Search PubMed⌕ Search

Biomedical subjects

B McGovern

Publications and source records attributed to B McGovern.

At least 37 records · Page 2Linked to original sources
PubMed1986

Ventricular tachycardia: historical perspective.

Ventricular tachycardia is now diagnosed frequently in patients with organic heart disease. Although ventricular tachycardia was first demonstrated electrocardiographically 75 years ago, the natural history, fundamental mechanisms, and optimal management have remained elusive. Early observers commented on the rarity of occurrence and poor prognosis associated with this arrhythmia, yet with time, some patients with ventricular tachycardia were reported to survive for prolonged periods. Because of the sporadic nature of the arrhythmia and its variable prognosis, assessment of the efficacy of therapies has been difficult. A wide variety of treatments has been advocated with enthusiasm, but only a few have been consistently reported to be effective. Citation of historical data to claim benefit from new treatments should be viewed with caution.

Cardiac Pacing, Artificial↗
PubMed1986

Precipitation of cardiac arrest by verapamil in patients with Wolff-Parkinson-White syndrome.

After the administration of verapamil for rapid tachycardias, five patients developed ventricular fibrillation or required urgent cardioversion. All episodes occurred in hospital emergency rooms, and each patient was resuscitated. Examination of electrocardiograms confirmed the presence of the Wolff-Parkinson-White syndrome. In four patients, the presenting tachyarrhythmia was atrial fibrillation with preexcited ventricular complexes, and in one patient a narrow QRS complex tachycardia was initially recorded. Acceleration of atrioventricular conduction occurred within 10 minutes of administration of verapamil, 5 to 10 mg intravenously. Subsequently, intracardiac electrophysiologic studies confirmed the presence of accessory atrioventricular pathways capable of rapid antegrade conduction in each patient. Because of this potentially fatal adverse response, verapamil should not be used in patients with atrial fibrillation and preexcited ventricular complexes.

Adolescent↗
PubMed1985

Aggravation of electrically provoked ventricular tachycardia during treatment with propafenone.

Propafenone is a new class Ic antiarrhythmic agent currently being investigated in the United States. It is generally well tolerated. We administered propafenone to 16 patients with ventricular tachycardia (VT) that had been refractory to conventional antiarrhythmic drug therapy. Three of these 16 patients developed electrically provoked incessant VT during treatment with propafenone without other evidence of toxicity. These arrhythmias subsided after lidocaine was administered. Propafenone therapy was discontinued in each case. Incessant VT did not develop in any of these patients in the absence of antiarrhythmic drugs or on antiarrhythmic drugs other than propafenone. Alternative effective treatment was identified for each patient. Although VT was initially provoked by pacing in each of these patients, these observations suggest that propafenone, like some other class Ic drugs, may favor the development of incessant VT in occasional patients. This appears most likely to occur in patients with ventricular dysfunction and prior sustained VT or ventricular fibrillation.

Aged↗
PubMed1985

A totally implantable venous access system for long-term chemotherapy in children.

A totally implantable venous access system consisting of a subcutaneously placed stainless steel portal with a silicone diaphragm attached to a Silastic elastomer central venous catheter was inserted in 39 children with poor venous access. The devices were utilized for blood drawing and the administration of antineoplastic drugs, parenteral nutritional fluids, antibiotics, and blood products. Cumulative duration of access was 6,724 days (range 5-491, median 172 days). Major complications necessitating removal of the device included catheter sepsis or pocket abscess (7%), catheter clot not responsive to enzyme declotting (5%), and catheter occlusion by too tight a ligature (2%). The system provided easy venous access and permitted full physical activity.

Anti-Bacterial Agents↗
PubMed1985

Serial analysis of electrically induced ventricular arrhythmias in a canine model of myocardial infarction.

To determine the rate of induction, specificity and evolution of electrically induced postmyocardial infarction ventricular arrhythmias, 10 dogs that underwent a sham operation and 20 dogs with experimental transmural apical myocardial infarction underwent serial closed chest electrophysiologic studies with programmed ventricular stimulation under light anesthesia 1, 2, 4 and 6 weeks after the operation. The reproducibility of the electrically induced ventricular arrhythmias was at a maximum when three extrastimuli were used during ventricular pacing for induction. The reproducibility of the arrhythmias was also a function of the age of the infarct. Electrically induced sustained monomorphic ventricular tachycardia, observed in 45 to 50% of the animals, was a highly specific postinfarction finding (0% specificity in control animals, regardless of the mode or timing of programmed cardiac stimulation), whereas nonsustained polymorphic ventricular tachycardia was not. The specificity of induced ventricular fibrillation was a function of the mode and timing of programmed stimulation. The rate of induction of the electrically induced ventricular arrhythmias did not change significantly during the 6 week period after myocardial infarction. A large infarct size (determined by postmortem examination) and a low left ventricular ejection fraction (determined during premortem cardiac catheterization) were the only variables identified that predisposed the animals to electrically induced sustained monomorphic ventricular tachycardia. These factors, however, did not correlate with the presence of electrically induced ventricular fibrillation or nonsustained ventricular tachycardia.

