Heart Disease

I looked up heart disease and this is what I found....

What is heart disease?

Heart disease is a number of abnormal conditions affecting the heart and the blood vessels in the heart. Types of heart disease include:
Coronary artery disease (CAD) is the most common type and is the leading cause of heart attacks. When you have CAD, your arteries become hard and narrow. Blood has a hard time getting to the heart, so the heart does not get all the blood it needs. CAD can lead to:
Angina. Angina is chest pain or discomfort that happens when the heart does not get enough blood. It may feel like a pressing or squeezing pain, often in the chest, but sometimes the pain is in the shoulders, arms, neck, jaw, or back. It can also feel like indigestion (upset stomach). Angina is not a heart attack, but having angina means you are more likely to have a heart attack.
Heart attack. A heart attack occurs when an artery is severely or completely blocked, and the heart does not get the blood it needs for more than 20 minutes.
Heart failure occurs when the heart is not able to pump blood through the body as well as it should. This means that other organs, which normally get blood from the heart, do not get enough blood. It does NOT mean that the heart stops. Signs of heart failure include:
Shortness of breath (feeling like you can't get enough air)
Swelling in feet, ankles, and legs
Extreme tiredness
Heart arrhythmias are changes in the beat of the heart. Most people have felt dizzy, faint, out of breath or had chest pains at one time. These changes in heartbeat are, for most people, harmless. As you get older, you are more likely to have arrhythmias. Don't panic if you have a few flutters or if your heart races once in a while. If you have flutters AND other symptoms such as dizziness or shortness of breath (feeling like you can't get enough air), call 911 right away.

I've had a heart murmur when I was younger, my grandfather had angina and died of a stroke and I have had dizzy spells. Should I be scared? Cause I am