[Evaluation of a new compact prothrombin time-international normalized ratio measurement device in pediatric management].

BACKGROUND: In a pediatric setting, the need for lifetime oral anticoagulation is increasing because of currency of extracardiac total cavo-pulmonary connection (TCPC) and pediatric valve surgery. We evaluated a new compact device "CoaguChek XS" for measuring prothrombin time-internatinal normalized ratio (PT-INR). METHODS: The international normalized ratio (INR) values obtained from 71 patients (223 samples) by a CoaguChek XS were compared with those obtained by a laboratory-based coagulation analyzer. RESULTS: The values from the CoaguChek XS had a significant correlation with the laboratory based results. (r2 = 0.92, p < 0.01, regression line y = 1.05 x -0.02). CONCLUSION: The CoaguChek XS will be useful in pediatric management.

[Senning operation for transposition of great arteries in a premature baby].

A male baby was delivered by emergency cesarean section due to fetal distress at 30 weeks of gestational age with a birth weight of 813 g. By fetal echocardiography, the patient had been diagnosed with transposition of great arteries (type 1). Early two-staged arterial switch operation was planned after 34 gestational age avoiding intracranial hemorrhage under cardiopulmonary bypass. At 19 days of life, vegetation was revealed on the pulmonary valve by echocardiography, so he was diagnosed as infectious endocarditis. Cefotaxime and gamma-globulin were given intravenously for 4 weeks. While waiting for the increase in the body weight, desaturation from chronic respiratory distress syndrome was exacerbated. At 8 months old, urgent Senning operation was performed to improve desaturation. The patient was discharged at 20 post operative day. We conclude that Senning operation can be feasible operation in such a complicated case.

Interventional treatment for fetus and newborn infant with congenital heart disease.

BACKGROUND: Catheter intervention has become popular not only in adult patients but in younger patients with congenital heart disease. The early neonatal catheter interventional treatment has also been attempted in conjunction with the development of prenatal diagnosis of the congenital heart disease. METHOD: Recent articles concerning several severe structural cardiac diseases in newborns, such as critical aortic stenosis, complete transposition of the great arteries, premature constriction of the ductus arteriosus, and pulmonary stenosis or atresia with intact ventricular septum are introduced with consideration. RESULTS: This study investigated our own experiences of early neonatal balloon valvuloplasty in a patient with critical aortic stenosis carried out immediately after the delivery following prenatal diagnosis. A case with prenatal diagnosis of premature constriction of ductus arteriosus which could prevent persistent pulmonary hypertension of the newborn by early delivery at 39 weeks and 1 day of gestation were reported. CONCLUSION: Several cardiac interventional treatments performed in the present time during the perinatal period and some prospects in the near future are described in the discussion.

Protein kinase A increases the rate of relaxation but not the rate of tension development in skinned rat cardiac muscle.

To clarify the contribution of cross-bridge kinetics to the contraction profile of cardiac twitch during beta-adrenergic stimulation, we studied the rate of tension development and relaxation following laser flash photolysis of caged compounds in rat-skinned ventricular trabeculae before and after treatment with the catalytic subunit of protein kinase A (PKA, 0.5 U/microl, 40 min). Tension development following nitrophenyl (NP)-EGTA photolysis was fitted with a single exponential function. The rate constant increased with an increase in postphotolysis steady tension, and the relation between the rate constant and the tension was not influenced by PKA. The rate of relaxation following diazo-2 photolysis was fitted with a double exponential function. The rate of both initial rapid and subsequent slow relaxation was independent of the extent of relaxation. PKA increased the rate of initial rapid relaxation by about twofold, but showed no significant effect on the rate of subsequent slow relaxation. These results suggest that in beta-receptor stimulated rat cardiac muscle, the increased rate of tension development and the facilitated relaxation rate during twitch can be partly explained as being due to the combined effects of decreased Ca(2+) affinity of troponin C and increased cycling rate of cross-bridges (subtractive combination for tension development and additive combination for tension relaxation).

[Intracardiac repair of tetralogy of Fallot with an anomalous coronary artery crossing the right ventricular outflow tract].

Between may 1993 and march 2001, 2 patients with tetralogy of Fallot and an anomalous coronary artery crossing the right ventricular outflow tract underwent intracardiac repairs. The anomalous coronary arteries included the left anterior descending from the right coronary artery (case 1), and the right coronary artery from the left coronary artery (case 2). In case 1, we turned down a flap of anterior wall of the main pulmonary artery, sutured it to the edge of the right ventriculotomy and placed a bicusped patch to the anterior aspect. In case 2, we underwent transpulmonary-transatrial repair and placed a transannular patch along by the left coronary artery. Right ventricular outflow tract reconstruction was successful in 2 cases.

