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Biomedical subjects

Andrew E Epstein

Publications and source records attributed to Andrew E Epstein.

At least 37 records · Page 2Linked to original sources
PubMed2004

Prophylactic implantable cardioverter-defibrillator therapy in patients with left ventricular systolic dysfunction: a pooled analysis of 10 primary prevention trials.

Strategies to decrease sudden cardiac death in patients with left ventricular systolic dysfunction are evolving. Recent clinical trials have evaluated the role of prophylactic implantable cardioverter-defibrillators (ICDs) in patients with and without additional risk stratifiers. We pooled studies comparing treatment with and without ICDs from published data and presented abstracts, irrespective of QRS duration and etiology of systolic dysfunction. On the basis of the available clinical trials, implantation of an ICD for primary prevention of death provides a 7.9% absolute mortality reduction (p = 0.003) in patients with left ventricular (LV) systolic dysfunction who were receiving optimized medical therapy. This finding was not sensitive to the exclusion of any individual trial. The ICD is an effective primary preventative measure in patients who are at risk for death; however, the application of this therapy needs to be individualized for the patient, similar to drug therapies in LV systolic dysfunction. In health care settings without unlimited resources, optimal use of this therapy will require better risk stratification methods or lowering of the initial device cost.

Confounding Factors, Epidemiologic↗
PubMed2004

Highlights of Heart Rhythm 2004, the Annual Scientific Sessions of the Heart Rhythm Society: May 19 to 22, 2004, in San Francisco, California.

Heart Rhythm 2004, the 25th Annual Scientific Sessions of the Heart Rhythm Society (formerly the North American Society of Pacing and Electrophysiology), met in San Francisco in May 2004. The meeting is the world's premier forum for the presentation of research and the exchange of state-of-the-art information in cardiac electrophysiology and pacing. Major new research findings were presented on the value of implantable cardioverter-defibrillator therapy, noninvasive methods for risk stratification, treatment of vasovagal syncope, radiofrequency ablation for atrial fibrillation, resynchronization therapy for heart failure, and new insights from basic science into the mechanisms of cardiac arrhythmias.

Arrhythmias, Cardiac↗
PubMed2004

Electrophysiological findings in adolescents with atrial fibrillation who have structurally normal hearts.

BACKGROUND: Atrial fibrillation (AF) is uncommon in children, and its mechanisms are unknown. This study describes the electrophysiological findings in children and adolescents with AF and the outcome of catheter ablation. METHODS AND RESULTS: Nine adolescents with symptomatic, lone AF who failed antiarrhythmic drug therapy were evaluated. All patients had ECG-documented AF and underwent invasive electrophysiological testing. Intracardiac mapping was performed to determine the site of spontaneous onset of AF and rapidly firing atrial foci. Only the triggering focus was targeted for ablation or isolation. The patients' mean age was 15.9+/-3.3 (range, 8 to 19 years). The most common finding was rapid, irregular atrial tachycardias in the region of the pulmonary veins (n=5), left atrium (n=2), or crista terminalis (n=3). One patient had foci in both the pulmonary veins and crista terminalis. The cycle lengths ranged from 108 to 280 ms. Catheter ablation was acutely successful in 8 patients (88.9%), whereas 1 patient with multiple left atrium foci was treated with the surgical maze operation. Over a mean of 35+/-22 months, 7 patients (77.8%) were arrhythmia free on no medications, while AF recurred in 2 patients who are controlled on antiarrhythmic medications. Two patients with tachycardia-induced cardiomyopathy had resolution of their left ventricular dysfunction after ablation. CONCLUSIONS: AF in adolescents with structurally normal hearts is usually due to foci in the pulmonary veins, crista terminalis, or left atrium. These foci usually induce irregular atrial tachycardias. Catheter ablation of the foci is effective in eliminating recurrent AF.

Adolescent↗
PubMed2004

Left cardiac sympathetic denervation in the management of high-risk patients affected by the long-QT syndrome.

