Sleep Apnea (cont.)

Obstructive sleep apnea (OSA) may be a risk factor for the development of other medical conditions. High blood pressure (hypertension), heart failure, heart rhythm disturbances, atherosclerotic heart disease, pulmonary hypertension, insulin resistance, and even death are some of the known complications of untreated obstructive sleep apnea. Cognitive impairment (memory problems), depression, anxiety, and gastroesophageal reflux disease (GERD) are also among possible complications of untreated sleep apnea.

High blood pressure

Sleep apnea can cause or worsen high blood pressure and heart problems. Cessation of breathing frequently during the night (every 1 to 4 minutes) can cause increased stress on the heart. As the oxygen saturation in the blood decreases and the apnea continues, the sympathetic nervous system (responsible for the "fight or flight" response of the body) is activated. This fight or flight response sends nerve signals to the blood vessels to constrict (tighten up) and to the heart to work harder. When the vessels constrict, more blood is sent to the brain and muscles. However, as a result this increases the blood pressure, which requires the heart to work harder to pump blood through the smaller caliber vessels. That, combined with the signal for the heart to work harder and the lower available oxygen in the blood from apnea, causes increased stress on the heart throughout the night. Sleep is normally the time when the heart has less work to do and can "rest."

Among patients with obstructive sleep apnea that do not have high blood pressure, 45% will develop high blood pressure within 4 years. If one examines patients who have hard-to-control blood pressure, that is, taking more than one medicine for control, up to 80% can potentially have obstructive sleep apnea. When the obstructive sleep apnea is treated, blood pressure decreases.

Heart complications

The risk for congestive heart failure increases by 2.3 times and the risk of stroke by 1.5 times with obstructive sleep apnea.

Obstructive sleep apnea can complicate the treatment of atrial fibrillation. Atrial fibrillation is an abnormal heart rhythm in which the upper part of the heart (atrium) is beating out of coordination with the lower part (ventricle). The treatment is to cardiovert the heart (resetting the atrium and allowing it to synchronize with the ventricle). After cardioversion, 50% of patients have a recurrence of atrial fibrillation, but patients with obstructive sleep apnea have an 80% recurrence.

Finally, obstructive sleep apnea can increase the risk of sudden death. Sudden death can kill not only the patient but also their loved ones, for example, if they are driving a car when the death occurs.

Source: MedicineNet.com
http://www.medicinenet.com/sleep_apnea/article.htm