Biomedical subjects

L M Epstein

Publications and source records attributed to L M Epstein.

At least 37 records · Page 2Linked to original sources

PubMed1997

Rabbit RAG-2 UTRs: characterization of an unusually large 3' untranslated region.

We previously characterized the rabbit recombination activating gene-2 (RAG-2) coding region and a portion of the cDNA. Rabbit RAG-2 mRNA, however, was shown to be approximately twice as large as the predominant form expressed in other vertebrate species, suggesting that it contained additional coding and/or untranslated regions (UTR). In this report, we map and sequence the complete 5' and 3' UTRs of the rabbit RAG-2 transcript and identify and sequence the genomic regions from which they are transcribed. The data show that, with the exception of a 300 nucleotide 5' UTR, almost all of the additional sequence belongs to the 3' UTR and that the 3' UTR sequence is transcribed from a single large exon that encodes most of the coding region and all of the 3' UTR. The 3' UTR contains four poly A signal sites, the last of which is closely followed by a GU-rich region. The rabbit 3' UTR has a high level of identity with the homologous region downstream of the human RAG-2 gene but not with the mouse RAG-2 gene. The region of identity extends several hundred nucleotides beyond the transcribed region and terminates in a series of dinucleotide (TG) repeats. The data are discussed in terms of RAG gene and 3' UTR function, regulation, and evolution.

Amino Acid Sequence↗

PubMed1997

Slow AV nodal pathway ablation utilizing a unique temperature controlled radiofrequency energy system.

Thirty-nine consecutive patients with symptomatic AV nodal reentrant tachycardia (AVNRT) underwent temperature guided slow AV nodal pathway ablation (group 1). Forty-three consecutive patients undergoing nontemperature guided slow AV nodal pathway ablation late in our experience compose the control population (group 2). Slow pathway ablation was achieved in all patients of both groups. The mean fluoroscopy and ablation times for group 1 were significantly shorter than for group 2 (26.1 +/- 14.9 vs 33.9 +/- 18.9 min, P < 0.05; 19.9 +/- 12.1 vs 30.9 +/- 23.3 min, P < or = 0.02). There were no episodes of coagulum formation in group 1, while there were 15 episodes (7.1% of energy applications) in group 2 (P = 0.0006) despite a significantly higher applied power in group 1 (53.4 +/- 25.1 vs 35.6 +/- 9.5W, P = 0.0001). Successful energy applications were associated with significantly higher temperatures than unsuccessful applications in group 1 (55.6 degrees +/- 5.8 degrees C vs. 52.9 degrees +/- 6.8 degrees C, P < or = 0.03). The minimum temperature required for successful ablation was 48 degrees C for two patients (5%) and was > or = 50 degrees C for the remainder of patients (37/39 [95%]). The catheter ablation system used in this study was safe, effective, and prevented coagulum formation while delivering relatively high power. In addition, shorter ablation times and radiation exposure were seen with this system. Although successful energy applications and the production of junctional rhythm were associated with higher achieved temperatures, temperature alone did not predict either endpoint. Future prospective, randomized trials are needed to confirm these findings and further evaluate the value of temperature monitoring.

Atrioventricular Node↗

PubMed1996

Site-dependent intra-atrial conduction delay. Relationship to initiation of atrial fibrillation.

