An arrhythmia is when the heart rhythm is different from normal. They know how normal rhythms are supposed to be by looking at EKGs. An arrhythmia is just a different rhythm from normal. Some are harmless. Some are not. Some are treatable with medicines, pacemakers, defibrillators, or ablation procedures, and some are not. Arrhythmias result from conduction differences, too, but not necessarily from extra conduction pathways like you have. There are entire chapters in cardiology books about various arrhtymias. Many are common, and a lot of them happen to people after they've had heart disease and heart attacks and high blood pressure, none of which are probably a problem for you.

OK, gotta sign off now for a while and study some of my own homework. Nice talking cardiology with you!