Left atrial ejection force in healthy newborn infants.

Background: Atrial ejection force (AEF) expresses the force exerted by the left atrium to the mass of blood passing through the mitral valve during atrial systole. It provides a diagnostic and predictive parameter for evaluating left ventricular diastolic abnormalities and a physiologic assessment of atrial systolic function.

Methods: We obtained normal values of AEF in a group of 47 newborn infants with normal heart function and structure, using Doppler echocardiographic parameters of transmitral filling flow.

A quantitative microscopic analysis of the myocardial interstitial tissue space and myocardial fiber diameter in rats with vitamin E and selenium deficiency.

Vitamin E (E) and selenium (Se) are important antioxidant nutrients, preventing membrane damage by lipid hydroperoxides. In a previous study on E + Se deficient rats it was shown that plasma levels of lipoproteins increase dramatically. In continuation of this study a quantitative microscopic study was undertaken to determine the behavior of myocardial interstitial tissue space (ITS) in E + Se deficient rats as compared to control rats.

Right ventricular obstruction in various types of hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is most probably a genetically transmitted disease with different clinical and hemodynamic features. In hypertrophic obstructive cardiomyopathy (HOCM) the obstruction is predominantly in the left ventricular outflow tract (IHSS). In a minority of cases the obstruction is strictly located in midventricle (midventricular obstruction, MO).

The effects of two strains of influenza virus on cardiac development in the chick embryo.

To investigate the teratogenic effects of influenza virus on cardiac development two strains of influenza virus (Ty/Calif/5142/66 and Ty/Calif/64/M. Meleagrium) were injected into the yolk sac of fertile white Leghorn eggs during stage 23. Eggs injected with normal saline served as controls.

Electrophysiologic effects of mexiletine in children.

The effects of intravenous administration of mexiletine on the refractory periods of the atrium and atrioventricular (AV) node were studied using His bundle recordings and the extrastimulus technique with atrial pacing. The drug was administered to 10 children with heart disease in an intravenous bolus dose of 3 mg/Kg, injected over a 5-min period, followed by an infusion of 1 mg/Kg/hr of mexiletine, achieving a mean therapeutic plasma concentration of 0.762 +/- 0.

Myocardial metal content in patients who expired from cyanotic congenital heart disease and acute rheumatic heart disease.

The importance of metals in normal and pathologic cardiovascular function has been recognized. Significant derangements in myocardial Ca2+, Mg2+, and Cu2+ have been reported in ischemic heart injury. We studied 3 groups of hearts: 1) fifteen specimens obtained from patients who had no heart disease, 2) nine specimens from patients who had expired from cyanotic congenital heart disease, and 3) ten specimens from patients who had expired from acute rheumatic heart disease with carditis and severe heart failure.

A profile of heart disease in children in a developing country.

Experience is presented of paediatric cardiology in a well-equipped and staffed centre during a six-year period in a developing country. Despite the success of the programme in offering first class medical investigation and surgical care to a large number of children, it is estimated that only about 2% of the existing cases in the country were operated upon. The main problems were the large numbers of cases, creating long waiting lists, and the lack of adequately trained paramedical personnel.

Priorities of pediatric cardiology in the developed and developing countries.

Congenital heart disease and pediatric cardiology problems exist all over the world. The approach, however, including diagnosis and management varies considerably depending on manpower available, the clinical facility and the sociophilosophical climate prevailing in different parts of the world. In this article the priorities existing in the developed and developing countries concerning the approach to pediatric cardiology problems are discussed from the point of view of patient load, facilities available, teaching and research in this large field of highly specialized pediatric practice.

Arrhythmias in infants and children.

A general discussion of arrhythmias as followed by a brief description of two of the commonly encountered dysrhythmias in the pediatric age group, i.e., paroxysmal supraventricular tachycardia and complete AV block.

Dual atrioventricular nodal pathways in children without supraventricular tachycardia.

Atrioventricular conduction characteristics were examined by atrial extrastimulus technique in 45 children aged 50 days to 14 years following diagnostic cardiac catheterization. None of the patients had a history of supraventricular tachycardia and none had evidence of pre-excitation on routine electrocardiogram. By plotting the A2H2 and H1H2 intervals against corresponding S1S2 intervals 2 types of conduction curve were obtained.

Electrophysiologic effects of disopyramide in children.

Disopyramide has been successfully used to treat a variety of supraventricular and ventricular arrhythmias. The electrophysiologic effects of this drug were studied following diagnostic cardiac catheterization in 14 children aged 7 months to 14 years, suffering from congential heart disease. Surface EKG, intra-atrial, and His bundle electrogram as well as right atrial pacing with the use of extrastimulus technique were obtained before and after a single intravenous dose of disopyramide (2 mg/Kg, max 50 mg).

Effect of verapamil on retrograde ventriculo-atrial conduction in children.

The effects of verapamil, a slow channel blocker and a potent antiarrhythmic drug, on retrograde V-A conduction were investigated following diagnostic cardiac catheterization in 12 children premedicated with lytic cocktail. Surface EKG, intra-atrial and His bundle electrograms, as well as right ventricular pacing with use of extra stimulus technique were obtained before and after a single intravenous dose of verapamil (0.15 mg/Kg, max 5 mg).

Reversal of digoxin-induced changes in erythrocyte electrolyte concentrations by penicillamine in children.

Previous reports from this laboratory have shown that penicillamine effectively reduces serum digoxin levels and is a clinically useful drug in correcting digoxin intoxication. To elucidate further the antidigitalis effects of penicillamine a prospective study was undertaken in 10 children aged 4--14 years with congestive heart failure. Plasma and intracellular erythrocyte concentrations of sodium, potassium, calcium as well as Na+/K+ and Na+/Ca++ ratios were measured before digitalization, 6 days after full digitalization while the patients were on maintenance doses of digoxin (0.

Electrophysiologic effects of verapamil in children.

The electrophysiologic effects of verapamil, a slow channel blocker, were investigated during diagnostic cardiac catheterization in 24 children premedicated with lytic cocktail. The ages ranged from 50 days to 12 years. Twenty had congenital and 4 had rheumatic heart disease.

Electrophysiologic effects of lidocaine in children.

The effects of intravenous lidocaine on the refractory periods of the atrium, AV node and right ventricular myocardium were studied using His bundle recordings and the extrastimulus technique with and without atrial and ventricular pacing. The drug was administered in an intravenous bolus dose of 1 mg/Kg followed by an infusion of 100 micrograms/Kg/min. The AH, HV intervals and resting sinus cycle length as well as functional and effective refractory periods of atrium, AV node and right ventricle were measured before and 5 min afrer bolus injection of lidocaine.

Isolated unilateral absence of the pulmonary artery. Review of the world literature and guidelines for surgical repair.

A 10-month-old boy is presented who had isolated unilateral absence of the right pulmonary artery. He suffered from hemoptysis and severe congestive heart failure. The patient underwent prosthetic anastomosis of the right to the main pulmonary artery.