BACKGROUND: Atrial dysrhythmia patients have exaggerated intra-atrial conduction delays and prolonged relative refractoriness in response to atrial premature depolarizations (APDs). Furthermore, atrial fibrillation (AF) is more readily inducible by APDs from the high right atrium (HRA) than the coronary sinus (CS). In this study, we postulated that site-specific intra-atrial conduction delays can explain why AF is initiated more from the HRA than from the CS. METHODS AND RESULTS: We examined 17 patients (age, 49 +/- 22 years) without a history of atrial flutter, AF, or structural heart disease. Programmed stimulation was carried out from the HRA and distal CS, and bipolar recordings were made at the HRA, His bundle, posterior triangle of Koch, and CS. More prolongations in conduction and relative refractoriness in all intra-atrial sites were observed during HRA than CS APDs. AF was induced in 8 patients after HRA and not CS stimulation. During HRA stimulation, patients with AF inducibility exhibited significant prolongation of conduction to the posterior triangle of Koch and marked broadening of the posterior triangle of Koch electrogram compared with CS stimulation. In patients without AF inducibility, the posterior triangle of Koch electrogram width was the same during HRA and CS stimulation. CONCLUSIONS: The existence of site-dependent intra-atrial conduction delays and site-dependent dispersion of refractoriness appears to be a common property of the atrial myocardium and does not necessarily forecast AF inducibility. However, the presence of nonuniform anisotropic characteristics of the posterior triangle of Koch may be critical for AF induction.

Adult↗

PubMed1996

Cloning and characterization of extended hammerheads from a diverse set of caudate amphibians.

Satellite 2 (sat2) elements from six species representing four caudate amphibian families were cloned and analyzed. Despite differences in the abundance of this element, the tandemly repeated genomic organization found for sat2 in earlier investigations was conserved in the newly investigated species. The ability of sat2 transcripts to catalyze their own site-specific self-cleavage using an extended hammerhead (HH) motif had also been conserved. This motif is similar to the HH found in a number of infectious plant RNAs, but has an abbreviated stem III region and an internally looped stem I extension that distinguish it from the prototypical HH. The extended HH analyzed in this survey can be further organized into two groups on the basis of shared sequences and structural details in the peripheral stem-loop structures. HH derived from the family Salamandridae constitute one group, whereas HH from all other salamanders that have been investigated belong to the other group. Although many of the natural variants did not cleave efficiently in vitro, examples of relatively active variants for each design were found. This survey has therefore identified two designs that are suitable starting models for the structural and functional analysis of the extended HH.

Amphibians↗

PubMed1996

Heterogeneity of retrograde fast-pathway conduction pattern in patients with atrioventricular nodal reentry tachycardia: observations by simultaneous multisite catheter mapping of Koch's triangle.

BACKGROUND: Selective ablation of either the fast of the slow pathway resulting in cure of AV nodal reentry tachycardia (AVNRT) has led to the concept that these pathways are discrete, anatomically defined structures. We hypothesized that if a discrete retrograde fast pathway exists, it should be possible to record a single focus of early atrial activation near the apex of Koch's triangle, with sequential spread of depolarization to the rest of the atria. METHODS AND RESULTS: We evaluated 46 patients (33 women, 13 men; mean age, 45 +/- 17 years) undergoing electrophysiology study and catheter ablation for typical AVNRT. Retrograde atrial activation during AVNRT (337 +/- 43 ms) and ventricular pacing at a similar cycle length (352 +/- 51 ms) was recorded in the region of Koch's triangle with a decapolar catheter in the His bundle position, a multipolar catheter in the coronary sinus, and a deflectable quadripolar catheter along the tricuspid annulus anterior to the coronary sinus ostium. Earliest atrial activation was recorded at the apex of the triangle of Koch in 38 patients during ventricular pacing and in 43 patients during AVNRT. A broad wave front of atrial activation was recorded in 17 patients during ventricular pacing and in 26 patients during AVNRT. During AVNRT, only 2 patients had a single early site with focal and sequential activation along the tendon of Todaro. There was concordance in the pattern of atrial activation between ventricular pacing and AVNRT in only 21 of 46 patients. CONCLUSIONS: Retrograde atrial activation over the fast pathway is heterogeneous within Koch's triangle and the coronary sinus, both for the entire population and for individual patients during different modes of activation. These data do not support the concept of an anatomically discrete retrograde fast pathway.

Adult↗

PubMed1996

Long-term results of electrophysiologically guided sotalol therapy for life-threatening ventricular arrhythmias.

