Comparision of the QRS complex morphology of PVCs/IVTs originating from the endocardial and epicardial mitral annulus.

EP MA: epicardial mitral annulus; EN-MA: endocardia mitral annulus; AL: anterolateral portion; PL: posterolateral portion; MS: midseptal portion; PS: posteroseptal portion; Early “Notching” indicates a Notching in the upstroke of the R wave in the inferior leads; Late “Notching” indicates a Notching in the downstroke of the R wave in the inferior leads.