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People who have a very slow heartbeat may find that they actually have a 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. Some common causes of sinus bradycardia include rigorous physical exercise, irregular sleep patterns, hypothermia, and the use of some medications. Aside from a rather slow heartbeat, some patients also experience additional symptoms such as lightheadedness, chest pain, and shortness of breath. Treatments vary depending on the severity of the case; some patients do not require treatment, others need medication, and still others require a pacemaker.
Named after the sinus node in the heart that is responsible for maintaining a heartbeat, sinus bradycardia can actually be a positive health condition, indicative of good health. Many athletes develop the condition as a result rigorous conditioning through physical exercise, causing the heart to pump at a steady speed. Oftentimes, a healthy person whom does not exercise regularly can still have the condition with or without additional symptoms.
Other, less healthy causes of sinus bradycardia can include conditions related to sleep such as irregular sleep patterns and sleep apnea. Hypothyroidism, hypothermia, hypoglycemia, seizures, and electrolyte disorders are some well-known conditions that may lead to sinus bradycardia. Exposure to certain toxins, such as atenolol, diltiazem, and organophosphate, 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 often 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.
Symptoms and Diagnosis
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 also 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.
Health professionals may be able to diagnose this condition after doing a physical exam, questioning the patient regarding symptoms, and completing an electrocardiogram (EKG). It should be noted that an EKG will only show signs of the condition the heart rate is slowed during the actual test; this can be a problem for some patients as the condition seems to come and go. One possible solution is for patients to use a portable electrocardiogram device, also known as a Holter moniter, to record the heart's rhythm.
As with most conditions with multiple causes, treatment varies with each case, and some patients do not need any treatment. A patient may be prescribed medication to rectify an abnormal heartbeat. For some patients, a pacemaker may also be needed, particularly in the case of a disease of the sinoatrial node. Some steps may be taken at home to help avoid and treat the condition such as controlling cholesterol and blood pressure, eating a diet low in sodium and fat, avoiding tobacco, and exercising regularly.