The efficacy and safety of sotalol therapy for ventricular arrhythmias was evaluated in 133 patients with drug-refractory ventricular arrhythmias. All patients had baseline electrophysiologic studies before and after oral sotalol therapy. Sixty-six patients were discharged home, treated with sotalol (52 patients without inducible ventricular tachycardia or fibrillation and 14 patients with hemodynamically stable inducible ventricular tachycardia). The mean follow-up period was 41 +/- 27 months for the 14 patients with hemodynamically stable ventricular tachycardia. Sotalol was effective in 8 of these 14 patients. Recurrent nonlethal ventricular tachycardia occurred in 3 patients; 2 patients had sudden death; and 1 patient had adverse side effects. The 52 patients without inducible ventricular tachycardia were followed up for a mean period of 36 +/- 30 months. Thirty-five of 52 patients were successfully treated. Two patients had recurrent ventricular tachycardia; both of these episodes of ventricular tachycardia occurred within the first year. Four patients had sudden cardiac death; three of these deaths occurred within the first month, and the last episode of sudden death occurred after 8 years of sotalol therapy. The actuarial incidence of sotalol efficacy was 76% at 1 year, 72% at 2 years, 64% at 4 years, and 52% at 5 years. Approximately 46% of patients receiving long-term sotalol treatment reported side effects. Side effects severe enough to warrant withdrawal of sotalol occurred in 7 (11%) patients. The results of our study suggest that sotalol is effective for selected patients with drug refractory ventricular arrhythmias. Although the incidence of side effects are high, patients appear to tolerate long-term sotalol therapy well.

Adult↗

PubMed1996

Quality of life and outcomes after radiofrequency His-bundle catheter ablation and permanent pacemaker implantation: impact of treatment in paroxysmal and established atrial fibrillation.

One hundred seven patients underwent atrioventricular (AV)-junctional ablation and pacing for atrial fibrillation, and 90 were alive 2.3 +/- 1.2 years later. Quality of life index (1.9 +/- 1.2 to 3.6 +/- 1.1; 3.6 +/- 1.1; p<0.001) and ease of activities of daily living (2 +/- 0.4 to 2.4 +/- 0.3; p<0.001) were significantly improved. Doctor visits (10 +/- 13 to 5.06 +/-7; p<0.03), hospital admissions (2.8 +/- 6.8 vs 0.17 +/- 0.54; p<0.03, and antiarrhythmic drug trials (6.2 +/- 4 to 0.46 +/- 1.5; p<0.001) decreased significantly after treatment. Congestive heart failure episodes decreased from 18 before to 8 afterward. Twenty-eight of 36 patients with dual-chamber pacemakers remained in a dual-chamber mode at follow-up. Radiofrequency AV-junctional catheter ablation and pacing is a highly successful form of treatment for medically refractory atrial fibrillation.

Activities of Daily Living↗

PubMed1996

Nonuniform anisotropy is responsible for age-related slowing of atrioventricular nodal reentrant tachycardia.

INTRODUCTION: AV nodal reentrant tachycardia cycle length has been shown to be longer in the elderly population. Microfibrosis associated with aging producing nonuniform anisotropic conduction or changes in membrane ionic properties could explain this finding. METHODS AND RESULTS: Forty-five patients (33 women and 12 men) with typical AV nodal reentrant tachycardia were studied to analyze the effects of age on electrophysiologic characteristics of the tachycardia using high-density catheter mapping of the triangle of Koch. We classified patients into group A (age < or = 45 years, mean [+/-SD] 32.7 +/- 8.8, n = 27) and group B (age > 45 years, mean [+/-SD] 61.1 +/- 10.2, n = 18). Retrograde atrial activation was recorded during tachycardia by means of a 2-mm decapolar catheter at the His bundle, a quadripolar catheter at the high right atrium, a multipolar catheter (6 to 10 poles) in the coronary sinus, and a deflectable quadripolar catheter at the posterior triangle of Koch. The AH interval at the AV junction as well as HA intervals at several atrial sites were measured during tachycardia. HA intervals at all atrial recording sites except in the posterior triangle of Koch were significantly longer in group B, as well as the tachycardia cycle length (362 vs 329 msec, P = 0.01). The mean AH interval was prolonged by 24 msec in group B, but this difference did not reach statistical significance. A sequential pattern of retrograde atrial activation during tachycardia was more frequently recorded in group B. CONCLUSIONS: Since the delayed activation to the atrium was heterogeneous, transverse nonuniform anisotropic conduction is a likely explanation of these age-related modifications of AV nodal reentrant tachycardia characteristics.

