Low-Energy Multistage Atrial Defibrillation Therapy Terminates Atrial Fibrillation With Less Energy Than a Single Shock

• Published in: Circulation. Arrhythmia and electrophysiology Vol. 4; no. 6; pp. 917 - 925
• Main Authors: Li, Wenwen, Janardhan, Ajit H, Fedorov, Vadim V, Sha, Qun, Schuessler, Richard B, Efimov, Igor R
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD American Heart Association, Inc 01.12.2011; Lippincott Williams & Wilkins
• Subjects: Animals; Atrial Fibrillation - diagnosis; Atrial Fibrillation - etiology; Atrial Fibrillation - physiopathology; Atrial Fibrillation - therapy; Atrial Function; Biological and medical sciences; Cardiac dysrhythmias; Cardiac Pacing, Artificial; Cardiology. Vascular system; Defibrillators, Implantable; Disease Models, Animal; Dogs; Electric Countershock - adverse effects; Electric Countershock - instrumentation; Electric Countershock - methods; Electrocardiography; Electrophysiologic Techniques, Cardiac; Equipment Design; Heart; Heart Atria - physiopathology; Heart Conduction System - physiopathology; Medical sciences; Pain - etiology; Pain - prevention & control; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Time Factors; Vagus Nerve Stimulation; Shock; Proximal; vagal nerve stimulation; Arrhythmia; Cardiovascular disease; Left atrium; cardioversion; Result; Coronary sinus; Pain; Energy; Heart disease; Vagus nerve; Dog; Right atrium; Vector; Superior vena cava; Threshold; Fissipedia; Intensive cardiocirculatory care; Carnivora; Multiple; Device; Atrial fibrillation; Instrumentation therapy; Method; Excitability disorder; Low energy; Drug conversion; Instrumental stimulation; Vertebrata; Mammalia; High energy; Implanted; Animal; Distal; Models; Limit; Technique; Defibrillation; Comparative study
• ISSN: 1941-3149; 1941-3084
• DOI: 10.1161/CIRCEP.111.965830

BACKGROUND—Implantable device therapy of atrial fibrillation (AF) is limited by pain from high-energy shocks. We developed a low-energy multistage defibrillation therapy and tested it in a canine model of AF. METHODS AND RESULTS—AF was induced by burst pacing during vagus nerve stimulation. Our novel defibrillation therapy consisted of 3 stagesstage (ST) 1 (1–4 low-energy biphasic [BP] shocks), ST2 (6–10 ultralow-energy monophasic [MP] shocks), and ST3 (antitachycardia pacing). First, ST1 testing compared single or multiple MP and BP shocks. Second, several multistage therapies were testedST1 versus ST1+ST3 versus ST1+ST2+ST3. Third, 3 shock vectors were comparedsuperior vena cava to distal coronary sinus, proximal coronary sinus to left atrial appendage, and right atrial appendage to left atrial appendage. The atrial defibrillation threshold (DFT) of 1 BP shock was <1 MP shock (0.55±0.1 versus 1.38±0.31 J, P=0.003). Two to 3 BP shocks terminated AF with lower peak voltage than 1 BP or 1 MP shock and with lower atrial DFT than 4 BP shocks. Compared with ST1 therapy alone, ST1+ST3 lowered the atrial DFT moderately (0.51±0.46 versus 0.95±0.32 J, P=0.036), whereas 3-stage therapy (ST1+ST2+ST3) dramatically lowered the atrial DFT (0.19±0.12 versus 0.95±0.32 J for ST1 alone, P=0.0012). Finally, the 3-stage therapy was equally effective for all studied vectors. CONCLUSIONS—Three-stage electrotherapy significantly reduces the AF DFT and opens the door to low-energy atrial defibrillation at or below the pain threshold.