurements of sCD62L plasma concentrations in a cohort of infants with congenital heart disease before, during, and after surgery for 4 consecutive days. SETTING AND PATIENTS: Infants aged 3-337 days undergoing cardiovascular surgery with (N = 27) or without (N = 12) cardiopulmonary bypass in a tertiary care center. RESULTS: sCD62L concentrations before surgery showed a strong correlation with the infant's age (r = 0.77, p < 0.001). During surgery, sCD62L levels dropped from 9.0 +/- 0.7 to 5.6 +/- 0.4 nmol/l (mean +/- SEM; p < 0.001). The minimum sCD62L concentration during and after surgery did not differ between infants operated upon with or without cardiopulmonary bypass (p > 0.1) or in infants who did (N = 10) or did not (N = 29) develop capillary leak syndrome. Whereas capillary leak syndrome was associated with prolonged mechanical ventilation (p < 0.01), there was no relationship between sCD62L concentrations at baseline or at any time thereafter and number of hours on the ventilator(p > 0.1). CONCLUSION: sCD62L concentrations before or after surgery are not apt to identify infants at increased risk of prolonged mechanical ventilation.

Acute ventilatory restriction in children after weaning off inhaled nitric oxide: relation to rebound pulmonary hypertension.

OBJECTIVE: To assess the interaction between pulmonary hemodynamics and respiratory mechanics during acute pulmonary hypertension. PATIENTS: Ventilated and paralysed children treated with inhaled nitric oxide because of post-operative pulmonary hypertension. INTERVENTIONS: Weaning of inhaled nitric oxide. MEASUREMENTS: Air flow and airway pressure, calculation of dynamic respiratory system compliance and respiratory system resistance for each breath by multiple linear regression. RESULTS: In four patients, increases in pulmonary arterial pressure from 26.1 to 56.7 mm Hg (p<0.001) during weaning off nitric oxide were associated with decreases in tidal volume (from 9.7-->8.2 ml/kg, p<0.01) and reductions in dynamic respiratory system compliance (from 0.52-->0.34 cm H20/ml/kg, p<0.001), while respiratory system resistance was unchanged. CONCLUSIONS: Impaired ventilation during acute pulmonary hypertension is predominantly related to a reduction in respiratory system compliance.

Capillary leak syndrome in children who undergo cardiopulmonary bypass: clinical outcome in comparison with complement activation and C1 inhibitor.

OBJECTIVES: Capillary leak syndrome (CLS) is associated with significantly increased morbidity and occurs after cardiopulmonary bypass in children with congenital heart disease. We investigated the early clinical parameters that predict the development of CLS and examined the relationship between the presence of CLS and complement and contact activation and C1 esterase inhibitor (C1-INH) during and after bypass. DESIGN: In this prospective study we took serial serological measurements of the complement and contact system and C1-INH in a cohort of 27 infants before, during, and up to 96 h after open-heart surgery. RESULTS: Complement and contact activation and a decrease in C1-INH were measured in all infants during and after CPB. Ten infants developed CLS postoperatively. Younger age and longer bypass time were strongly correlated to the development of CLS. No relationship was found between the degree of hypothermia, weight, gender, or cross-clamp time. C1-INH concentration and activity were lower peri- and postoperatively in the CLS group. Infants with CLS had a more pronounced postoperative increase in the C5a and C3a levels, higher postoperative level of factor XIIa, and lower prekallikrein activity than those without CLS. CONCLUSION: Contact and complement activation occurs during cardiopulmonary bypass and contributes to CLS more frequently in infants of a younger age and with a prolonged bypass time. This activation and decrease in C1-INH was strongly expressed in the CLS group, and therefore early substitution of C1-INH may prevent CLS after open-heart surgery in high-risk infants.

Eleven-year follow-up after descending thoracic aorta replacement in a small child.

Eleven years after the prosthetic replacement of a hypoplastic thoracic aorta in a 3.5-year-old child, there was normal growth of the aortic arch and abdominal aorta without signs of restenosis. This case illustrates that growth of the aorta can be normal after replacement of its thoracic part in a growing child.

Sergei S. Brukhonenko: the development of the first heart-lung machine for total body perfusion.

Sergei S. Brukhonenko designed and constructed one of the earliest heart-lung machines. He was the first to experimentally perform a total body perfusion with the heart of the animal isolated from the circulation. His work paved the way to the first experimental operations on heart valves. Although Brukhoneko's pioneering contributions have not received the recognition they deserve, his work represents an important landmark in cardiac surgery.

Cavo-pulmonary shunt: from the first experiments to clinical practice.

The cavo-pulmonary anastomosis is often referred to as Glenn shunt today. The concept of cavo-pulmonary shunting, however, was developed independently by many surgeons. While the work of some of them is widely recognized, the pioneering contributions of many others fall into oblivion. Nonetheless, each of them contributed something original and precious to the total sum of our modern knowledge. It seems timely, as we enter the new millennium, to give due credit to those individuals who put their minds and efforts into helping sick children. These people deserve recognition.

