Low-energy multistage atrial defibrillation therapy terminates atrial fibrillation with less energy than a single shock

Circ Arrhythm Electrophysiol. 2011 Dec;4(6):917-25. doi: 10.1161/CIRCEP.111.965830. Epub 2011 Oct 6.

Abstract

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 stages: stage (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 tested: ST1 versus ST1+ST3 versus ST1+ST2+ST3. Third, 3 shock vectors were compared: superior 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Atrial Fibrillation / diagnosis
  • Atrial Fibrillation / etiology
  • Atrial Fibrillation / physiopathology
  • Atrial Fibrillation / therapy*
  • Atrial Function*
  • Cardiac Pacing, Artificial
  • Defibrillators, Implantable
  • Disease Models, Animal
  • Dogs
  • Electric Countershock / adverse effects
  • Electric Countershock / instrumentation
  • Electric Countershock / methods*
  • Electrocardiography
  • Electrophysiologic Techniques, Cardiac
  • Equipment Design
  • Heart Atria / physiopathology
  • Heart Conduction System / physiopathology*
  • Pain / etiology
  • Pain / prevention & control
  • Time Factors
  • Vagus Nerve Stimulation