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Biomedical subjects

J J Gallagher

Publications and source records attributed to J J Gallagher.

At least 73 records · Page 4Linked to original sources
PubMed1986

Characteristics and clinical effects of myopotential signals in a unipolar DDD pacemaker population.

Myopotential signals were recorded from atrial and ventricular leads during isometric exercise in 25 patients who had chronically implanted dual chamber pacemakers using the electrogram telemetry capability of the pacemakers. Average electrogram amplitude on the atrial channel was 0.92 mV (range 0.3 to 1.9) and on the ventricular channel was 0.98 mV (range 0.3 to 2.2); the difference was not significant. There was a strong correlation (R = 0.82) between the amplitude of myopotentials on the atrial and ventricular leads for individual patients. Myopotential sensing caused ventricular output inhibition in two patients (8%) and ventricular tracking in sixteen patients (64%). Pacemaker reprogramming abolished ventricular myopotential inhibition in all patients and stopped ventricular myopotential tracking in seven patients. We conclude that myopotentials can be analyzed and their effects ameliorated by a multiprogrammable pacemaker with electrogram telemetry capability.

Adult↗
PubMed1985

Comparison of two-dimensional echocardiographic and angiographic findings in arrhythmogenic right ventricular dysplasia.

Comparison of 2-dimensional (2-D) echocardiographic and right ventricular (RV) angiographic findings was performed in 10 patients with arrhythmogenic RV dysplasia. Diagnosis was based on accepted electrocardiographic and angiographic criteria. Nine patients underwent invasive electrophysiologic study, which confirmed RV source of ventricular tachycardia (VT) in 7. Biopsy findings of RV dysplasia were available in 3 patients. Two-dimensional echocardiography and angiography corresponded closely when diffuse RV enlargement and hypokinesia were present. Such diffuse findings were not invariably present. Localized abnormalities consisting of bulging or sacculation of the RV wall were noted by both techniques, even in the absence of diffuse changes. Echocardiographic evidence of localized disease predicted the presence of similar lesions at angiography, but agreement as to specific location was poor. Subjectivity in interpreting subtle RV abnormalities by either technique and the inherent differences in information provided by the 2 methods probably account for the inconsistencies. In the patient with suspected arrhythmogenic RV dysplasia, 2-D echocardiographic evidence of diffuse RV enlargement, otherwise unexplained, strongly supports the diagnosis and angiography may be avoided. Isolated local changes seen by echocardiography should increase suspicion of RV dysplasia, but complementary angiographic study is warranted.

Adolescent↗
PubMed1985

Popliteal vein aneurysm causing pulmonary embolus.

A case of pulmonary embolus arising from a popliteal vein aneurysm is reviewed. These aneurysms are believed to be developmental in origin; with the exception of embolic phenomenon, these venous anomalies are generally asymptomatic. To our knowledge, only six cases have been previously reported. Physical examination was not helpful, and noninvasive studies were of no value in detecting the aneurysm. Venography was the only reliable diagnostic test. Because popliteal vein aneurysms are a potential source of emboli, surgical intervention is recommended. Venous aneurysmorrhaphy or excision of the aneurysm with a venous bypass are the surgical procedures most often carried out. Aneurysmorrhaphy appears to be associated with an unacceptably high rate of thrombosis; excision with placement of a vein graft may be a more satisfactory alternative.

Aneurysm↗
PubMed1985

Electrophysiologic and histopathologic correlations in a case of permanent form of reciprocating tachycardia.

