EP Year in Review: 2009

This month EP Lab Digest debuted online-only content on our website, including this feature article by J. David Burkhardt, MD, FACC and Andrea Natale, MD, FACC, FHRS. In the article, the authors discuss electrophysiology advancements from the past year. Here is a special preview of the article, now available on www.eplabdigest.com. The year 2009 has yielded some interesting developments in the field of cardiac electrophysiology. Many of the advances reported in the last decade in atrial fibrillation have focused on ablative therapy. This year is no exception; however, new treatment options are also available in both stroke prevention and rhythm control. Left atrial appendage occlusion devices and direct thrombin inhibitors have reported promising results, and the first new anti-arrhythmic medication for atrial fibrillation in nearly a decade is available. Device-based therapy for congestive heart failure continues to evolve, with a trial showing benefit of cardiac resynchronization therapy in patients with relatively asymptomatic left ventricular dysfunction and cardiac dyssynchrony. Ablative therapy for cardiac arrhythmias also continues to expand. This year reported improved success rates in atrial fibrillation ablation with repeat ablation procedures, success with endoscopic laser balloon based ablation systems, successful reduction of ventricular tachycardia with ablation in patients with prior myocardial infarction, and new methods for improving the success and reducing the complications associated with epicardial ablation. Options for Stroke Prevention and Rhythm Control The options for stroke prevention associated with atrial fibrillation have been limited to aspirin and warfarin for many years. Devices that occlude the left atrial appendage may soon be added to the treatment options. In a study of 707 patients with atrial fibrillation and stroke risk factors, the left atrial occlusion device was not inferior to warfarin for stroke prevention. The device was associated with a higher rate of complications, most of which were peri-procedural complications such as bleeding or pericardial effusion.1 This device is currently being evaluated by the Food and Drug Administration for possible approval to prevent stroke in such a population. Warfarin is the only drug option currently available for patients with atrial fibrillation who are at high risk for stroke; however, a new direct thrombin inhibitor may be an option in the near future. Dabigatran was studied in over 18,000 patients with atrial fibrillation and stroke risk factors. The lower dose studied showed similar stroke prevention to warfarin with lower bleeding complications, while the higher dose showed superior stroke prevention with similar bleeding complications.2 Obviously, one of the major benefits is the lack of dose adjustment and monitoring that is necessary with warfarin. The first new anti-arrhythmic medication in nearly a decade was approved this year. Dronederone is an amiodarone analog that is approved for atrial fibrillation. It does not appear to have many of the side effects of amiodarone, but may not be as effective.3 Its major contraindication is advanced heart failure, but it can be used in the presence of coronary artery disease and left ventricular dysfunction. In the ATHENA trial, dronedarone reduced hospitalization due to cardiac events or death compared to placebo.2 In a post hoc analysis, dronedarone also appeared to reduce the risk of stroke, but this will need further investigation.4 Cardiac Resynchronization Therapy Cardiac resynchronization therapy continues to be a powerful tool in combating congestive heart failure. The MADIT-CRT trial published this year showed that this therapy reduced the risk of heart failure events as well as improved the left ventricular ejection fraction and reduced left ventricular volumes in patients with NYHA Class 1-2 congestive heart failure, left ventricular dysfunction and a wide QRS on EKG.5 We may soon see the expansion of cardiac resynchronization therapy to any patient with left ventricular dysfunction and a wide QRS complex. To read the complete article, please visit our website at: www.eplabdigest.com Readers, if you would like to submit an online article, please contact Jodie Elrod at “jelrod@hmpcommunications.com” for author guidelines. Disclosures: Dr. J. David Burkhardt is a Chief Medical Advisor to Stereotaxis, and consultant to Medtronic, Biosense Webster, and St. Jude Medical. Dr. Andrea Natale is a consultant to Stereotaxis, Biosense Webster, St. Jude Medical, Medtronic, Atritech, and CardioFocus.