It is worth noting that current clinical trials assessing PDE5-Is in CVS diseases are mainly focused on right ventricular dysfunction, congenital heart disease, or cystic fibrosis, so further trials are yet needed to explore the efficacy of PDE5-Is on cardiac outcomes in myocardial infarction, coronary artery disease, heart failure, and ventricular arrhythmia. This evidence concerns the gene PDE5A and cystic fibrosis.