A case of permanent junctional reciprocating tachycardia with post-mortem documentation of an accessory atrioventricular pathway as the substrate of the arrhythmia is reported. Tachycardia had lasted for 15 years and showed a retrograde P wave (P') and R-P' longer than P'-R interval. The tachycardia circuit utilized a concealed posterior septal accessory pathway as the retrograde limb. Because the arrhythmia was disabling and unresponsive to pharmacological treatment, the patient underwent closed chest ablation of the His bundle. After the procedure, no anterograde or retrograde conduction over the normal conduction system was observed; anterograde conduction over the anomalous pathway showed decremental properties. Because of previous myocardial infarction, the patient developed a ventricular aneurysm and died suddenly 5 months after His bundle ablation. Histological examination of the heart revealed a group of tiny fibromuscular bundles joining the lower rim of the coronary sinus outlet to the summit of the interventricular septums; the anomalous atrioventricular connection pursued a sinuous, tortuous path. The geometrical disposition of the accessory pathway may have been responsible for the decremental properties of conduction observed during life.

Atrioventricular Node↗
PubMed1985

Right ventricular isolation procedures for nonischemic ventricular tachycardia.

Nonischemic ventricular tachycardia most commonly arises in the right ventricular free wall and is frequently refractory to medical therapy. Many different types of surgical procedures have been employed to treat medically refractory nonischemic ventricular tachycardia arising in the right ventricle, but the results of these procedures have been less than optimal. The majority of these surgical procedures have been directed toward ablation of the site (or sites) of origin of the tachyarrhythmia and have failed because of the frequent occurrence of multifocal or polymorphic ventricular tachycardia in these patients. We first employed localized surgical isolation procedures to control nonischemic ventricular tachycardia arising in the right ventricular free wall in 1979. These localized procedures evolved into the development of a technique for isolating the entire right ventricular free wall from the remainder of the heart to control ventricular tachyarrhythmias arising from multiple sites in the right ventricle. Case histories are reported of two patients who underwent localized isolation procedures in 1979 as well as two patients who underwent total disconnection of the right ventricle in 1982. The follow-up period in these four patients ranges from 2 to 5 years and the control of their tachyarrhythmias has been uniformly successful. However, surgical isolation of the entire right ventricular free wall has resulted in progressive dilatation of the right ventricle as documented by serial echocardiography. The pathophysiology of the progressive right ventricular dilatation postoperatively is discussed in terms of etiology and prevention, and the indications for application of localized and total isolation procedures for nonischemic right ventricular tachycardia are outlined.

Adolescent↗
PubMed1985

Catheter ablation of accessory pathway in the permanent form of junctional reciprocating tachycardia.

Successful transvenous catheter ablation of accessory pathway (AP) in a patient (pt) with the permanent form of junctional reciprocating tachycardia is reported. A concealed AP with long conduction time comprised the retrograde limb of tachycardia circuit. The atrial end of the AP was near the coronary sinus (CS) orifice. Catheter ablative technique was performed after assessment of its feasibility and safety by using a canine model. During an electrophysiologic study CS mapping was obtained; the earliest retrograde activity was recorded 1-2 cm inside the orifice of the CS. Two unipolar shocks of 120 J were delivered on the sites exhibiting the earliest retrograde atrial activity. After the procedure, the AP was no longer conducting in both anterograde and retrograde direction. During a follow-up period of 13 months, the pt remained free of tachycardia on no antiarrhythmic medication.

Adult↗
PubMed1985

Experience with 118 consecutive patients undergoing operation for the Wolff-Parkinson-White syndrome.