Adolescent↗

PubMed1996

Effect of patient characteristics on the yield of prolonged baseline head-up tilt testing and the additional yield of drug provocation.

OBJECTIVE: To define the value of tilt testing and hte additional yield of drug provocation over prolonged baseline tilt in different patient subgroups. (Many different protocols are in use for head-up tilt testing in heterogeneous groups of patients. Not all patients in reported series have recurrent syncope, and there is often a wide age range and a variable incidence of structural heart disease.) DESIGN: In a prospective study, baseline 60 degrees head-up tilt testing was undertaken for 45 minutes, initially without drug provocation. Patients who remained symptom free were given intravenous isoprenaline (isoproterenol) and further tilting or edrophonium (10 mg bolus) during tilt, in an order determined randomly before the start of the test. If they were symptom free after the first drug, they were given the other drug. A positive test was recorded when syncope or pre-syncope occurred with a rapid fall (> 30%) in blood pressure. The impact on tilt result of the type of symptoms, presence of significant structural heart disease (SHD), presence of a non-cardiovascular cause of sudden diminished consciousness (SDC), and age was then assessed by subgroup analysis. PATIENTS: 145 patients (73 female, mean age 51 (25), range 8-94) with one or more episodes of pre-syncope or syncope. RESULTS: 39 patients (27%, 21 female, age 49 (25) years) had positive tests and 106 (73%, 52 female, age 52 (25) years) negative tests. 27 (69%) had a positive test during baseline tilt at 20.5 (10.8) minutes, five (13%) with isoprenaline infusion, and seven (18%) with edrophonium bolus. Patients with recurrent syncope rather than single syncopal episodes or single or recurrent pre-syncope were more likely to have a positive tilt test (41% v 17%, P < 0.005) and patients with SHD or SDC (69/14 patients) were much less likely than patients without (16% v 42%, P < 0.0001). The yield of positive tests was similar if patients were below (26%) or above (27%) the mean age (50 years). When multiple factors were combined, the yield ranged from 0% for 21 patients under 50 years with SHD or SDC and without recurrent syncope to 73% in 11 patients over 50 years with recurrent syncope and no SHD or SDC. The additional yield in subgroups over 45 minute baseline tilt (70 (11)%) of isoprenaline (13 (10)%) was similar to that of edrophonium (17 (8)%, P = NS), but six (50% of those who were drug positive) patients required a second drug to produce a positive result (two with isoprenaline second, four with edrophonium second). CONCLUSIONS: Head-up tilt testing in a heterogeneous population has a low yield. Simple clinical characteristics define the type of patient who is likely to have a positive tilt test and the patient who is not and in whom other investigations should receive priority. The great majority of positive tests will occur during prolonged baseline testing if this is used. Isoprenaline and edrophonium produced similar additional yields of positive tests.

Age Factors↗

PubMed1996

Novel requirements in peripheral structures of the extended satellite 2 hammerhead.

A number of RNAs that infect plants self-cleave using a domain called the hammerhead. The consensus plant hammerhead has three base paired stem structures. Stems I and III flank the cleaved phosphodiester and are connected to stem II by two unpaired and highly conserved sequences. We demonstrated previously that satellite 2 transcripts from the newt, Notophthalmus viridescens, use a modified hammerhead structure for self-cleavage. Here we show that hammerheads with similar modifications occur in satellite 2 from species representing two additional families of salamanders (Ambystoma talpoideum and Amphiuma tridactylum). The distinctive features of the modified satellite 2 hammerheads include unusually short stem III regions and internally looped extensions to stem I that are required for cleavage. However, despite the strict nucleotide requirement in the internal stem I loop of the newt hammerhead, the details of the stem I extensions differ in the three salamanders. An analysis of chimeric transcripts indicated that, in order for a specific stem I extension to be functional, it must be compatible with other regions of the modified satellite 2 hammerhead. One such region is stem II, and a mutational analysis has confirmed that there are specific sequence and/or structural requirements in stem II.

