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Kenneth A Ellenbogen

Publications and source records attributed to Kenneth A Ellenbogen.

At least 19 recordsLinked to original sources
PubMed2006

Accuracy of intracardiac echocardiography for assessing the esophageal course along the posterior left atrium: a comparison to magnetic resonance imaging.

BACKGROUND: Atrioesophageal fistula is a potentially fatal complication of ablation in the left atrium (LA) to treat atrial fibrillation. OBJECTIVE: The objective of our study was to systematically evaluate the diagnostic potential of intracardiac echocardiography (ICE) for accurately assessing the esophageal course along the posterior LA. METHODS: Thirty-five patients underwent magnetic resonance imaging (MRI) before and ICE during pulmonary vein (PV) isolation to visualize the esophagus. The location of the esophagus was determined in relation to the PVs and anatomic regions of the LA by both ICE and MRI. Using the MRI images as a reference, the accuracy of ICE localization was assessed. RESULTS: The most common location for the esophagus to appear was the mid-posterior wall (80% of patients by ICE, 71% of patients by MRI), followed by the left posterior wall (71% of patients by ICE, 63% of patients by MRI) and the right posterior wall (60% of patients by ICE, 51% of patients by MRI). The esophagus was seen to course near the left PV antrums (left superior PV antrum 34% of patients by ICE and MRI; left inferior PV antrum 34% of patients by ICE, 37% of patients by MRI), left superior PV (17% of patients by ICE, 20% of patients by MRI), left inferior PV (17% of patients by ICE and MRI), right inferior PV antrum (29% of patients by ICE, 37% of patients by MRI) and the right inferior PV (3% of patients by ICE, 17% of patients by MRI). The sensitivity for esophageal location by ICE compared to that by MRI ranged between 33% (right inferior PV) and 92% (left superior PV antrum, left inferior PV antrum, and mid-posterior wall). The specificity for esophageal location by ICE compared to that by MRI ranged between 60% (mid-posterior wall) and 100% (right inferior PV). The positive predictive value ranged between 80% (left inferior PV) and 100% (right inferior PV). The negative predictive value ranged between 84% (right inferior PV antrum) and 96% (left superior PV antrum). CONCLUSION: Phased array ICE provides rapid, real-time localization of the esophagus during LA ablation that is comparable to MRI.

Atrial Fibrillation↗
PubMed2006

Atrial arrhythmias following ostial or circumferential pulmonary vein ablation.

AIMS: The incidence, clinical significance and optimum treatment of AF ablation-induced proarrhythmia is not entirely known. This report describes the incidence and management of atrial arrhythmias occurring after various techniques for the ablative therapy of atrial fibrillation (AF). METHODS: Five hundred and forty-four patients with paroxysmal atrial fibrillation were subjected to ostial pulmonary vein (PV) (n = 204), antral (n = 300), or circumferential (n = 40) ablation around the PV ostia. RESULTS: Atrial tachycardia or flutter during the first 6 months after AF ablation was detected in 14 patients and was more common among patients subjected to circumferential or circumferential and linear ablation (18% and 22%, respectively) than to other techniques (p < 0.001). The risk of atrial tachycardia or flutter among patients who underwent ostial, ostial with lines and antral ablation was 1%, 8% and 1%, respectively. No difference was observed in the risk of atrial arrhythmia between patients who underwent ablation with or without additional lines, either ostial (p = 0.17) or circumferential (p = 0.99). Re-ablation was performed in patients with sustained atrial arrhythmia (11 out of 14 patients). At 6 months, no recurrence was seen in 10 of these patients as well as in 3 patients with non-sustained atrial tachycardia or flutter. CONCLUSIONS: The incidence of atrial tachycardia or flutter following AF ablation is lower for ostial than circumferential ablation. The addition of lines along the mitral isthmus and between the superior PVs does not significantly affect the risk of ablation-induced arrhythmia. Non-sustained atrial tachycardia or flutter following AF ablation procedures does not always require additional ablation.

