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Biomedical subjects

J J Gallagher

Publications and source records attributed to J J Gallagher.

At least 199 records · Page 11Linked to original sources

Educational strategies for the autistic child.

This paper includes some of the latest discussions regarding educational programming for autistic children. Until the last decade, special educators have not been either effective or optimistic regarding the prognosis for such children. Recent educational developments with such techniques as behavior modification, the behaviorally engineered classroom, and early identification of the condition have caused increased interest in the possible contributions of educators to the puzzling syndrome. The various alternative treatment possibilities will be presented together with an evaluation of the effectiveness of such programs to date.

Association↗

The surgical treatment of Wolff-Parkinson-White Syndrome: evolution of improved methods for identification and interruption of the Kent Bundle.

Fifty patients have been operated upon for the tachyarrhythmias associated with Kent bundles. The indications for operation were supraventricular tachycardia (SVT) in 23 and life-threatening tachyarrhythmia in 27. Among the unusual variants noted were multiple Kent bundles that conducted only retrograde in 3. Forty-nine patients underwent attempted interruption of the bundle of Kent followed by His bundle division in 6. One had elective division of the bundle of His. The surgical problems occurred in 13 patients with posterior septal Kent bundles. A new approach is outlined for this group. Division of the Kent bundle was successful in 31 patients, but 2 deaths occurred from cardiomyopathy. Seven patients had successful control of SVT by His bundle interruption. One patient with postoperative retrograde conduction has the SVT controlled with drugs. Eight have postoperative delta waves, but their SVT is controlled with drugs. There were 3 failures.

Adolescent↗

Ventriculo-atrial conduction time during reciprocating tachycardia with intermittent bundle-branch block in Wolff-Parkinson-White syndrome.

Records from patients with the Wolff-Parkinson-White syndrome were reviewed with particular emphasis on the occurrence of bundle-branch block aberration during reciprocating tachycardia and the significance of this observation with respect to accessory pathway location. Increase by greater than 25 ms in the ventriculoatrial interval during reciprocating tachycardia with bundle-branch block, when compared to reciprocating tachycardia with normal intraventricular conduction, occurred only with right or left free wall accessory pathways. No patient with a septal accessory pathway proven by epicardial mapping showed a ventriculoatrial interval prolongation greater than 20 ms during bundle-branch block aberration. Measurement of ventriculo-atrial interval during bundle-branch block abe-ration also helped to diagnose accessory pathways AH and HV intervals as well as ventriculo-atrial times, may give midleading information. In one patient increase in cycle length during left bundle-branch block was the result of prolonged HV interval rather than prolonged ventriculo-atrial interval. In another patient cycle length remained the same during bundle-branch block while the ventriculo-atrial interval increased by an increment identical to the decrease in AH interval.

Bundle-Branch Block↗

Multiple accessory pathways in patients with the pre-excitation syndrome.

We have studied 135 patients with the pre-excitation syndrome and have demonstrated evidence of multiple accessory pathways in 20 patients. Five patients had two distinct accessory atrioventricular (A-V) connections, associated with enhanced A-V node conduction in one patient. Twelve patients had a single accessory A-V connection associated with enhanced A-V conduction. In one of these there was an additional fasciculo-ventricular connection. One patient had an accessory A-V connection associated with a nodoventricular bundle. Two patients had fasciculo-ventricular connections combined with enhanced A-V conduction. The latter two patients had electrocardiograms suggestive of a complete accessory A-V connection. Patients with enhanced A-V conduction had shorter cycle lengths during reciprocating tachycardia, primarily because of a short A-H during the dysrhythmia, than those without such conduction. In addition, patients with enhanced A-V conduction demonstrated more rapid conduction from atrium to His bundle during induced atrial fibrillation and two developed life-threatening ventricular responses during atrial fibrillation. A nodo-ventricular pathway was documented to participate in reciprocating tachycardia in one patient. Surgery was undertaken in 13 patients. In 11, the intraoperative mapping studies confirmed the preoperative predictions. In two patients, the presence of a second accessory A-V connection was documented after ablation of one.

Adolescent↗

Retrograde atrial preexcitation following premature ventricular beats during reciprocating tachycardia in the Wolff-Parkinson-White syndrome.

