Rhea Pimentel

Feasibility and Safety of Dabigatran Versus Warfarin for Periprocedural Anticoagulation in Patients Undergoing Radiofrequency Ablation for Atrial Fibrillation Results From a Multicenter Prospective Registry

OBJECTIVES The purpose of this study was to evaluate the feasibility and safety of periprocedural dabigatran during atrial fibrillation (AF) ablation. BACKGROUND AF ablation requires optimal periprocedural anticoagulation for minimizing bleeding and thromboembolic complications. The safety and efficacy of dabigatran as a periprocedural anticoagulant for AF ablation are unknown. METHODS We performed a multicenter, observational study from a prospective registry including all consecutive patients undergoing AF ablation in 8 high-volume centers in the United States. All patients receiving dabigatran therapy who underwent AF ablation on periprocedural dabigatran, with the dose held on the morning of the procedure, were matched by age, sex, and type of AF with an equal number of patients undergoing AF ablation with uninterrupted warfarin therapy over the same period. RESULTS A total of 290 patients, including 145 taking periprocedural dabigatran and an equal number of matched patients taking uninterrupted periprocedural warfarin, were included in the study. The mean age was 60 years with 79% being male and 57% having paroxysmal AF. Both groups had a similar CHADS(2) score, left atrial size, and left ventricular ejection fraction. Three thromboembolic complications (2.1%) occurred in the dabigatran group compared with none in the warfarin group (p = 0.25). The dabigatran group had a significantly higher major bleeding rate (6% vs. 1%; p = 0.019), total bleeding rate (14% vs. 6%; p = 0.031), and composite of bleeding and thromboembolic complications (16% vs. 6%; p = 0.009) compared with the warfarin group. Dabigatran use was confirmed as an independent predictor of bleeding or thromboembolic complications (odds ratio: 2.76, 95% confidence interval: 1.22 to 6.25; p = 0.01) on multivariate regression analysis. CONCLUSIONS In patients undergoing AF ablation, periprocedural dabigatran use significantly increases the risk of bleeding or thromboembolic complications compared with uninterrupted warfarin therapy.

Autocrine Regulation of Myocyte Cx43 Expression by VEGF

Cardiac myocytes can rapidly adjust their expression of gap junction channel proteins in response to changes in load. Previously, we showed that after only 1 hour of linear pulsatile stretch (110% of resting cell length; 3 Hz), expression of connexin43 (Cx43) by cultured neonatal rat ventricular myocytes is increased by ≈2-fold and impulse propagation is significantly more rapid. In the present study, we tested the hypothesis that vascular endothelial growth factor (VEGF), acting downstream of transforming growth factor-&bgr; (TGF-&bgr;), mediates stretch-induced upregulation of Cx43 expression by cardiac myocytes. Incubation of nonstretched cells with exogenous VEGF (100 ng/mL) or TGF-&bgr; (10 ng/mL) for 1 hour increased Cx43 expression by ≈1.8-fold, comparable to that observed in cells subjected to pulsatile stretch for 1 hour. Stretch-induced upregulation of Cx43 expression was blocked by either anti-VEGF antibody or anti-TGF-&bgr; antibody. Stretch-induced enhancement of conduction was also blocked by anti-VEGF antibody. ELISA assay showed that VEGF was secreted into the culture medium during stretch. Furthermore, stretch-conditioned medium stimulated Cx43 expression in nonstretched cells. This effect was also blocked by anti-VEGF antibody. Upregulation of Cx43 expression stimulated by exogenous TGF-&bgr; was blocked by anti-VEGF antibody, but VEGF-stimulation of Cx43 expression was not blocked by anti-TGF-&bgr; antibody. Thus, stretch-induced upregulation of Cx43 expression is mediated, at least in part, by VEGF, which acts downstream of TGF-&bgr;. Because the cultures contained only ≈5% nonmyocytic cells, these results indicate that myocyte-derived VEGF, secreted in response to stretch, acts in an autocrine fashion to enhance intercellular coupling.

Radiofrequency ablation of atrial fibrillation in patients with mitral or aortic mechanical prosthetic valves: A feasibility, safety, and efficacy study

BACKGROUND Patients with prosthetic valves have a high prevalence of atrial fibrillation (AF). We report a multicenter experience of performing pulmonary vein antral isolation (PVAI) in this challenging, high-risk cohort of patients. OBJECTIVE The purpose of this study was to assess the feasibility, safety, and efficacy of radiofrequency (RF) ablation for sinus rhythm restoration in AF patients with mitral or aortic mechanical prosthetic valves. METHODS A total of 50 patients with prosthetic valves (group I) who underwent RF ablation for AF between January 1, 2007, and April 30, 2009, were identified prospectively at four tertiary care centers. A matched group of 50 patients (group II) acted as controls. RESULTS Total procedural time (199.4 ± 49 minutes vs 166.6 ± 27.5 minutes, P <.001) and fluoroscopy time (60 ± 17 minutes vs 53.8 ± 6.8 minutes, P <.01) were prolonged, with a higher incidence of atrial flutter at 3 months in group I (18% vs 6%, P = .1) compared to group II. At 12 months, 80% of patients in the valve group were in sinus rhythm after an average of 1.3 procedures, and 82% of controls were in sinus rhythm after an average 1.2 procedures (P = .9). There was a trend toward a higher nonfatal complication rate in the valve group than in the control group (8% vs 4%, P = .1). CONCLUSION In patients with prosthetic valves, RF ablation for AF is feasible, safe, and efficacious, with a trend toward a higher nonfatal complication rate and an increased rate of postablation atrial flutter.

