An occasional heart rate of about 37 beats per minute in the second half of the night is dangerous; a heart rate of 37 beats per minute may be the result of a bradyarrhythmia such as third-degree atrioventricular block or sinus bradycardia. A complete conduction block between the atria and the ventricles is called third-degree atrioventricular block, and its symptoms depend on the speed of the ventricular rate and the accompanying lesions. Symptoms include fatigue, malaise, dizziness, fainting, angina pectoris, and heart failure; sinus bradycardia can also be present at a heart rate of 37 beats per minute. In sinus bradycardia, the heart rate can also be 37 beats per minute. The slow heart rate leads to cerebral ischemia, and the patient may experience temporary loss of consciousness or even convulsions, which can lead to sudden death in severe cases. In the case of third-degree AV block or sinus bradycardia with a significant slowing of the heart rate, prompt cardiac pacing therapy is required when combined with significant symptoms or hemodynamic disturbances. Therefore, when the heart rate is 37 beats per minute/minute, it is necessary to seek medical attention in order to avoid delays.