sinusbradykardia

Sinus bradycardia is a heart rhythm where the heart beats at a slower than normal rate. Specifically, it is characterized by a heart rate of less than 60 beats per minute in adults. This rhythm originates in the sinoatrial (SA) node, which is the heart's natural pacemaker. Despite the slow rate, the electrical impulses are generated and conducted in a normal pattern through the atria and ventricles, meaning the rhythm is regular.

Sinus bradycardia can be a normal physiological finding in some individuals. For example, it is common in well-conditioned athletes during rest, sleep, and even during wakefulness, as their hearts are more efficient and require fewer beats to circulate blood. It can also occur in response to certain medications, such as beta-blockers and calcium channel blockers, which are used to treat conditions like high blood pressure and arrhythmias. Other contributing factors can include hypothyroidism, hypothermia, and increased intracranial pressure.

In some cases, sinus bradycardia can be a sign of an underlying medical problem. Symptoms associated with symptomatic bradycardia can include dizziness, lightheadedness, fatigue, fainting (syncope), and shortness of breath. If the heart rate is too slow to adequately supply the body with oxygenated blood, it can lead to more serious complications. Diagnosis typically involves an electrocardiogram (ECG) which shows a regular rhythm with a heart rate below 60 bpm, with normal P waves, QRS complexes, and PR intervals. Treatment depends on the underlying cause and whether the bradycardia is causing symptoms. If it is asymptomatic and not causing problems, no treatment may be necessary. If symptoms are present, treatment may involve addressing the underlying condition or, in severe cases, the use of medications to increase heart rate or implantation of a pacemaker.