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Biomedical subjects

J J Gallagher

Publications and source records attributed to J J Gallagher.

At least 181 records · Page 10Linked to original sources
PubMed1978

Characteristics of atrioventricular conduction and the spectrum of arrhythmias in lown-ganong-levine syndrome.

Electrophysiological characteristics of atrioventricular (A-V) conduction and refractoriness were examined in 12 patients with Lown-Ganong-Levine (LGL) syndrome referred for assessment of the following arrhythmias: (group I) regular narrow QRS tachycardia 6/12 (50%), (group II) atrial fibrillation (AF) 2/12 (17%), group III) ventricular tachycardia (VT) 4/12 (33%). A-V node refractory periods were shorter, and enhanced A-V conduction more frequent (7/12, 58% vs 7/28, 25%) in LGL patients compared to similar studies in 28 normal controls. During laboratory study reciprocating tachycardia (RT) due to re-entry within the A-V node occurred in 4/12 (33%) LGL patients, and exhibited a shorter cycle length (294 +/- 60.4 msec) than did the same arrhythmia in 11/28 (39%) controls 372 +/- 51.8 msec, P less than 0.05). Similarly, RT utilizing a concealed accessory pathway had a shorter cycle length (228 +/- 3.5 msec) in 2/12 (17%) LGL patients than in 11/28 (39%) controls (314 +/- 24.3 msec, P less than 0.001). In AF, the shortest R-R intervals in 4/12 (33%) LGL patients (2 group I, 2 group II) were shorter than in 15/28 (54%) control patients (254 +/- 42.2 msec vs 325 +/- 64.2 msec, P less than 0.05). The mean R-R internvals did not differ significantly (LGL 372 +/- 89 msec vs control 428 +/- 82.6 msec). This study suggests that the characteristics of A-V conduction and refractoriness may permit development of more rapid heart rates during certain arrhythymias in LGL patients compared to normal controls. Furthermore, the occurrence of VT in patients with LGL sydrome indicates that symptomatic arrhythmias require specific diagnosis.

Adolescent↗
PubMed1978

Determinants of antegrade echo zone in the Wolff-Parkinson-White syndrome.

Forty-five patients with the Wolff-Parkinson-White syndrome and reciprocating tachycardia which utilized the atrioventricular (A-V) node for antegrade conduction and an accessory pathway for ventriculo-atrial (retrograde) conduction were studied. The extrastimulus technique in the right atrium and coronary sinus at multiple pacing cycle lengths was used. Three types of "echo zones" were defined by the relationship of the antegrade effective refractory period (ERP) of the accessory pathway, the longest coupling interval accompanied by an atrial echo, the ERP of the A-V node, and the functional refractory period of the atrium. Eighteen of 45 patients (40%) had more than one type of echo zone demonstrated by changing either pacing site or pacing cycle length or both. Pacing site and intraventricular conduction delay were found to have important effects on the longest coupling interval accompanied by an atrial echo in those echo zones in which the longest coupling interval accompanied by an atrial echo was less than the antegrade ERP of the accessory pathway. The echo zone is a useful concept to explain the physiology of the common reciprocating tachycardia in patients with the Wolff-Parkinson-White syndrome. However, the echo zone is profoundly affected by pacing site and pacing cycle length. When these variables are changed, many patients can be shown to have more than one type of echo zone. Studies of the echo zone have limited value as therapeutic guides.

Cardiac Pacing, Artificial↗
PubMed1978

Epicardial mapping in the Wolff-Parkinson-White syndrome.

Epicardial mapping provides a method for defining antegrade and retrograde sites of pre-excitation. It is best undertaken only after a careful, detailed preoperative electrophysiological study has been performed. The potential pitfalls of the technique are many and technical expertise must be constantly available to maintain a functioning system. For these reasons, it is not likely to lend itself to widespread application. The same techniques can be applied to localization of the site of origin of atrial or ventricular dysrhythmias, localization of myocardial ischemia and infarction, as well as to differentiate between epicardial delays due to conduction delay and those caused by intramural myocardial delay.

Arrhythmias, Cardiac↗
PubMed1978

Temporary, catheter-induced block in accessory pathways.

Catheter-induced conduction delay or block in the accessory atrioventricular pathway of four patients with the preexcitation syndrome was observed. Block in the accessory pathway occurred during routine catheter placement and lasted from 90 seconds--14 hours. All of the pathways were in locations readily accessible to catheter trauma, located in the right anterior septal/paraseptal area in three patients, and in the posterior septum near the orifice of the coronary sinus in the fourth. The location of the acessory pathway was confirmed at surgery by endocardial mapping in three of the four patients. The fourth patient did not undergo survey. These findings suggest the need for caution in performing and interpreting electrode catheter studies which are undertaken to document the presence of accessory pathways.

Adult↗
PubMed1978

The permanent form of junctional reciprocating tachycardia: further elucidation of the underlying mechanism.

