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Biomedical subjects

E N Prystowsky

Publications and source records attributed to E N Prystowsky.

At least 55 records · Page 3Linked to original sources
PubMed1996

Electrophysiologic Study versus Electrocardiographic Monitoring (ESVEM): a critical appraisal.

This paper reviews the Electrophysiologic Study versus Holter Monitoring (ESVEM) trial, addressing several areas of concern including potential enrollment bias, an inadequate electrophysiologic testing protocol during drug therapy, and an unexpectedly high recurrence rate in patients deemed to be controlled by either method. The paper concludes that there are insufficient data to warrant extrapolation of the ESVEM results to survivors of cardiac arrest.

Anti-Arrhythmia Agents↗
PubMed1994

A consensus report on antiarrhythmic drug use.

During the past few years, a number of new antiarrhythmic agents have become available for use in the United States, encainide has been withdrawn from use, and others have had indications for use modified. Therefore, a meeting of arrhythmia specialists was convened in an attempt to develop guidelines for antiarrhythmic therapy. The resultant discussions and guidelines presented in this article address general issues such as the most important antiarrhythmic drug attributes, as well as therapy for particular arrhythmias such as premature ventricular contractions, ventricular tachycardia, ventricular fibrillation, ventricular ectopy, and supraventricular tachyarrhythmias.

Anti-Arrhythmia Agents↗
PubMed1994

Inpatient versus outpatient initiation of antiarrhythmic drug therapy for patients with supraventricular tachycardia.

In-hospital initiation of antiarrhythmic drug therapy is often recommended to observe the effects of the drug and monitor for possible adverse reactions, especially proarrhythmia. However, the actual risk of proarrhythmia in patients undergoing treatment for supraventricular tachyarrhythmias is not well defined. While patients with ventricular tachycardia or ventricular fibrillation most often have underlying structural heart disease, this is not true for many patients with supraventricular tachycardia. It is therefore necessary to define more precisely which patients with supraventricular tachycardia are at risk for ventricular proarrhythmia and sudden cardiac death. An indepth analysis was conducted of 162 patients from 51 published reports of ventricular proarrhythmic events in patients treated for supraventricular tachycardia. Heart disease of various etiologies was present in 96% of patients. Proarrhythmia occurred most commonly with quinidine (72% of cases), and torsade de pointes was the most frequently proarrhythmic event (54%). More than half of all proarrhythmic events occurred within the first 3 days of initiating therapy or soon after increasing the dose of chronic drug therapy. Information was scant regarding the time to occurrence of ventricular proarrhythmia with flecainide and propafenone. With flecainide, nine cases were reported at varying times after initiation of therapy, from in-hospital to 8 months. Two cases of proarrhythmia with propafenone occurred at Day 10 and at 2 years. Because of the low frequency of proarrhythmia, in-hospital initiation of antiarrhythmic drug therapy may not be cost-effective. It is recommended when the effects of the drugs on the arrhythmia must be monitored, or when initiating treatment or increasing the drug dose in patients with structural hear disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulatory Care↗
PubMed1993

Radiofrequency catheter ablation of idiopathic recurrent ventricular tachycardia with right bundle branch block, left axis morphology.

Idiopathic ventricular tachycardia with right bundle branch block and left axis deviation morphology is a well described clinical syndrome. Previous studies have mapped the tachycardia focus to the inferior septal region at the base of the posterior papillary muscle of the left ventricle. We describe two typical cases in a 20-year-old man and 29-year-old woman in which the tachycardia focus was localized with endocardial mapping techniques. In both cases the ventricular tachycardia focus was ablated with application of radiofrequency current at the inferior septal region. There were no complications of the procedures. The patients remain asymptomatic over follow-up of 7 and 4 months, respectively.

Adult↗
PubMed1993

Differential effects of isoproterenol on sustained ventricular tachycardia before and during procainamide and quinidine antiarrhythmic drug therapy.

