Friday, January 20, 2006

Understanding coronary artery disease: Conclusion

This is part four in our series entitled the Heart of the Matter. Part three can be found here. Please read our disclaimer.

Cholesterol accumulation in heart artery, causing obstruction to heart arteries is called coronary artery disease or CAD for short. Other synonyms include coronary heart disease, atherosclerotic heart disease and ischemic heart disease.

What is most frightening about CAD is that it can occur and progress insidiously in a very silent manner by which we mean without the person knowing that it is there. In fact it is the minority, about 30%, of patients with CAD who have symptoms and even less present themselves to the doctors. For the "lucky" minority, the earliest symptom is usually chest discomfort ( or pain ) on effort, relieved by rest (angina pectoris). The chest discomfort is sometimes described as "heaviness", "band-like", "suffocating", "crushing", or just "numbness".

It may begin over the chest, and spread to the throat, the back, the left shoulder or left forearm. Site and spread is important, but it is more important to note that it comes with effort and is relieved by rest. Angina pectoris is usually stable and sometimes, the chest pain episodes are predictable. If I do this, I’ll get it, if I rest, it will go away.

Sometimes this pattern changes and the chest discomfort occurs at rest, with minimal effort, and last longer and does not go away with rest. They have become “unstable”. This often mean that the CAD has progressed and this instability may be the forerunner of a heart attack. The instability is often the result of a crack in the plaque, with resulting blood clots in the heart artery lumen.

It is important to note that with angina pectoris, there is obstruction to cardiac blood flow, and chest pains, but no death of heart muscle cells, as the lumen is still patent (not blocked). With unstable angina, the blood flow may be so compromised, that it may be insufficient for the heart muscle cells to function, and may result in some heart muscle cell death. Should the blood flow cease completely, and suddenly, as in a complete blockage of the artery by a blood clot, significant amounts of muscle may be lost, resulting in a heart attack.

We can therefore understand that coronary artery disease may present in one of four ways.

1. Silent CAD
2. Stable angina pectoris
3. Unstable angina
4. Acute myocardial infarction (Heart attack).

These will be covered in future installments of the series.

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