Animal fats do not thicken the blood. Only someone ignorant of blood chemistry would make a claim. Dehydration will cause blood to thicken.

True or false – Animal fat contains primarily saturated fat?
Beef fat is approximately 44% saturated and 44% monounsaturated.
Pork fat is primarily monounsaturated.

Clogged arteries are caused by inflammatory processes. Small, dense LDL particles enter the walls of arteries and cause inflammation. Small, dense LDL particles are increased on a high carbohydrate diet. Eating saturated fat drastically reduces the number small, dense LDL particles.

You are more likely to have another heart attack if your coronary arteries are badly affected with atheroma (plaque build up) or further build up of atheroma continues- if there is a high risk of this a bypass may be considered.

To reduce your chances of further atheroma, try and eat a healthy diet, take regular exercise and stay as close to your ideal weight as possible. Only drink alcohol in moderation. That is all you can do, atheroma is also to a certain extent part of the ageing process.

Generally you would have been put on the cardiac rehabilitation programme which includes a graded exercise component- this is suitable for most patients with stable left ventricular dysfunction.
References :
Cardiac Nurse

also, is it brought on by negative emotions as well as a poor diet?
Emotional stress is a big factor. This is reduced by cognitive therapy, meditation, and prayer. The Western diet is too rich in fats and calories.

is their any cure?
According to Dr. Dean Ornish, heart disease can be at least partially reversed through lifestyle changes. This includes no smoking, no drinking, and eating a low-fat vegetarian diet. Love and stress reduction does help reverse damage.

and describe what is happening?

A primary source of cholesterol is fatty foods like meat, fast foods, and even vegetable sources of oils. If you eat a low-fat vegetarian diet, most people will see better cardio vascular performance. Of course, you should also get good aerobic exercise.

how does it contribute to actual "heart attack" and what is this?

Sometimes there is so much fatty tissue in the heart itself, that the performance of heart valves is compromised. There comes a point where an artery becomes blocked, which blocks blood flow and oxygen to the heart muscle. This kills muscle tissue.
References :

The effects stress has on the body are well documented but CHD is to a certain extent part of the ageing process anyway and is generally seen in older people, but a poor diet and lack of exercise will accelerate this.

Heart attacks occur when there is a prolonged reduction in oxygen supply to a region of myocardium (heart muscle). Tissue death then follows as a result of this and the area is said to be infarcted. As I explained above, MIs generally occur in people with coronary artery disease where there is significant narrowing of one of more of the three major coronary arteries.

As a result of turbulent blood flow at the site of the atheroma, platelets aggregate to form thrombi and blockage of the artery can then occur.

There is no cure as such, just management and adopting a healthy lifestyle will prevent further problems or reduce the risk of having cardiovascular events. One should make sure that they stop smoking, lose weight if overweight, reduce alcohol consumption, eat healthily (reduce salt and saturated fats) and exercise.
References :
Cardiac Nurse