Rest Angina Causes
The main cause of Rest Angina is Coronary Atherosclerosis, which affects coronary arteries. Rest Angina joins Angina of Effort with the progression of the coronary luminal narrowing and worsening the course of the latter.
Besides Atherosclerosis, some other diseases accompanied with the increased cardiac muscle oxygen demand may contribute to the development of Myocardial Ischemia:
- Arterial Hypertension – promotes left ventricle hypertrophy and also may provoke spasm of coronary arteries resulting in insufficient oxygen supply to the heart;
- Hypertrophic Cardiomyopathy – characterized by the hypertrophy of the left ventricle walls causing insufficiency of the blood flow;
- Aortic Valve Stenosis (narrowing) – due to the narrowing of the aortic valve opening there is a decrease in the volume of blood which gets to the heart, reducing the amount of oxygen supplied to the heart;
- Coronaritis – inflammation of the coronary arteries walls, which causes narrowing of the arterial lumen;
- Partial Coronary Artery Occlusion – reduces arterial patency; therefore, the heart does not receive sufficient quantities of oxygen;
As in most of the cases, Unstable Angina attacks occur during sleep. It is believed that the peculiarity of the development of the condition is from increased impulses from the vagus nerve that inhibits the heartbeat (Vagal Tone).
The development of Rest Angina is often provoked by the conditions that worsen myocardial ischemia:
- Hypoxia – when the body does not get adequate oxygen supply and; therefore, the heart also suffers from oxygen deficiency;
- Anemias – that prevent blood from carrying enough oxygen required for the heart;
- Tachyarrhythmia – increased heart rate causes increased myocardial oxygen demand;
- Fever, infections;
- Diabetes – Angina may first reveal itself during a hypoglycemic state (when the level of glucose in blood is too low.) The risk of ischemic heart disease and Angina progression increases two fold if a patient suffers from diabetes.
- Thyrotoxicosis – a condition caused by the increase in the thyroid hormone level which speeds up metabolism. This condition causes coronary circulation deficiency associated with the increased workload on the heart.
There are also factors that increase the risk and aggravate Rest Angina:
- Obesity – promotes Atherosclerosis development;
- Smoking – may cause oxygen starvation of the cardiac muscle, as a great number of blood cells that transport oxygen (red blood cells) are “occupied” by carbon monoxide. In addition, it promotes the formation of the atherosclerotic plaques. Also, smoking makes Angina attacks more frequent and severe, and significantly in increases the risk of myocardial infarction;
- Sedentary lifestyle – causes a decrease in the heart muscle contractility, and reduces the size of the heart, leading to the disturbance of the processes taking place in the heart;
- Metabolic syndrome – promotes early progression of the Cardiac Ischemia and Coronary Atherosclerosis;
- Increased blood viscosity – leads to the poor blood passing through the vessels and capillaries, blood congestion, varicosities and thrombosis.
Next chapter: Symptoms of rest angina