Animals↗

PubMed1995

Radiofrequency catheter modification of the sinus node for "inappropriate" sinus tachycardia.

BACKGROUND: Radiofrequency catheter ablation is the treatment of choice for patients with paroxysmal supraventricular tachycardias refractory to medical therapy. However, in symptomatic patients with inappropriate sinus tachycardia resistant to drug therapy, catheter ablation of the His' bundle with permanent pacemaker insertion is currently applied. We evaluated the safety and efficacy of radiofrequency modification of the sinus node as alternative therapy for patients with inappropriate sinus tachycardia. METHODS AND RESULTS: Sixteen patients with disabling episodes of inappropriate sinus tachycardia refractory to drug therapy (4.2 +/- 0.3 drug trials) underwent either total sinus node ablation or sinus node modification. The region of the sinus node was identified as the region of earliest atrial activation in sinus rhythm during electrophysiological study. This region was further defined by use of intracardiac echocardiography (ICE) in 9 patients, in whom it was found that an ablation catheter could be guided reliably and maintained on the crista terminalis. Radiofrequency energy was delivered during tachycardia between either a standard 4-mm or custom 10-mm thermistor-imbedded catheter tip and a skin patch. Total sinus node ablation was performed successfully in all 4 patients in whom it was attempted and was characterized by a junctional escape rhythm. Sinus node modification was successfully achieved in all 12 patients in whom it was attempted and was characterized by a 25% reduction in the sinus heart rate. For the group as a whole, exercise stress testing after ablation revealed a gradual chronotropic response, with a significant reduction in maximal heart rate (132.8 +/- 6.5 versus 179.5 +/- 3.6 beats per minute [bpm]; P < .001) without evidence of an exaggerated heart rate response to a light workload (103.0 +/- 4.1 versus 139.5 +/- 3.5 bpm; P < .001). Twenty-four-hour ambulatory ECG monitoring revealed a significant decrease in maximal heart rate and mean heart rate after ablation (167.2 +/- 2.6 versus 96.7 +/- 5.0 bpm, P < .001, and 125.6 +/- 5.0 versus 54.1 +/- 5.3 bpm, P < .001, respectively). There was a significant decrease in the number of applications of radiofrequency energy required in patients undergoing modification of the sinus node when guided by ICE compared with fluoroscopy alone (3.6 +/- 0.8 versus 10.4 +/- 2.1; P < .01) as well as a decrease in fluoroscopy time (33.0 +/- 9.5 versus 58.5 +/- 8.4 minutes). After a mean follow-up period of 20.5 +/- 0.3 months, there were no recurrences of inappropriate sinus tachycardia in patients who underwent a total sinus node ablation. However, 2 patients who had a total sinus node ablation subsequently required permanent pacing because of symptomatic pauses, and 1 patient developed an ectopic atrial tachycardia. After a mean follow-up of 7.1 +/- 1.7 months, there were two recurrences of inappropriate sinus tachycardia in patients who underwent sinus node modification. However, no significant bradycardia or pauses were observed. Complications encountered during the study included 1 patient who developed transient right diaphragmatic paralysis and another patient who developed transient superior vena cava syndrome. CONCLUSIONS: Sinus node modification is feasible in humans and should be considered as an alternative to complete atrioventricular junctional ablation for patients with disabling inappropriate sinus tachycardia refractory to medical management. Sinus node modification may be aided by ICE.

Adult↗

PubMed1995

Use of P wave configuration during atrial tachycardia to predict site of origin.

