It's been well known to cardiologists that silent myocardial infarction and silent myocardial ischemia

are a lot more common than what physicians figure, not to mention what the lay people think.

For example, when a cardiologist reads 24 hr Holter monitor recording of a patient with CAD,

he often sees multiple episodes of ischemic ST depression, but the patient reports no episode of chest pain.

Another common example would be positive stress tests where cardiologists see clear evidence of ischemia 

on ECG and on imaging scans, yet most of the time the patients report no chest pains.

In other words, silent ischemia, not accompanied by cardiac symptoms, is a lot more common than symptomatic 

ischemia.

Then cardiologists often see new patients who present with ECG evidence of MIs but with negative history.

In addition, from the autopsy studies done on American soldiers, average age around 21,

killed during Korean War and Vietnamese War showed clear evidence of CAD in over 60% of them,

with some having a total occlusion of coronary arteries. Incidentally none of the matched native soldiers showed evidence of CAD.

The point is that what this study showed is not surprising, and

once again demonstrates the importance of preventive cardiology.

The other point I want to make is that when a patient complains of chest pain or first onset of angina,

his or her doctor must pay attention and carry out the necessary diagnostic test asap because he may not get 

the second chance. In other words, by the time the patient presents with the first episode of chest pain, chances are

the patient may already have had many episodes of silent ischemic attacks, one of which can lead to

AMI in the middle of the night.

I might add that it appears diabetic patients experience silent ischemia and silent myocardial infarction

more commonly. I had observed, for example, that a number of type 1 diabetic patients,

who lived to be middle ages and were diagnosed to have severe CAD by stress tests and cardiac cath,

never experienced angina although they all underwent CABG.

It is my medical opinion that symptomatic CAD patients, in a way, are lucky because chest pains

are protecting them.