In 34 successive patients with Wolff-Parkinson-White syndrome premature beats were induced from the right ventricular apex during reciprocating tachycardia (RT) at progressively shorter coupling intervals. The presence of an accessory pathway was confirmed by a reduction in the atrial cycle length (A-A interval) during which the premature ventricular beat was introduced. This retrograde preexcitation occurred at a time when the His-AV node pathway was refractory; i.e. there was premature activation of the atria over a pathway other than the His-AV node. 3 patients were excluded because of unsatisfactory or unstable H-H intervals. In the remaining 31 patients with constant preceding H-H intervals, the A-A interval shortened; (a) 35-65 msec in 4 patients with right-sided pathways and normal conduction during RT and by 110 msec in a 5th patient with a right-sided pathway, in whom bundle branch block aberration persisted during RT, (b) 45 msec in the single patient with both a right-sided and a septal accessory pathway, (c) 35-65 msec in 5 patients with septal pathways, and (d) 15-35 msec in only 4/20 patients with left-sided pathways and normal conduction during RT. Left-sided ventricular premature beats were introduced in 5 patients with left-sided pathways and normal conduction in RT. In 4/5, left-sided premature beats shortened the A-A interval 40-75 msec whereas right-sided premature beats at the same coupling interval failed to do so. In the fifth case, the left-sided premature resulted in a 65 msec abbreviation of the A-A interval compared to 30 msec from the right ventricular outflow tract and 15 msec from the right ventricular apex. In 5 patients with left-sided pathways, right ventricular premature beats were introduced during RT with left bundle branch block aberration, and shortened the A-A interval 30-50 msec in all of these, whereas right-sided premature beats in 4 of the 5 during normal conduction failed to do so. This technique is useful to confirm the participation of accessory pathways in reciprocating tachycardias associated with the preexcitation syndromes, and emphasizes the importance of the site of stimulation used relative to the location of the accessory pathway. Because of the possibility of multiple accessory pathways, stimulation of the left ventricle should be performed in patients undergoing surgery for preexcitation unless the left ventricle is already inplicated by right-sided studies.

Adolescent↗

Sinus nodal function in the intact dog heart evaluated by premature atrial stimulation and atrial pacing.

Sinus nodal function was analyzed in 25 dogs by premature stimulation of the right atrium. The return (AT-AR) and post-return (AR-A) cycles were plotted as a function of the premature cycle, and four zones were identified. Zone I (compensatory zone) was observed during the last 4.8 percent (mean value) of the sinus cycle (A-A). Zone II was observed during 43.6 to 95.2 percent (mean value) of the sinus cycle. During the latter part of zone II, AT-AR was nearly constant and AR-A remained nearly equal to A-A during the last 29 percent (mean value) of the cycle. Earlier in zone II three distinct patterns of return cycle responses were observed whereas post-return cycles either remained nearly equal to A-A or showed progressive lengthening. Zone III (interpolation) was observed in 10 animals during 39.5 to 46.2 percent (mean value) of the sinus cycle. AR-A was nearly equal to A-A in zone III. Interpolation was incomplete late and complete early in the zone. Zone IV (echo zone) was seen in another 10 animals during 40.9 to 45.3 percent (mean value) of the sinus cycle and in this zone AR-A was greater than A-A. No significant difference in these zones was seen among the animals anesthetized with pentobarbital or alpha-chloralose, or given 6-OH-dopamine. The AR-A was important in the analysis of these zones and appears to be essential to the interpretation of data derived from premature atrial stimulation. Responses to premature atrial stimulation through a catheter electrode positioned against the sinus nodal region compared favorably with responses to direct epicardial stimulation. After periods of continuous right atrial pacing a vairety of patterns of sinus nodal depression were observed at different rates and durations of stimulation. The frequent occurrence of a short sinus escape cycle followed by the maximal pause observed during rapid pacing rates suggests sinus nodal entrance block. This may be an important factor to consider in determining an optimal pacing rate for assessing sinus nodal function.

Anesthesia, Intravenous↗

Wolff-Parkinson-White syndrome. The problem, evaluation, and surgical correction.

Physiological studies of the type we have described, when performed in patients with the WPW syndrome, can yield diagnostic information regarding the mechanism of arrhythmia, demonstrate functional properties of therapeutic import, facilitate therapeutic decision-making about drug regimens and presumptively localize the site of pre-excitation as a basis for possible surgical intervention. Based on our experience, we feel that in selected patients, surgical correction of the WPW syndrome is entirely feasible, and can be accomplished in the majority of patients in whom free wall A-V connections are present. The continuing challenge of identification and correction of septal accessory pathways directs our present work with the WPW syndrome.