OBJECTIVES: This study sought to construct an algorithm to differentiate left atrial from right atrial tachycardia foci on the basis of surface electrocardiograms (ECGs). BACKGROUND: Atrial tachycardia is an uncommon form of supraventricular tachycardia, often resistant to drug therapy. METHODS: A total of 31 consecutive patients with atrial tachycardia due to either abnormal automaticity or triggered rhythm underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation of a single atrial focus. P wave configuration was analyzed from 12-lead ECGs during tachycardia during either spontaneous or pharmacologically induced atrioventricular block. P waves inscribed above the isoelectric line (TP interval) were classified as positive, below as negative, above and below (or conversely, below and above) as biphasic and flat P waves as isoelectric (0). In 17 patients the tachycardia was located in the right atrium: crista terminalis (n = 4); right atrial appendage (n = 4); lateral wall (n = 4); posteroinferior right atrium (n = 3); tricuspid annulus (n = 1); and near the coronary sinus (n = 1). In 14 patients, atrial tachycardia was located in the left atrium: at the entrance of the right (n = 6) or left (n = 4) superior pulmonary veins; left inferior pulmonary vein (n = 1); inferior left atrium (n = 1); base of left atrial appendage (n = 1); and high lateral left atrium (n = 1). RESULTS: There were no differences in P wave vectors between sites at the right atrial lateral wall versus the right atrial appendage or between sites at the entrance of right versus left superior pulmonary veins. However, analysis of P wave configuration showed that leads aVL and V1 were most helpful in distinguishing right atrial from left atrial foci. The sensitivity and specificity of using a positive or biphasic P wave in lead aVL to predict a right atrial focus was 88% and 79%, respectively. The sensitivity and specificity of a positive P wave in lead V1 in predicting a left atrial focus was 93% and 88%, respectively. CONCLUSIONS: 1) Analyses of surface P wave configuration proved to be reasonably good in differentiating right atrial from left atrial tachycardia foci. 2) Leads II, III and aVF were helpful in providing clues for differentiating superior from inferior foci.

Adolescent↗

PubMed1995

A direct midseptal approach to slow atrioventricular nodal pathway ablation.

OBJECTIVES: The purpose of this study was to describe a midseptal approach to selective slow pathway ablation for the treatment of AV nodal reentrant tachycardia (AVNRT). In addition, predictors of success and recurrence were evaluated. METHODS: Selective ablation of the slow AV nodal pathway utilizing radiofrequency (RF) energy and a midseptal approach was attempted in 60 consecutive patients with inducible AVNRT. RESULTS: Successful slow pathway ablation or modification was achieved in 59 of 60 patients (98%) during a single procedure. One patient developed inadvertent complete AV block (1.6%). A mean of 2.7 +/- 1.4 RF applications were required with mean total procedure, ablation, and fluoroscopic times of 191 +/- 6.3, 22.8 +/- 2.3, and 28.2 +/- 1.8 minutes, respectively. The PR and AH intervals, as well as the antegrade and retrograde AV node block cycle length, were unchanged. However, the fast pathway effective refractory period was significantly shortened following ablation (354 +/- 13 msec vs 298 +/- 12 msec; P = 0.008). The A/V ratio at successful ablation sites were no different than those at unsuccessful sites (0.22 +/- 0.04 vs 0.23 +/- 0.03). Junctional tachycardia was observed during all successful and 60 of 122 (49%) unsuccessful RF applications (P < or = 0.0001). A residual AV nodal reentrant echo was present in 15 of 59 (25%) patients. During a mean follow-up of 20.1 +/- 0.6 months (11.5-28 months) there were four recurrences (5%), 4 of 15 (27%) in patients with and none of 44 patients without residual slow pathway conduction (P = 0.002). CONCLUSIONS: A direct midseptal approach to selective ablation of the slow pathway is a safe, efficacious, and efficient technique. Junctional tachycardia during RF energy application was a highly sensitive but not specific predictor of success and residual slow pathway conduction was associated with a high rate of recurrence.

