If you have a strong family history of coronary artery disease (and you do) -- those "clogged artery" problems -- then please have your cholesterol and triglycerides monitored regularly, eat a heart-healthy diet, and get some regular exercise. Walking is great. You can't fix heredity, but you can control some of the other risk factors.

Like Scubatooth, I can't give you percentages without cracking some books, but I can tell you this much:

The majority of heart problems start with coronary artery disease. As the arteries that supply your heart muscle with oxygen clog up, a part of your heart muscle (your "myocardium") begins to starve for oxygen and, ultimately to die from lack of oxygen and scar. That tissue death is an "infarction". So, a myocardial infarction is the death of tissue in your heart muscle.

Most times, the glitches that happen (like V-tach and V-fib and and other sorts of changes in your heart's normal rhythm) are the result of the infarction, which came from the clogged arteries.

Your heart is a remarkably durable organ that will put up with a lot of abuse. But if you do enough damage, eventually either the muscle itself will fail (a whole different animal with its own set of problems), or -- more commonly -- the heart's electrical system will be disturbed or interrupted by the damage and more-or-less begin to short out. Depending on how much damage is done and where, exactly, the damage is located, we start seeing V-tach and runs of V-tach and V-fib and other onery critters that are dangerous to your continued existence. Mostly, all of these problems stem from some kind of interference in the smooth conduction of electrical signals through the heart muscle.

This is a decidedly simplified explanation of a much more complex answer, but I hope it helps clarify things for you.

~~ Irish