There were no significant associations between ID and METs (p = 0.364), 6MWT distance (p = 0.352), NYHA class (p = 0.544), NT-proBNP (p = 0.859), EF (p = 0.383), or clinical symptoms including angina (p = 0.762), dyspnea (p = 0.447), dizziness (p = 0.948), or fatigue (p = 0.697). The gene discussed is NPPB; the disease is angina pectoris.