Rapid heart rate in the second trimester is a common phenomenon and needs to be addressed after identifying physiologic or pathologic causes. It is necessary to exclude pathological factors and clarify whether there is a history of primary heart disease, such as the presence of cardiac disease, such as severe valvular disease, dilated cardiomyopathy, arrhythmias. In late pregnancy, as the volume of body fluids increases, symptoms of heart failure, such as panic, shortness of breath, and arrhythmic manifestations appear. If combined with cardiac insufficiency, active improvement of cardiac function is required. Some patients with gestational hypertension, gestational diabetes mellitus, and thyroid function abnormalities need to be analyzed according to specific causes. In patients with gestational hypertension, of course, blood pressure should be actively controlled to prevent complications. In the case of diabetes, blood glucose should be actively controlled, including diet and medication, to avoid hypoglycemic symptoms. Patients with hyperthyroidism need to control thyroid hormones in the appropriate range. In patients with anemia, nutrition is enhanced and hematocrit is supplemented. After ruling out the possibility of pathology, the patient is considered to have a physiological increased heart rate. The patient is advised to rest more, to rest in the lateral position, to maintain a good state of mind and to reduce activities appropriately.