A Case of Sustained Ventricular Tachycardia Originated from Left Ventricular Posterior Papillary Muscle, Which Was Misinterpreted as Posterior Fascicular Ventricular Tachycardia in ECG Morphology

A case was 18 years old male who complained of severe palpitation.12lead ECG showed sustained ventricular tachycardia (VT) rate 180 beat per minute with left axis deviation and right bundle branch block. Verapamil was effective to terminate the arrhythmia. As suntained VT was not induced in Catheter laboratory, we misdiagnosed as posterior fascicular VT from etiological prevalence and pharmacological behavior at first. With CARTO system we found Purkinje potential with location information, and then RF energy applied at the distal site with Purkinje potential. After several RF delivered, we thought the ablation as unsuccessful from reasons of imperfect pacemap and inducibility of non-sustained VT. By re-mapping in left ventricule and observating CARTO image, we had good pace mapping at posterior papillary muscle near the former ablation site. As Successful ablation with heating effect, we conclude that VT arose from posterior papillary muscle. In this case, 12lead ECG characteristics were not enough to differentiate these arrhythmias which had other origins. So we had to rule out these arrhythmias to correct diagnosis and therapy.