Adult↗
PubMed2006

The Managed Ventricular pacing versus VVI 40 Pacing (MVP) Trial: clinical background, rationale, design, and implementation.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) reduce mortality among appropriately selected patients who have had or are at risk for life-threatening ventricular arrhythmia. Right ventricular apical (RVA) pacing has been implicated in worsening heart failure and death. The optimal pacemaker mode for bradycardia support while minimizing unnecessary and potentially harmful RVA pacing has not been determined. METHODS: The Managed Ventricular pacing vs. VVI 40 Pacing Trial (MVP) is a prospective, multicenter, randomized, single-blind, parallel, controlled clinical trial designed to establish whether atrial-based dual-chamber managed ventricular pacing mode (MVP) is equivalent or superior to back-up only ventricular pacing (VVI 40) among patients with standard indications for ICD therapy and no indication for bradycardia pacing. The MVP Trial is designed with 80% power to detect a 10% reduction in the primary endpoint of new or worsening heart failure or all-cause mortality in the MVP-treated group. Approximately 1,000 patients at 80 centers in the United States, Canada, Western Europe, and Israel will be randomized to MVP or VVI 40 pacing after successful implantation of a dual-chamber ICD. Heart failure therapies will be optimized in accordance with evidence-based guidelines. Prespecified secondary endpoints will include ventricular arrhythmias, atrial fibrillation, new indication for bradycardia pacing, health-related quality of life, and cost effectiveness. Enrollment began in October 2004 and concluded in April 2006. The study will be terminated upon recommendation of the Data Monitoring Committee or when the last patient enrolled and surviving has reached a minimum 2 years of follow-up. CONCLUSION: The MVP Trial will meet the clinical need for carefully designed prospective studies to define the benefits of atrial-based dual-chamber minimal ventricular pacing versus single-chamber ventricular pacing in conventional ICD patients.

Canada↗
PubMed2006

ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients With Atrial Fibrillation): developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society.

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Algorithms↗
PubMed2006

Percutaneous intrapericardial echocardiography during catheter ablation: a feasibility study.

BACKGROUND: Percutaneous pericardial access, epicardial mapping, and ablation have been used successfully for catheter ablation procedures. OBJECTIVES: The purpose of this study was to evaluate the safety and feasibility of closed-chest direct epicardial ultrasound imaging for aiding cardiac catheter ablation procedures. METHODS: An intracardiac ultrasound catheter was used for closed-chest epicardial imaging of the heart in 10 patients undergoing percutaneous epicardial access for catheter ablation. All patients underwent concomitant intracardiac echocardiography and preprocedural transesophageal echocardiography. Using a double-wire technique, two sheaths were placed in the pericardium, and a phased-array ultrasound catheter was manipulated within the pericardial sinuses for imaging. RESULTS: Multiple images from varying angles were obtained for catheter navigation. Notably, image stability was excellent, and structures such as the left atrial appendage were seen in great detail. No complications resulting from use of the ultrasound catheter in the pericardium occurred, and no restriction of movement due to the presence of the additional catheter in the pericardial space was observed. Wall motion was correlated to voltage maps in five patients and showed that areas of scars correlated with wall-motion abnormalities. Normal wall-motion score correlated to sensed signals of 4.2 +/- 0.3 mV (normal myocardium >1.5 mV), and scores >1 correlated to areas with signals <0.5 mV in that territory). CONCLUSION: Intrapericardial imaging using an ultrasound catheter is feasible and safe and has the potential to provide additional valuable information for complex ablation procedures.

Adult↗
PubMed2006

Paradoxical undersensing during atrial flutter: what is the mechanism?

A patient with congenital complete heart block underwent implantation of a dual-chamber pacemaker. He presented to the emergency room with fatigue and was found to be in atrial flutter. Device interrogation revealed undersensing of 5 mV flutter waves at a programmed sensitivity of 0.5 mV. Due to undersensing, mode switch did not occur. This case illustrates apparently paradoxical undersensing of atrial flutter waves by a dual-chamber pacemaker and can be explained by a phenomenon known as "quiet timer blanking."

Adult↗
PubMed2006

Management of recalled pacemakers and implantable cardioverter-defibrillators: a decision analysis model.