BACKGROUND: The management of long-QT syndrome (LQTS) patients who continue to have cardiac events (CEs) despite beta-blockers is complex. We assessed the long-term efficacy of left cardiac sympathetic denervation (LCSD) in a group of high-risk patients. METHODS AND RESULTS: We identified 147 LQTS patients who underwent LCSD. Their QT interval was very prolonged (QTc, 543+/-65 ms); 99% were symptomatic; 48% had a cardiac arrest; and 75% of those treated with beta-blockers remained symptomatic. The average follow-up periods between first CE and LCSD and post-LCSD were 4.6 and 7.8 years, respectively. After LCSD, 46% remained asymptomatic. Syncope occurred in 31%, aborted cardiac arrest in 16%, and sudden death in 7%. The mean yearly number of CEs per patient dropped by 91% (P<0.001). Among 74 patients with only syncope before LCSD, all types of CEs decreased significantly as in the entire group, and a post-LCSD QTc <500 ms predicted very low risk. The percentage of patients with >5 CEs declined from 55% to 8% (P<0.001). In 5 patients with preoperative implantable defibrillator and multiple discharges, the post-LCSD count of shocks decreased by 95% (P=0.02) from a median number of 25 to 0 per patient. Among 51 genotyped patients, LCSD appeared more effective in LQT1 and LQT3 patients. CONCLUSIONS: LCSD is associated with a significant reduction in the incidence of aborted cardiac arrest and syncope in high-risk LQTS patients when compared with pre-LCSD events. However, LCSD is not entirely effective in preventing cardiac events including sudden cardiac death during long-term follow-up. LCSD should be considered in patients with recurrent syncope despite beta-blockade and in patients who experience arrhythmia storms with an implanted defibrillator.

Adolescent↗
PubMed2004

Relationships between sinus rhythm, treatment, and survival in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Study.

BACKGROUND: The AFFIRM Study showed that treatment of patients with atrial fibrillation and a high risk for stroke or death with a rhythm-control strategy offered no survival advantage over a rate-control strategy in an intention-to-treat analysis. This article reports an "on-treatment" analysis of the relationship of survival to cardiac rhythm and treatment as they changed over time. METHODS AND RESULTS: Modeling techniques were used to determine the relationships among survival, baseline clinical variables, and time-dependent variables. The following baseline variables were significantly associated with an increased risk of death: increasing age, coronary artery disease, congestive heart failure, diabetes, stroke or transient ischemic attack, smoking, left ventricular dysfunction, and mitral regurgitation. Among the time-dependent variables, the presence of sinus rhythm (SR) was associated with a lower risk of death, as was warfarin use. Antiarrhythmic drugs (AADs) were associated with increased mortality only after adjustment for the presence of SR. Consistent with the original intention-to-treat analysis, AADs were no longer associated with mortality when SR was removed from the model. CONCLUSIONS: Warfarin use improves survival. SR is either an important determinant of survival or a marker for other factors associated with survival that were not recorded, determined, or included in the survival model. Currently available AADs are not associated with improved survival, which suggests that any beneficial antiarrhythmic effects of AADs are offset by their adverse effects. If an effective method for maintaining SR with fewer adverse effects were available, it might be beneficial.

Adrenergic beta-Antagonists↗
PubMed2004

Resumption of electrical conduction in previously isolated pulmonary veins: rationale for a different strategy?

BACKGROUND: Atrial fibrillation (AF) may recur after pulmonary vein isolation (PVI) as the result of either recurrent PV conduction or non-PV foci. This study characterized the electrophysiological findings of patients with recurrent AF after initially successful PVI and the clinical outcome after a repeat procedure. METHODS AND RESULTS: Among 185 patients undergoing PVI, 52 reported no significant improvement in their clinical course. We analyzed PV conduction in 51 PVs (15 patients) at repeat PVI. All PVs were isolated with either RF (30 W, 50 degrees C, 60 seconds) or cryoablation (-80 degrees C for 5 minutes). At repeat study, 42 of the previously isolated 51 PVs had return of conduction. All patients had recurrent conduction in > or =2 PVs, with only 1 non-PV focus identified. The mean number of RF applications required to re-isolate the PVs was fewer at the repeat compared with the initial procedure (10+/-6 versus 4+/-2, P<0.005). Over a period of 15+/-6 months, all but 1 patient was clinically improved by the second procedure. CONCLUSIONS: In patients with recurrent AF after PVI, return of PV conduction can be expected. Repeat PVI provides significant clinical benefit for these patients. These results suggest that if permanent PV isolation is the ablation strategy, different techniques may be required to improve long-term efficacy.

