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Biomedical subjects

J C Perry

Publications and source records attributed to J C Perry.

14 recordsLinked to original sources
PubMed1992

Late ventricular arrhythmia and sudden death following direct-current catheter ablation of the atrioventricular junction.

Early reports of direct-current catheter ablation (DCCA) of the atrioventricular (AV) junction for resistant AV tachycardias documented efficacy of DCCA with little morbidity. Nine patients underwent DCCA at our institution 4 to 9 years ago: 3 patients had DCCA in the coronary sinus for permanent junctional reciprocating tachycardia, 2 patients had His ablation, 2 had coronary sinus and His ablation for permanent junctional reciprocating tachycardia, and 2 had DCCA for congenital tachycardia, and 2 had DCCA for congenital junctional ectopic tachycardia. Shocks (total 1 to 5) ranged from 12.5 to 400 J. Five patients had pacemaker implant at the time of DCCA. During follow-up, 3 patients developed clinical ventricular tachycardia: all 3 had DCCA of the His bundle. One asymptomatic patient with ventricular tachycardia, who had DCCA of the bundle of His, died suddenly 6 years later with ventricular fibrillation. Autopsy revealed 2 ventricular scars: 1 extending from the AV junction and 1 in the outflow tract. No patient with DCCA limited to the coronary sinus developed ventricular tachycardia. DCCA of the His bundle can result in late ventricular arrhythmias, possibly a result of extension of the DCCA lesion into the ventricle. These late findings should be considered in evaluating the safety and efficacy and follow-up for patients undergoing radiofrequency ablation.

Atrioventricular Node↗
PubMed1992

Flecainide acetate for treatment of tachyarrhythmias in children: review of world literature on efficacy, safety, and dosing.

A review of all published experience with flecainide in infants, children, and fetuses was performed to evaluate the appropriate place of the drug in pediatric practice and to determine dosing guidelines. A total of 704 case references was generated. Flecainide appeared to be safe (no deaths with usual oral dosing, < 1% serious proarrhythmia) and effective (73% to 100% control, depending on mechanism) in children with supraventricular tachycardia. The drug was very effective for treatment of fetal tachyarrhythmias. Flecainide may not be safe for children who have structurally abnormal hearts and atrial flutter or ventricular arrhythmias. The safety of flecainide for patients with ventricular arrhythmias and normal hearts requires further investigation. Pharmacokinetic data reveal an age-dependent change in elimination half-life. Patients younger than 1 year of age have a plasma elimination half-life that is similar to that in children older than 12 years (i.e., 11 to 12 hours). Children aged 1 to 12 years have a mean elimination half-life of 8 hours. The effective flecainide dose is 100 to 200 mg/m2/day or 1 to 8 mg/kg/day. Toxicity may occur with doses in excess of these ranges, especially when high doses are accompanied by low serum trough levels. Milk blocks flecainide absorption, and toxicity may become manifest when milk products are removed from the diet.

Arrhythmias, Cardiac↗
PubMed1992

Mood and global functioning in borderline personality disorder: individual regression models for longitudinal measurements.

This report addresses the need for prospective studies of personality disorders, as well as some of the difficulties encountered in longitudinal studies when missing data occur due to subject attrition and variable follow-up intervals. Various statistical methods for handling repeated measurements data are reviewed. Many of these methods are quite complex and require expert statistical skills. A simpler way to handle multivariate data using single-number summary scores is proposed as an alternative which is efficient and more readily understood by professionals in many disciplines. Findings are presented from a prospective study of borderline personality disorder which utilized repeated observations over time. Individual regression models were applied to each subject's repeated measurements to obtain a summary of his or her trend on measures of mood and global functioning. The individual regressions produced separate statistics, slopes summarizing rates of change and intercepts which estimated initial levels of functioning. These summaries were then used in group analyses. Findings indicated that subjects showed mild to moderate impairment in mood and moderate impairment in overall functioning. The individual slopes indicated that little overall change was observed during the 5-year period after initial assessment. Neither presence of borderline diagnosis (definite vs. trait vs. no borderline diagnosis) nor gender predicted initial levels of functioning or rates of change. Further examination of other predictors which may influence longterm outcome, such as history of childhood trauma or presence of schizotypal personality features, is suggested. It is concluded that prospective studies are essential in establishing the validity of personality disorders and in understanding individual variation in outcomes.

