Elliott Weinhouse

Dilated cardiomyopathy complicating a case of epidermolysis bullosa dystrophica.

Abstract: A Child with epidermolysis bullosa dystrophica, recessive type (EBDR) developed significant anemia at 9 years of age and was treated with long‐term transfuslon therapy. At age 17 he had symptoms of congestive heart failure secondary to dilated cardlomyopathy. Treatment with digoxin and vasodilators for the past year has failed to improve his cardiomyopathy significantly. Chronic iron overload and secondary hemosiderosis may have contributed to his problems, and we propose that chelation therapy be used in any child received long‐term transfusion therapy.

Lyme Disease Presenting as Heart Block

Lyme disease is now recognized as an infectious process capable of involving multiple organs including the cardiovascular system. We recently treated a boy whose complaints on admission related only to symptomatic heart block that was severe enough to require transvenous pacing. This boy was subsequently determined to have had Lyme Disease after his medical testing was reevaluated for possible tick exposure. In rare instances symptomatic heart block may be the sole presenting complaint of Lyme Disease in children.

Young Long Distance Runners Physiological and Psychological Characteristics

This study presents the physiological and psychological characteristics and the running histories of 16 subjects who began long distance running at age 4-12 years. Running duration was 3-15 years (mean 8.4 ± 3.6 yrs). Seven children completed 41 marathons, seven 30-mile races, and eight 60-mile races. The other nine competed at shorter distances. All trained at 30-105 miles/week. Two stress fractures, one back sprain and one knee injury occurred. Athletes who reported injuries from recollection may have underreported some injuries. At age 15.4 ± 4.2 years bone age was 15.3 ± 2.6 years and height was at 51 ± 26.0 percentile. Athletes had larger left ventricular diastolic diameter, higher max O 2 uptake, and delayed onset of anaerobic metabolism compared to controls. Psychological profile: IQ = 121 ± 11, scholastic grade point average (GPA) (n = 13) was ≤3.0 in four, 3.6-3.9 in four, and 4.0 in five. Cattell 16 personality factor (PF): Seven scored above the 85th percentile on boldness, warmth, conformity, sensitivity, dominance, and high drive with tension. Eight scored above the 93rd percentile for self discipline and emotional stability. Human Figure Drawing showed a distorted body image in seven. Two developed anorexia nervosa, and another girl committed suicide. Thus, high physical fitness and no growth retardation were observed. These runners, however, shared distinct positive and negative personality characteristics. The relatively high incidence of severe psychological disorders possibly suggests a need for psychological screening for young children entering a strenuous training program and for close monitoring for development of psychological problems during the program.

Cardiac glycoside toxicity in small laboratory animals

Cardiac glycosides are frequently administered to laboratory animals for research purposes. The effects achieved depend not only upon the particular glycoside and dose administered, but also upon an entire array of variables from the species of animal to the temperature of the animal housing facility. We review a number of these factors and their influence upon the effects achieved by the administration of cardiac glycosides to laboratory animals.

Mechanisms of digoxin-amiodarone interaction in the rat.

Abstract Amiodarone and digoxin are often used in combination and clinical experience suggests that amiodarone may increase serum digoxin levels and toxicity. We have investigated the influence of amiodarone on digoxin pharmacokinetics and tissue distribution in the rat. Forty-nine rats were injected with 10 mg/kg amiodarone sc three times a day for 7 days, while 49 others were injected with saline only. On the eighth day, all the rats received 0.5 mg/kg digoxin ip; 4, 5, 6, 7, 8, 10, and 12 hr later, groups of 7 amiodarone-pretreated and control animals were sacrificed, and plasma, heart, liver, muscle, brain, and kidney digoxin concentrations measured by radioimmunoassay. Data were analyzed by two-way ANOVA, with group comparisons using the Waller-Duncan multiple comparison procedure. Digoxin levels were significantly higher in the plasma, heart, muscle, and kidney of the amiodarone-pretreated rats at most points of measurement (P < 0.05) whereas liver digoxin levels were elevated at 8, 10, and 12 hr. Kidney/plasma, heart/plasma, muscle/plasma, and especially liver/plasma ratios in the control groups significantly exceeded the values found in the amiodarone-pretreated group at most time points. Concentrations of digoxin in brain were not changed. This suggests that the volume of distribution is significantly altered in the amiodarone-pretreated group. Amiodarone increases plasma digoxin levels in rats as it does in humans, but the mechanism is unclear.