Adolescent↗

PubMed1994

Transcription of satellite 2 DNA from the newt is driven by a snRNA type of promoter.

The transcriptional promoter of satellite 2 from the eastern newt, Notophthalmus viridescens, was analyzed by assaying the activity of deleted or mutated satellite 2 clones in Xenopus laevis oocytes. Two elements in the promoter were found to be important for transcription. These elements have sequences that are similar to the sequences of the octamer and the proximal sequence element of vertebrate snRNA genes transcribed by RNA polymerase II. Furthermore, the organization of these elements and their respective roles in transcription are the same as their organization and roles in the snRNA genes. To further investigate the relationship between the satellite 2 and snRNA gene promoters, the ability of the satellite 2 promoter to drive transcription of a true snRNA gene was tested. The satellite 2 promoter initiated transcription of the Xenopus U1b2 snRNA gene as efficiently as the native U1b2 promoter, and the 3' ends of the resulting U1b2 transcripts were accurately formed. This latter result confirms that the satellite 2 promoter is a functional analog of the snRNA promoter, since 3'-end formation of snRNA genes transcribed by RNA polymerase II requires that transcription be initiated from a compatible promoter. The structural and functional similarities between the satellite 2 and the snRNA gene promoters suggest that these elements are evolutionarily related. These findings were used to extend a previously proposed model concerning the nature and derivation of satellite 2.

Animals↗

PubMed1994

Intracardiac echocardiography during radiofrequency catheter ablation of cardiac arrhythmias in humans.

OBJECTIVES: The purpose of this study was to describe our preliminary experience using catheter-based intracardiac echocardiography as an adjunct to biplane fluoroscopy for guiding radiofrequency catheter ablation of atrial arrhythmias in the right side of the heart. BACKGROUND: Catheter ablation requires precise positioning and stable ablation electrode-endocardial contact. This procedure is currently guided by an analysis of intracardiac electrograms and fluoroscopy. However, the use of fluoroscopy does not allow the endocardium and certain anatomic landmarks to be identified and is associated with the hazards of radiation exposure. METHODS: Seventeen symptomatic patients were studied. A 10F 10-MHz intracardiac imaging catheter was used to visualize specific anatomic landmarks in the right atrium for directing the ablation electrode in 15 patients undergoing radiofrequency ablation of 19 arrhythmias and to assist with interatrial septal puncture in 3 patients. RESULTS: Continuous intracardiac imaging was performed for a mean +/- SD of 63.6 +/- 39.2 min and demonstrated distal electrode-endocardial tissue contact in 81 (60%) of 134 radiofrequency applications. Movement of the catheter was demonstrated during 36 (44%), microcavitations during 39 (48%) and thrombus during 15 (19%) of the 81 imaged applications. In 7 of 10 procedures for atrial flutter, successful ablation was directed at anatomic corridors in the right atrium visualized with intracardiac echocardiography. During ablation of atrial tachycardia, imaging identified abnormal atrial anatomy related to previous surgery and guided successful ablation of a reentrant tachycardia circulating around these anatomic obstacles. In two procedures for slow pathway modification of atrioventricular node reentrant tachycardia, intracardiac echocardiography confirmed catheter stability at the tricuspid annulus anterior to the coronary sinus. CONCLUSIONS: During catheter ablation, intracardiac echocardiography augments fluoroscopy by visualizing anatomic landmarks, ensuring stable endocardial contact and assisting in transseptal puncture. Ablation of typical atrial flutter can be successfully directed at anatomic corridors identified using intracardiac imaging.

Atrial Flutter↗

PubMed1994

Clinical and electrophysiologic features and role of catheter ablation techniques in adult patients with automatic atrioventricular junctional tachycardia.