Animals↗
PubMed1985

Determinants of the outcome of electrophysiologic study in patients with ventricular tachyarrhythmias.

To determine those factors predictive of the ability to both initiate and suppress ventricular tachyarrhythmias during electrophysiologic study, the results of programmed cardiac stimulation were evaluated in 261 patients: 66 presenting with nonsustained ventricular tachycardia, 91 with sustained ventricular tachycardia and 104 with ventricular fibrillation. Multivariate logistic regression analysis revealed that the presenting arrhythmia was a potent and independent predictor of the ability to provoke ventricular arrhythmias at electrophysiologic study; a history of myocardial infarction and male sex were also significant independent predictors. Of patients presenting with sustained ventricular tachycardia, 89% (81 of 91) had inducible ventricular arrhythmias compared with 61 (40 of 66) and 66% (69 of 104) of patients with nonsustained ventricular tachycardia and ventricular fibrillation, respectively. Complete suppression of inducible arrhythmias could be achieved in only 52% (34 of 66) of patients with sustained ventricular tachycardia, compared with 73 (24 of 33) and 75% (46 of 61) of patients presenting with nonsustained ventricular tachycardia and ventricular fibrillation, respectively. Multivariate analysis showed that the major independent determinants of the ability to suppress inducible arrhythmias were the number of drug trials performed before electrophysiologic study (inversely correlated) and the nature of the induced arrhythmia. The nature of the presenting clinical arrhythmia is, therefore, a highly significant and independent predictor of the ability to induce ventricular arrhythmias during electrophysiologic testing and an important determinant of the ability to suppress induced arrhythmias in patients with spontaneous ventricular tachyarrhythmias.

Adolescent↗
PubMed1984

Long-term reproducibility of responses to programmed cardiac stimulation in spontaneous ventricular tachyarrhythmias.

Programmed electrical stimulation (PES) of the heart has been used to initiate and terminate ventricular tachyarrhythmias under controlled conditions in patients in whom these arrhythmias have occurred spontaneously. The long-term reproducibility of the response to programmed cardiac stimulation in patients with ventricular arrhythmias is unknown. Seventeen patients with previously documented spontaneously occurring ventricular tachyarrhythmias were evaluated: 5 with nonsustained ventricular tachycardia (VT), 10 with sustained VT and 2 with ventricular fibrillation. The underlying cardiac diagnosis was atherosclerotic coronary heart disease (CAD) in 11 patients, dilated cardiomyopathy in 2 patients, congenital heart disease in 1 patient and no structural heart disease in 3. All patients underwent PES in the absence of antiarrhythmic drug treatment, and patients with inducible VT underwent serial electrophysiologic-pharmacologic testing in an attempt to suppress the arrhythmia. All 17 patients were reexamined with PES at a mean of 18 months (range 2 to 42) after their initial electrophysiologic study, during which time none had a myocardial infarction or intervening cardiac surgery. Repeat electrophysiologic studies, performed in the absence of antiarrhythmic agents, were undertaken because of drug intolerance, availability of new drugs, recurrent arrhythmia or preoperative reevaluation. All 11 patients with CAD had inducible VT on both the first and second electrophysiologic evaluation. Of the 6 patients with no CAD, only 1 had inducible VT on both occasions. Thus, long-term reproducibility of PES-induced VT in patients with stable CAD appears to be high.

Adolescent↗
PubMed1984

Long-term clinical outcome of ventricular tachycardia or fibrillation treated with amiodarone.

The determinants of long-term clinical outcome were studied in 42 patients with recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) who were treated with amiodarone as the sole antiarrhythmic agent. Of the 42 patients, 11 (26%) either died suddenly or had recurrent, symptomatic, sustained VT during a mean follow-up period of 10 months (range 0.3 to 45). Of the 19 patients without inducible VT/VF during electrophysiologic study while receiving amiodarone, 1 patient died suddenly but no patient had recurrent VT/VF. Ten of the 23 patients (43%) with persistently inducible arrhythmia have died suddenly or have had recurrent VT/VF. Using survival and stepwise logistic regression analyses, 2 significant independent predictors of recurrent arrhythmia were identified; persistently inducible VT during electrophysiologic testing in patients receiving amiodarone therapy (p less than 0.002) and the left ventricular ejection fraction at rest (p less than 0.05). The predictive accuracy of the response to serial electrophysiologic testing during amiodarone therapy was 67%, the sensitivity was 58% and the specificity was 91%. Thus, serial electrophysiologic testing is useful for determining the prognosis in patients with inducible VT/VF treated with amiodarone.

