A narrow QRS complex requires highly synchronous electrical activation of the ventricular myocardium through the rapidly<unk> g His-Purkinje system (HPS). and<unk><unk><unk> s (IVCDs) affects the morphology or duration, or both, of the QRS complex.  These changes can be fixed and present at all heart rates, or they can be transient aberration either tachycardia or bradycardia dependent.
Intraventricular conduction delay EKG examples
Premature ventricular contraction EKG examples
Paroxysmal AV Block EKG examples
Atrial fibrillation EKG examples
Junctional bradycardia EKG examples
Arrhythmogenic right ventricular dysplasia ECG
Long QT Syndrome other diagnostic studies
Cardiomyopathy other diagnostic studies