Critical subaortic stenosis in a newborn caused by accessory mitral valve tissue.

A 2-week-old newborn girl underwent successful surgery in our clinic for critical subaortic stenosis caused by accessory mitral valve tissue, which, because of excessive growth, protruded into the left ventricular outflow tract. The preoperative pressure gradient below the aortic valve was 80 mm Hg. The operation consisted of resection of the accessory tissue through a combined aortotomy and atriotomy approach without residual pressure gradient and mitral valve incompetence. This approach is recommended to ensure that accessory tissue is removed without damaging the mitral valve.

Thrombosis of intracardiac or extracardiac conduits after modified Fontan operation in patients with azygous continuation of the inferior vena cava.

BACKGROUND: The Fontan procedure in patients with azygous continuation of the inferior vena cava, requires a cavo-pulmonary anastomosis, and deviation of the hepatic venous drainage to the pulmonary arteries using an intra- or extracardiac conduit. METHODS: We report thrombosis of two pericardial conduits and one Gore-Tex (W. L. Gore & Assoc, Flagstaff, AZ) graft used for deviation of hepatic venous blood to the pulmonary arterial tree in 3 patients aged 11, 24, and 28 years. Two of the conduits (pericardial) were intraatrial. The Gore-Tex graft was placed in an extracardiac position. The two pericardial conduits obstructed completely. RESULTS: One patient died at reoperation. In the 2nd patient, the conduit was excised and the hepatic veins were allowed to drain into the atrium. In the 3rd patient, partial thrombosis of the Gore-Tex conduit was noted 30 months after operation. The thrombus resolved with oral anticoagulation. CONCLUSIONS: Conduits carrying only hepatic venous blood flow may have a higher risk of thrombosis. Anticoagulation or alternative methods of directing hepatic blood flow to the pulmonary circulation must be considered in these patients.

Prolonged open sternotomy after pediatric open heart operation: experience with 113 patients.

Between April 1990 and November 1993, 1,252 open heart operations were performed in infants and children with congenital heart defects. Prolonged open sternotomy was used in 113 patients (9%) in 10 surgical categories. Thirty-six of these children (32%) were infants and 43 (38%) were newborns. Twenty-four patients (21%) had undergone operation previously; 3 newborns had been treated with extracorporeal membrane oxygenation before the operation. The patients were grouped according to indications for prolonged open sternotomy as follows: group I, 31 patients with squeezed (large) heart syndrome (1 death); group II, 14 patients with hemodynamic instability after sternal approximation (2 deaths/14.2%); group III, 35 patients with low output state after bypass (17 deaths/48.5%); group IV, 21 patients with extracorporeal circulatory assist devices (15 deaths/71.4%); group V, 3 patients with severe arrhythmias (no deaths); and group VI, 9 patients with atypical tamponade that necessitated reopening the sternum in the intensive care unit (6 deaths/66.6%). Overall mortality was 36.2% (41 patients). Four group IV patients were weaned successfully from extracorporeal membrane oxygenation and heart transplantation was performed successfully on two others. All but one of the deaths occurred before delayed sternal closure. After hemodynamic stabilization was achieved, the sternum was closed in all 72 surviving patients with absorbable sutures (in 86% within the first 6 days after operation). In 50 patients (69% of survivors) pericardial substitution with a polytetrafluoroethylene membrane was performed. One newborn with mediastinal infection after extracorporeal membrane oxygenation was treated successfully with retrosternal drain and suction lavage.(ABSTRACT TRUNCATED AT 250 WORDS)

Correction of complete atrioventricular septal defects with the double-patch technique and cleft closure.

BACKGROUND: Controversy continues to surround determining which is the most beneficial method of complete atrioventricular septal defect repair, eg, one- versus two-patch repair, closure of mitral cleft, and the necessity of annuloplasty. METHODS: Between January 1988 and November 1995, 120 patients with complete atrioventricular septal defect underwent total correction at the German Heart Institute Berlin. Sixty-nine of the patients were infants and 51 were children or adolescents. Eleven patients had previously undergone pulmonary artery banding. One hundred three patients had Down's syndrome. In all 120 patients complete atrioventricular septal defect repair was performed using the two-patch technique. The mitral cleft was closed with interrupted sutures in 119 cases. RESULTS: Thirty-four patients required aggressive treatment of postoperative pulmonary hypertensive crises (including nitric oxide inhalation). There were 12 hospital deaths (10%). Mortality was highest in patients with persistently high postoperative pulmonary arterial pressure (pulmonary artery pressure/systemic artery pressure > 0.6) (7 of 17 patients died; 41%). Associated atrioventricular valve anomalies, especially dysplastic valve tissue and severe preoperative cardiopulmonary instability necessitating catecholamine support and artificial ventilation, represented other risk factors. There were six late deaths (5%); cumulative mortality was 15%. Four patients suffered a complete heart block and sick sinus node syndrome necessitating pacemaker implantation 1 to 6 months after operation. During the follow-up period (3 to 80 months after operation), 7 patients (6.8% of survivors) were successfully reoperated on after significant mitral valve incompetence due to an open "cleft" (suture failure) developed. CONCLUSIONS: Correcting complete atrioventricular septal defect using the two-patch technique, routine cleft closure, and atrial septal incision led to a low incidence of residual mitral valve incompetence. Mortality was primarily influenced by severe cardiopulmonary instability and additional atrioventricular valve anomalies preoperatively and the persistence of high pulmonary arterial hypertension postoperatively.