CONTEXT: Limited information exists to direct clinical management after an implantable device has been put under advisory. A better understanding of the risks and benefits of device replacement compared with continued clinical follow-up would be helpful to clinicians. OBJECTIVE: Using the tools of decision analysis, to determine the best management approach (immediate device replacement vs continued monitoring) in the setting of a device advisory. DESIGN: A decision model was constructed to evaluate the risks and benefits associated with immediate device replacement compared with continued monitoring. MAIN OUTCOME MEASURES: Variables considered included indications for device implantation, anticipated course following device failure, device failure rates from the advisory ranging from 0.0001% to 1.0% per year, and device replacement mortality rates ranging from 0.10% to 1.00% per procedure. Device replacement was preferred to continued follow-up when replacement led to greater patient survival. RESULTS: The decision to replace a recalled device depends primarily on the advisory's estimated device failure rate and the likely effects of device failure on mortality. Procedural mortality is an important secondary factor, while patient age and remaining generator life have the least influence on the decision. For pacemaker-dependent patients, advisory device failure rates exceeding 0.3% warrant device replacement in most situations. In patients with implantable cardioverter-defibrillators for primary or secondary prevention, a failure rate associated with an advisory of 3.0% is needed to favor replacement in most cases, decreasing to close to 1.0% as procedural mortality rates decrease to 0.1% or risk of fatal arrhythmias increase to near 20% per year. In cases of pacemaker implantation for non-life-threatening situations (eg, carotid sinus hypersensitivity), most device advisories do not warrant device replacement. CONCLUSIONS: The decision to replace a device under advisory is determined primarily by the incidence of device malfunction and the likely effects of device failure. This analysis provides a framework for managing recalled devices in the context of device, patient, and institutional characteristics.

Decision Support Techniques↗
PubMed2006

Cardiovascular outcomes with atrial-based pacing compared with ventricular pacing: meta-analysis of randomized trials, using individual patient data.

BACKGROUND: Several randomized trials have compared atrial-based (dual-chamber or atrial) pacing with ventricular pacing in patients with bradycardia. No trial has shown a mortality reduction, and only 1 small trial suggested a reduction in stroke. The goal of this review was to determine whether atrial-based pacing prevents major cardiovascular events. METHODS AND RESULTS: A systematic review was performed of publications since 1980. For inclusion, trials had to compare an atrial-based with a ventricular-based pacing mode; use a randomized, controlled, parallel design; and have data on mortality, stroke, heart failure, or atrial fibrillation. Individual patient data were obtained from 5 of the 8 identified studies, representing 95% of patients in the 8 trials, and a total of 35 000 patient-years of follow-up. There was no significant heterogeneity among the results of the individual trials. There was no significant reduction in mortality (hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.87 to 1.03; P=0.19) or heart failure (HR, 0.89; 95% CI, 0.77 to 1.03; P=0.15) with atrial-based pacing. There was a significant reduction in atrial fibrillation (HR, 0.80; 95% CI, 0.72 to 0.89; P=0.00003) and a reduction in stroke that was of borderline significance (HR, 0.81; 95% CI, 0.67 to 0.99; P=0.035). There was no convincing evidence that any patient subgroup received special benefit from atrial-based pacing. CONCLUSIONS: Compared with ventricular pacing, the use of atrial-based pacing does not improve survival or reduce heart failure or cardiovascular death. However, atrial-based pacing reduces the incidence of atrial fibrillation and may modestly reduce stroke.

Arrhythmias, Cardiac↗
PubMed2006

Atrial activation during atrioventricular nodal reentrant tachycardia: studies on retrograde fast pathway conduction.

BACKGROUND: Detailed right and left septal mapping of retrograde atrial activation during typical atrioventricular nodal reentrant tachycardia (AVNRT) has not been undertaken and may provide insight into the complex physiology of AVNRT, especially the anatomic localization of the fast and slow pathways. OBJECTIVES: The purpose of this study was to investigate the pattern of retrograde atrial activation during typical AVNRT by means of right-sided and left-sided septal mapping and implementation of pacing maneuvers for separating atrial and ventricular electrograms recorded during tachycardia. METHODS: Twenty-two patients with slow-fast AVNRT were studied by means of simultaneous His-bundle recordings from the right and left sides of the septum. Patterns of retrograde atrial activation were recorded during tachycardia following specific pacing maneuvers and during right ventricular apical (RVA) pacing at the tachycardia cycle length. RESULTS: The pattern of retrograde atrial activation could be mapped in 17 of 22 patients during AVNRT. In 9 (53%) patients, the earliest retrograde atrial activation was recorded on the left side of the septum, in 3 (17%) patients on the right side, and in 5 (29%) patients both right and left atrial septal electrograms occurred simultaneously. Stimulus to atrial electrogram times recorded during RVA pacing in 14 patients were 138.5 ms from the right His bundle, 134.5 ms from the left His bundle, and 148.0 ms from the ostium of the coronary sinus (P <.001). The predominant site of earliest retrograde atrial activation during RVA pacing was the left side of the septum (10 patients [71%]). Only 8 (57%) of 14 patients demonstrated concordance in the pattern of retrograde atrial activation during AVNRT and RVA pacing. CONCLUSION: Earliest retrograde atrial activation during AVNRT is most often recorded on the left side of the septum. Breakthrough of atrial activation may be discordant from that observed during RVA pacing.

