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J J Gallagher

Publications and source records attributed to J J Gallagher.

At least 91 records · Page 5Linked to original sources
PubMed1984

Identification of reproducible ventricular tachycardia in a canine model.

Epicardial mapping was used as a standard to investigate how well the limb leads, both alone and in conjunction with 5 select epicardial electrodes, can verify reproducibility in a common, open-chest canine model of ventricular tachycardia (VT). Reproducible VT was defined as 2 or more episodes of monomorphic VT with similar rates, limb lead tracings and epicardial maps. In this study, 21 dogs underwent 2-hour occlusion of the left anterior descending coronary artery followed by reperfusion. Three days later, programmed stimulation was used to induce VT that was analyzed with limb leads I, II and III and 27 simultaneously recorded, bipolar epicardial electrodes. Thirteen dogs had VT of which 11 had polymorphic VT (varying QRS morphology). Twelve dogs yielded at least 1 form of monomorphic VT. Eight had 2 or more distinct forms of monomorphic VT (pleomorphism). Four of these 8 dogs had pleomorphic VT that was not apparent from the limb lead tracings, but was recognized from the epicardial activation maps constructed from the 27 epicardial recordings. To provide a method of distinguishing various VTs without the need of full epicardial mapping, 5 of the 27 epicardial electrodes were selected. These were positioned over the midanterior and midposterior right and left ventricles, and the left ventricular apex. By analyzing electrogram morphology and activation time, VT reproducibility could be as accurately identified with these 5 electrodes as with epicardial mapping derived from 27 electrodes. In conclusion, multiple VT morphologies are common in this open-chest canine model. Limb lead recordings alone are inadequate for analysis of VT reproducibility.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Evaluation of noninvasive tests for identifying patients with preexcitation syndrome at risk of rapid ventricular response.

Intermittent preexcitation, block in the accessory pathway after intravenous injection of ajmaline or procainamide, and block in the accessory pathway during exercise usually exclude a short antegrade refractory period of an accessory pathway in patients with the Wolff-Parkinson-White syndrome. This report describes three patients with these findings suggestive of a relatively long antegrade effective refractory period of the accessory pathway in whom life-threatening ventricular response occurred during atrial fibrillation. In the first patient with a pattern of intermittent preexcitation, rapid ventricular response with wide QRS was present during atrial fibrillation. In the second patient in whom preexcitation disappeared after intravenous injection of ajmaline or procainamide as well as during exercise testing, atrial pacing showed 1:1 conduction over the accessory pathway at a cycle length of 220 msec and the shortest R-R interval during induced atrial fibrillation was 190 msec. The third patient, with no evidence of preexcitation during sinus rhythm, presented antidromic reciprocating tachycardia and atrial fibrillation with life-threatening ventricular response, the minimal R-R interval being 220 msec. Noninvasive tests in the preexcitation syndrome lack sufficient prognostic sensitivity. The evaluation of ventricular response during induced atrial fibrillation represents the most reliable means of identifying such patients at risk.

Adult↗
PubMed1984

Functional properties of accessory atrioventricular pathways in Wolff-Parkinson-White syndrome. Clinical implications.

The Wolff-Parkinson-White syndrome is an uncommon cardiac disorder due to the presence of an accessory atrioventricular pathway resulting in ventricular pre-excitation and supraventricular tachycardias. The recognition of the Wolff-Parkinson-White syndrome is important because of the potential for the development of extremely rapid ventricular rates during atrial fibrillation that may lead to ventricular fibrillation and sudden death. The diagnosis of the Wolff-Parkinson-White syndrome is obvious when classic delta waves and short P-R intervals are present, but the electrocardiographic manifestations of the syndrome may be subtle and vary considerably from patient to patient. Certain commonly used antiarrhythmic medications may be useful for the treatment of reciprocating tachycardia in these patients and yet prove to be ineffective--or even deleterious--in preventing excessively rapid conduction to the ventricles during atrial fibrillation. An appreciation of the functional properties of the accessory pathways in the Wolff-Parkinson-White syndrome and how they are affected by pharmacologic agents should result in improved recognition of this entity and more effective medical management of patients with a risk of sudden death.

