Myocardial infarction: thrombolysis: increased tachyarrhythmias in general, but decreased VF.

Clinical bottom line (level 1a)

  1. In patients with myocardial infarction treated with thrombolysis, there is no apparent excess in early ventricular fibrillation.
  2. In patients with myocardial infarction, thrombolysis decreases the risk of ventricular fibrillation during hospitalisation (NNT = 100 at unknown) .
  3. Ventricular tachyarrhythmias, in general, were increased with thrombolysis during hospitalisation (NNH = 43 at unknown) .
Solomon et al: Circulation 1993; 88 (6): 2575-2581
Expires March 2003

The study

Systematic review of all RCTs comparing thrombolysis to no therapy and reporting ventricular fibrillation (VF) as a discrete event of
  • Patients: acute myocardial infarction
  • Intervention: intravenous thrombolytic agents compared with placebo
  • Outcome: VT or VF



Articles found in not stated using Medline, 1980-1991 (search terms: (myocardial infarction, thrombolysis, fibrinolytic agents, tPA, streptokinase, anistreplase, anisoylated streptokinase) AND (randomized-controlled trials, clinical trials) ) and reference list searching

Selection criteria: as above
Appraisal criteria: not stated
Articles excluded if: trials of intracoronary thrombolysis

15 trials reporting on 39,613 patients
No significant heterogeneity was noted.

The evidence

Outcome Time to outcome CER OR
(95% CI)		 NNT
(95% CI)
VF in first 6 hours 6 hours 33/1024
(3.23%)		 0.98
(0.6 to 1.6) 		1600
(NNT = 54 to infinity;
NNH = 79 to infinity)
VF at any time during hospitalisation . unknown 1181/19657
(6.01%)		 0.83
(0.76 to 0.9) 		100
(73 to 180)
VT at any time during hospitalisation unknown /
(7.5%)		 1.34
(1.15 to 1.55) 		-43
(-97 to -27)

Comments

  1. Search strategy not maximally sensitive; may have missed poorly indexed trials.

Citation

  1. Solomon SD, Ridker PM, Antman EM: Ventricular arrhthymias in trials of thrombolytic therapy for acute myocardial infarction. A meta analysis. Circulation 1993; 88 (6): 2575-2581
Contributor: Bob Phillips and Clare Wotton, November 1999
Reviewer:

Clinical Question.
Patient acute myocardial infarction
Intervention or Exposure thrombolytic therapy
Outcome risk of ventricular fibrillation (VF) or ventricular tachycardia (VT)