Left sinus of Valsalva-Electroanatomic basis and outcomes with ablation for outflow tract arrhythmias.

The cases presented emphasize the importance of a region centered below the left sinus of Valsalva, where multivariable morphology QRS may be successfully ablated. Consideration of mapping and ablation even when signals are late in this region may be warranted in previously failed ablation attempts or first-line evaluation.