[Epicardial atrial pacing using an active fixation bipolar endocardial lead in children].

Good performance was observed over 10 years after implantation of bipolar epicardial atrial pacing using an active fixation bipolar endocardial lead in 3 pediatric patients with congenital heart block. The bipolar endocardial lead which was supposed to be fixed transvenously was implanted on the atrial surface by first screwing the lead's helix into the myocardium. The catheter was then laid down on the atrial surface, and both electrodes were wrapped by the atrial tissue. The good performance of this pacing lead seemed to depend on stable positioning of the electrode. This lead is superior to the commercially available, and steroid eluting epicardial bipolar pacing lead, on the point of its small size in head and body, and could be applied to dual chamber pacing in smaller children.

[Management of mediastinitis after pediatric cardiac surgery with continuous closed irrigation method].

Two cases are presented as a successful management for mediastinitis with the continuous closed irrigation method after pediatric cardiac surgery. The continuous closed irrigation method has significant advantages over conventional open irrigation method or muscle flap in pediatric cases, because the system is simple to handle and easy to wash out any infectious tissue debris without additional invasive intervention. However, adequate duration of the irrigation and subsequent antibiotic regimen is still unclear. We conclude that the continuous closed irrigation method is an effective management which is applicable to most of mediastinitis cases after pediatric cardiac surgery.

Persistent fifth aortic arch associated with type A aortic arch interruption. Histological study and morphogenesis.

A male infant, having a persistent fifth aortic arch and interruption of the aorta distal to the left subclavian artery, underwent successful surgical treatment. A histological study of the excised segment of the aorta showed that the ductal tissue extended to the junction between the fifth arch and the descending aorta with consequent narrowing in the corresponding region. The ductal tissue, however, did not contribute to occlusion in the fourth aortic arch. The morphogenesis of this combination of aortic arch anomalies was also discussed.

Recovery of high-frequency QRS potentials following cardioplegic arrest in pediatric cardiac surgery.

We examined the hypothesis that recovery of high-frequency QRS potentials at reperfusion is influenced by the duration of myocardial ischemia during cardioplegic arrest in pediatric cardiac surgery. Signal-averaged electrocardiograms were recorded after induction of anesthesia (baseline data) and every 1 to 5 minutes after aortic declamping in 14 patients aged 2 months to 6 years. The signals were processed with a band-pass filter between 80 Hz and 300 Hz to obtain high-frequency potentials in the QRS complex. The high-frequency QRS potentials (80-300 Hz) were expressed as the root mean square voltage over the filtered QRS complex. The high-frequency QRS potentials at baseline were 33.9 +/- 4.4 microV. They decreased to 13.7 +/- 9.6 microV 1 minute after aortic declamping (p = 0.005). Subsequently they gradually increased and then returned to the baseline level. The time that the potentials were over 90% of baseline value ranged from 10 to 35 minutes after aortic declamping. The recovery time of this reduction in the high-frequency QRS potentials correlated with the duration of aortic cross-clamping (r = 0.80, p = 0.0009) and the value of postoperative MB isozyme of the creatine kinase (r = 0.81, p = 0.0042). This study demonstrated that the high-frequency QRS potentials decreased at early reperfusion following cardioplegic arrest and then returned to preischemic levels. The recovery time of the high-frequency QRS potentials significantly correlated with cardioplegic arrest time and postoperative MB isozyme of the creatine kinase values. Our results raise the possibility that changes in high-frequency electrocardiographic signals in the QRS complex may reflect myocardial ischemia during cardioplegic arrest.

Right aortic arch with isolation of the left subclavian artery and bilateral patent ductus arterioses.

Of the right aortic arch anomalies, a right arch with isolation of the left subclavian artery is the least common. In a neonate who had a right arch with isolation of the left subclavian artery and bilateral patent ductus arterioses, pulmonary artery steal phenomenon developed after ligation of the right ductus. We performed division of the left ductus and reimplantation of the left subclavian artery into the left common carotid artery.

