Tachycardia: Implantable Atrioverters converted rhythm safely.

Clinical bottom line (level 2c)

  1. Patients with atrial fibrillation who were given an implantable Atrioverter, were likely to have conversion to sinus rhythm with few complications.
  2. Patients were likely to experience early recurrence of atrial fibrillation following shock.
Wellens et al: Circulation 1998; 98: 1651-1656
Expires October 2003

The study

Outcome study with objective outcomes, ?adjusted for confounding factors, not validated in an independent set of patients.

Setting: 19 centres in 9 countries (The Netherlands, China, Germany, USA, UK, Belgium, France, Sweden, Canada)

51 patients (aged range 31 to 77 years; mean 58, 78% male) prior episodes of atrial fibrillation that had spontaneously converted to normal sinus rhythm with intervals of recurrence of atrial fibrillation episodes between 1 week and 3 months

Excluded if
  • implanted heart valve
  • atrial fibrillation of reversible cause (eg. after cardiac surgery, hyperthyroidism)
  • Wolff-Parkinson-White syndrome
  • myocardial infarction or myocardial revascularisation = year
  • active angina or cardiac ischaemia
  • history of left atrial thromboembolic events
  • congestive heart failure (NYHA class >II)
  • left ventricular ejection fraction <40%
  • ECG documentation of sustained or nonsustained ventricular tachycardia (>3 consecutive beats)
  • defibrillation level >240 V at inclusion testing procedure


    • Implantable atrial defibrillator (Atrioverter)-starting with 180 V shock, shock intensity was increased in 20 V steps until successful defibrillation was achieved. After this success, fibrillation was reinduced and a shock 20 V less than the successful shock was given. The intensity was decreased in 20 V steps until there was a failure to convert. Shocks were then delivered at 20 V steps of increasing intensity until atrial fibrillation was successfully converted with the delivery of 2 shocks at this intensity.

    followed for 3 months
    Outcomes studied:
  • termination of atrial fibrillation
  • early recurrence of atrial fibrillation resumption within 1 minute after shock that resulted in sinus rhythm for = 1 beat
  • serious complications subclavian venous thrombosis, pericardial effusion, infection requiring explantation of the device and leads

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    termination of atrial fibrillation 3 months 41/51 80.4%
    (69.5% to 91.3%)
    early recurrence of atrial fibrillation 3 months 21/51 41.2%
    (27.7% to 54.7%)
    serious complications 3 months 5/51 9.80%
    (1.60% to 18.0%)

    Comments

    1. No information is given about the complications with or without anticoagulation. Benefits and harms due to anticoagulation would need a much larger series of patients.

    Citation

    1. Wellens HJJ, Lau C-P, Luederitz B, et al: Atrioverter: An implantable device for the treatment of atrial fibrillation. Circulation 1998; 98: 1651-1656
    Contributor: Clare Wotton and Musab Hayatli, October 1999
    Reviewer: Bruce Arroll

    Clinical Question.
    Patient atrial fibrillation
    Intervention or Exposure implantable defibrillator (Atrioverter)
    Comparison
    Outcome restoration of sinus rhythm