Atrial Fibrillation↗
PubMed2004

Comparison of perception of health status by physicians, nurses, and patients in the Dual-chamber And VVI Implantable Defibrillator (DAVID) trial.

Previous studies have shown a poor correlation between health and quality-of-life assessments by patients, physicians, and nurses. Some have argued that patients are treated impersonally in clinical trials. Because one would expect that patient care would be compromised if this were the case, we used the Dual-chamber And VVI Implantable Defibrillator (DAVID) clinical trial setting to see if these assertions truly reflect the assessments of quality of life by health care professionals. Physicians, nurses, and patients in the DAVID trial had concordant assessments of the patients' perception of health status. The findings dispel assertions that patient concerns are not reliably assessed.

Clinical Trials as Topic↗
PubMed2004

Alternative endpoints for mortality in studies of patients with atrial fibrillation: the AFFIRM study experience.

OBJECTIVES: The purpose of this study was to examine possible alternatives for death, particularly hospitalization for cardiovascular reasons (CV hospitalization), as an endpoint in studies of atrial fibrillation (AF) using the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) database. BACKGROUND: AF is associated with increased mortality, but large numbers of patients are needed to demonstrate even a moderate effect of a therapy on mortality. METHODS: AFFIRM studied 4,060 patients with AF, randomized to either rate-control or rhythm-control strategy with death as the primary endpoint. RESULTS: Only CV hospitalization occurred more frequently than death. Like death, CV hospitalization was more frequent in the rhythm-control arm (46% vs 36%, P < .001) overall but not in a cohort that attempted to exclude those CV hospitalizations possibly related to treatment strategy (e.g., cardioversion, 24% vs 27%). In either model there was no interaction of CV hospitalization (analyzed as a time-dependent covariate) with treatment arm (P = .18 and P = .21, respectively). CV hospitalization was highly predictive of death in both treatment arms (P < .001) in either model, but after this event, there was no difference in time to death. A composite endpoint of CV hospitalization combined with death might increase power and reduce the size of trials of therapy for AF in such patients. CONCLUSIONS: In patients with AF such as those in the AFFIRM study, CV hospitalization has many attributes of a surrogate for mortality. More research on CV hospitalization, alone or as part of a composite endpoint, is warranted.

Aged↗
PubMed2004

Relative utility of magnetic resonance imaging and right ventricular angiography to diagnose arrhythmogenic right ventricular cardiomyopathy.

INTRODUCTION: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by fibrofatty replacement of the RV myocardium. Two imaging techniques used to assess patients suspected of having ARVC are magnetic resonance imaging (MRI) and right ventricular angiography (RVA). Traditionally, RVA has played a central role in the diagnosis of ARVC, but the non-invasive nature of MRI and its unique ability to detect fatty tissue infiltration has increased its popularity as a diagnostic tool. The objective of this study was to assess the relative diagnostic accuracy of MRI and RVA for ARVC. METHODS AND RESULTS: Seventeen patients (9 men, 8 women; ages 42 +/- 17 [range 16-78] years) with documented ventricular arrhythmias were investigated for ARVC. A positive diagnosis of ARVC was based on criteria set forth by the ISFC Working Group on Cardiomyopathies and Dysplasia. ECG-gated spin-echo and gradient-echo MR images in multiple planes and RAO/LAO RV angiograms were compared for diagnostic concordance. Based on working group criteria, 7 patients were diagnosed with ARVC. In ten patients, MRI suggested ARVC. The remaining 7 patients had no MRI findings suggestive of the disease. Four patients with MRI findings of ARVC were incorrectly diagnosed based on Task Force criteria. Conversely, 1 patient with a normal MRI met Task Force criteria for the diagnosis of ARVC. Based on RV angiograms, 7 patients had findings suggestive of ARVC. The 10 patients without AVRD (based on RVA) also did not meet the necessary criteria for diagnosis of ARVC using Task Force standards. RVA was 100% specific and 100% sensitive compared to MRI that was only 86% sensitive and 60% specific. MRI proved to be most reliable when the images demonstrated gross, lipomatous infiltration, evidenced by a large area of hyperintensity. When the results of MRI and RVA were congruent, the diagnosis was always accurate. CONCLUSION: RVA is more sensitive and specific to diagnose ARVC diagnosis than MRI, at least until MRI protocols are better developed. MRI results are most robust when indicators of ARVC are grossly apparent. False-positive diagnosis by MRI was primarily related to perceived motion abnormalities that were not seen by RVA. One of its greatest potential assets (fat detection) did not enhance diagnostic specificity.