Anti-Arrhythmia Agents↗
PubMed1984

Anatomic and electrophysiologic substrate of the permanent form of junctional reciprocating tachycardia.

Data are reported on three patients with the permanent form of junctional reciprocating tachycardia, in whom conduction over a slow accessory pathway was observed after His bundle ablation. Tachycardia was almost incessant and showed a retrograde P wave (P') and RP' interval longer than P'R interval in all patients; during sinus rhythm, the PR interval was normal and there was no evidence of a delta wave. An accessory pathway with a long conduction time located in the posterior pyramidal space provided the retrograde limb of the reentry circuit. After His bundle ablation, the accessory pathway was capable of conducting in both anterograde and retrograde directions with decremental properties in all patients. Postmortem documentation of the accessory pathway was achieved in one patient. Serial sections revealed an accessory atrioventricular connection composed of ordinary myocardium joining the lower rim of the coronary sinus outlet to the uppermost ventricular muscle. This anomalous atrioventricular connection pursued a sinuous, tortuous path. As a result of changing cross-sectional area, such an accessory pathway might exhibit slow conduction, thus explaining its decremental characteristics.

Adolescent↗
PubMed1984

Surface electrocardiographic clues suggesting presence of a nodofascicular Mahaim fiber.

Standard electrocardiograms from 87 consecutive patients with tachycardia of left bundle branch block configuration were analyzed retrospectively for features that might be characteristic of tachycardia utilizing a nodofascicular Mahaim fiber. The study group consisted of 13 patients with nodofascicular tachycardia, 34 with supraventricular tachycardia and aberrant conduction over the His-Purkinje system, 22 with ventricular tachycardia and 18 with antidromic tachycardia utilizing a right-sided accessory atrioventricular pathway. Six variables present during tachycardia of left bundle branch block configuration were predictive of a nodofascicular fiber: cycle length between 220 and 450 ms, QRS axis of 0 to -75 degrees, QRS duration 0.15 second or less, R wave in lead I, rS wave in precordial lead V1 and a precordial transition from a negative to a positive QRS complex after lead V4. All six criteria were present in 16 of the 87 patients. No patient with ventricular tachycardia satisfied these criteria, whereas 3 of 34 with supraventricular tachycardia, 1 of 18 with antidromic tachycardia and 12 of 13 with tachycardia using a nodofascicular fiber did. It is concluded that analysis of the surface electrocardiogram during tachycardia may suggest the presence of a nodofascicular fiber.

Adolescent↗
PubMed1984

Utility of electrophysiologic studies in the management of tachycardia, sudden death, and syncope.

The demonstrable value of EP studies for any given diagnostic or therapeutic category, in the last analysis, is largely a function of the subjects studied. Extrapolations from published data (that generally reflect a highly select patient population) to an individual patient can be fraught with error. Considerations of sensitivity and specificity must be balanced against the important need for information in patients at risk from life-threatening arrhythmias. We must never forget, however, that the EP substrate for any arrhythmia is not, as one might wish, a "black box" that should be expected to respond in a reproducible fashion to stimulation. The substrate is dynamic and subject to modification by change in autonomic tone, stretch, blood flow, basal rate, pH, electrolytes, oxygenation, and exposure to perhaps as yet undiscovered humoral mediators. The challenge to the clinical electrophysiologist is therefore not to exaggerate his efforts in one direction (i.e. programmed stimulation) while disregarding the other variables mentioned. Nor should we be disappointed and discard this approach because our expectations of an oversimplified model of arrhythmia testing are not fulfilled. Thus, in addition to careful stratification of patients, baseline studies should perhaps be carried out with more deliberate consideration of autonomic tone (exercise, isoproterenol), stretch (volume, handgrip, afterload), stress (physical and psychological), local anesthetic used, and body position. Only in this way will the scientific basis for acute and chronic EP testing be firmly established.

