I think you are describing a heart attack in the distribution of the right coronary artery--- these tend to be less severe than the other coronary arteries, unless they are very proximal (high up, where the artery begins). The right coronary artery supplies blood to the inferior wall of the heart so it sounds like you sustained significant damage to that wall; often you can still have a normal ejection fraction (or % of blood pumped out) because the other arteries tend to supply larger territories of muscle with blood flow. The best long-term predictor for how you will do is your ejection fraction.