Extended septoplasty for subaortic stenosis developed 19 years after double-outlet right ventricle repair.

A 27-year-old woman developed subaortic stenosis 19 years after double-outlet right ventricle repair. Subaortic stenosis was caused by a narrow ring of fibromuscular ridge associated with a bulge of the underlying septal muscle. The aortic valve was bicuspid and stenotic. We conducted extended septoplasty, replacing the aortic valve. Postoperative cineangiogram showed an adequate left ventricular outflow pathway. Double-outlet right ventricle repair may thus be followed by subaortic stenosis as long as 19 years after initial surgery. This lesion was assumed due to acquired disease secondary to flow disturbances in the left ventricular outflow, so reconstructing an adequate outflow pathway is effective and appears to help avoid recurring stenosis.

Right coronary artery to left ventricular fistula associated with left ventricular aneurysm.

An infant with right coronary artery to left ventricular fistula associated with left ventricular aneurysm successfully underwent a division of fistula under cardiopulmonary bypass. Follow-up angiogram showed the patency of the right coronary artery, no recurrence of fistula, and the regression of the left ventricular aneurysm. Because the lesion may progress with age, early diagnosis and surgical intervention are indicated to prevent later complications.

[A case of lateral femoral circumflex artery as a free graft for coronary artery bypass surgery].

A 46-year-old man had a three-vessel coronary disease. We performed quadruple coronary artery bypass grafting (CABG) with the left internal thoracic artery (LITA), right gastroepiploic artery (RGEA), saphenous vein and lateral femoral circumflex artery (LFCA). Postoperative coronary angiogram showed that the LFCA bypass graft was patent and supplied sufficient blood to the anastomosed vessel. There was no stenosis at the anastomotic site. However, the LFCA graft showed a string sign. Long-term follow-up and angiographic studies is necessary to establish the use of LFCA as an arterial free graft for coronary revascularization.

Lower extremity hematoma as a complication of warfarinization in patients with artificial heart valves.

Four cases of lower extremity hematoma in patients undergoing anticoagulant therapy after heart valve replacement are herein reported, with special emphasis on the comparative diagnostic value of ultrasonography and computerized tomography. Although conservative management is sufficient for patients with no neurological impairment, needle aspiration after autolysis of the hematoma, which can be confirmed by CT study, is also recommended.

Low-dose protamine based on heparin-protamine titration method reduces platelet dysfunction after cardiopulmonary bypass.

OBJECTIVE: The heparin-protamine titration method that uses the Hepcon hemostasis management system (Medtronic HemoTec Inc, Englewood, Colo) reduced blood loss in cardiac surgery in previous reports, but the mechanism is not fully understood. This study tests the hypothesis that reduced protamine administration preserves platelet function in human cardiac surgery. METHODS: Platelet count, alpha-granule secretion, and aggregation to thrombin before and after cardiopulmonary bypass in human beings were evaluated. In the control group (n = 14), a fixed dose of protamine (3 mg/kg) was administered. In the titration group (n = 20), protamine doses were based on the heparin concentration measured by the Hepcon system. RESULTS: Heparin concentrations before protamine administration were higher in the titration group (P =.0012), but protamine doses of patients in the titration group were markedly lower than those of the control group (P <.0001). During protamine infusion at a rate of 0.3 mg. kg(-1). min(-1), the percentage of granule membrane protein-140-positive platelets significantly increased in the control group compared with the titration group (18.8% +/- 8.6% vs 13.0% +/- 5.3%, P =.0188). After protamine administration, aggregation of washed platelets to thrombin recovered almost to the preoperative level in the titration group; however, it remained lower in the control group (20% +/- 20% vs 55% +/- 18%, P =.0009). CONCLUSION: Low-dose administration of protamine, based on a heparin-protamine titration method, restores not only the blood coagulation but also the platelet responses to thrombin and attenuates platelet alpha-granule secretion during heparin neutralization. Overdose of protamine activates platelets and may predispose patients to excessive bleeding after cardiac surgery.