Death, Sudden↗
PubMed1984

The nonpharmacologic management of the permanent form of junctional reciprocating tachycardia.

The permanent or recurring form of junctional reciprocating tachycardia (PJRT) is an incessant tachycardia that has characteristic clinical and electrophysiologic features of PJRT. Each patient demonstrated near-incessant reciprocating tachycardia with a 1:1 atrioventricular (AV) relationship and with a retrograde P wave (P') occurring closer to the succeeding QRS complexes (i.e., long RP'). With initiation of the tachycardia, there was no prolongation of the PR or AH interval. All patients had evidence of early retrograde atrial activation in their posterior atrial septa and this retrograde limb had properties of decremental conduction. Eight of the nine patients underwent elective surgical ablation of the retrograde limb of tachycardia, and in seven it was successful. Epicardial and endocardial atrial maps recorded during PJRT demonstrated that the site of earliest retrograde activation was in the posterior atrial septum near the coronary sinus orifice. The seven patients in whom surgery was successful left the hospital in sinus rhythm with antegrade conduction, and all are free of tachycardia during the mean follow-up period of 31 months (range 1 to 70 months). In the two remaining patients PJRT was controlled by interruption of the antegrade limb of the tachycardia, the AV node-His bundle. In one patient this was done under direct vision at surgery after an unsuccessful attempt at pathway dissection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Preexcited reciprocating tachycardia in patients with Wolff-Parkinson-White syndrome: incidence and mechanisms.

During the electrophysiologic study of 435 patients referred for evaluation of Wolff-Parkinson-White syndrome, 42 (10%) had preexcited reciprocating tachycardia (defined as a macro-reentrant tachycardia that used an accessory atrioventricular [AV] pathway for antegrade conduction). The ages of the patients ranged from 9 to 67 years (27 +/- 14). Thirty-three were male patients, nine female, and eight had Ebstein's anomaly. Preexcited reciprocating tachycardia cycle length was 220 to 430 msec (294 +/- 42). Significant hemodynamic compromise in the laboratory directly related to preexcitated reciprocating tachycardia occurred in only one patient. However, in 10 patients a transformation to atrial fibrillation was seen after a spontaneously occurring premature atrial contraction. Only 17 of the 42 patients with preexcited reciprocating tachycardia during electrophysiologic study had the same tachycardia documented clinically. These 17 patients were more often younger with multiple accessory pathways and with no history of orthodromic reciprocating tachycardia when compared with 25 patients in whom preexcited reciprocating tachycardia could be induced only in the laboratory. Preexcited reciprocating tachycardia was induced in the laboratory in 22 of 374 (6%) patients with single accessory pathways and in 20 of 61 (33%) of those with multiple accessory pathways. In the 20 patients with multiple accessory pathways, the spectrum of reentrant circuits included fusion over two or more accessory pathways or fusion over both an accessory pathway and the AV node. In the 22 patients with a single accessory pathway and true antidromic reciprocating tachycardia, all but two episodes were at least 4 cm from the AV node. No patient with true antidromic reciprocating tachycardia had a posterior septal accessory AV pathway. Only in patients with multiple accessory pathways was the posterior septal accessory AV pathway used as the antegrade limb.

Adolescent↗
PubMed1983

Ventricular tachycardia induced by atrial stimulation in patients without symptomatic cardiac disease.

