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Biomedical subjects

T Dillon

Publications and source records attributed to T Dillon.

32 records · Page 2Linked to original sources
PubMed1983

Immediate effects of heavy exercise on the circulating thyroid hormones.

Sera from 20 patients with suspected or known coronary artery disease were measured for thyroxine (T4), tri-iodothyronine (T3), tri-iodothyronine uptake ratio (T3UR), thyroid stimulating hormone (TSH), and reverse tri-iodothyronine (rT3), before and after maximal or near-maximal exercise. On the average the patients achieved 92% (rang 68-108) of the predicted maximum heart rate. There were no statistically significant differences between the pre- and the post-exercise serum levels of thyroid hormones. When five patients who achieved less than 90% of the predicted maximum heart rate were excluded, the results remained unchanged. It appears that the circulating thyroid hormones are not acutely affected after maximal or near-maximal exercise; however, the patient population was highly select.

Adult↗
PubMed1982

Radionuclide angiographic and echocardiographic quantitation of left-to-right shunts in children with ventricular septal defect.

Pulmonary to systemic blood flow ratios (Qp:Qs) were estimated in 16 children with ventricular septal defects using simultaneous echocardiography and radionuclide angiography, and compared to Qp:Qs measured at cardiac catheterization by the Fick principle method (Fick). When ratios of echographic left atrial dimensions (LAD) to body surface area (LAD/M2), body length (LAD/ht), and aortic root diameter (LAD/Ao) were compared to the Qp:Qs determined by Fick, the correlation coefficients were r = 0.70 for LAD/M2, r = 0.66 for LAD/ht, and r = 0.54 for LAD/Ao. The correlation coefficients between Qp:Qs by Fick, and left ventricular dimensions/M2 and fractional shortening of the left ventricle were not significant. The correlation coefficients between Qp:Qs and the ratios estimated by gamma-variate and area-ratio analysis of radioisotope pulmonary dilution curves were r = 0.92 and r = 0.84, respectively. Thus, radionuclide angiography provided more accurate quantitation of left to right shunting through a ventricular septal defect than echocardiography. However, difficulty in obtaining adequate bolus injections of the radioisotope may result in technical failures whereas echocardiographic measurement is possible in almost all pediatric patients. Finally, the gamma-variate method cannot accurately quantitate shunt ratios greater than 3.5 to 1.

Adolescent↗
PubMed1982

Asplenia syndrome with atypical cardiac anomalies.

Two infants with asplenia and complex cyanotic congenital heart disease showed unusual findings at cardiac catheterization. Each had a patent pulmonary outflow tract and a severe obstructive lesion of the aortic arch. These cases emphasize the heterogeneity of the asplenia-polysplenia syndromes. Pulmonary atresia or critical pulmonic stenosis is not an invariable accompaniment of the asplenia syndrome. Obstructive lesions of the aortic outflow tract, which occur in about 1/3 of patients with the polysplenia syndrome, also can occur with asplenia.

Blood Gas Analysis↗
PubMed1982

Electrophysiologic effects of propranolol on sinus node function in children.

Little is known regarding the effects of propranolol (P) on sinus node function in children. In this study, corrected sinus node recovery time (CSNRT) and estimated sinoatrial conduction time (SACT) were measured in 10 children (ages 3 to 16 years; mean 8.3 years) without clinical evidence of sinus node dysfunction before and after intravenous P. The spontaneous sinus cycle length (SCL) increased after P(0.1 mg/kg) in all patients. Mean SCL increased 13.4% from 635 +/- 200 msec (+/- SD) to 720 +/- 202 msec (p less than 0.01). Maximum CSNRT increased in nine patients after P and mean CSNRT increased 63% from 203 +/- 61 msec to 330 +/- 190 msec (p less than 0.05). SACT changed in a random fashion after P. Mean SACT did not change significantly. We conclude that P significantly suppresses sinus node automaticity in children with normal sinus node function but has little or no effect on sinoatrial conduction.

Adolescent↗
PubMed1982

Noninvasive pulsed Doppler determination of cardiac output in neonates and children.