Incidence of atrial flutter/fibrillation in adults with atrial septal defect before and after surgery.

BACKGROUND: There is controversy about the benefit of surgical repair for atrial septal defect in adults, especially its effect on the incidence of supraventricular dysrhythmias, atrial flutter and fibrillation. We studied their incidence before and after operation. METHODS: We examined surface and 24-hour Holter electrocardiograms before, early (between 3 and 7 days), and late (more than 6 months) after operation, performed at age 42.2 years (range, 18.5 to 74.9 years), in 211 adults with atrial septal defect. Patients were arbitrarily divided into three groups: age 18 to 40 years (n = 101), age 40 to 60 years (n = 83), and age more than 60 years (n = 27). All consecutive patients operated on between January 1988 and December 1996 and having a pulmonary to systemic flow ratio of 1.5:1 or greater were included in this study. RESULTS: The age of patients without arrhythmias before or after atrial septal defect closure (39+/-13 years) was significantly lower than that of patients with flutter (54+/-12 years) or fibrillation (59+/-8 years). The incidence of atrial flutter was influenced by surgical repair as atrial flutter converted to sinus rhythm late after operation in 10 of 18 patients. However, there was no change in the incidence of atrial fibrillation before (n = 28) and after (n = 21) operation. CONCLUSIONS: Our data show that surgical correction of atrial septal defect leads to regression of the incidence of atrial flutter but not fibrillation. Thus, surgical repair of atrial septal defect to abolish supraventricular tachyarrhythmias in adults is warranted, but in patients with fibrillation, it may have to be combined with a Maze operation in the future.

Origin of the circumflex coronary artery from the pulmonary artery in infants.

Two infants with anomolous origin of the left circumflex coronary artery from the pulmonary artery had to be operated on at ages 40 days and 30 days because of severe myocardial dysfunction. This illustrates that the clinical course of anomalous origin of the circumflex artery from the pulmonary artery may not always be as favorable as reported in the literature.

Nikolai Terebinski: a pioneer of the open valve operation.

On the occasion of the hundredth anniversary of heart surgery, this article presents the remarkable work of the Russian scientist and surgeon Nikolai Terebinski. The medical world today remains largely unaware that he performed the first successful open valve operations. These experimental operations were conducted in Russia between 1926 and 1937 through the use of an extracorporeal circulation device known as the autojector. The experiments were reviewed based on Terebinski's original articles and experimental notes. Here we present the techniques and results of his landmark open valve operations on dogs. He performed more than 250 open valve operations, which were the first of their kind. In his attempt to create and then later correct tricuspid and mitral valve stenosis and insufficiency, Terebinski developed many principles of open heart surgery that are valid today. His work represents a milestone in the history of heart surgery.

Development of subneopulmonary obstruction early after arterial switch operation in an adult.

In a 19-year-old woman who had previously undergone pulmonary artery banding at the age of 1.5 years, a muscular right ventricular outflow tract obstruction developed 3 days after an arterial switch operation. Although conservative therapy proved successful, prophylactic surgical intervention on the conal septum may be beneficial in preventing the postoperative development of right ventricular outflow tract obstruction.

Early experience with extracardiac Fontan operation.

BACKGROUND: The extracardiac Fontan (ECFO) operation has gained more widespread use over last decade. In this article we analyze our early experience with ECFO. METHODS: Thirty-three patients underwent ECFO at median age 4.1 years. Normothermic perfusion with the heart beating was used in 24 patients and cardioplegia in 7. Fenestration was not performed in the last 16 patients who underwent surgery without cardioplegia. RESULTS: The hospital mortality was 6% (2 patients). Necessity or duration of inotropic support, duration of mechanical ventilation, intensive care unit and hospital stay, and incidence of prolonged pleural effusions of patients operated on without cardioplegia were shorter and the rate of complications in these patients was lower than in patients who underwent cardioplegia. CONCLUSIONS: Our preliminary experience shows that ECFO can be performed in many patients with normothermic cardiopulmonary bypass and without cardioplegia and fenestration. Avoidance of cardioplegia seems to decrease postoperative morbidity. Incidence of early postoperative arrhythmias is low. Despite encouraging early results, longer follow-up is necessary to prove the real advantages of ECFO.