A case of the permanent form of junctional reciprocating tachycardia studied by endocardial and epicardial mapping is presented. The ability of the retrograde impulse to penetrate the atrium in 2 different areas, one near the region of the recorded His potential and the other near the orifice of the coronary sinus, is demonstrated. Retrograde conduction persisted after the surgical creation of complete antegrade heart block suggesting the existence of an accessory ventriculo-atrial connection. The decremental properties of retrograde conduction observed suggest that an accessory ventriculo-artrial nodal structure may be the underlying substrate of this arrhythmia.

Adolescent↗
PubMed1978

Reentry within the atrioventricular node in man: a reassessment.

6 patients with reentrant supraventricular tachycardia were studied using the atrial extra-stimulus (S1-S2) technique. 3 patients had smooth curves of H1-H2 intervals plotted against A1-A2 intervals, and echoes occurred only in the relative refractory period of the AV node. These patients met traditional criteria for reentry within the AV node, but all 3 were found to have accessory pathways which functioned only in the retrograde direction. 3 other patients had discontinuous curves of H1-H2 intervals plotted against A1-A2 intervals, and the echo zone was confined to coupling intervals producing the longer of the two observed AV node responses. Accessory pathways could not be demonstrated in these latter 3 patients. In patients with accessory pathways the effect of changing atrial pacing site on the echo zone was studied. Pacing at a site remote from the accessory pathway shifted the echo zone to shorter coupling intervals. Some patients previously thought to have reentry within the AV node may have had accessory pathways which conducted only in the retrograde direction. The prevalence of this syndrome is unknown but is important because ablation of the accessory pathway is curative.

Atrioventricular Node↗
PubMed1978

Surgical treatment of tachyarrhythmias in patients with both an Ebstein anomaly and a Kent bundle.

The report relates experience with six patients with Kent bundles, five of whom had the Wolff-Parkinson-White syndrome, operated upon for tachyarrhythmias caused by the presence of the pathway. It was successfully divided in four patients, its antegrade conduction capacity interrupted in one, and a failure occurred in the sixth patient. In the three patients who had a Kent bundle with a short effective refractory period for antegrade conduction, the life-endangering potential of the Kent pathway was corrected. To emphasize the complexities of the tachyarrhythmias in Ebstein's anomaly, two patients have mild but controllable postoperative supraventricular tachyarrhythmias (SVT) due to a Mahaim pathway. The surgical problems encountered in these patients are reviewed.

Adolescent↗
PubMed1978

The surgical anatomy of Kent bundles based on electrophysiological mapping and surgical exploration.

The development of the procedure for interruption of a Kent bundle for the correction of the tachyarrhythmias associated with the Wolff-Parkinson-White syndrome has been hampered by the lack of anatomic descriptions of the pathways. Only 21 descriptions are given in enough detail for guidance to the surgeon. Our experience with our first 100 patients operated upon for serious dysrhythmias associated with Kent bundles has supplemented this information. In our first 40 patients the Kent was divided in 22 of 39, one having elective and four having forced interruption of the His bundle, with success in 28. In the next 60 the Kent was divided in 52 of 59 attempts, one had elective and three had forced His bundle interruption, and the success rate was 56 of 60 patients. This increased success occurred because we learned the following: (1) The anomalous pathways are best approached through the atrium and can be for out in the fat, even subepicardial in the coronary sulcus or adjacent to the anulus. (2) Interruption should be started with an incision made just above the anulus fibrosus. (3) Posterior septal pathways can be adjacent to the His bundle or in the septum from this point posteriorly to the crux. (4) Anterior septal pathways can be divided and the His bundle protected. The details for the approach to the right and left free wall, posterior septal, and anterior septal pathways will be given. The approach to all pathways is now safe enough to allow the surgeon to offer this operation to patients with life-threatening tachyarrhythmias as well as the ones with rhythm disturbances that are either burdensome or impossible to treat medically.

Arrhythmias, Cardiac↗
PubMed1977

Atrial fibrillation in the preexcitation syndrome.

One hundred patients with proved accessory pathways of the Kent bundle type were studied with multiple intracardiac catheters. During the procedure 16 had atrial fibrillation. Two patterns of induction of atrial fibrillation were noted. In most patients an earlier than expected atrial deflection appeared in one of the atrial recordings and was followed by atrial flutter (cycle length less than 220 msec) or atrial fibrillation either immediately or after a brief period of acceleration of atrial rate. In a few patients, intraatrial conduction delay, manifested as 2:1 block or Wenckebach block from the right to the left atrium or vice versa, occurred before the onset of atrial fibrillation. The incidence of atrial fibrillation was not statistically related to any associated cardiac abnormalities. A significantly large incidence of ventricular fibrillation was recorded in patients who had documented atrial fibrillation either before admission or during the catheter study.

Adult↗
PubMed1977

Construction of a multipolar needle electrode for activation study of the heart.

The study of transmural activation of the intact heart requires placement of multipolar needle electrodes through the wall of the beating heart. This report describes a method developed for constructing lightweight multipolar needles with 10-30 leads mounted 1 mm apart. The electrodes are constructed from readily available materials and no special equipment is required. The electrodes are well suited to the intraoperative mapping studies required to surgically correct arrhythmias.

