Decoding the results of an electrocardiogram

Dear Dr. Roach: I had an EKG that showed first-degree heart block and “inferior infarct, age undetermined.” What does that mean? What should I do? I will see a cardiologist to get an exercise stress echo. What is that? — C.P.

Dear C.P.: The EKG uses the electrical activity in the heart to get information about the structure and function of the heart. It isn’t perfect.

“First-degree heart block” means the electrical impulse in the heart is a little slow. By itself, it is not concerning, but it does suggest that there is a risk of other heart problems. These sometimes need treatment (a pacemaker). It’s something to keep an eye on.

An “infarct” is a heart attack. The EKG has characteristic findings of heart attack. In your case, that is the bottom part of the heart, supplied by the right coronary artery. This type of heart attack is often complicated by first-degree heart block.

A stress test looks for damage to the heart, and to see if the heart is at risk for another heart attack. With a stress echocardiogram, the heart is “stressed” by exercise or by medication, and the movement is examined by sound waves. This test can help determine whether you did have a heart attack and whether you need treatment.

Many people who have had a heart attack never knew it. Either they had no symptoms or they thought it was something else.

But if you have had a heart attack, then certain medicines are helpful in preventing another. If the stress echo is worrisome, the cardiologist may recommend an angiogram, which is the best test we have to identify parts of the heart at risk for heart attack.