Atrial fibrillation after coronary artery bypass grafting. An increase in high-frequency atrial activity in patients with right coronary artery revascularization.

The increase in atrial high-frequency activity has been reported as a marker of the risk of paroxysmal atrial fibrillation. The presence of proximal right coronary artery disease is a predictor of atrial fibrillation after bypass surgery, however, the potential mechanism remains controversial. In this study, high-frequency atrial activity to clarify the electrophysiologic background for the predisposition to have proximal right coronary artery disease leading to atrial fibrillation after coronary revascularization was investigated. Before and soon after coronary revascularization, frequency analyses were performed on the 100 ms segment at the end of signal-averaged P waves in 22 patients with right coronary artery disease as opposed to the 23 patients without disease. Under the spectrum curve, area ratio (AR50) and magnitude ratios (MR) were calculated as follows; AR50 = (area 20-50 Hz/0-20 Hz) x 100, and MR = (magnitude at 20, 30, 40 and 50 Hz, respectively/maximal magnitude) x 100. In patients with proximal right coronary artery disease, high-frequency atrial components increased significantly in the 20 to 50 Hz range after coronary revascularization, and the incidence of postoperative atrial fibrillation was higher than in those without disease. In patients without right coronary artery disease, the frequency distribution of P waves was unchanged. Postoperatively, the two groups showed the same atrial frequency distribution. This data suggests that the increase in high-frequency atrial activity after right coronary artery revascularization might be associated with the pathogenesis of postoperative atrial fibrillation.

Aortic dissection in an elderly patient with atrial septal defect.

We report a case of acute aortic dissection that occurred in the late course of surgically untreated atrial septal defect. A 60-year-old man with acute aortic dissection and atrial septal defect was operated on successfully, and we discuss the causal relationship between these two unusual conditions.

Right thoracotomy as an alternative for redo mitral valve replacement and concomitant repair of the tricuspid valve.

BACKGROUND: We report the results of a right thoracotomy for reoperation on the mitral plus concomitant procedures. Access to aorta or repair of other lesions by this approach is controversial. EXPERIMENTAL DESIGN AND SETTING: Retrospective study. Institutional practice (University of Tsukuba Hospital, Tsukuba Japan). METHODS: Until 1995, 9 patients underwent right thoracotomy for mitral reoperation. The indication for this approach was no retrosternal space with the pericardium left open. Seven patients had deteriorated bioprosthesis, 1 periprosthetic valve leakage, and 1 re-stenosis. Four were associated with moderate tricuspid regurgitation. Operations were performed under fibrillation. Cardioplegia was used in 1. RESULTS: Through thoracotomy, 4 underwent mitral valve re-replacement, and 4 mitral valve re-replacement plus tricuspid annuloplasty. One was abandoned because of severe pleural adhesion. No neurological injury, or perioperative myocardial infarction occurred. CONCLUSIONS: The right thoracotomy was an effective alternative to repeat sternotomy for redo mitral valve operation. Also, concomitant repair of the tricuspid valve could be safely done by this approach.

Aprotinin inhibits plasmin-induced platelet activation during cardiopulmonary bypass.

BACKGROUND: In the past few years, aprotinin has been used in cardiac surgery with impressive results of reducing blood loss, but several adverse effects of aprotinin also have been reported. One of the most likely mechanisms is the inhibition of plasmin by aprotinin, although this indirect effect has not been reproduced in all experimental studies. METHODS AND RESULTS: We evaluated the platelet function and fibrinolytic activity during human cardiac surgery, with or without aprotinin. During cardiopulmonary bypass (CPB) in humans without aprotinin (n=16), decrease of platelet aggregation induced by thrombin, increase of alpha-granule secretion of platelet and microparticle formation, and increase of plasmin/alpha2-antiplasmin complex (PIC) were observed. In contrast, low-dose aprotinin (1.0 x 10(6) KIU), which was administered only into the priming fluid of extracorporeal circuits (n=10), maintained platelet aggregation induced by thrombin and reduced alpha-granule secretion and microparticle formation of platelets during CPB. In vitro, plasmin (0.8 CU/mL) released alpha-granules of washed platelets, and this activation was completely inhibited by aprotinin (10 KIU/mL). CONCLUSIONS: Aprotinin has indirect effects to inhibit platelet activation, and this may partly explain the reduction of blood loss during cardiac surgery. To prevent the adverse effects, a single and minimal use of aprotinin is important. The results of in vivo and in vitro studies suggest that platelet preservation was demonstrated by the lower concentration of aprotinin (1.0 x 10(6) KIU per patient or 10 KIU/mL) compared with the concentration that inhibits plasma fibrinolysis.