BACKGROUND: Autonomic modulation, especially increased sympathetic activity may play a role in the genesis of ventricular arrhythmias. The purpose of this study was to determine whether beta-sympathetic stimulation with isoproterenol would alter sustained ventricular tachycardia (VT) circuits similarly during the drug-free and antiarrhythmic drug-treated states. METHODS AND RESULTS: Twenty-five patients with repeatedly inducible, hemodynamically stable, sustained VT were evaluated by programmed ventricular stimulation. In the antiarrhythmic drug-free state, isoproterenol (0.03 microgram/kg per minute) shortened the following intervals (in milliseconds; mean +/- SEM; 25 patients; paired t test): sinus cycle length (792 +/- 37 to 568 +/- 18; (p < 0.001), ventricular paced QT interval (386 +/- 8 to 348 +/- 6; p < 0.001), ventricular paced QRS duration (185 +/- 4 to 182 +/- 4; p = 0.014), ventricular effective (238 +/- 5 to 208 +/- 4; p < 0.001) and functional (261 +/- 6 to 227 +/- 5; p < 0.001) refractory periods, and the VT cycle length (VTCL) (311 +/- 9 to 291 +/- 9; p < 0.001). Isoproterenol (0.03 microgram/kg per minute) was administered during 31 antiarrhythmic drug trials (procainamide, n = 18; quinidine, n = 13) in 22 patients. Isoproterenol shortened the sinus cycle length, QT interval during ventricular pacing, and ventricular effective and functional refractory periods before and during procainamide and quinidine therapy (ANOVA; isoproterenol effect, p < or = 0.0002 for all). The amount of decrease in these intervals with isoproterenol was the same before and during procainamide and quinidine therapy (ANOVA interaction, p = NS for all). The QRS duration during ventricular pacing and VTCL were also shortened by isoproterenol before and during procainamide (baseline, n = 17; QRS, 182 +/- 4 to 178 +/- 4 msec; VTCL, n = 18, 314 +/- 11 to 291 +/- 11 msec; during procainamide, QRS, 218 +/- 7 to 197 +/- 6 msec; VTCL, 422 +/- 15 to 359 +/- 11 msec) and quinidine (baseline, n = 13; QRS, 190 +/- 6 to 185 +/- 5 msec; VTCL, n = 12, 298 +/- 10 to 280 +/- 9 msec; during quinidine, QRS, 223 +/- 9 to 208 +/- 8 msec; VTCL, 415 +/- 14 to 355 +/- 10 msec) (isoproterenol effect p < or = 0.0003 for all). However, the amount of decrease in QRS duration and VTCL with isoproterenol was greater during procainamide and quinidine than in the drug-free state (ANOVA interaction, p < or = 0.02 for all). These changes continued to be significant when normalized for the initial QRS duration and VTCL (p < or = 0.03 for all). CONCLUSIONS: Isoproterenol affects presumed reentrant sustained VT circuits less in the absence of antiarrhythmic drugs but markedly attenuates the antiarrhythmic drug-induced slowing of sustained VT. To the extent that the change in QRS duration reflects a change in conduction within the VT circuit, these data imply that the attenuation of drug-induced slowing of VT by isoproterenol is due to a greater change in conduction rather than refractoriness.

Adult↗
PubMed1992

Effects of bepridil on cardiac electrophysiologic properties.

The current classification system for antiarrhythmic drugs has several shortcomings; for example, electrophysiologic effects are defined in normal tissue, whereas antiarrhythmic drugs are often used clinically in diseased or injured tissue. Consideration of the electrophysiologic effects of bepridil in humans emphasizes the drawbacks of the classification system. Bepridil is primarily a calcium antagonist with class IV action. However, because the drug has class IA action as well, it should not be considered a typical class I or class IV agent. Bepridil has been observed to prolong the QT interval in the majority of patients in whom it is used for treatment of angina. However, in US clinical trials, including open extensions, only 7 cases of torsades de pointes have been recorded. In France, where the drug is approved for treatment of angina, the incidence of torsades de pointes was 0.01% in 1989. No consensus currently exists regarding what degree of QT prolongation constitutes increased risk for a ventricular proarrhythmic event. Based on current information, bepridil should be used cautiously in patients with a propensity toward hypokalemia, which can exacerbate or induce a proarrhythmic state. The drug should not be used in patients with a prolonged QT interval at baseline, a history of torsades de pointes, or long QT interval syndrome. Bepridil also should be avoided in patients with sinus node dysfunction or second- or third-degree atrioventricular block.

Arrhythmias, Cardiac↗
PubMed1992

New observations on atrial fibrillation before and after surgical treatment in patients with the Wolff-Parkinson-White syndrome.

