Sudden cardiac death, not to be confused with cardiac arrest, is described as an acute loss of consciousness within one hour of the onset of symptoms. There are several other forms of sudden death that are noncardiac in nature, including respiratory arrest, toxicity or poisoning, anaphylactic shock, or trauma.
The most probable cause of sudden cardiac death is coronary artery atheroma, normally presenting in adults over the age of 30. This is generally caused by coronary artery stenosis of at least one of the major coronary arteries of the heart which limits the heart muscle blood suppl. Additionally, significant numbers of postmortem examinations identify a thrombus or a clot in a major coronary artery which causes an occlusion of the vessel.
Left ventricular hypertrophy (LVH) is the second leading cause of sudden cardiac death in adults, with causation being long-term hypertension, which causes secondary damage to the left ventricle. Hypertrophy Cardiomyopathy is a thickening of the septal wall of the heart, to the point of blockage of the aortic valve, in the sinuses of Valsalva region of the left ventricle.
Unlike myocardial infarction, sudden cardiac arrest does not present with chest pain or angina or even shortness of breath. Generally there is a period of prolonged ischemia in the myocardium which produces an arrhythmia, usually a ventricular arrhythmia which then progresses on to ventricular fibrillation.
The most frequent cause of sudden cardiac death is coronary artery disease, (CAD) and the top three risk factors for coronary artery disease in order are Hypercholesterolemia, or high serum LDL cholesterol levels, smoking, and hypertension, more commonly referred to as high blood pressure.
Smoking causes the heart rate to rise and can increase by as much as 30% during the first 10 minutes of smoking. Carbon monoxide in the cigarette smoke reduces the blood’s ability to carry oxygen and also increases the chances of heart disease. Smoking leads to narrowing of the blood vessels which increases the likelihood of blockage in the smaller vessels and thus sudden cardiac death.
Smoking increases serum blood cholesterol levels, and the ratio of high density lipoprotein, or good cholesterol, too low-density lipoprotein, or bad cholesterol is lower in smokers compared to non-smokers. Smoking also increases fibrinogen and platelet creation which makes the blood more vicious.
These are just a few of the factors that make smokers more at risk of developing arteriolosclerosis, and as the arteriolosclerosis progresses bloodflow is decreased through the narrowed blood vessels making the blood more likely to clot, and an occlusion of the blood vessel may lead to myocardial infarction and heart muscle necrosis.
Cessation of smoking has been shown to significantly reduce the instance of sudden cardiac death, and eventually eliminate the sudden cardiac death risk all together.
Smoking may cause infertility problems in women as well, as nicotine and other harmful chemicals in cigarettes interfere with the body’s ability to create estrogen, the hormone that regulates ovulation. Women who smoke are 60% more likely to be infertile than non-smokers, and smoking reduces the chances of in-vitro fertilization producing a live birth by 34% and increases the risk of miscarriage by 30%.
Stopping smoking now will decrease your chances with respect to risk factors for sudden cardiac death, and overall heart disease in general.
Article by Jim Donahue