Response of the stroke volume and blood pressure of young patients with nonobstructive hypertrophic cardiomyopathy to exercise.

Stroke volume (SV), cardiac output (CO) and systolic blood pressure (SBP) were measured during maximal symptom-limited bicycle exercise testing in 13 young patients (age, 11-26 years) with nonobstructive hypertrophic cardiomyopathy (HCM). SV was measured by impedance plethysmocardiography; %SVend, %COend, and %SBPend represent the ratio of the value at termination of the exercise to the respective value at rest. In all patients of HCM-I (the Cardiac Event Group, 3 patients) and 3 of HCM-II (the Non-Cardiac Event Group, 10 patients), the %SVend was less than 100%. The %SVend of HCM-I was significantly lower than the respective values of the HCM-II and Control groups. The %COend values of the HCM-I and HCM-II groups were each significantly lower than that of the Control. The %SBPend values of the HCM-I and HCM-II groups were each significantly lower than that of the Control. Among the HCM patients, the %SVend value was positively correlated with the %SBPend value. The patients who had more severe HCM had poorer exercise-induced increases in SV and SBP. These results suggest that sudden cardiac death in young HCM patients is associated with inhibition of the increase in SV upon exercise.

Idiopathic sustained left ventricular tachycardia in pediatric patients.

BACKGROUND: Idiopathic sustained ventricular tachycardia originating from the left ventricle (ILVT) has been an indication for catheter ablation. The present study evaluated the clinical features, long-term prognosis and indications for treatment in pediatric patients with ILVT. METHODS: The subjects of the present study were eight patients (four males and four females) with a mean age at onset of 11.0 years (range 3-15 years). The mean follow-up period was 7.7 years (range 2.1-11.3 years). RESULTS: In electrophysiologic studies, intravenously administered verapamil was effective for the termination of tachycardia in all six patients who received this treatment and for the prevention of tachycardia in four of five patients. Oral administration of verapamil was effective in five of seven patients. Propranolol or flecainide was added to the treatment protocol for two patients who did not respond to verapamil alone. Tachycardia disappeared without drugs in four patients during the follow-up period and became non-sustained in another patient. Two of three patients with persistent tachycardia underwent catheter ablation. Pharmacologic treatment was very effective for ILVT among these patients. CONCLUSIONS: Pharmacologic therapy, such as with verapamil, is still the treatment of choice for ILVT because of a good long-term prognosis and potential risks and complications by manipulation of catheter ablation.

Has fetal echocardiography improved the prognosis of congenital heart disease? Comparison of patients with hypoplastic left heart syndrome with and without prenatal diagnosis.

BACKGROUND: As prenatal diagnosis of congenital heart disease has gained in popularity, the questions of whether prenatal diagnosis of congenital heart disease is beneficial for the patient and whether fetal echocardiography has improved the prognosis of congenital heart disease are arising. METHODS: We compared four patients with prenatally diagnosed hypoplastic left heart syndrome (HLHS) with 10 patients of non-prenatally diagnosed HLHS from the view points of (i) age at transfer to our Children's Hospital; (ii) whether the oxygen was inhaled during perinatal period; (iii) whether prostaglandin E1 was administered in the period of waiting before operation; (iv) whether the patient had ductal shock; (v) timing of operation; and (vi) surgical outcome. RESULTS: The timing of the transfer to our Children's Hospital was earlier in prenatally diagnosed group than in non-diagnosed group. Oxygen was not given to any of the patients in prenatally diagnosed group. In contrast, oxygen inhalation was given in two of 10 patients in the non-prenatally diagnosed group. Prostaglandin E1 was administrated in three of four patients in the prenatally diagnosed group and seven of 10 patients in the non-prenatally diagnosed group. In terms of ductal shock, none of the patients in prenatally diagnosed group had ductal shock. However, four of 10 patients had ductal shock in the non-prenatally diagnosed group. The median age at Norwood operation was 7 days in the prenatally diagnosed group; however, it was 19 days in non-prenatally diagnosed group. Surgical outcomes showed no significant changes between the two groups. CONCLUSIONS: Prenatal diagnosis of HLHS was surely beneficial for preventing ductal shock and for keeping the patients' preoperative condition good.

Dynamic relations among length, tension, and intracellular Ca2+ in activated ferret papillary muscles.

