Valvular heart diseases (VHD) impose two types of loads on hearts: pressure and volume. The types of cardiac loads likely to occur and the hemodynamic effects on the left and right cardiac systems differ depending on the type of VHD. In addition, VHD often has a chronic course, and many patients acquire compensatory mechanisms. However, the compensatory mechanisms eventually fail, leading to bilateral heart failure. Therefore, it is essential to understand the characteristics of each VHD and to evaluate which stage of heart failure it has reached in the treatment of VHD. To date, no study has adequately evaluated the impact of oxygenation or positive pressure ventilation on the disease state in chronic VHD. Therefore, we need to consider the effects of oxygen supply and positive pressure ventilation for patients with VHD based on theories and the results of similar studies. We should administer oxygen to patients with chronic VHD when hypoxemia is present. In the cases of non-hypoxia patients, no studies have explicitly shown the effects of oxygen administration for these VHD patients. However, according to recent studies in the field of oxygen, hyperoxemia leads to tissue damage from reactive oxygen species, increased coronary resistance, and increased vascular resistance. Therefore, we would refrain from providing excessive oxygen to non-hypoxia patients with VHD. In addition, positive pressure ventilation can either reduce or exacerbate hemodynamics in patients with VHD, depending on the type of VHD, because the effects of positive pressure ventilation on the left and right cardiac systems are different. Therefore, we should perform positive pressure ventilation for VHD patients with constant monitoring of their respiration and circulation and an understanding of the hemodynamics of VHD and the effects of positive pressure ventilation on the left and right cardiac systems.