title: Interruption of Pacing Following Nonsustained Ventricular Tachycardia in an AAI Programmed Implantable Cardioverter Defibrillator.
abstract: BACKGROUND
  Unnecessary ventricular pacing from cardiac implantable electronic devices has been associated with long-term risks (heart failure, atrial fibrillation, and possibly stroke). Several device programming strategies are available to minimize ventricular pacing, each potentially associated with unintended consequences. Occasionally, the only effective means is to program to the AAI(R) pacing mode. However, in one manufacturer's implantable cardioverter defibrillators (ICDs), the AAI(R) mode has the potential risk of prolonged pacing cessation following a nonsustained ventricular tachycardia (NSVT).
  
  
  METHODS
  Patients with ICDs, managed through the Cleveland Clinic device clinic, follow the Heart Rhythm Society consensus document recommendations for device monitoring with remote interrogations (every three months) and yearly in-person evaluations. Clinically significant findings also trigger additional evaluations by the nurse and physician.
  
  
  RESULTS
  Two patients having Boston Scientific ICDs (E110 Teligen 100; Boston Scientific Corp., Natick, MA, USA), had asystole and marked bradycardia following untreated NSVT. These pauses in pacing were due to use of the AAI(R) pacing mode. In order to enhance ventricular tachycardia detection, by design atrial pacing is disabled during, and for a time after, an episode of ventricular tachycardia when the device operates in the "ventricular tachycardia response" (VTR) phase. Thus, following spontaneous termination of the NSVT, no pacing occurred in these patients until the VTR period ended. Nonconventional programming was utilized to permit AAI(R) pacing while avoiding these asystolic and bradycardic events during VTR.
  
  
  CONCLUSIONS
  Unintended consequences can occur when complex VT detection parameters interact with specific pacing modes. At times, nonconventional programming can avoid these interactions while still achieving effective AAI(R) pacing.
authors.affiliation: Department of Cardiovascular Medicine, Section of Cardiac Electrophysiology and Pacing, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Paul
authors.initials: P
authors.lastname: Egan
authors.affiliation: Department of Cardiovascular Medicine, Section of Cardiac Electrophysiology and Pacing, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Wilkoff
authors.affiliation: Department of Cardiovascular Medicine, Section of Cardiac Electrophysiology and Pacing, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio.
authors.forename: Patrick
authors.initials: P
authors.lastname: Tchou
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001919:Bradycardia / Q000209:etiology* / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004868:Equipment Failure; D006801:Humans; D008297:Male; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation*; D017211:Treatment Failure
keywords: AAI pacing; implantable cardioverter defibrillator