People who have a very slow heartbeat may find that they actually have the condition known as sinus bradycardia. Patients with this condition may still have normal, regular heartbeats. However, they are much slower than average heartbeats, at only 60 beats per minute or less while at rest.

Having sinus bradycardia can actually be a positive symptom, indicative of good health. Many athletes have the condition as a result of a healthy heart. A slow heartbeat can result from rigorous conditioning through physical exercise, causing the heart to pump at a steady speed.

Other, less healthy causes of sinus bradycardia can include irregular sleep patterns, sleep apnea, hypothyroidism, inferior wall myocardial infarction, hypothermia, hypoglycemia, increased intracranial pressure, seizures, and electrolyte disorders. Exposure to certain toxins can also be a cause of the condition. The use of some medications has also been known to create a slow heartbeat.

Common drugs that can cause the condition are normally heart medications, such as beta-blockers, calcium channel-blocking medicines, and digitalis glycosides. These are prescribed to treat high blood pressure and other heart-related conditions. Some other drugs known to cause the condition include toluene, fentanyl, clonidine, lithium, topical ophthalmic acetylcholine, sufentanil, paclitaxel, alfentanil, dimethyl sulfoxide, and reserpine.

Cases of severe sinus bradycardia may present more of a concern. These can be caused by a disease of the sinoatrial node, such as sick sinus syndrome, which usually occurs in the elderly, and has a poor prognosis. In rare cases, the condition may also be a symptom of another infection, such as viral myocarditis, Diphtheria and rheumatic fever.

Sinus bradycardia symptoms can vary. Aside from a slow heart rate, patients may encounter dizziness, vertigo, lightheadedness, hypertension, and syncope. Chest pain, shortness of breath, and an inability to exercise may be experienced. Irregular heat beats can also occur, including junctional, atrial, or ventricular ectopic rhythms.

Fainting may also result should the heart delay to a very slow beat. It can be caused by choking as well, which is known as the vasovagal reflex. Since sinus bradycardia patients already have a slow heartbeat, when the heart slows even further during choking, fainting can result.

As with most conditions with multiple causes, treatment varies with each case. Some patients need no treatment. A patient may be prescribed medication to rectify an abnormal heartbeat. A pacemaker may also be needed, particularly in the case of a disease of the sinoatrial node.

The condition is named after the sinus node within the heart. This node is responsible for maintaining heartbeat. Bradycardia translates to a slower-than-normal beat.