Bradycardia: fewer patients developed pacemaker syndrome with dual-chamber pacemakers

Clinical bottom line (level 1b)

  1. Elderly patients requiring a pacemaker to prevent or treat bradycardia who received a single-chamber ventricular pacemaker compared with a dual-chamber pacemaker were more likely to require pacemaker reprogramming due to pacemaker syndrome (NNH = 4 at 18 months) .
  2. There was no clear effect on stroke, hospitalisation with heart failure or death.
  3. There was no clear difference in overall physical function.
Lamas et al: New England Journal of Medicine 1998; 338: 1097-1104
Expires August 2003

The study

Single-blinded ?concealed randomised trial with intention-to-treat
Setting: 29 centres, USA

407 patients (aged range 65 to 96 years; mean 76, 60% male) in sinus rhythm and requiring a pacemaker for the prevention or treatment of bradycardia (70% in NYHA class I or II)

Excluded if
  • could not participate in quality of life assessments
  • clinically overt congestive heart failure at the time of implantation
  • atrial fibrillation without any documented sinus mechanism for >6 months
  • serious noncardiac illness
  • inadequate atrial-capture or sensing thresholds


    • Control Group: (n = 203, 203 analysed): dual-chamber pacing (DDDR mode)
    Experimental Group: (n = 204, 204 analysed): single-chamber ventricular pacing (VVIR mode)
    A lower limit of at least 50 beats per minute was required in both groups, and an upper limit of <130 beats per minute was suggested. Programming of all other features was left to the discretion of the investigations.
    100% followed for 18 months
    Outcome notes:
    • pacemaker syndrome requiring reprogramming of pacemaker : fatigue, dyspnoea, exercise intolerance; orthopnoea, paroxysmal nocturnal dyspnoea or presyncope

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    death 18 months 32
    (15.8%)    		 34
    (16.7%)    		 -6.00%
    (-64.0% to 32.0%)    		 -0.90%
    (-8.06% to 6.26%)    		 -111
    (NNT = 12 to infinity;
    NNH = 16.0 to infinity)
    stroke, hospitalised with heart failure or death 18 months 44
    (21.7%)    		 56
    (27.5%)    		 -27%
    (-79% to 10%)    		 -5.78%
    (-14.1% to 2.57%)    		 -17
    (NNT = 7 to infinity;
    NNH = 39 to infinity)
    atrial fibrillation 18 months 35
    (17.2%)    		 38
    (18.6%)    		 -8%
    (-64% to 29%)    		 -1.39%
    (-8.84% to 6.07%)    		 -72
    (NNT = 11 to infinity;
    NNH = 16 to infinity)
    pacemaker syndrome requiring reprogramming of pacemaker 18 months 4
    (1.97%)    		 53
    (26.0%)    		 -1220%
    (-3480% to -390%)    		 -24.0%
    (-30.3% to -17.7%)    		 -4
    (-6 to -3)

    Outcome Control Group
    (SD)    		 Experimental Group
    (SD)    		 Mean Difference
    (95% CI)
    physical function 58.4
    ()     		58.4
    ()     		0.00
    (-2.09 to 2.09)

    Comments

    1. The study is too small to show any difference in mortality between the treatments.
    2. Physical function was assessed using the 36-item Medical Outcomes Study Short-Form General Health Survey (SF-36) which includes a multi-item scale measuring 8 health-related aspects (physical function, social function, physical role emotional role, energy, mental health, pain, general health perceptions) with scores ranging from 0 (worst) to 100 (best).

    Citation

    1. Lamas GA, Orav EJ, Stambler BS, et al: Quality of life and clinical outcomes in elderly patients treated with ventricular pacing as compared with dual-chamber pacing. New England Journal of Medicine 1998; 338: 1097-1104
    Search Terms: pace* in Cochrane or Best Evidence
    Contributor: Clare Wotton and Martin Dawes, August 1999
    Reviewer: Martin Dawes

    Clinical Question.
    Patient elderly with bradycardia
    Intervention or Exposure ventricular pacing
    Comparison dual-chamber pacing
    Outcome death