The hazards of heart failure include decreased blood circulation function and arrhythmia, as follows: 1. Decreased blood circulation function: The hazards of heart failure are mainly a decrease in blood circulation function, because the heart’s ability to eject blood decreases and cannot drive the body’s blood circulation, which is prone to insufficient perfusion of tissues and organs, insufficient blood supply and oxygen supply in organs, and finally patients may experience pump failure. 2. Arrhythmia: Heart failure may also trigger serious arrhythmia. When serious arrhythmia occurs, the heartbeat is irregular and the pumping is uneven, which may cause a drop in cardiac blood displacement and make it easier to form blood clots and trigger the appearance of stroke. If the arrhythmia deteriorates further, ventricular tachycardia and ventricular fibrillation may occur, and in severe cases, cardiac arrest may occur, leading to sudden death. Therefore, once a patient develops heart failure, he or she should be treated immediately and the triggering factors for heart failure should be reduced.