Hot weather has a significant effect on the heart in two ways. Firstly, in hot weather, the blood vessels of the body are dilated, and in this case, blood accumulates in the peripheral blood vessels, resulting in a relative decrease in circulating blood volume. If the patient is suffering from a combination of myocardial blood supply deficiency, the symptoms of angina pectoris, such as chest pain and tightness, will be acutely aggravated by this trigger. Secondly, the weather can have an emotional and neurological impact on the person, in which case irritability and sympathetic excitement can easily occur. The patient’s heart rate may increase compensatorily, and if the patient has a combination of arrhythmia, he or she may have an acute attack due to this trigger. Patients with a history of heart disease are advised to stay hydrated and avoid thermal stimulation and to maintain emotional stability during the summer months.