Adolescent↗

Coexistence of functional Kent and Mahaim-type tracts in the pre-excitation syndrome. Demonstration by catheter techniques and epicardial mapping.

An unusual patient with Ebstein's anomaly of the tricuspid valve and the Wolff-Parkinson-White syndrome is presented. Ventricular pre-excitation related to conduction over both a right posterior Kent bundle and Mahaim fibers coursing from the atrioventricular node to the right ventricle. Two types of supraventricular tachycardia were demonstrable. These were due to re-entry involving antegrade conduction over either the normal or Mahaim paths, and retrograde retrograde conduction via the Kent bundle. Surgical division of the Kent bundle has abolished the clinically debilitating arrhythmias.

Adult↗

Electrophysiological evaluation of the Wolff-Parkinson-White syndrome: problems in assessing antegrade and retrograde conduction over the accessory pathway.

The effect of atrial pacing and recording site and ventricular pacing site on assessment of conduction over the accessory pathway (AP) was examined in a group of patients with the Wolff-Parkinson-White syndrome. The importance of initial localization of the AP by recording the sequence of retrograde atrial activation during circus movement tachycardia is demonstrated. Inability to record or pace near the AP may lead to significant errors in the assessment of the antegrade and retograde conduction properties of the AP. During ventricular pacing, retrograde atrial fusion was consistently demonstrated with laterally located APs.

Cardiac Catheterization↗

Refractory periods of the accessory pathway in the Wolff-Parkinson-White syndrome.

Antegrade (AERPAP) and retrograde (RERPAP) effective refractory periods of the accessory pathway were measured at multiple cycle lengths in 47 patients with the Wolff-Parkinson-White syndrome. In 20 patients the effect of changing cycle length on AERPAP could be determined. In 12 patients Aerpap decreased by 10-45 msec, in six it increased by 10-35 msec, and in two it was unchanged. In 13 of 15 patients in whom the effect of decreasing cycle length on RERPAP could be assessed, RERPAP decreased by 10-60 msec. In eight patients, the shortest AERPAP correlated well (r equals 0.83) with the shortest R-R interval of consecutive pre-excited beats in atrial fibrillation. However, predominantly normal conduction was observed in six of 28 patients with atrial fibrillation, probably because of concealment in the bypass. Therefore, induction of atrial fibrillation during electrophysiological evaluation may privide additional information. The RERPAP at the cycle length of the arrhythmia was shorter than the cycle length of reciprocating tachycardia in all but one of 21 patients. At the same or comparable cycle lengths, AERPAP was usually greater than RERPAP.

Adolescent↗

Initial forces of ventricular depolarization in the Wolff-Parkinson-White Syndrome. Analysis based upon localization of the accessory pathway by epicardial mapping.

The epicardial activation sequence of 34 patients with the Wolff-Parkinson-White syndrome was determined. Epicardial pre-excitation occurred at a spectrum of sites over either the free wall of the left or right ventricle or in a paraseptal region, always adjacent to the atrioventricular rings. The site of pre-excitation was related to the spatial position of the 10 msec vector of the vectorcardiogram (VCG) in 15 patients and the 20 msec vector of the electrocardiogram (ECG) in 29 patients with a single accessory pathway. All patients whose 20 msec vector (ECG) was directed to the right had accessory pathways which caused epicardial breakthrough over the free wall of the left ventricle. When the 20 msec vector (ECG) was to the left and inferior, epicardial pre-excitation was over either the right ventricular free wall or in the region of the pulmonary outflow tract. Superior location of the initial forces, especially the 10 msec vector (VCG), strongly suggested the presence of a septal bypass tract. The polarity of the delta wave and maximum QRS forces in precordial lead V1 were discordant in a significant number of patients, pointing to probable shortcomings of a classification based upon the latter.

Adolescent↗

Anterograde block in accessory pathways with retrograde conduction in reciprocating tachycardia.

3 patients with reciprocating tachycardia are described. In all 3, tachycardia was due to a reentrant mechanism. Anterograde conduction was via the AV node while retrograde conduction was over an accessory (Kent) pathway. In none of the 3 patients did this pathway sustain anterograde conduction despite pacing the atrium close to its location. With the advent of surgical modes of therapy, it is important to recognize such 'silent' bypasses. The observations which allow this diagnosis of unidirectional anterograde block in an accessory pathway and the exclusion of AV nodal reentry, the main differential diagnostic possibility, are discussed.

Adult↗