Pulmonary hypertension (PH) due to left heart failure (HF) accounts for approximately half of PH cases worldwide. It has been demonstrated that PH is a frequent complication of HF but is difficult to recognize in its early stage because it is characterized by nonspecific symptoms including shortness of breath and decreased tolerance of activity. Moreover, nearly all multicentric clinical trials targeting pulmonary circulation in PH-HF have reported negative results.1 Thus, there are no effective methods for diagnosing early PH, and the current treatment of PH-HF is insufficient.