Arrhythmias, Cardiac↗
PubMed1977

Effects of procainamide and quinidine sulfate in the Wolff-Parkinson-White syndrome.

Thirty-three patients with Wolff-Parkinson-White syndrome were studied electrophysiologically before and after administration of intravenous procainamide and oral quinidine sulfate. Procainamide prolonged the shortest R-R (SRR) interval between two consecutive pre-excited beats during atrial fibrillation 20-70 msec in 15 of 21 patients with no change observed in 6 of 21 patients. Quinidine sulfate prolonged the SRR 20-170 msec in all 16. In 14 of 18 patients where procainamide and quinidine were comparable, quinidine prolonged the SRR 30-100 msec more than procainamide.

Atrial Fibrillation↗
PubMed1977

Cryosurgical ablation of the A-V node-His bundle: a new method for producing A-V block.

A cryosurgical instrument was used to ablate atrioventricular conduction. The procedure was carried out in 20 dogs and subsequently in three patients with drug resistant, life-threatening supraventricular tachycardias. In patients, the cryosurgical unit lowered the temperature of the His bundle area to 0 degrees C, effecting complete but reversible heart block. Rewarming resulted in resumption of normal atrioventricular conduction. The His bundle region then was cooled to -60 degrees C; complete heart block was produced with two or more 90-120 second freezes. Postoperative evaluations revealed persistent atrioventricular conduction block. The lesion showed no tendency to rupture, form aneurysm, or interfere with valvular function. In the clinical cases, postoperative studies demonstrated a stable pacemaker arising proximal to the branching portion of the His bundle. A potential application of the cryosurgical technique might be ablation of sites of dysrhythmia (i.e., ectopic foci, re-entry circuits, accessory pathways).

Adult↗
PubMed1977

Cryosurgical ablation of accessory atrioventricular connections: a method for correction of the pre-excitation syndrome.

Cryothermia, a new technique for definitive treatment of the pre-excitation syndrome, is described in two patients. The first patient presented with a normal P-R interval with a delta wave and reciprocating tachycardia. Preoperative electrophysiologic study suggested a free-wall atrioventricular connection on the left posterior atrioventricular (A-V) groove. At surgery, epicardial mapping confirmed the site of pre-excitation on the posterior left ventricular (LV) wall. An electrogram arising from the accessory pathway (AP) was recorded at the site of earliest ventricular activation. Interatrial delay combined with an apparently long accessory pathway to the ventricle caused the P-R interval to appear normal. Local pressure abolished pre-excitation. The site of early ventricular activation was cooled to -60 degrees C with a specially designed cryoprobe. All evidence of pre-excitation and arrhythmias disappeared. The second patient presented with a refractory reciprocating tachycardia and was found to have an AP in the septum capable of only retrograde conduction. Retrograde conduction was abolished by applying a temperature of 0 degrees C to the anulus at this site during tachycardia. Conduction over the AP and reciprocating tachycardia returned with rewarming. Ablation of the AP was obtained by applying a temperature of -60 degrees C for 90 seconds on two occasions to the same area. The His bundle was not injured.

Adult↗
PubMed1977

Digitalis in the pre-excitation syndrome. Analysis during atrial fibrillation.

The effect of digitalis in 21 patients with Wolff-Parkinson-White syndrome was anlayzed with respect to the ventricular response during atrial fibrillation and antegrade and retrograde refractory periods of accessory pathways. Digitalis shortened the cycle length of the most rapid ventricular response (shortest R-R) (i.e., increased the ventricle response) in 6/21 patients, increased the cycle length in 7/21 patients, had no effect on the cycle length in 5/21, and could not be determined in 3/21. Digitalis could be directly related to the onset of ventricle fibrillation resulting from atrial fibrillation in 9/21 patients. Each of these patients had shortest R-R intervals (220 msec or less) during atrial fibrillation in the control data. The results of this study indicate that no a priori prediction about the effect of digitalis on the antegrade conduction of accessory pathways can be made. By elective induction of atrial fibrillation it is possible to separate WPW patients into groups at high and low risk for developing ventricular fibrillation with the administration of digitalis.

Adolescent↗
PubMed1977

Surgical treatment of supraventricular tachyarrhythmias.

In this report, we have outlined our experiences with the direct surgical treatment of 16 patients with supraventricular tachyarrhythmias (SVTA). Re-entry supraventricular tachycardia (SVT) was demonstrated by the 4 patients who had retrograde-conducting Kent pathways. The SVT was corrected by the successful division of the Kent bundle in 3 and a partially successful His bundle division in one patient. The remaining 9 patients with re-entry, which included 6 with Kent pathways and WPW, all had His bundle section. The remaining 3 with His interruption had focal tachycardias associated with dysfunction of the atrioventricular (AV) node. Of the 13 His bundle interruptions, nine were successful, three resulted in questionable AV conduction, and one failed. Problems with suture ligation and cautery explained the failures. Cryothermia was the most successful procedure used. However, excision of that portion of the atrium containing the AV node shows promise of being satisfactory. The possibility is discussed of using measures much more precise and less destructive than His bundle interruption for SVTA.

Adolescent↗