Between July 1, 1980, and April 1, 1985, 118 patients underwent operation for correction of the Wolff-Parkinson-White syndrome. There were 72 male and 46 female patients with ages ranging from 9 months to 70 years (mean 28 +/- 6 years). The major indications for operation were medical refractoriness or drug intolerance (60%) and previous cardiac arrest (14%). Associated abnormalities included Ebstein's anomaly (12%), other arrhythmias (34%), coronary artery disease (6%), cardiomyopathy (6%), and congenital heart disease other than Ebstein's anomaly (22%). Two patients had undergone operations for Wolff-Parkinson-White syndrome previously at other institutions. Twenty percent of patients had multiple (two to four) accessory pathways, a total of 149 pathways being present in the 118 patients. Distribution of the accessory pathways was as follows: 58% left free wall, 24% posterior septal, 13% right free wall, and 5% anterior septal. The surgical technique employed previously for the Wolff-Parkinson-White syndrome and for the first 10 patients in the present series was modified in August, 1981, to include 2.5 power optical magnification, exclusive use of the endocardial approach under cardioplegic arrest, wider margins of surgical dissection, sharp dissection of the involved valve anulus, division of only the ventricular insertion of the accessory pathway, and internal identification of the ventricular epicardial peel in all regions of dissection. Of the 149 accessory pathways present, 148 were successfully divided in the 118 patients and, by means of the above modifications, 137 of 137 accessory pathways have been divided successfully in the last 108 patients in the series. The surgical results in these patients document an increase in the success rate for division of accessory pathways from 86% to 99.3%, a decrease in the reoperation rate from approximately 15% to 0%, and a decrease in the incidence of permanent complete heart block from 10.5% to 0.8%. The mortality was 5.0% in the entire series, but only one death occurred following elective operation in the absence of associated cardiac abnormalities (0.8%). Using the present surgical technique, these results suggest that surgical therapy is a conservative alternative to a lifetime of medical therapy in young, otherwise healthy patients with the Wolff-Parkinson-White syndrome.

Adolescent↗
PubMed1984

Histologic observations after closed chest ablation of the atrioventricular conduction system.

Postmortem examination of the heart was done in a case with disabling supraventricular tachyarrhythmia successfully treated by closed-chest ablation of the His bundle. A ventricular aneurysm developed as a result of a previous myocardial infarction, and death occurred suddenly five months after the procedure. Histologic studies of the atrioventricular (AV) junctional tissue demonstrated severe damage to the nearby AV node and penetrating His bundle. No damage to the branching His bundle or either bundle branch was observed.

Atrioventricular Node↗
PubMed1984

The role of plasma membranes in the transfer of non-esterified cholesterol to the acyl-CoA:cholesterol acyltransferase substrate pool in liver microsomal fraction.

The incubation at 37 degrees C of rat-liver microsomal fraction followed by re-isolation of the treated microsomal vesicles results in a time-dependent increase in the activity of acyl-CoA:cholesterol acyltransferase. The rate of this increase was higher in the microsomal fraction from rats fed cholesterol-supplemented diet or starved overnight as compared with that in the microsomal fraction from rats fed standard diet. The presence of a plasma membrane preparation in the incubation mixture also resulted in a time-dependent increase in acyl-CoA:cholesterol acyltransferase activity at a rate that was dependent on the concentration of plasma membranes. During the incubation of the microsomal fraction in the presence of phosphatidylcholine liposomes, cholesterol is transferred from the microsomal to liposomal vesicles. This transfer followed first-order kinetics with respect to cholesterol concentration in the donor with a rate that increased with the concentration of liposomes in the incubation mixture. The presence of phospholipid was also associated with a decrease in the activity of the acyltransferase that was related to the concentration of phospholipid in the incubation mixture. The incubation of the microsomal fraction in the presence of phosphatidylcholine-cholesterol liposomes resulted in a time-dependent and concentration-dependent transfer of liposomal cholesterol to the microsomal fraction and the acyltransferase substrate pool. The measurement of the rate of transfer of liposomal cholesterol to the microsomal vesicles and to the acyltransferase substrate pool at various temperatures showed that activation energies for the two processes are similar. Similar to these various was also the activation energy for the increase in acyl-CoA:cholesterol acyltransferase activity due to preincubation in the absence of artificial membrane vesicles. The present results suggest that there is, under the present conditions, a time-dependent and temperature-dependent flow of cholesterol from plasma membranes to the acyltransferase substrate pool and that this flow is either diverted in the presence of phospholipid liposomes or increased in the presence of cholesterol-phospholipid liposomes.

Acyltransferases↗