Aged↗
PubMed1984

Serious adverse effects of amiodarone.

Amiodarone is an effective antiarrhythmic drug which has been used successfully to treat a variety of cardiac arrhythmias. Early reports emphasized both the striking efficacy of this agent and the relative paucity of side effects necessitating discontinuing treatment with this drug. As amiodarone has been used more widely and in more diverse patient populations, reports of serious thyroid, pulmonary, cardiovascular, and other adverse reactions have appeared in the literature. In this paper, we review the serious adverse effects that have been reported to date. The incidence of these reactions varies considerably in different series, and cannot be explained solely by different doses employed or by varying methods of drug administration. The final role of amiodarone in the therapy of cardiac arrhythmias cannot be determined until the long-term toxicity has been more thoroughly investigated.

Amiodarone↗
PubMed1984

Oral mexiletine in the treatment of refractory ventricular arrhythmias: the role of electrophysiologic techniques.

Mexiletine is a useful antiarrhythmic agent for the treatment of ventricular arrhythmias. Its efficacy in suppressing ventricular arrhythmias during serial electrophysiologic evaluation has come under investigation only recently. Experience to date in more than 300 patients suggests that suppression of inducible ventricular arrhythmias by mexiletine either alone or in combination with another antiarrhythmic agent may be achieved in approximately 30% of patients. Furthermore, suppression sometimes may be achieved when mexiletine is tested in combination with a type IA antiarrhythmic or beta-adrenergic blocking agent in patients for whom neither agent alone has been effective. The likelihood of suppressing inducible ventricular tachycardia (VT) with mexiletine therapy alone or in combination may vary as a function of the spontaneous ventricular arrhythmia with which a patient presents at the time of electrophysiologic study; patients presenting with sustained VT appear to have inducible arrhythmias that are more difficult to suppress. A significant incidence of adverse effects attributable to mexiletine has been observed, particularly gastrointestinal and neurologic effects. These side effects, although common, are frequently eliminated by reducing the dosage of the drug and administering the drug with food. A facilitation of arrhythmia induction has also been observed in a small percentage of patients. Early experience suggests that selected patients with ventricular arrhythmias that are refractory to conventional antiarrhythmic agents may derive long-term benefit from chronic therapy with oral mexiletine.

Administration, Oral↗
PubMed1984

Janeway gastrostomy in children with cerebral palsy.

Brain damaged children frequently are unable to eat by mouth due to incoordination of tongue and pharyngeal swallowing muscles. The commonly utilized Stamm gastrostomy has several drawbacks relative to the indwelling catheter. A permanent gastrostomy consisting of a mucosal-lined tube flap from the stomach wall, as described by Janeway, is easily constructed using the GIA stapler. This provides a simple, tubeless, and safe way to feed cerebral palsied children unable to eat by mouth.

Cerebral Palsy↗
PubMed1983

Adverse reactions during treatment with amiodarone hydrochloride.

Amiodarone was administered to 80 patients with recurrent cardiac tachyarrhythmias previously resistant to drug treatment. Forty nine patients were treated for ventricular tachycardia or fibrillation and 31 for supra-ventricular arrhythmias. The mean (range six days to 51 months), permitting a total of 100 patient years of observation. Adverse reactions were observed in 69 patients. Severe side effects were encountered in 13: four patients developed interstitial pneumonitis, four patients developed incessant ventricular tachycardia, three patients taking amiodarone and digoxin sustained sinus node arrest with depression of escape foci, one patient developed hepatitis, and one patient developed hypercalcaemia with renal failure. Furthermore, a rise in the serum concentration of digoxin and potentiation of warfarin anticoagulation occurred in cases in which these agents were combined with amiodarone. Amiodarone was stopped in 14 patients because of side effects. Although amiodarone is effective in suppressing arrhythmias in most patients in whom extensive use of antiarrhythmic drugs has been unsuccessful, it is associated with diverse and serious toxicity. These observations suggest that at present the use of amiodarone should be reserved for patients with life threatening or seriously disabling arrhythmias in whom longer established drugs have been ineffective or are contraindicated.

Adult↗