The records of 342 patients who received surgical treatment for the Wolff-Parkinson-White syndrome between 1968 and 1986 were reviewed to evaluate the characteristics of atrial fibrillation. The patients were classified into two groups according to the presence (n = 166) or absence (n = 176) of documented episodes of atrial fibrillation preoperatively. The mean follow-up duration was 6 years (range 2 to 20). As compared with reports based on smaller patient groups and shorter follow-up, the study revealed several new findings. 1) During follow-up, nine patients in the atrial fibrillation group developed recurrent atrial fibrillation after a successful operation; five of these nine patients did not have associated heart disease. 2) All three patients with a history of atrial fibrillation and an accessory pathway conducting in the anterograde direction only had a successful surgical procedure and no postoperative atrial fibrillation. 3) The cycle length of atrioventricular (AV) reciprocating tachycardia was significantly shorter in the atrial fibrillation group (304 +/- 42 ms, mean +/- SD) than in the no-atrial fibrillation group (321 +/- 54 ms, p less than 0.005), and the cycle length of AV reciprocating tachycardia that degenerated into atrial fibrillation (289 +/- 26 ms) was shorter than that for the AV reciprocating tachycardia without subsequent atrial fibrillation (316 +/- 51 ms, p less than 0.005). 4) Sustained atrial fibrillation was induced in 30% of patients without a history of atrial fibrillation. 5) Atrial fibrillation occurred in four patients with an accessory pathway that conducted only in the retrograde direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Bedside termination of sustained ventricular tachycardia by transesophageal atrial pacing.

Transesophageal atrial pacing was used to terminate hemodynamically stable sustained monomorphic ventricular tachycardia in two patients. The procedure was performed at the bedside, no anesthesia was required, there were no complications, and one of the patients went home after the procedure was performed. This method should be considered prior to using direct current cardioversion in patients with hemodynamically stable sustained monomorphic ventricular tachycardia.

Aged↗
PubMed1992

Physiological substrate for antidromic reciprocating tachycardia. Prerequisite characteristics of the accessory pathway and atrioventricular conduction system.

BACKGROUND: Although the anatomic "substrate" for the occurrence of antidromic reciprocating tachycardia (ART) has been previously examined, the underlying physiological substrate for this unusual arrhythmia in patients with the Wolff-Parkinson-White syndrome has not been thoroughly characterized. METHODS AND RESULTS: The electrophysiological properties of the accessory pathway and normal ventriculoatrial conduction system in 30 patients with ART and a single accessory pathway were compared with those observed in a control group of 36 patients without this arrhythmia to elucidate the critical physiological substrate essential for the development and maintenance of ART. Inducible ART had a mean cycle length of 286 +/- 31 msec. The average retrograde ventriculoatrial conduction system effective refractory period in ART patients was significantly less than that in the control group (244 +/- 32 versus 291 +/- 46 msec, p = 0.0002). All of the ART patients showed retrograde conduction over the normal conduction system at cycle lengths of less than or equal to 360 msec; 23 had 1:1 conduction to less than or equal to 300 msec, and 16 showed 1:1 propagation at cycle lengths of less than or equal to 260 msec. The shortest cycle length accompanied by 1:1 retrograde propagation over the normal conduction system in patients with ART was also significantly less than that observed in the control group (274 +/- 39 versus 347 +/- 73 msec, p less than 0.001). The accessory pathway anterograde ERP in ART patients with 1:1 retrograde conduction over the normal ventriculoatrial conduction system at cycle lengths of less than or equal to 360 was significantly less than that seen in comparable control patients (247 +/- 23 versus 284 +/- 56 msec, p = 0.001), and the accessory pathway location was significantly further from the atrioventricular node in 21 patients with ART undergoing surgery than that in 22 operated control patients (3.8 +/- 0.8 versus 2.9 +/- 0.8 mapping units, p = 0.0025) who also had retrograde ventriculoatrial conduction to cycle lengths of less than or equal to 360 msec. No significant differences in anterograde atrioventricular conduction system properties, retrograde accessory pathway refractoriness, or shortest ventricular pacing cycle lengths maintaining 1:1 conduction via the accessory pathway were observed between groups. CONCLUSIONS: This quantitative characterization of the properties of conduction and refractoriness of both the accessory pathway and ventriculoatrial conduction system and the relation between these characteristics and the accessory pathway location in ART patients provides additional insight into the prerequisites for the initiation and maintenance of this rhythm disturbance.

Adult↗
PubMed1992

Effect of Ebstein's anomaly on short- and long-term outcome of surgically treated patients with Wolff-Parkinson-White syndrome.