Increasing extracellular calcium concentration does not prevent hypotensive effects of verapamil in neonatal swine

Effects of CaCl2 on cardiac function and regional circulatory responses to verapamil (V) infusion were studied in pentobarbital-anesthetized 2-week-old swine. V 100 micrograms/kg (n = 15) or 300 micrograms/kg (n = 15), given as a 2-min intravenous infusion, was repeated after 30 min. Only V was given to 15 of these. The other 15 were given CaCl2 (15 mg/kg) over 2 min, pre-V (protocol A), and over 4 min, 2 min pre-V and during V (protocol B). Positive chronotropic and negative inotropic responses to V were attenuated by CaCl2; hypotensive effects were unaltered. Renal, but not mesenteric and femoral, vasodilation was augmented by CaCl2, CaCl2 alone produced marked positive inotropic and renal vasodilatory effects which contributed to maintenance of the hypotensive effect of V.

RISK OF RECURRENCE OF SUPRAVENTRICULAR TACHYCARDIA, AS A FUNCTION OF AGE AND PRESENCE OF WOLFF-PARKINSON-WHITE SYNDROME. 146

RISK OF RECURRENCE OF SUPRAVENTRICULAR TACHYCARDIA, AS A FUNCTION OF AGE AND PRESENCE OF WOLFF-PARKINSON-WHITE SYNDROME. 146

REVIEW OF 1,116 CONSECUTIVE OUTPATIENT PEDIATRIC CARDIOLOGY VISITS.194

1,116 outpatient visits to a single cardiologist (EW) from 1993-95 were reviewed. 405 new and 711 follow-up patients (pts) were seen.

1311 CARDIOVASCULAR RESPONSES TO INCREASED CEREBROSPINAL FLUID PRESSURE (CSFP) BY SIMULATED INTRAVENTRICULAR HEMORRHAGE (IVH) IN 1 DAY OLD PIGLETS

The adult Cushing reflex is an increase in blood pressure (BP) and a decrease in heart rate (HR) in response to elevated CSFP. Is this response seen in neonates during IVH? Cardiovascular responses to simulated IVH were studied in anesthetized piglets ≤24 hours old. CSFP, BP, HR and phasic femoral, carotid and renal flows were recorded; resistance (R) was calculated as BP/mean flow. Every 10 minutes 0.5ml of the animals own blood (IVH,n=6) or artificial CSF (n=3) was injected into the right lateral ventricle. With IVH, CSFP increased 10-20cm H2O with each injection; peak CSFP was 90cm H2O with IVH and 40cm H2O with CSF. HR responses were variable. Consistent changes in BP were not elicited until a total volume of 2.5ml had been injected in all animals. Immediate increases in BP after IVH were 28%, 53% and 95% with totals of 2.5, 5.0 and 7.5ml of blood injected, while with CSF, the BP increases averaged 21% with 2.5-7.5ml injected. Femoral R increased 37%, 101% and 168% and renal increased 37%, 88% and 153% with 2.5, 5.0 and 7.5ml respectively. With CSF, femoral and renal R were variable. Carotid R increased in all animals. Our results indicate that the HR decrease accompanying the BP increase with elevated CSFP is not consistently present in neonates. Thus, the adult Cushing reflex is not obtained in neonates. Furthermore, careful monitoring of cardiovascular parameters is essential in the care of infants susceptible to IVH.

CARDIOVASCULAR RESPONSES TO INTRAVENTRICULAR HEMORRHAGE IN NEONATAL PIGLETS

In view of the prevalence of intraventricular hemorrhage (IVII) as a cause of neonatal demise, the cardiovascular responses to experimental IVII were studied. 18 piglets ranging in age from birth to 16 days were anesthetized with 0.25% halothane in an H2O-O2 mixture and artificially ventilated. Blood gas parameters were controlled. Aortic pressure (AoP), spinal fluid pressure (SFP), heart rate (HR), and femoral, renal and carotid flows were recorded continuously. IVH was simulated by serial injections of 0.5 ml of blood into the right lateral ventricle. Norepinephrine was used to test responsiveness of peripheral receptors. Age-dependency of effects was evaluated statistically for all parameters. A total of 4.0 ml IVH with at least 70% increase in SFP led to a maximum of 59% increased mean AoP; and 50% increased HR in all piglets younger than 5 days of ane. Renal resistance (R) increased at all ages but femoral R did not. Carotid R increased 16.0%±3.9 in animals 4 days old or less and 49.6%±10.4 in one week old animals. Immaturity of the cardiovascular regulatory system was apparent as an absence of the adult pattern of response to increased SFP during IVH in the piglets. There was a precipitous fall in cardiovascular parameters just before the demise of the animal resembling that seen in terminal infants.