3.6 Publication bias
To investigate potential publication bias of the association of a spontaneous Type-1 Brugada pattern and increased risk of MAE, we examined the funnel plot of the included studies in assessing change in log OR of MAE (Figure 6). The vertical axis represents study size (standard error) while the horizontal axis represents effect size (log OR). From this plot, no bias was observed because distribution of studies was symmetrical on both sides of the mean. Egger’s test showed no small study bias (p = 0.688).
Only four studies included in this meta-analysis could be used to assess the association between ventricular tachyarrhythmia during drug challenge testing and increased risk of MAE. Thus, we did not perform a funnel plot or Egger’s test (12).