Danish Study

1
Danish Study
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Danish Study Overview

• Hypothesis
• In patients with SND, atrial pacing (AAI) will
  result in less atrial fibrillation,
  thromboembolism, heart failure and overall
  mortality than ventricular pacing (VVI).
• Study Design
• Single center, prospective, randomization of
  patients referred for first pacemaker implant

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Danish Study Endpoints

• Primary
• Mortality
• Cardiovascular death
• Secondary
• Atrial fibrillation
• Thromboembolic events
• Heart failure
• AV block

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Danish Study Inclusion Criteria

• First pacemaker implant
• Symptomatic bradycardia (lt50 bpm or symptomatic
  QRS pauses gt2 seconds)
• gt50 years of age
• No history of
• Chronic AF or AF gt50 of time or AF with QRS rate
  lt40 bpm
• Grade 1, 2, 3 AV block
• Bundle branch block
• Stroke within last 3 months
• Hypertension (gt250/120)

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Danish Study Patient Characteristics
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Danish Study Patient Characteristics
P 0.04, atrial versus ventricular group
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Danish Study
Study Population (n225)
Randomised to AAI (n 110)
Randomised to VVI (n 115)
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Danish Study Overall survival by pacing mode
Andersen H, et al. Lancet 1997 350 1210-16.
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Danish Study Cardiovascular death by pacing mode
1-0
Atrial pacing
0-8
p 0.0065
0-6
Cumulative survival
Ventricular pacing
0-4
0-2
0
Time (years)
0
2
4
6
8
10
Number of patients at risk during
follow-up Atrial Ventricular
Andersen H, et al. Lancet 1997 350 1210-16.
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Danish Study Cumulative risk of PAF by pacing
mode
Andersen H, et al. Lancet 1997 350 1210-16.
11
Danish Study Cumulative risk of chronic AF by
pacing mode
Andersen H, et al. Lancet 1997 350 1210-16.
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Danish Study Mortality as a result of CHF
Andersen H, et al. Lancet 1997 350 1210-16.
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Danish Study CHF Analysis

• NYHA classification was higher in the ventricular
  group vs. the atrial group (p0.010) at long term
  follow up.
• During follow up, NYHA class worsened in the
  ventricular group vs. the atrial group (plt0.005)
• Mean dose of diuretics increased in the
  ventricular group vs. the atrial group (p0.033)

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Danish StudyConclusions

• In patients with SND, atrial pacing is
  associated with a significantly higher survival,
  less atrial fibrillation, fewer thromboembolic
  complications, and less heart failure compared to
  ventricular pacing.

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Danish Study Limitations

• Physical exam, NYHA classification and M-mode
  echocardiography at follow-up were not done
  blinded with regard to randomization.
• Possible impact Observer bias in these
  parameters.
• NYHA class was difficult to define precisely, but
  the higher use of diuretics in the ventricular
  group suggested a higher incidence of heart
  failure in this group.
• Pacemaker event counters were not checked
  regularly.
• Possible impact it was not possible to
  correlate cumulative percent atrial or
  ventricular pacing to the changes in left atrial
  and left ventricular dimensions, LVFS, or
  occurrence of heart failure.

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Danish Study References

• Andersen HR, Thuesen L, Bagger JP, et al.
  Prospective Trial of Atrial versus Ventricular
  Pacing in Sick Sinus Syndrome. Lancet 1994 344
  1523-28.
• Andersen HR, Nielsen JC, Thomsen PE, et al.
  Long-Term Follow-Up of Patients from a Randomised
  Trial of Atrial Versus Ventricular Pacing for
  Sick Sinus Syndrome. Lancet 1997 350 1210-16.
• Nielsen JC, Andersen HR, Thomsen PE, et al.
  Heart Failure and Echocardiographic Changes
  During Long-term Follow-up of Patients with Sick
  Sinus Syndrome Randomized to Single-Chamber
  Atrial or Ventricular Pacing. Circulation. 1998
  97 987-995.