[NO inhalation therapy for post-operative pulmonary hypertensive crisis of the case of truncus arteriosus].

Two-months-old baby underwent complete correction by Barbero-Marcial's procedure for type I truncus arteriosus. Postoperative hemo-dynamics was fairly stable immediately after the operation. However, the acute rise in pulmonary pressure occurred on the 2nd postoperative day. The pulmonary vasodilation therapy with prostaglandin E1 and amrinone had failed. Thirty ppm of inhaled nitric oxide (NO) was started and it resulted in an immediate decrease in pulmonary arterial pressure. Complete weaning from NO was achieved 9 days after surgery by simultaneous administration of PGE1 and amrinone. Although inhalation of NO reduced pulmonary arterial pressure, combination of PGE1 and amrinone with NO inhalation exerted a pulmonary vasodilation and brought the patient to full recovery in this case with pulmonary hypertensive crisis.

Absent pulmonary valve with intact ventricular septum presenting as cardiorespiratory failure at birth.

Absent pulmonary valve with intact ventricular septum is a rare congenital anomaly. Most cases are not diagnosed until years after birth, although several cases have been reported in the literature in which cardiorespiratory distress developed during the neonatal period. We present a patient who showed improvement after fairly conservative therapy to alleviate the pulmonary vascular resistance, with ultimate palliative surgery. The aneurysmal dilatation of the pulmonary artery was for the most part confined to the proximal portion of the trunk, possibly because the ductus arteriosus was patent. The literature is reviewed.

[Aortic valve regurgitation due to quadricuspid valve: a report of complicated case].

A 66-year-old male with the congestive heart failure was diagnosed grade 4 aortic valve regurgitation due to quadricuspid valve associated with bacterial endocarditis, widely patent left coronary artery ostium, chronic renal failure, and secondary hyperparathyroidism. Coronary arteriography showed that the size of left coronary ostium was widely patent 10 mm in diameter, and trans-esophageal echo cardiogram revealed perforation and vegetations on the coronary cusps of the aortic valve.

[Management of postoperative pulmonary hypertensive crisis in children--indication and usefulness of inhaled nitric oxide therapy as a pulmonary vasodilator].

Among 176 pediatric patients who underwent open heart surgery from 1990 to 1996, 7 developed severe pulmonary hypertensive crisis (PHC) postoperatively. All patients were treated with conventional medical therapy consisting of hyperventilation and deep sedation. Prostaglandin E1 and/or amrinone were administered initially as a pulmonary vasodilator, and in 3 of the 7 patients this resulted in immediate improvement in hemodynamics. These patients subsequently weaned off ventilatory support and they were discharged from the hospital. In 4 other patients, pulmonary vasodilator therapy with prostaglandin E1 and amrinone had failed and they were treated with inhaled nitric oxide (NO). In all patients, inhalation of NO resulted in immediate decrease in pulmonary pressure without significant change in systemic arterial pressure. Two patients successfully weaned from the ventilator, whereas in 2 patients decrease in pulmonary pressure was transient. They developed airway bleeding and died as a result of respiratory insufficiency. Although inhaled NO effectively reduced pulmonary pressure in patients with PHC, this effect was not maintained over 12 hours in patients associated with bronchopulmonary dysplasia. In patients at risk for severe PHC, rapid treatment with NO inhalation after initial event as well as the prevention of lung injury caused by mechanical ventilation were found to be important in the postoperative management.