Accumulating scientific evidence in cardiology with special reference to the Japanese contribution.

Clinical practice guidelines have been released as a current summary of the most recent scientific evidence in various areas. The paradigm by which evidence is regarded important is called evidence-based medicine (EBM). Sources of EBM are valid randomized controlled trials (RCT) and meta-analyses (MA). Only well-qualified studies should be used for the EBM. The characteristics for both RCTs and MAs are considered. controversial issues are also discussed, such as the safety of calcium channel blockers and the efficacy of magnesium for acute myocardial infarction. Finally, Japanese RCTs, either finished or ongoing, are summarized. International collaboration will become more important for registering and evaluating evidence followed by summarizing and updating the evidence.