In a rat model of myocardial I/R injury, 28 days of rofecoxib pretreatment was found to increase the mortality and irreversible ventricular fibrillations during cardiac ischemia [3]; thus, it showed hidden cardiotoxic effects according to our definition, while we have found that the PPAR-γ agonist antidiabetic drug, rosiglitazone, does not show major hidden cardiotoxic effects, but it interferes with the antiarrhythmic effect of ischemic preconditioning [23]. The gene discussed is PPARG; the disease is ventricular fibrillation.