Mean blood flow velocity (VAo) in the ascending aorta was measured noninvasively in 33 children, ages 3 days to 17 years, by pulsed Doppler technique at the time of cardiac catheterization. Measurements were made from a suprasternal approach with a portable, range-gated device. The ascending aortic diameter was determined echocardiographically and aortic cross sectional area calculated (A = pi d2/4 cm2). Aortic flow (QAo) was computed from Doppler recordings: QAo (ml/minute) = VAo (cm/second) X A (cm2) X 60 (second/minute). Values were compared with cardiac outputs determined according to the Fick principle, using measured oxygen consumption calculated oxygen capacity, and oxygen saturation. Subjects with aortic valve abnormalities or left ventricular outflow tract obstruction were excluded from study. Agreement between the two methods was excellent (linear regression r = 0.98, slope = 1.07, y-intercept = -4.5 ml, range 403 to 5.540 ml/minute). The Doppler technique is a quick, noninvasive, and accurate method of determining ascending aortic blood flow in neonates and children.

Adolescent↗
PubMed1982

The use of the three-phase bone scan in the early diagnosis of heterotopic ossification (HO) and in the evaluation of Didronel therapy.

The purpose of this study is to investigate the use of a three-phase bone scan for early detection of HO formation and as a method of evaluating Didronel treatment. A marked vascular blush and blood pool was noted about the hips sometimes with a normal bone scan and normal X-ray of the hips. This appeared to represent the precursor phase of HO formation since, on repeat scans, the bone scan showed accumulation of the bone-seeking radionuclide usually in 2 to 4 weeks and the X-ray revealed ossification. Fifty-two patients treated with Didronel between October 1978 and December 1979 were reviewed to determine the value of Didronel treatment. There were 23 patients in the series who either showed HO by X-ray on admission or developed HO on follow-up X-rays before beginning Didronel therapy. A three-phase bone scan revealed increased vascularity and accumulation of radioactivity on the bone scan in all areas of ossification on the X-ray and in some areas that did not appear to be involved. The other 29 patients had serial three-phase bone scans, X-ray study, and an alkaline phosphatase determination at approximately 2-week intervals. Didronel treatment was started as soon as the precursor phase of HO was demonstrated on the three-phase bone scan in most of these patients. Nine have not developed ossification that could be seen in X-rays during 3 months of continuing study. Six patients seen at follow-Up during the past year had known HO of 4 to 7 years duration. The three-phase bone scan was used to predict the maturity of HO in these patients. Our study in indicates that increased vascularity precedes rather than being secondary to HO formation as is suggested in the literature. Didronel treatment appears to be most effective if initiated during this precursor phase.

Diphosphonates↗
PubMed1982

Symptomatic sinus node dysfunction in children without structural heart disease.

Symptomatic sinus node dysfunction rarely occurs in children with structurally normal hearts. Three children with syncope and bradycardia are described. Noninvasive and invasive testing revealed isolated sinus node dysfunction and normal cardiac anatomy. Electrophysiologic evaluation showed abnormalities of sinus node automaticity and sinoatrial conduction. All three patients were treated with permanent ventricular pacemakers and have remained asymptomatic. Sinus node dysfunction should be considered in the differential diagnosis whenever a child is seen with unexplained dizziness or syncope.

Adolescent↗
PubMed1982

Evaluation of infants with bronchopulmonary dysplasia using cardiac catheterization.

Nine infants with bronchopulmonary dysplasia underwent cardiac catheterization to define thier circulatory status. In room air, the mean cardiac index was normal (3.4 liters/min/sq m), but pulmonary arterial pressure (39 mm Hg, mean) and pulmonary vascular resistance (8.6 Wood units . sq m) were elevated. Preejection period/right ventricular ejection time ratios determined echocardiographically correlated well with values obtained at catheterization, but did not correlate well with hemodynamic values. Administration of 40% and 88% oxygen caused variable responses in hemodynamic measurements. Studies of left ventricular function were normal in all patients. These findings raise questions about the long-term prognosis of infants with bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1981

Vascular ring due to left aortic arch and right descending aorta.

