OK first degree heart block is when the PR interval is greater than .20 sec. This means the electric is moving slower than it should be from the top of the heart through the middle to the bottom. No big deal there, but it is an abnormality. There is no need for any treatment. QRS prolongation means that the electric is passing through the heart tissue slower as well and creating a slower beat from the ventricles. The chambers that force blood from the heart out to the body This may be due to an incomplete block or just slower conduction, your Doctor will figure that out. The QTC is a corrected QT interval made by the diagnosing physician. This is the measurement in time from the Q wave to the T wave Your whole complex will be in the following letters P atria or top part of the heart Q if you had a heart attack some time ago you will have a Q wave R The upward line of the complex S The downward line of the complex T The large hump after the complex (repolarization) re charge U May or may not be present depends on the electrolytes. Jerry Hello Bradycardia, is a slow heart rate that is less than 60 beats per minute. The heart works off of an electrolye / electrical / mechanical system. At the top is the (Sino atrial node) this is the rate maker for the heart. It sends electric to the middle of the heart where the (Atrio ventricular node) is. This second node creates a 1/10 second delay which it is supposed to do. That lets the blood fill into the bottom half before it is pumped. The electrial charge then goes down through the bottom of the heart and causes the bottom to beat, pumping the blood out to the body. This is the electrical / mechanical part. The electrolyte part is where the sodium and potassium create the charge to begin with, and when it is released it disturbes this balance. the balance wants to maintain itself so every time it makes an electrical pulse it has to reset itself, which again creates another charge. This cycle goes on till the day you die. Now in the case that you are talking about everything is slowed down in the electrical system. ( It s like a really rough road and traffic has to go much slower.) So hopefully this gives you a better idea of what is going on inside the heart. Jerry NavyHM1983@Yahoo.com