CS angiography is suggested prior to catheter ablation of left posteroseptal APs to facilitate the ablation procedure.

Various types of venous branches and anomalies are associated with the majority of patients with left posteroseptal APs.

Some posteroseptal APs may be located epicardially, or may be associated with venous anomalies or related to the middle cardiac vein.

The aim of this study was to identify ECG features of manifest posteroseptal APs requiring ablation in the CS or the middle cardiac veins (MCVs).