Broad QRS Complexes?
Normally it takes less than 0.12 seconds for ventricular depolarisation to happen and so the QRS complex should be narrow (smaller than 3 small squares).
If the QRS is broader than this, that suggests there is something causing a slowing of conduction through the ventricles e.g. a bundle branch block or ventricular tachycardia.
Normal QRS Complex
