What are the causes of myocardial ischemia and myocardial infarction in obstructive sleep apnea? These are the presence of persistent hypertension, increased adrenergic activity, hypoxemia and oxidative stress, endothelial dysfunction, increased lipid levels, and various cardiac arrhythmias.

The stressful effect of frequent and regular sleep apnea leads to the release of catecholamines and an increase in sympathetic tone, not only at night, but also during the daytime. The release of catecholamines also supports hypoxemia. Impaired respiratory function during sleep adversely affects myocardial blood perfusion, which creates conditions for the development of chronic myocardial ischemia and myocardial infarction. It is the constant increase in nocturnal blood pressure and a sharp hypoxemia due to severe blood desaturation that contributes to the development of myocardial infarction, hemorrhagic or ischemic stroke, and aortic dissection.

Endothelial dysfunction has been proven to be a risk factor for the development of cardiovascular diseases. An apnea episode causes the release of vasoactive substances (vasoconstrictors, an example of endothelin-1). After several hours of erratic bouts of sleep apnea, endothelin-1 levels rise and blood pressure rises in response.

Hypoxemia during sleep apnea provokes coronary blood flow disorders in patients with coronary artery disease. Patients had typical angina attacks and ECG changes characteristic of ischemia. Most episodes of myocardial ischemia are observed in the phase of rapid movements of the eyeballs – this is the time of the maximum number of apnea attacks and severe hypoxemia. In patients with severe sleep apnea during this period, a high level of adenosine in the blood plasma (a marker of myocardial ischemia) is determined. Nocturnal episodes of angina and silent myocardial ischemia may not be prevented even by nitrates. At the same time, the development of myocardial infarction is noted.

Obstructive sleep apnea syndrome, of course, should not be considered as the only causative factor in the development of myocardial infarction. In this case, it is necessary to take into account the age of patients, the presence of coronary heart disease and atherosclerotic lesions of the coronary vessels. Obstructive sleep apnea syndrome is an additional factor contributing to acute myocardial ischemia and sudden death during sleep. However, there is a description of the development of myocardial infarction at night in an obese patient who suffered from moderate sleep apnea in the absence of coronary artery lesions. Therefore, we can conclude that nocturnal hypoxemia played an independent role, which caused the development of myocardial infarction.

In any case, about a third of patients with coronary artery disease have obstructive sleep apnea and are at risk of developing myocardial infarction. Correction of obstructive sleep apnea in this case can be considered the only treatment that will effectively eliminate myocardial ischemia during sleep. Treatment of obstructive sleep apnea slows the progression of coronary artery disease and reduces the risk of myocardial infarction and death. Modern effective method of treatment CPAP-therapy allows to eliminate breathing disorders during sleep and accompanying hypoxia. The development of therapeutic devices with the Auto-CPAP function made it possible to automatically select the required pressure value depending on the severity of respiratory disorders. As an option, we can recommend the Prisma 20A device from Weinmann – Loewenstein (Germany).

The use of the best advanced CPAP devices Prisma Line from the new line of Weinmann – Loewenstein (Germany) allows the most efficient and comfortable treatment of the entire spectrum of respiratory disorders in patients suffering from obstructive sleep apnea and coronary heart disease.

Video review of a patient of the Center for Sleep Medicine, who was initiated CPAP therapy. Prior to the diagnosis of obstructive sleep apnea syndrome, the patient had suffered several myocardial infarctions.