Adaptation, Psychological↗
PubMed1992

Problems and considerations in the valid assessment of personality disorders.

This article reviews evidence for the reliability and diagnostic concordance of structured-interview and self-report questionnaire methods for the diagnosis of personality disorders. The findings of nine studies that compared two or more axis II diagnostic instruments administered to the same groups of subjects are summarized. Across the eight studies with sufficient data, a summary of the overall diagnostic agreement between any two instruments yielded a low reliability (median kappa = 0.25) for making individual personality disorder diagnoses. Diagnostic concordance was lower between self-report questionnaire and interview methods than between interview methods. Comparing dimensional scores of different methods did not appreciably improve the level of agreement. The author concludes that current methods for making personality disorder diagnoses have high reliability but yield diagnoses that are not significantly comparable across methods beyond chance, which is not scientifically acceptable. Sources for the disagreement include variance due to different raters, interview occasions, data sources (self-report versus observer report), information bases obtained, and instrument sensitivity to state effects (e.g., mood). Serious problems in assessment validity may also arise from the yes/no format, which, despite probes for confirmatory examples, may fail to distinguish adequately between sporadic occurrences and longstanding patterns. Efforts should be made to improve and demonstrate the validity of axis II diagnostic methods. One route to increasing validity is to improve the clinical interview, because personality patterns are best revealed by the recurring patterns one finds when taking a systematic history.

Humans↗
PubMed1991

The child with recurrent syncope: autonomic function testing and beta-adrenergic hypersensitivity.

Recurrent syncope in the child with a normal heart poses both diagnostic and therapeutic problems. To assess autonomic contributions to syncope, formal autonomic function testing was performed in 22 children (aged 7 to 18 years) with recurrent syncope and a normal heart. Autonomic testing consisted of eight to nine separate tests; 14 of the 22 patients had reproduction of syncope or symptoms during testing. Patients with a positive test had a lower norepinephrine level while supine (334 +/- 86 versus 547 +/- 169 pg/ml, p less than 0.01) and lower norepinephrine level in the upright position (628 +/- 219 versus 891 +/- 270 pg/ml, p less than 0.05) than did patients with a negative test. The slope of heart rate response versus log isoproterenol dose was greater in patients with a positive test than in those with a negative test (1.70 +/- 0.70 versus 0.89 +/- 0.19, p less than 0.01). All five patients with a positive test who were given intravenous propranolol had elimination of syncope with repeat testing. Eight of 10 patients with a positive test were successfully treated with atenolol, including 2 patients without prior resolution of symptoms after pacemaker implantation for symptoms attributed to bradycardia. Beta-adrenergic hypersensitivity may cause recurrent syncope in young patients. Inappropriate heart rate response to standing may elicit the Bezold-Jarisch reflex, resulting in bradycardia or hypotension, or both, in some patients. Beta-adrenergic blockade is of benefit in many of these patients.

Adolescent↗
PubMed1991

Bradycardia and syncope in children not controlled by pacing: beta-adrenergic hypersensitivity.

Cardiac pacing is frequently employed in the therapy of children with syncope and documented bradycardia. This report describes two children, ages 7 and 9 years, who underwent placement of demand ventricular pacing systems for documented bradycardia and syncope. Cardiac catheterization and intracardiac electrophysiological studies failed to show evidence of structural abnormalities, sinus node or conduction system disease, inducible arrhythmias, or VA conduction in each patient. Both patients had persistent symptoms after pacemaker implantation. Autonomic function testing with continuous heart rate and blood pressure monitoring revealed exaggerated beta-adrenergic responses to simple standing and small doses of isoproterenol. Symptoms were completely eliminated with atenolol. In these two children, cardiac pacing alone was not adequate for relief of symptoms. Autonomic mechanisms of bradycardia and hypotension should be considered prior to implantation of permanent pacing systems in children.

Adrenergic beta-Antagonists↗
PubMed1991

The pulmonary artery lasso: epicardial pacing lead causing right ventricular outflow obstruction.

Permanent pacing in small children may require placement of an epicardial pacing system. This report describes a young child who underwent pacemaker implantation with epicardial ventricular lead placement in infancy as an adjunct to antiarrhythmic therapy for congenital junctional ectopic tachycardia. At 5 years of age, a harsh systolic murmur was detected for the first time. Evaluation by catheterization and transluminal echocardiography showed right ventricular outflow obstruction (pressure gradient 40 mmHg) secondary to extrinsic compression by the epicardial lead. Surgical removal of the lead relieved the obstruction.

