Bradycardia: theophylline may decrease heart failure.

Clinical bottom line (level 1b-)

  1. Patients with sick-sinus rhythm who are given theophylline, may be less likely to suffer overt heart failure than those given no treatment (NNT = 7 at 48 months)
Alboni et al: Circulation 1997; 96: 260-266
Expires August 2003

The study

Unblinded ?concealed randomised trial with intention-to-treat
Setting: 3 hospitals, Italy

71 patients (aged mean 72 years, 56% male) symptomatic sick-sinus syndrome

Excluded if
  • patient refusal
  • follow-up not possible
  • <45 years old
  • mean resting sinus rate >50 beats per minute
  • very severe sick sinus syndrome-symptomatic resting sinus rate <30 beats per minute or sinus pauses >3 seconds in standard ECGs recorded during diurnal hours or heart failure refractory to treatment with ACE inhibitors and diuretics
  • recent (within last 3 months) myocardial infarction or stroke or other acute diseases
  • very severe general diseases likely to be fatal in <2 years
  • significant renal or hepatic disease (serum creatinine >2 times upper limit of normal; serum glutamic oxaloacetic acid transferase and/or total bilirubin >2 times upper limit of normal)
  • history of documented sustained ventricular tachyarrhythmias
  • bradycardia secondary to transient causes (effects of drugs etc)
  • prior use of theophylline
  • a need for beta-blockers or calcium antagonists (verapamil or diltiazem)
  • other definite or potential causes of syncope in patients complaining of syncopal attacks, as previously reported


    • Note:
  • Three-arm study, with third arm being pacemaker insertion


    • Control Group: (n = 35, 35 analysed): no treatment
    Experimental Group: (n = 36, 36 analysed): theophylline 550 mg/d in two doses with a slow-release tablet. Serum theophylline was determined after 5 days of treatment, and the initial dosage was appropriately decreased in case of serum theophylline level >15 ng/mL
    Patients were allowed to receive nitrates, diuretics, ACE inhibitors and other antihypertensive medications, aspirin and anticoagulants.
    100% followed for 48 months
    Outcome notes:
    • syncope : transient loss of consciousness with inability to maintain postural tone
    • overt heart failure : appearance of worsening dyspnea or peripheral oedema requiring hospitalisation during which the signs of pump failure were present
    • permanent atrial fibrillation and paroxysmal tachyarrhythmias : atrial fibrillation considered permanent if it was recorded at 2 consecutive follow-up visits
    • thromboembolism : stroke defined as neurological symptoms of presumably cerebral ischaemic origin persisted for >24 hours; peripheral embolus diagnosed if typical from the clinical point of view or if verified during angiographic investigation or at embolectomy>24 hours

    The evidence

    Outcome Time to outcome CEREERRRR
    (95% CI)    		ARR
    (95% CI)    		NNT
    (95% CI)
    syncope 48 months 8
    (22.9%)    		 6
    (16.7%)    		 27.0%
    (-89.0% to 72.0%)    		 6.19%
    (-12.3% to 24.7%)    		 16
    (NNT = 4 to infinity;
    NNH = 8 to infinity)
    overt heart failure 48 months 6
    (17.1%)    		 1
    (2.78%)    		 84.0%
    (-28.0% to 98.0%)    		 14.4%
    (0.77% to 28.0%)    		 7
    (4 to 129)
    permanent atrial fibrillation and paroxysmal tachyarrhythmias 48 months 9
    (25.7%)    		 10
    (27.8%)    		 -8.00%
    (-134% to 50.0%)    		 -2.06%
    (-22.7% to 18.5%)    		 -48
    (NNT = 5 to infinity;
    NNH = 4 to infinity)
    thromboembolism 48 months 1
    (2.86%)    		 3
    (8.33%)    		 -192%
    (-2572% to 68.0%)    		 -5.48%
    (-16.1% to 5.11%)    		 -18
    (NNT = 20 to infinity;
    NNH = 6 to infinity)

  • There were no significant differences between the pacemaker and theophyline groups.

    • Comments

    1. The study is too small to show any clear difference in syncope, permanent atrial fibrillation and thromboembolism between the two groups.

    Citation

    1. Alboni P, Menozzi C, Brignole M, et al: Effects of permanent pacemaker and oral theophylline in sick sinus syndrome. The THEOPACE study: a randomized controlled trial. Circulation 1997; 96: 260-266
    Contributor: Clare Wotton and Bob Phillips, August 1999
    Reviewer:

    Clinical Question.
    Patient symptomatic sick-sinus syndrome
    Intervention or Exposure theophylline
    Comparison no treatment
    Outcome syncope, heart failure, thromboembolic events and permanent atrial fibrillation