Adult↗
PubMed2006

Is time to first recurrence of atrial fibrillation correlated with atrial fibrillation burden?

The time to the first recurrence of atrial fibrillation (AF) and the AF burden have commonly been used as end points for AF therapy. We conducted a retrospective analysis of data from a large pacemaker registry to assess the relation between the time to the first recurrence and the AF burden. Although a statistical association exists, the small correlation coefficients limit the clinical value of the time to first recurrence as an indicator of AF burden.

Aged↗
PubMed2006

Are implantable cardioverter defibrillator shocks a surrogate for sudden cardiac death in patients with nonischemic cardiomyopathy?

BACKGROUND: Ventricular tachyarrhythmias long enough to cause implantable cardioverter defibrillator (ICD) shocks are generally thought to progress to cardiac arrest. In previous ICD trials, shocks have been considered an appropriate surrogate for sudden cardiac death (SCD) because the number of shocks has been thought to be equivalent to the mortality excess in patients without ICDs. The practice of equating ICD shocks with mortality is controversial and has not been validated critically. METHODS AND RESULTS: The Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial was a prospective, randomized, multicenter trial of ICD therapy in 458 patients with nonischemic cardiomyopathy. Patients were randomized to receive standard medical therapy (STD) or STD plus an ICD. Shock electrograms were reviewed, and the cause of death was evaluated by a separate blinded events committee. There were 15 SCD or cardiac arrests in the STD group and only 3 in the ICD arm. In contrast, of the 229 patients randomized to an ICD, 33 received 70 appropriate ICD shocks. Patients in the ICD arm were more likely to have an arrhythmic event (ICD shock plus SCD) than patients in the STD arm (hazard ratio 2.12, 95% CI 1.153 to 3.893, P=0.013). The number of arrhythmic events when one includes syncope as a potential arrhythmic event was similar in both groups (hazard ratio 1.20, 95% CI 0.774 to 1.865, P=0.414). Approximately the same number of total events was noted in each arm when we compared syncope plus SCD/cardiac arrest in the STD arm with SCD plus ICD shocks plus syncope in the ICD arm. CONCLUSIONS: Appropriate ICD shocks occur more frequently than SCD in patients with nonischemic cardiomyopathy. This suggests that episodes of nonsustained ventricular tachycardia frequently terminate spontaneously in such patients.

Aged↗
PubMed2006

Effect of slow pathway ablation in atrioventricular nodal reentrant tachycardia on the electrophysiologic characteristics of the inferior atrial inputs to the human atrioventricular node.

The inferior atrial extensions of the atrioventricular (AV) node have been related to the anatomic substrate of the slow pathway, but their role in AV nodal reentrant tachycardia (AVNRT) is unknown. Ten patients with slow-fast AVNRT were studied before and after successful slow pathway ablation. Simultaneous His bundle recordings from the right and left sides of the septum were made during right and left inferoparaseptal pacing. Longer stimulus to His (St-H) intervals were measured during right inferoparaseptal pacing than during left inferoparaseptal pacing (284 +/- 55 vs 246 +/- 46 ms, p = 0.005 for right His recordings and 283 +/- 56 vs 244 +/- 46 ms, p = 0.005 for left His recordings) at similar coupling intervals during AVNRT induction. After ablation, the St-H intervals at the maximum AV nodal conduction decrement were similar during right inferoparaseptal and left inferoparaseptal pacing (217 +/- 32 vs 207 +/- 21 ms, p = 0.10 for right His and 215 +/- 32 vs 206 +/- 20 ms, p = 0.13 for left His) at similar coupling intervals. The difference (DeltaSt-H) between St-H intervals during AVRNT induction or at the maximum conduction decrement and during constant pacing for right His recordings with right inferoparaseptal pacing were significantly greater than DeltaSt-H measured with left His during left inferoparaseptal pacing (173 +/- 64 vs 137 +/- 55 ms, p = 0.005) before ablation, but not after (117 +/- 39 vs 100 +/- 40 ms, p = 0.44). Resetting of AVNRT with delivery of left inferoparaseptal extrastimuli was achieved in 7 of 10 patients. In conclusion, the electrophysiologic characteristics of the right and left inferior atrial inputs to the human AV node in patients with AVNRT and their response to slow pathway ablation provide further evidence that the inferior nodal extensions represent the anatomic substrate of the slow pathway.

Adult↗