BACKGROUND: Ebstein's anomaly is the most commonly occurring congenital abnormality associated with the Wolff-Parkinson-White (WPW) syndrome. However, the effects of Ebstein's anomaly on the risks and benefits of surgical ablation of accessory pathways in patients with WPW syndrome are unknown. METHODS AND RESULTS: This study compared the long-term outcome of 38 WPW patients with Ebstein's anomaly undergoing accessory pathway ablation to a reference population of 384 similarly treated patients without the anomaly. Ebstein's anomaly was mild in 21 patients (55%) and moderate-to-severe in 17 patients (45%). Sixteen patients (42%) required tricuspid valve surgery, and 23 (61%) had an atrial septal defect or patent foramen ovale repaired. Baseline clinical characteristics and preoperative clinical arrhythmias were similar in both groups. Ten-year survival was 92.4% and 91.2% for patients with and without Ebstein's anomaly, respectively (p = NS). During a mean follow-up of 6.2 +/- 3.8 and 5.3 +/- 3.6 years, 82% of patients with and 90% without Ebstein's anomaly had either clinically insignificant or no arrhythmias, and 18% versus 10% reported symptoms suggesting arrhythmias lasting longer than 1 minute, respectively. Atrial fibrillation was reduced postoperatively to 9% (p less than 0.001) in patients with and to 4% (p less than 0.001) in those without the anomaly. Fewer hospitalizations were reported postoperatively by 90% versus 96% of patients with and without Ebstein's anomaly; 9.4% versus 6.0% of patients were disabled at follow-up, respectively (p = NS). CONCLUSIONS: Patients with Ebstein's anomaly are improved significantly after accessory pathway ablation. The presence of this anomaly should not preclude accessory pathway ablation in these patients.

Adolescent↗
PubMed1992

Antiarrhythmic drug therapy in the management of cardiac arrest survivors.

Antiarrhythmic drugs may be used as primary therapy to prevent recurrent cardiac arrest or as adjunctive treatment in patients given an implantable cardioverter defibrillator. In the latter instance, drugs are given to suppress nonlethal arrhythmias that are capable of initiating defibrillator discharge or to slow and/or decrease the number of episodes of sustained ventricular tachyarrhythmias. When used as primary therapy, drug efficacy should be judged by nonempirical methods, preferably serial electrophysiological testing. Although no study has compared noninvasive with invasive testing to determine antiarrhythmic drug effectiveness in a substantial number of cardiac arrest survivors, several investigations have demonstrated that electrophysiological testing is useful for this purpose. One important limitation of serial electrophysiological testing is that nearly 40% of cardiac arrest survivors do not have a sustained ventricular tachyarrhythmia initiated at baseline study; nonpharmacological treatment would appear preferable in these patients. Further, since a relatively high arrhythmic recurrence rate has been noted in individuals with suppressible sustained ventricular tachycardia/fibrillation during drug therapy and a left ventricular ejection fraction less than 30%, we recommend serial electrophysiological/pharmacological testing primarily for patients with inducible sustained ventricular tachyarrhythmias with an ejection fraction greater than or equal to 30%.

Amiodarone↗
PubMed1991

Role of concealed and supernormal conductions during atrial fibrillation in the preexcitation syndrome.

The hypothesis that retrograde concealed and anterograde supernormal conductions over the accessory pathway are determinants of anterograde accessory pathway conduction during atrial fibrillation (AF) was prospectively tested. For 17 patients during AF, 90 +/- 13 (mean +/- standard deviation) consecutive beats were analyzed for morphology and VV interval preceding each QRS complex. In 15 patients with both preexcited and normal QRS complexes, after normal complexes, the cycle length preceding the first preexcited QRS complex was 389 +/- 69 ms, which was longer than the average cycle length of consecutive preexcited complexes (325 +/- 55 ms; p = 0.001). The mean difference was 61 +/- 53 ms. After preexcited QRS complexes, the cycle length preceding the first normal QRS complex averaged 423 +/- 65 ms, which was significantly longer than the average cycle length of 345 +/- 47 ms between consecutively conducted normal QRS complexes (p less than 0.001). The mean difference was 86 +/- 45 ms. These findings suggest retrograde concealed conduction of normally conducted QRS complexes to the accessory pathway can affect anterograde conduction over the accessory pathway, and vice versa. In 2 patients with multiple accessory pathways, 1 accessory pathway conducted only after short preceding cycle lengths (355 to 360 and 181 to 185 ms), which was consistent with supernormal conduction. In conclusion, retrograde concealed conduction to the accessory pathway conduction are factors that, in part, determine accessory and anterograde supernormal accessory pathway conduction are factors that, in part, determine accessory pathway conduction during AF.

Atrial Fibrillation↗