Furthermore, recent studies demonstrated that riociguat ameliorated PAH due to left heart disease and prevented RV hypertrophy in experimental models of PAH.4,13 In addition, riociguat improved systolic function and reduced fibrotic tissue remodeling and degeneration.13 We found that even under the same PASP, RV strain was improved after riociguat administration compared to that measured before treatment, suggesting that riociguat may have an additional effect on RV contraction other than PASP reduction. The gene discussed is CPB1; the disease is heart disorder.