<unk> s are typically diagnosed with an electrocardiogram, Holter monitor, or cardiac event monitor. Electrocardiogram On an electrocardiogram (ECG),<unk> s are characterized by an abnormally shaped P wave. Since the<unk>  beat initiates outside the sinoatrial node, the associated P wave appears different from those seen in normal sinus rhythm. Typically, the atrial impulse propagates normally through the atrioventricular node and into the cardiac ventricles, resulting in a normal, narrow QRS complex. However, if the atrial beat is<unk>  enough, it may reach the atrioventricular node during its refractory period, in which case it will not be conducted to the ventricle and there will be no QRS complex following the P wave.
Premature atrial contraction
Premature ventricular contraction
Benign early repolarization
Wandering atrial pacemaker
Premature junctional contraction
AV nodal reentrant tachycardia
Ventricular escape beat
Ectopic pacemaker