Adolescent↗
PubMed2004

An update on implantable cardioverter-defibrillator guidelines.

PURPOSE OF REVIEW: This review describes changes in indications for implantable cardioverter-defibrillator (ICD) implantation made in the American College of Cardiology, American Heart Association, and North American Society of Pacing and Electrophysiology 2002 update of the 1998 guideline for the implantation of cardiac pacemakers and antiarrhythmia devices. RECENT FINDINGS: Recent observational and clinical data support changes in the guidelines for ICD implantation to include patients with no structural heart disease and spontaneous ventricular tachycardia not amenable to other treatments; left ventricular ejection fractions of 0.30 or less at least 1 month after myocardial infarction and at least 3 months after coronary revascularization surgery (the Multicenter Automatic Defibrillator Implantation Trial II); syncope of unexplained origin or a family history of unexplained sudden cardiac death in association with typical or atypical right bundle branch block and ST-segment elevations (Brugada syndrome); and syncope in the setting of advanced structural heart disease when thorough invasive and noninvasive investigations have failed to define a cause. SUMMARY: With the completion of multiple important randomized clinical trials, the application of ICD technology continues to evolve. Indications have expanded from secondary to primary prevention. Most importantly, currently available data support the prophylactic use of ICDs in patients with coronary artery disease and poor left ventricular function. Further trial data are awaited to determine if the same benefits for survival and quality of life will be afforded to patients with nonischemic heart diseases and poor left ventricular function.

Cardiology↗
PubMed2004

Functional assessment of pulmonary vein stenosis using radionuclide ventilation/perfusion imaging.

Pulmonary vein (PV) stenosis following catheter ablation of atrial fibrillation (AF) is a new clinical syndrome. The optimal method of assessing this syndrome is not known. We evaluated radionuclide perfusion imaging, anatomic imaging, and direct measurements of PV-left atrial (LA) pressure gradients in patients suspected of having PV stenosis after catheter ablation for the treatment of AF. The study included 11 consecutive patients who were referred to a tertiary referral center for the evaluation of symptoms suggesting or imaging evidence of PV stenosis following catheter ablation for AF. All patients underwent anatomic imaging of their PVs with direct pulmonary venography or CT scanning as well as radionuclide perfusion imaging. PV stenosis (> 50% diameter) was diagnosed by venography in 6 of the 11 patients and in 16 of 44 PVs. All six patients with PV stenosis had perfusion defects in the affected pulmonary lobe. In contrast, all of the patients without anatomic evidence of PV stenosis had normal perfusion. There were 14 PVs with stenoses of > 80% of the luminal diameter, all of which had a corresponding perfusion abnormality ascertained by perfusion scanning. In all 14 PVs with a resting PV-LA gradient of > 5 mm Hg, there was a corresponding perfusion defect. PV stenosis results in decreased perfusion in the affected lobe when the resting PV-LA pressure gradient is at least 5 mm Hg or when there is 80% luminal stenosis. A perfusion scan may serve as an effective screening tool for PV stenosis and may be most useful in assessing the hemodynamic significance of an anatomic PV stenosis.

Adult↗
PubMed2003

Evidence for longitudinal and transverse fiber conduction in human pulmonary veins: relevance for catheter ablation.