Ten patients with an unusual form of ventricular tachycardia (VT) are described. All were young (mean age 21 years) at the onset of VT, symptoms were of long duration (mean 7 years), none had symptomatic organic heart disease, VT was induced by atrial and ventricular stimulation, VT had a characteristic QRS morphologic picture resembling right bundle branch block with left-axis deviation and 9 had early retrograde His deflections during VT. Supraventricular tachycardia (SVT) was excluded in every patient by electrophysiologic study, although QRS morphologic characteristics and clinical stability of these patients during tachycardia frequently led to the diagnosis of SVT before referral. Four patients received verapamil during electrophysiologic testing. Verapamil slowed and terminated VT in all. Three patients are being treated chronically with oral verapamil, 3 patients with conventional antiarrhythmic agents and 1 with a radiofrequency ventricular pacemaker.

Adolescent↗
PubMed1983

Differentiation of septal from free wall accessory pathway location: observations during bundle branch block in reciprocating tachycardia in the presence of type I antiarrhythmic drugs.

In patients with Wolff-Parkinson-White syndrome, observations during bundle branch block (BBB) in reciprocating tachycardia are of value in accessory pathway localization. Most importantly, an increase in the ventriculoatrial (VA) interval of greater than or equal to 35 ms has indicated an ipsilateral free wall location and excluded a septal location. The present study examined whether data collected in the presence of type I antiarrhythmic drugs retained localizing value. Review of retrospective data showed that observations in the drug-free state were precluded by the need to suppress atrial arrhythmia during electrophysiologic study in 20% of patients with Wolff-Parkinson-White syndrome who underwent preoperative workup. Prospectively, in 15 patients with left free wall or posteroseptal pathways, we observed transient left BBB during tachycardia before and after administration of procainamide, disopyramide or quinidine. Serum drug levels ranged from 4.6 to 6.9 mg/liter, except in 1 patient with a serum procainamide level of 18 mg/liter. Drugs increased the VA interval during narrow QRS tachycardia by 17% (p less than 0.01). However, the change in the VA interval with left BBB was not significantly affected. The baseline and drug values averaged 73 ms (range 39 to 94) and 70 ms (range 39 to 90), respectively, for left free wall pathways (n = 8), and 19 ms (range 0 to 28) and 21 ms (range 2 to 35), respectively, for posteroseptal pathways (n = 7). Among the latter, the interval increased less than 30 ms during left BBB except in the patient with the high serum procainamide level, in whom the increase was 35 ms. Thus, the VA interval change that accompanied left BBB remained of localizing value with moderate blood levels of type I drugs, and an increase greater than or equal to 35 ms indicated a left free wall rather than posteroseptal pathway.

Adolescent↗
PubMed1983

Clinical spectrum of ventricular tachycardia with left bundle branch morphology.

Twenty-nine patients with apparent ventricular tachycardia (VT) of left bundle branch block (LBBB) morphology were evaluated. Tachycardia was associated with an organic basis in 24 of 29 patients: 7 had Mahaim fibers of the nodoventricular type, 7 had arrhythmogenic right ventricular dysplasia, 5 had coronary heart disease, 3 had biventricular cardiomyopathy, and 2 had associated congenital heart disease. In many patients the underlying cardiac disease was not readily apparent. In the patients with a Mahaim fiber, the electrocardiogram taken during sinus rhythm was frequently normal. A reentry tachycardia with anterograde conduction over the nodoventricular fiber could mimic VT as diagnosed by the usual criteria; nodoventricular fibers were, therefore, often unsuspected before electrophysiologic evaluation. In patients with arrhythmogenic right ventricular dysplasia, cineangiography demonstrated abnormalities of the right ventricle, but only minor or no abnormalities of the left ventricle. Clinical and electrocardiographic features were not distinctive. Of the 29 patients, 22 had serious symptoms accompanying the tachyarrhythmia or had required cardioversion. Patients were followed up for an average of 20 months: 4 patients died. Thus, VT exhibiting an LBBB morphology is not uncommon and is frequently associated with organic heart disease, serious symptoms, and significant mortality. Right ventricular angiography and electrophysiologic study may clarify the diagnosis in these patients.

Adolescent↗
PubMed1983

Transvenous ablation of the atrioventricular conduction system in dogs: electrophysiologic and histologic observations.

