If the patient’s resting heart rate is below 60 beats/min, the first step is to determine what causes it, for example, whether it is because the patient is an athlete or may have been engaged in heavy physical labor for a long time and has a relatively slower heart rate than most people, and often there is no discomfort, just simple sinus bradycardia, which does not require intervention in clinical practice. In addition, the resting heart rate below 60 beats/min depends on whether the patient is in deep sleep, and the heart rate itself is lower during sleep, especially during deep sleep, than when the patient is awake. In addition, some patients may have hypothyroidism or hyperkalemia. Some patients with acute inferior wall myocardial infarction may also have a resting heart rate below 60 beats/min.