To study the effects of mechanical constraints on the Ca2+ affinity of cardiac troponin C, we analyzed the tension and aequorin light (AL) responses to sinusoidal length changes (5-10% of the initial muscle length) in aequorin-injected, tetanized cardiac muscles. The amplitude of the quasi-sinusoidal tension and AL responses decreased with increasing length-perturbation frequency from 0.5 to 1 Hz at 24 degreesC and from 1 to 3 Hz at 30 degreesC. The increase in AL corresponded well to the decrease in tension; likewise, the decrease in AL to the increase in tension and the tension response lagged behind the length change. A further increase in frequency (>1 Hz at 24 degreesC and >3 Hz at 30 degreesC) markedly increased the amplitude of the tension responses but decreased the amplitude of the AL responses. The increase in AL lagged behind the decrease in tension; likewise, the decrease in AL lagged behind the increase in tension, and the tension response led the length change. From previous mechanistic interpretations of the frequency dependence of the amplitude of tension response, we argue that the Ca2+ affinity of cardiac troponin C changes in parallel with the active tension (i.e., the number of active cross bridges) but not with the passive tension produced by the length perturbation-induced cross-bridge strain.

Influences of protein kinase A and D-cAMP on actin-myosin interaction and energy consumption of cardiac muscles.

To address controversies concerning the effects of beta-adrenergic stimulation on the rate of myocardial cross-bridge cycling, we measured three mechanical variables, isometric tension development, transient tension response to a step stretch in length (< 1% of muscle length), maximum velocity of shortening, and a chemical variable, ATPase activity before and after treatment with the catalytic subunit of protein kinase A (PKA) in demembranated rat right ventricular trabeculae, and also measured three mechanical variables before and after treatment with D-cAMP in intact ryanodine-induced tetanized preparations. PKA treatment (I U/microliter, 40 min) shifted the pCa-tension relation to the right from 5.41 to 5.26 at pCa50 (the [Ca2+] required for half maximal steady tension) without changing the steepness of the pCa-tension relation and the maximum tension. The rate of the transient tension changes was significantly increased after either PKA or D-cAMP treatment (5 mM, 15 min), regardless of the level of isometric tension. Vmax was increased for a given Ca2+ concentration after either the PKA or D-cAMP treatment, despite the reduced level of isometric tension. The PKA treatment also shifted the pCa-ATPase activity to the right slightly from 5.47 to 5.40 at pCa50, but increased the ATPase activity during a given level of steady isometric tension generation, resulting in an increased tension cost (ATPase activity/tension). These results suggest that, in rat right ventricular trabeculae, beta-adrenergic stimulation may increase the rate of cross-bridge cycling by increasing the rate of crossbridge detachment from actin through a PKA-mediated mechanism, although PKA reduces the Ca(2+)-sensitivity of the contractile system.

Successful blade atrial septostomy in a patient with severe primary pulmonary hypertension--a case report.

Blade atrial septostomy (BAS) for pulmonary hypertension has increased long-term survival and is an effective and palliative preliminary to heart and/or lung transplantation. We treated an 18-year-old woman with severe pulmonary primary hypertension whose symptoms had worsened as a resulted low cardiac output. The patient's right ventricular pressure was 150/23 mmHg, cardiac index (CI) 1.0 L/min per m2, and she showed signs and symptoms of severe primary pulmonary hypertension. We performed BAS successfully, paying particular attention to the following points. To maintain pulmonary blood flow after creating an atrial right-to-left shunt, the patient was infused intravenously with packed red blood cells and volume expander. Oxygen delivery was also increased by the transfusion of packed red blood cells. To avoid unacceptable hypoxemia immediately after the procedure, the atrial septum was initially incised with a very small-blade catheter. Nine months after the BAS, catheterization revealed a decrease in mean pulmonary arterial pressure to 73 mmHg and an increase in CI to 2.5 L/min per m2. Thirteen months after the BAS, the patient died as a result of progressive worsening of right-sided heart failure. We concluded that BAS could be successful in patients with severe pulmonary hypertension providing attention is paid to the patient's condition and that BAS is an effective therapy for prolonging survival.

Treatment of infantile primary pulmonary hypertension by intravenous infusion of lipo-prostaglandin I2 analog.

We used a new vasodilator, TTC-909 (a prostaglandin I2 analog incorporated in lipid microspheres), which produced marked reduction in the pulmonary arterial pressure and resistance in an infant with primary pulmonary hypertension.