Two children presented with symptoms suggestive of a vascular ring. Barium esophagrams in each case showed a posterior impression caused by a retroesophageal aortic arch. Angiographic studies defined a rare form of vascular ring resulting from an ascending left-sided aorta, a descending right-sided aorta and a right-sided ligamentum arteriosum. At surgery, the diagnosis was confirmed and the anomaly was corrected in each patient. Left pulmonary anomalies were present in each patient.

Aorta, Thoracic↗
PubMed1981

Aberrant systemic arterial supply to the left lung with congestive heart failure.

A six-month-old girl with an aberrant systemic arterial supply from the descending thoracic aorta to the left lower lobe had congestive heart failure. Although the pulmonary parenchyma was normal, there was an absence of normal pulmonary arterial supply to the left lower lobe. Main pulmonary arterial and aortic cineangiograms led to the correct diagnosis. Left lower lobectomy was performed and resulted in clinical and hemodynamic improvement.

Aorta, Thoracic↗
PubMed1981

Bedside evaluation of postoperative sinus node function in children.

Sinus node dysfunction in children frequently results from the surgical correction of congenital heart defects. We evaluated postoperative sinus node function at the bedside in 25 children by utilizing atrial epicardial electrodes which were placed near the sinus node at the time of operation. Sinoatrial conduction times (SACTs) and corrected sinus node recovery times (CSNRTs) were determined within 3 days of operation in each patient. Group 1 consisted of 20 patients (aged 1 month to 13 years) with normal postoperative sinus node function. Mean (+/- SD) SACTs and CSNRTs were 122 +/- 33 msec (range 61 to 187 msec) and 165 +/- 54 msec (range 52 to 253 msec), respectively. Preoperative evaluation of sinus node function during cardiac catheterization showed that preoperative and postoperative SACTs and CSNRTs were not significantly different (p greater than 0.05) in any of nine patients. Group 2 was composed of five children (aged 1 to 14 years) with postoperative sinus node dysfunction. Three had abnormal SACTs of 230 msec or greater and two children had first-degree sinus node entrance block. Two patients had prolonged CSNRTs. Electrocardiographic (ECG) monitoring revealed evidence of sinus node dysfunction in four of the five patients in Group 2. This report describes a simple and safe means of evaluating postoperative sinus node function at the bedside. The data are comparable to those obtained using more conventional methods during cardiac catheterization.

Adolescent↗
PubMed1980

Use of atrial epicardial electrodes to diagnose and treat postoperative arrhythmias in children.

Temporary Teflon-coated stainless steel wires were placed on the right atrium of 100 consecutive infants and children undergoing open heart surgery. The patients' ages ranged from 1 day to 17 years. The wires were used for diagnosis or treatment 40 times in 30 patients. Atrial electrograms were recorded 14 times to diagnose arrhythmias and conduction disturbances that were unsuspected or misdiagnosed from the standard electrocardiogram. In 10 patients, atrial pacing was used to treat postoperative arrhythmias. Atrial pacing was also used as an adjunct to therapy in 16 children with postoperative low cardiac output and bradycardia with intact atrioventricular conduction. The wires were removed before discharge and no complications resulted from their use. Previous studies have demonstrated the usefulness of temporary atrial wires after cardiac surgery in adults. This experience confirms that the technique is easy and safe and can be of great diagnostic and therapeutic value in children.

Adolescent↗
PubMed1980

Management of infective endocarditis using echocardiography.

Serial echocardiograms of five children who had infective endocarditis were analyzed and correlated with the clinical course. Vegetations were visualized initially on M-mode in four and on two-dimensional echocardiograms in all patients. The appearance of the vegetation was unexpected in one. More accurate anatomic localization of the vegetation was possible using two-dimensional echography. Four of the five patients died despite vigorous medical treatment and valve replacement in two. Complete resolution of the vegetation was documented for the first time in a child following medical therapy. This study suggests that echocardiography plays an important role in the diagnosis of endocarditis, allows objective follow-up of the size of the vegetations and their effects on valve function, and, therefore, may prove helpful in the management of these patients.

Adolescent↗