Cardiac Pacing, Artificial↗
PubMed1978

The borderline patient. A comparative analysis of four sets of diagnostic criteria.

In reviewing the evidence for the validity of the diagnosis borderline, four descriptions in the literature seem to offer comprehensive criteria for the diagnosis. When the four are compared, a total of 104 criteria are enumerated encompassing the mental status, history, interpersonal relationships, defense mechansisms, and other judgments of personality functioning of the borderline patient. Half of these criteria are mentioned in only one of the four diagnostic descriptions. This apparent lack of agreement over diagnostic criteria has three possible interpretations: (1) the borderline concept is an illusion; or (2) the concept is adequately defined by those criteria held in common, the others being nonessential; or (3) apart from the concept defined by the common criteria, there are subtypes emphasized by different authors. Although we favor the third interpretation, it is suggested that further speculation await an adequate test of existing diagnostic criteria.

Diagnosis, Differential↗
PubMed1975

Fluroxene toxicity induced by phenobarbital.

Because of reports of fluroxene toxicity in man, the effect of phenobarbital treatment on the toxicity and metabolism of fluroxene was studied in 9 rhesus monkeys. Six monkeys that were exposed to a mean calculated alveolar fluroxene concentration of 5.8% for 4-hr periods up to a total of 16 hr showed no evidence of toxicity. Two animals were sacrificed after a single 4-hr exposure to obtain control measures of fluroxene metabolites in tissues. Four monkeys that had previously survived received exposures to fluroxene and 3 monkeys that had no exposure to fluroxene died during fluroxene anesthesia after treatment with phenobarbital (mean time, 3 hr). Toxicity was manifested by arterial hypotension, pulmonary edema, and arterial hypoxemia. Phenobarbital treatment enhanced production of fluroxene metabolites, including the highly toxic trifluoroethanol. Concentrations of trifluoroethanol in mixed-expired gas, blood, and urine, and of total nonvolatile fluorine in blood, urine, and tissues of animals treated with phenobarbital were 2 to 10 times as in control animals. The results suggest that the rhesus monkey is a valuable model for the study of fluroxene pharmacology and that inclusion of an enzyme-inducing challenge in the evaluation of potential toxicity of other anesthetics seems warranted.

Anesthesia↗
PubMed1975

Cardiorespiratory effects of high positive end-expiratory pressure.

Five healthy rhesus monkeys were ventilated with intermittent mandatory ventilation and 20 torr positive end-expiratory pressure (PEEP) for 8 hours. PEEP was increased to 25 torr and the monkeys were ventilated for 4 more hours. Lactated Ringer's solution and human salt-poor albumin were used to expand plasma and extracellular fluid volume throughout the entire period of study. Homologous blood was administered to maintain hematocrit at control levels and maintenance fluids were infused to maintain transmural pulmonary capillary wedge pressure at 5 to 15 torr. Although cardiac output, mean aortic blood pressure, oxygen consumption, venous admixture, transmural pulmonary capillary wedge pressure, HCO3- and in-vivo base excess were not changed when intermittent mandatory ventilation was employed, cardiac output and blood pressure were significantly depressed by brief periods of controlled mechanical ventilation when alternated with intermittent mandatory ventilation. Sporadic increases in arterial-venous oxygen content difference occurred. Arterial carbon dioxide tension was elevated moderately, with a concomitant depression of arterial pH. No pneumothorax occurred. High PEEP was well tolerated with intermittent manditory ventilation, intravascular volume expansion, and careful cardiovascular monitoring.

Animals↗
PubMedDate not supplied

Venous air embolism prophylaxis with a surface-active agent.

The protective effect of a nonionic surface-active polyol agent (Pluronic F-68) against bolus injection and constant-rate IV infusion of air was studied in 21 dogs anesthetized with pentobarbital. Aortic, pulmonary artery and right ventricular pressures, cardiac output, end-tidal CO2 concentration, wasted ventilation, and blood surface tensions were measured before and after the IV administration of this surfactant. The magnitudes of change in the cardiorespiratory responses measured after venous air embolism were significant (p less than 0.05) reduced in the treated animals. This agent may be advantageous for surgical patients when an increased risk of venous air embolism exists.

Animals↗