BACKGROUND: Segmental ostial ablation of the pulmonary veins (PVs) allows for successful control of paroxysmal atrial fibrillation in many patients. We hypothesized that mapping of the left atrial-PV junction with a 64-electrode basket catheter would allow characterization of conduction patterns that would identify sites where ablation is required to electrically isolate the PV. METHODS AND RESULTS: A 64-electrode basket catheter was used to map the PVs of 50 patients undergoing PV isolation procedures for the treatment of atrial fibrillation. Activation along each spline was classified as reflecting either longitudinal, transverse, or no activation. A longitudinal activation pattern recorded along a spline during sinus rhythm in right-sided PV and during CS pacing in left-sided PV before the delivery of any RF energy application had a sensitivity and specificity for a required ostial ablation site of 83% and 82%, respectively. When longitudinal activation along the spline was present during preablation recordings in both sinus rhythm and CS pacing, the sensitivity and specificity were 92% and 90%, respectively. A longitudinal activation pattern after the first RF application that produced a change in PV activation sequence had a sensitivity and specificity for sites where further ablation was required of 91% and 94%, respectively. CONCLUSIONS: Mapping of PV activation with a 64-electrode basket catheter allows characterization of conduction patterns that predict requirement for ablation. The presence of a longitudinal activation pattern is a strong predictor of ostial sites where ablative energy is required to electrically isolate the PV.

Atrial Fibrillation↗
PubMed2003

Comparison of arrhythmia recurrence in patients presenting with ventricular fibrillation versus ventricular tachycardia in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial.

Because many episodes of ventricular fibrillation (VF) are believed to be triggered by ventricular tachycardia (VT), patients who present with VT or VF are usually grouped together in discussions of natural history and treatment. However, there are significant differences in the clinical profiles of these 2 patient groups, and some studies have suggested differences in their response to therapy. We examined arrhythmias occurring spontaneously in 449 patients assigned to implantable cardioverter-defibrillator (ICD) therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) trial to determine whether patients who receive an ICD after VT have arrhythmias during follow-up that are different from patients who present with VF. ICD printouts were analyzed both by a committee blinded to the patients' original presenting arrhythmia and by the local investigator. During 31 +/- 14 months of follow-up, 2,673 therapies were reported. Patients who were enrolled in the AVID trial after an episode of VT were more likely to have an episode of VT (73.5% vs 30.1%, p <0.001), and were less likely to have an episode of VF (18.3% vs 28.0%, p = 0.013) than patients enrolled after an episode of VF. Adjustment for differences in ejection fraction, previous infarction, and beta-blocker and antiarrhythmic therapy did not appreciably change the results. Ventricular arrhythmia recurrence during follow-up is different in patients who originally present with VT than in those who originally present with VF. These findings suggest there are important differences in the electrophysiologic characteristics of these 2 patient populations.

Adrenergic beta-Antagonists↗
PubMed2003

Analysis of implantable cardioverter defibrillator therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial.

INTRODUCTION: The implantable cardioverter defibrillator (ICD) is commonly used to treat patients with documented sustained ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia recurrence rates in these patients are high, but which patients will receive a therapy and the forms of arrhythmia recurrence (VT or VF) are poorly understood. METHODS AND RESULTS: The therapy delivered by the ICD was examined in 449 patients randomized to ICD therapy in the Antiarrhythmics Versus Implantable Defibrillators (AVID) Trial. Events triggering ICD shocks or antitachycardia pacing (ATP) were reviewed for arrhythmia diagnosis, clinical symptoms, activity at the onset of the arrhythmia, and appropriateness and results of therapy. Both shock and ATP therapies were frequent by 2 years, with 68% of patients receiving some therapy or having an arrhythmic death. An appropriate shock was delivered in 53% of patients, and ATP was delivered in 68% of patients who had ATP activated. The first arrhythmia treated in follow-up was diagnosed as VT (63%), VF (13%), supraventricular tachycardia (18%), unknown arrhythmia (3%), or due to ICD malfunction or inappropriate sensing (3%). Acceleration of an arrhythmia by the ICD occurred in 8% of patients who received any therapy. No physical activity consistently preceded arrhythmias, nor did any single clinical factor predict the symptoms of the arrhythmia. CONCLUSION: Delivery of ICD therapy in AVID patients was common, primarily due to VT. Inappropriate ICD therapy occurred frequently. Use of ICD therapy as a surrogate endpoint for death in clinical trials should be avoided.

Aged↗