Acute myocardial infarction caused by transient coronary vasospasm in a child with Kawasaki disease and no coronary aneurysms.

We report a 15-month old girl with acute myocardial infarction 3 months after treatment for Kawasaki disease (KD); she had no coronary aneurysms. In the first 2 months after KD, she had normal electrocardiograms (ECGs) and echocardiograms that showed mildly dilated coronary arteries. At 3 months, she was asymptomatic but developed ECG changes of anteroseptal MI and increased troponin levels.

Crosstalk signaling between mitochondrial Ca2+ and ROS.

Mitochondria are central to energy metabolism as the source of much of the cell's ATP, as well as being a hub for cellular Ca2+ signaling. Mitochondrial Ca2+ is a positive effector of ATP synthesis, yet Ca2+ overload can lead to mitochondrial dysfunction and cell death. Moreover, Ca2+ uptake by mitochondria is involved in shaping cellular Ca2+ dynamics by regulating the concentrations of Ca2+ within microdomains between mitochondria and sarco/endoplasmic reticulum and plasma membrane Ca2+ transporters.

Responses of non-obese white children to treadmill exercise.

Objective: To determine the response to maximal treadmill exercise with the Bruce protocol in a cohort of healthy non-obese American children and adolescents.

Study Design: A retrospective review of treadmill exercise studies on 347 white American children (188 boys, 159 girls) aged 5 to 18 years was performed with metabolic criteria to verify maximal exercise effort. Data on exercise endurance time, heart rate, blood pressure, and metabolic variables were assessed and compared between age groups and sexes by unpaired t testing and analysis of variance.

Procainamide for rate control of postsurgical junctional tachycardia.

This study was conducted to determine the efficacy of procainamide therapy for rapid rate control of postoperative junctional tachycardia (JT). Postoperative JT is one of the most difficult forms of tachycardia to manage. Reported success with a variety of treatments of JT in infants and children has been inconsistent and limited.

Exaggerated blood pressure response to exercise in children with increased low-density lipoprotein cholesterol.

Arterial vascular responses are characteristically altered with hypercholesterolemia: conduit vessels manifest increased stiffness, and conduit and resistance vessels demonstrate impaired endothelium-dependent dilation and augmented vasoconstriction to neurohumoral stimulation. These changes should be reflected in an exaggerated blood pressure increase in response to exercise. To evaluate this hypothesis, we compared the blood pressure response to treadmill exercise in children with hypercholesterolemia and children with normal lipid levels.

Postoperative assessment of a modified surgical approach to repair of tetralogy of Fallot. Long-term follow-up.

Background: After repair of tetralogy of Fallot, right ventricular (RV) dilation has been associated with increased risk of ventricular arrhythmias and sudden death. To address this, a modified repair was developed.

Methods And Results: We followed two postoperative groups: group 1 (n = 20) received repair of tetralogy of Fallot with the modified technique with transatrial ventricular septal defect closure, a short infundibular incision with avoidance of muscle resection, and patch expansion of the RV outflow tract; group 2 (n = 22) received repair of tetralogy of Fallot by the traditional technique with ventricular septal defect closure through a ventriculotomy with resection of obstructing muscle.

Loss of sinus rhythm after total cavopulmonary connection.

Background: Total cavopulmonary connection (TCPC) to repair functional single ventricle involves the sinus node area, in contrast to the Fontan procedure. We compared ECG findings after TCPC and Fontan to evaluate the impact of the cavopulmonary connection on sinus rhythm postoperatively.

Methods And Results: The Fontan group consisted of 17 patients repaired at 7.

Modified technique for balloon valvuloplasty of critical pulmonary stenosis in the newborn.

Objectives: We report our experience in eight consecutive neonates who underwent attempted balloon dilation as an initial therapy for critical valvular pulmonary stenosis, and we review in detail technical modifications that improved the success rate.

Background: Balloon dilation of the pulmonary valve has become the treatment of choice for valvular pulmonary stenosis in children and adults. There are few reports of its effectiveness in critical pulmonary stenosis in the newborn.

When is echocardiography unreliable in patients undergoing catheterization for pediatric cardiovascular disease?

Technologic advances in echocardiography (e.g., better spatial resolution, Doppler, and color flow mapping) have improved our ability to demonstrate anatomy and physiology in previously problematic conditions, precluding catheterization and angiography in some instances.

Age-related changes in electromechanical properties of canine ventricular muscle: effect of ouabain.

In this report, alterations between the electrical and mechanical responses of isolated neonatal and adult canine ventricular muscle preparations before and after ouabain exposure are described. No significant differences were observed between the two age groups in the concentration-dependent effects of ouabain on increasing contractile force or decreasing maximum diastolic transmembrane potential. The action potential plateau duration was decreased by high concentrations of ouabain (0.

Age-related digoxin effects in an intact canine model.

The inotropic and electrophysiologic effects of digoxin were studied in anesthetized neonatal and adult dogs to test the hypothesis that digoxin had comparable effects in these groups. Recordings of the ECG and central arterial pressure were made starting at 5.75 hours after an intravenous injection of 50 micrograms/kg of the drug.

Flow-independent improvement by diltiazem of ischemia-induced conduction delay in porcine hearts.

The calcium channel blocking agent, diltiazem, improves ischemia-induced conduction delays in the canine heart. It is not known, however, if the improvement of myocardial blood flow caused by diltiazem participates in this response. Accordingly, ischemia-induced conduction delay was measured during brief coronary artery occlusion before and after administration of diltiazem in nine anesthetized pigs with fixed heart rate.

Age-related changes in electrophysiological properties of canine Purkinje fibers: effect of ouabain.

Transmembrane potentials were recorded in Purkinje fibers obtained from dogs aged 1 day, 1 week, 2 weeks, 4 weeks and more than 1 year. After the initial impalements there was a time-dependent increase in diastolic potential. This hyperpolarization was more pronounced in the younger Purkinje fibers.

Primary benign intramural ventricular tumors in children: pre- and postoperative electrocardiographic, echocardiographic, and angiocardiographic evaluation.

The clinical, ECG, echocardiographic, and angiographic data, as well as the operative findings and postoperative courses of three children with intramural ventricular tumors are presented. In all three children, the specific diagnosis of intramural tumor was unsuspected. The ECGs showed a superior axis in all patients.

Chaotic atrial tachycardia in childhood.

Ten cases of chaotic atrial tachycardia (CAT) in childhood are reported. Patients' ages ranged from 1 day to 18 years (average, 3.5 years) at the time of diagnosis.

Ventricular tachycardia in infancy: evidence for a reentrant mechanism.

Ventricular tachycardia is unusual in infancy. Three infants are described in whom this arrhythmia was documented by electrophysiologic studies. The ability to start and terminate this rhythm by critically timed premature ventricular stimulation suggests a reentrant mechanism.

Left atrial size in childhood.

To determine the accuracy of the diagnosis of left atrial enlargement (LAE) by vectorcardiogram (VCG) and electrocardiogram (ECG), we analyzed the magnitude of the P loop on VCG and the P wave duration, amplitude, and deflection on the ECG and compared them with echographic and angiographic data. Twenty-eight children with LAE were selected who had congenital or acquired heart disease. The control population consisted of 24 children with normal left atrial (LA) dimensions.