The correlation of histologic and electrophysiologic findings in dogs undergoing transvenous ablation of atrioventricular (AV) conduction has not been described. The creation of complete AV block in 10 dogs was attempted by delivering a direct-current shock transvenously through a standard tripolar electrode catheter. The catheter was positioned to record the largest unipolar atrial and His bundle electrograms. A 280 J shock was delivered to the recording electrode by a standard cardioversion unit. After 1 shock, all dogs were in complete AV block refractory to isoproterenol (1 to 4 micrograms/min) and atropine (0.5 to 2.0 mg). Four weeks later, 5 dogs remained in complete AV block, 1 had first-degree block, and 4 had resumed normal AV conduction. Each dog with complete heart block had histologic evidence of severe damage to the AV node, His bundle, or both. On gross examination, these dogs were found to have discrete scars at the base of the septal leaflet of the tricuspid valve. Of the 5 dogs that had resumption of AV conduction, only 1 had histologic evidence of significant damage to the AV conduction system. That animal manifested a marked increase in the P-R interval (100 to 210 ms). Although temporary heart block occurred in each animal, chronic interruption of AV conduction was more difficult. Catheter location, atrial and His bundle electrogram relations, and the electrode used for delivery of energy were factors determining the effectiveness of this technique.

Animals↗
PubMed1983

Effects of exercise and isoproterenol during atrial fibrillation in patients with Wolff-Parkinson-White syndrome.

The effects of exercise and isoproterenol on atrial fibrillation (AF) were studied in 17 patients with Wolff-Parkinson-White syndrome (WPW) to assess the risk of developing a rapid ventricular response. Mean cycle length (R-R interval) and shortest R-R interval between both preexcited and nonpreexcited QRS complexes were recorded, as well as the percentage of preexcited complexes during control periods, during bicycle exercise, and during isoproterenol infusion. Exercise resulted in significantly shorter mean cycle length and the shortest R-R interval between nonpreexcited complexes. Exercise also resulted in a significantly lower percentage of preexcited complexes during AF, but had no effect on the R-R intervals between preexcited complexes. Isoproterenol had a variable effect on the percentage of preexcited QRS complexes, but resulted in significant shortening of mean cycle length and the shortest R-R interval between both normal and preexcited complexes. With isoproterenol, 12 of 17 patients had shortest preexcited R-R intervals less than or equal to 215 ms, compared with 6 of 17 in the control state. Isoproterenol infusion increased the rate of conduction over the accessory pathway during AF and allowed better assessment of the risk of excessively rapid rates occurring during AF. Exercise is not an adequate test for this purpose.

Atrial Fibrillation↗
PubMed1983

Localization of septal pacing sites in the dog heart by epicardial mapping.

To examine whether different septal pacing sites could be distinguished by their epicardial activation patterns, six to eight stimulating electrodes were placed throughout the septum in seven open chest dogs. Unipolar electrograms were obtained from 52 epicardial electrodes during pacing from each stimulating electrode and isochronous epicardial maps were constructed. The location of each stimulating electrode was found by dissection, and its distance from the overlying epicardium was measured. To allow comparison among epicardial maps, the septum was conceptually subdivided into nine regions to which stimulating electrodes were assigned. Epicardial activation patterns from the same region were similar and these patterns allowed the region containing a stimulating electrode to be identified in many cases. Three other variables were found to have additional localizing value. There were: 1) the time from the stimulus to epicardial breakthrough, 2) the duration of epicardial activation, and 3) the area of epicardium activated in the first 5 ms after epicardial breakthrough. For those stimulating electrodes that could not be localized by their epicardial activation patterns, the distance of the stimulating electrode beneath the epicardium was well fit from these three variables by multiple regression (correlation coefficient [r] = 0.97). Thus, using all the previous factors, localization of septal pacing sites was possible in the noninfarcted dog heart by epicardial mapping.

Animals↗