Effect of Atrial Fibrillation Ablation on Gastric Motility The Atrial Fibrillation Gut Study

Background—Collateral damage to the vagal nerve and the upper gastrointestinal (UGI) system during atrial fibrillation ablation has not been systematically evaluated. Methods and Results—We performed a prospective, observational study assessing the effect of atrial fibrillation ablation on the function of the vagus nerve/UGI system. All patients underwent esophageal manometry, gastric emptying study, and sham-feeding test (corresponding to esophageal, gastric, and small intestinal function evaluation, respectively) before ablation (baseline) and subsequently at 24 hours, 90 days, and 180 days after the procedure. In addition, UGI symptom assessment using the patient assessment of upper gastrointestinal disorders–symptom severity index (PAGI-SYM) questionnaire was performed at baseline and during each of the subsequent evaluations. Of the 27 patients enrolled in the study, 9 (33%) patients had abnormal UGI function at baseline; defined as at least one of the 3 abnormal tests. At 24 hours after the radiofrequency catheter ablation, 20 (74%) patients had at least 1 new abnormality on the UGI function tests (P<0.001). New onset esophageal dysmotility, delayed gastric emptying time, and abnormal sham-feeding tests were observed in 13 (48%), 13 (48%), and 9 (33%) patients, respectively. Mean PAGI-SYM scores increased from 7.78±6.6 at baseline to 15.56±13.4 (P=0.002) at 24 hours. New onset abnormalities persisted in 9 (33%) patients at 3 months and normalized in all patients at 6 months. Conclusions—Atrial fibrillation ablation results in functional impairment of the UGI system, including the esophagus, stomach, and small intestine. This impairment is transient and is probably mediated by the injury to the components of the vagal nerve. Clinical Trial Registration—URL: http://clinicaltrials.gov. Unique Identifier: NCT01396356.

The Effect of Atrial Fibrillation Ablation on Gastric Motility "The AF Gut Study"

Background—Collateral damage to the vagal nerve and the upper gastrointestinal (UGI) system during atrial fibrillation ablation has not been systematically evaluated. Methods and Results—We performed a prospective, observational study assessing the effect of atrial fibrillation ablation on the function of the vagus nerve/UGI system. All patients underwent esophageal manometry, gastric emptying study, and sham-feeding test (corresponding to esophageal, gastric, and small intestinal function evaluation, respectively) before ablation (baseline) and subsequently at 24 hours, 90 days, and 180 days after the procedure. In addition, UGI symptom assessment using the patient assessment of upper gastrointestinal disorders–symptom severity index (PAGI-SYM) questionnaire was performed at baseline and during each of the subsequent evaluations. Of the 27 patients enrolled in the study, 9 (33%) patients had abnormal UGI function at baseline; defined as at least one of the 3 abnormal tests. At 24 hours after the radiofrequency catheter ablation, 20 (74%) patients had at least 1 new abnormality on the UGI function tests (P<0.001). New onset esophageal dysmotility, delayed gastric emptying time, and abnormal sham-feeding tests were observed in 13 (48%), 13 (48%), and 9 (33%) patients, respectively. Mean PAGI-SYM scores increased from 7.78±6.6 at baseline to 15.56±13.4 (P=0.002) at 24 hours. New onset abnormalities persisted in 9 (33%) patients at 3 months and normalized in all patients at 6 months. Conclusions—Atrial fibrillation ablation results in functional impairment of the UGI system, including the esophagus, stomach, and small intestine. This impairment is transient and is probably mediated by the injury to the components of the vagal nerve. Clinical Trial Registration—URL: http://clinicaltrials.gov. Unique Identifier: NCT01396356.

