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  1. Neda Parnianfard1,
  2. Ilghar Eskandariyan1,
  3. Reza Parvan1,
  4. Hanieh Azizi1
  1. Member of Iran evidence based medicine center, Students' research committee, Tabriz University of medical science, Tabriz, Iran.


Background and aims: An arrhythmia is an abnormality in the heart's rhythm, or heartbeat pattern. The heartbeat could be too slow, too fast, have extra beats, skipa beat, or otherwise beat irregularly. Meta-analysis of randomized controlled trials (RCTs) with low risk, considered the highest level of evidence available for evaluating an intervention. The aim of this study was to systematically review the quality of RCTs included in Cochrane reviews regarding arrhythmias.

Methods: We reviewed all RCTs from systematic reviews published between1999-2015 by the Cochrane databases of systematic reviews. The titles were screened and those related to arrhythmias were chosen. The risk of bias of randomized controlled trials included in each review was studied. Also, it was assessed whether or not the studies had come to a particular conclusion.

Results: We found 800 reviews in group of Heart and Circulation Cochrane, of the total 21 RCTs were included. There was a study that did not report any high risk of bias. The studies did not report high or unclear risk of reporting biases and any publication biases. The maximum number of biases reported for high risk of performance bias was 87, while the total maximum number of biases reported for detection bias was 109.

Conclusion: The risk of providing a treatment based on a biased effect estimate must be balanced against the difficulty of conducting trials with very low risk of bias. Bias in RCTs may overestimate or underestimate the true effectiveness of an intervention. Better understanding of the risk of bias may result in improved trials with a closer estimate of the true effectiveness of an intervention. Based on these results we recommend more high quality evidence based RCTs in the field of arrhythmias.

  • arrhythmias
  • risk of bias
  • systematic review
  • randomized controlled trials

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