Myocardial infarction: class of antiarrhythmic agent affects mortality.

Clinical bottom line (level 1a)

  1. Patients at risk from sudden cardiac death who are given class I antiarrhythmics, are more likely to die than those given a control (NNH = 163 at unknown) .
  2. Patients given class II antiarrhythmics (beta-blockers) are less likely to die than those given a control (NNT = 85 at unknown) .
  3. Class III antiarrhythmics (amiodarone) decrease death (NNT = 36 at unknown) .
  4. Class IV antiarrhythmics (calcium channel antagonists) have no clear effect.
McAlister and Teo: Drugs 1997; 54 (2): 235-252
Expires March 2003

The study

Systematic review of randomised trials of
  • Patients: high risk of cardiac sudden death
  • Intervention: antiarrhythmics compared with no antiarrhythmics
  • Outcome: mortality



Articles found in ? language using MEDLINE, ? dates (search terms: not given ) and hand-searching of references from all identified articles and some data from presentations at scientific meetings

Selection criteria: as above
Appraisal criteria: detailed in text
Articles excluded if: not truly randomised, crossover trials or trials without placebo controls

157 trials with 104, 364 patients

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
mortality with class I agents unknown 584/11651
(5.01%)		 1.13
(1.01 to 1.27) 		-163
(-2102 to -79)
mortality with class II agents unknown 1736/26418
(6.57%)		 0.81
(0.75 to 0.87) 		85
(64 to 124)
mortality with class III agents unknown 558/2853
(19.6%)		 0.83
(0.72 to 0.95) 		36
(21 to 126)
mortality with class IV agents unknown 992/10847
(9.14%)		 1.03
(0.94 to 1.13) 		-402
(NNT = 94 to infinity;
NNH = 200 to infinity)

Comments

  1. This is an update of the data in Teo 1993's analysis.
  2. The trials are too small to show any clear difference in mortality between the use of class IV drugs and placebo, but there is a strong suspicion of no effect.

Citation

  1. McAlister FA, and Teo KK: Antiarrhythmic therapies for the prevention of sudden cardiac death. Drugs 1997; 54 (2): 235-252
Contributor: Clare Wotton and Bob Phillips, October 1999
Reviewer:

Clinical Question.
Patient high risk for sudden death
Intervention or Exposure antiarrhythmics
Comparison no antiarrhythmics
Outcome mortality