Practice variation in the re-initiation of dofetilide: An observational study

BACKGROUND Dofetilide is a class III antiarrhythmic drug that has been reported to be safe and efficacious in the treatment of atrial dysrhythmias with a known initial risk of QT prolongation and torsades de pointes (TdP). As a result, the Federal Drug Administration (FDA) mandated in-hospital dofetilide initiation and adherence to a common dosing protocol. However, there is a lack of clarity on how to manage dofetilide re-initiation. METHODS An observational survey was performed including 347 cardiologists in the United States and worldwide to evaluate the deviations from approved manufacturers protocol during dofetilide initiation and re-initiation among practicing cardiologists. RESULTS Most practicing cardiologists were cautious about outpatient dofetilide use and adhered to the manufacturers in-patient dofetilide protocol during de-novo initiation and reported low incidence of TdP in clinical practice. There were substantial differences among practicing cardiologists with deviation from the manufacturers protocol during re-initiation of dofetilide. About 21% cardiologists always admitted patients to the hospital while 37% admitted patients <10% of the time for dofetilide re-initiation. Only 4% reported major adverse events with outpatient dofetilide re-initiation. There was also wide variation regarding monitoring of electrolytes and QT interval as an outpatient with dofetilide. CONCLUSION There is significant practice pattern variation in the use of dofetilide for the management of AF. This degree of variation noted is concerning and is a reflection of the current lack of substantial clinical evidence in the re-initiation dofetilide protocol to help direct the provider.

REAL-WORLD PRACTICE PATTERNS OF DOFETILIDE AND SOTALOL UTILIZATION FOR ATRIAL FIBRILLATION: A MULTI-NATIONAL SURVEY

To evaluate the real-world practice patterns of utilization of dofetilide for treating Atrial Fibrillation (AF). We performed an online survey of cardiologists and cardiac electrophysiologists in US and Europe. Participation was voluntary. 31 specific questions were included in the study, primarily

USE OF ORAL STEROID AND ITS EFFECTS ON ATRIAL FIBRILLATION RECURRENCE AND INFLAMMATORY CYTOKINES POST ABLATION - THE STEROID AF STUDY: A RANDOMIZED CONTROL TRIAL

To evaluate the impact of pre-procedural oral prednisone on inflammatory cytokines (TNF-α, Interleukin (IL)-1, IL-6, and IL-8) levels and outcomes of atrial fibrillation (AF) ablation in patients with paroxysmal AF. A total of 60 patients with paroxysmal AF undergoing AF ablation were randomized (

Under-Utilization of Implantable Cardioverter Defibrillators in Patients with Heart Failure - The Current State of Sudden Cardiac Death Prophylaxis.

Background Despite ACC/AHA guidelines indicating implantable cardioverter defibrillator (ICD) as class I therapy for primary prevention of sudden cardiac death in patients with EF≤35%, ICD utilization rates in real world practice have been low. Objective To determine the rate of ICD implantation at a tertiary care academic center and to assess the reasons for under-utilization of the same. Methods Review of a prospectively collected database which included all patients diagnosed with an EF≤35% was performed to assess the rate of ICD implantation and mortality. Reasons for non-implantation of ICD were then assessed from detailed chart review. Results A total of 707 patients (age 69.4 ± 14.1 years) with mean EF of 26±7% were analyzed. Only 28% (200/707) of patients had ICDs implanted. Mortality was lower in the group with ICD (25% vs 37%, p=0.004). When patients who either died or were lost to follow-up prior to 2005 were excluded, ICD utilization rate was still low at 37.6%. The most common reason for non-implantation of ICD was physicians not discussing this option with their patients. Patient refusal was the second most common reason. Conclusions ICD Implantation rates for primary prevention of SCD in patients with EF≤35% is low. Physician and patient education should be addressed to improve the utilization rates.BACKGROUND Despite ACC/AHA guidelines indicating implantable cardioverter defibrillator (ICD) as class I therapy for primary prevention of sudden cardiac death in patients with EF≤35%, ICD utilization rates in real world practice have been low. OBJECTIVE To determine the rate of ICD implantation at a tertiary care academic center and to assess the reasons for under-utilization of the same. METHODS Review of a prospectively collected database which included all patients diagnosed with an EF≤35% was performed to assess the rate of ICD implantation and mortality. Reasons for non-implantation of ICD were then assessed from detailed chart review. RESULTS A total of 707 patients (age 69.4 ± 14.1 years) with mean EF of 26±7% were analyzed. Only 28% (200/707) of patients had ICDs implanted. Mortality was lower in the group with ICD (25% vs 37%, p=0.004). When patients who either died or were lost to follow-up prior to 2005 were excluded, ICD utilization rate was still low at 37.6%. The most common reason for non-implantation of ICD was physicians not discussing this option with their patients. Patient refusal was the second most common reason. CONCLUSIONS ICD Implantation rates for primary prevention of SCD in patients with EF≤35% is low. Physician and patient education should be addressed to improve the utilization rates.

EXTERNALIZATION OF CONDUCTOR CABLES IN QUICKSITE AND QUICKFLEX LEFT VENTRICULAR LEADS

We intended to evaluate the incidence of electrical and mechanical failure of QuickSite (QS) and QuickFlex (QF) left ventricular (LV) leads which are a part of a lead advisory. We invited all 154 alive patients who had the QS and QF leads implanted at our center to participate in this prospective