Ventricular Pre‐excitation

The term “ventricular pre-excitation” implies that the myocardium depolarizes earlier than expected if the stimulus follows the normal pathway through the specific conduction system. In fact, this is not really what happens before excitation (pre-excitation). Instead, it refers to ventricular excitation occurring earlier than expected. Three types of pre-excitation have been defined: Wolff–Parkinson–White pre-excitation (WPW), atypical pre-excitations, and short PR pre-excitation. Patients with WPW pre-excitation can present paroxysmal reentrant tachycardia using an AP (slow–fast type), accounting for 50% of all supraventricular paroxysmal tachycardias. The likelihood that reentrant paroxysmal arrhythmias are generated is lower than in WPW-type pre-excitation. In comparison with WPW-type pre-excitation, fewer cases of reentrant paroxysmal tachyarrhythmias are observed and the risk of sudden death is probably lower, although the occurrence of atrial fibrillation with rapid ventricular response is a potential risk.