Myocardial infarction: mortality differs between class of antiarrhythmic.

Clinical bottom line (level 1a)

  1. Patients who have had a myocardial infarction and are given a class I antiarrhythmic drug, are more likely to die than those given placebo (NNT = -151 at unknown) .
  2. Patients who have had a myocardial infarction and are given a beta-blocker (class II antiarrhythmic), are less likely to die (NNT = 84 at unknown) .
  3. Patients given amiodarone (class III antiarrhythmics) are less likely to die (NNT = 29 at unknown) .
  4. Patients given calcium channel blockers (class IV antiarrhythmics) have no clear benefit or harm.
Teo et al: Journal of the American Medical Association 1993; 270 (13): 1589-1595
Expires March 2003

The study

Systematic review of randomised controlled trials of
  • Patients: acute myocardial infarction
  • Intervention: prophylactic antiarrhythmics compared with placebo
  • Outcome: mortality


Articles found in ? language using MEDLINE, ? dates (search terms: not given ) and informal searches of references of all previously identified articles and correspondence with other investigators and pharmaceutical industry scientists about other published and unpublished trials

Selection criteria: as above
Appraisal criteria: not given
Articles excluded if: treatment allocation determined before deciding whether or not to include patient, crossover trials that did not allow clear attribution of mortality to active treatment or control, and trials with 'head-to-head' comparison of two or more antiarrhythmic agents without a placebo control group.

138 trials with more than 98 000 patients

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
mortality risk with class I antiarrhythmics unknown 571/11517
(5.00%)		 1.14
(1.01 to 1.28) 		-151
(-2106 to -76)
mortality risk with class II antiarrhythmics (beta-blockers) unknown 1727/26295
(6.60%)		 0.81
(0.75 to 0.87) 		84
(64 to 124)
mortality risk with class III antiarrhythmics (amiodarone) unknown 101/779
(13.0%)		 0.71
(0.51 to 0.97) 		29
(17 to 294)
mortality risk with class IV antiarrhythmics (calcium channel blockers) unknown 949/10188
(9.30%)		 1.04
(0.95 to 1.14) 		-297
(NNT = 236 to infinity;
NNH = 86 to infinity)

Citation

  1. Teo KK, Yusuf S, Furberg CD: Effects of prophylactic antiarrhythmic drug therapy in acute myocardial infarction. Journal of the American Medical Association 1993; 270 (13): 1589-1595
Contributor: Clare Wotton and Bob Phillips, October 1999
Reviewer:

Clinical Question.
Patient acute myocardial infarction
Intervention or Exposure prophylactic antiarrhythmics
Comparison control
Outcome mortality