A total of 8 patients with junctional tachycardia (JT) were included for study. Patients with JT had a supraventricular arrhythmia that was initiated by a junctional complex without PR prolongation and episodes of atrioventricular (AV) dissociation. JT could not be initiated by pacing and occurred either spontaneously (3 patients) or with isoproterenol (5 patients). Tachycardia could be consistently terminated by either carotid sinus massage (1 patient), intravenous adenosine (2 patients), or critically timed ventricular premature complexes (3 patients). In 6 of the 8 other patients, tachycardia foci (atrial or ventricular) or mechanisms (AV node reentry) were found. Two patients underwent complete AV junctional ablation and 2 had termination of tachycardia without change in the AV conduction by perinodal application of radiofrequency lesions. AVJT appears to be due to abnormal automaticity and may be successfully ablated by application of radiofrequency energy to perinodal areas.

Adult↗

PubMed1994

Radiofrequency catheter ablation in the treatment of supraventricular tachycardia in the elderly.

OBJECTIVES: The purpose of this study was to evaluate the efficacy and safety of radiofrequency catheter ablation for the treatment of supraventricular tachycardias in an elderly (> or = 70 years of age) group of patients. BACKGROUND: Supraventricular tachycardias are the most common form of cardiac arrhythmia and affect all age groups. Although usually well tolerated in youth, supraventricular tachycardias may be associated with disabling symptoms and have life-threatening potential in the elderly. In addition, antiarrhythmic agents are less well tolerated and may be associated with a higher incidence of toxicity in the elderly. METHODS: From May 1989 to March 1993, 454 patients underwent a radiofrequency catheter ablation procedure at the University of California, San Francisco, for the treatment of symptomatic supraventricular tachycardia. Sixty-seven of these patients were > or = 70 years of age and constituted the study group. Patients underwent one of the following catheter ablation procedures: complete atrioventricular (AV) junctional ablation for ventricular rate control in patients with atrial fibrillation (37 patients), AV node modification for the treatment of AV node reentrant tachycardia (17 patients), accessory pathway ablation (9 patients), ablation of the "slow zone" to cure atrial flutter (4 patients) and atrial tachycardia ablation (1 patient). One patient underwent ablation for both AV node reentrant tachycardia and atrial flutter. RESULTS: Success was achieved in 67 (98.5%) of 68 ablation procedures. There were no procedural or early deaths. The overall complication rate was 7.4%, and only one patient (1.5%) had long-term sequelae (permanent cardiac pacing for complete heart block). At a mean (+/- SD) follow-up of 22.1 +/- 12.9 months, 63 (94%) of 67 patients were alive, with no antiarrhythmic agents for the treatment of their presenting arrhythmia. CONCLUSIONS: In this series radiofrequency catheter ablation appears to be an effective and safe treatment option for elderly patients (> or = 70 years of age) with a variety of symptomatic, drug-resistant supraventricular tachycardias. Because of the high incidence of severe symptoms associated with tachycardic episodes, the expense and the possible severe proarrhythmic problems associated with antiarrhythmic medications in this age group, catheter ablation may be considered an early rather than a "last resort" treatment option.

Aged↗

PubMed1994

An evaluation of an education programme, for prevention and early diagnosis of malignancy in Israel.

A community-wide health education programme for the prevention and early detection of cancer was performed in the Krayot municipalities, north of Haifa, Israel, during the years 1985-86. In order to assess its effectiveness, an evaluation programme was conducted. The knowledge, attitudes and behaviour of women who had been exposed to the education programme and of a control group, were compared before the programme started and 2.5 years later, after it ended. The programme was conducted in five clinics and included changes in the functioning of the clinics and their teams to be used in the interaction with the insured women. A piloted questionnaire was used to evaluate knowledge, attitudes and behaviour of these women. Emphasis was placed on smoking, sun tanning, self-examination of breast and other aspects of possible early detection of cancer. The education programme was ineffective not only with regard to behaviour but also in relation to knowledge on the relationship between health behaviour and cancer. The need for the establishment of more effective means for health education is eminent. If health education programmes are to succeed, we must understand what motivates or prevents compliance with recommended health behaviour.

Adolescent↗