Eliminating the Trigger for Polymorphic Ventricular Tachycardia

A 60-year-old female patient was referred to our hospital because of recurrent syncope. The resting 12-lead ECG showed sinus rhythm with left bundle branch block and a high burden of monomorphic single premature ventricular beats (PVCs). Imaging studies confirmed a structurally normal heart and ischaemic heart disease was ruled out by coronary angiography. Telemetry revealed repeated episodes of polymorphic ventricular tachycardia (VT) triggered by monomorphic PVCs causing syncope. Therefore, an ICD was implanted and the patient was discharged on bisoprolol 10 mg/day. A few weeks later, she was referred to our hospital owing to repeated ICD shocks triggered by monomorphic PVCs with long-short sequences. Radiofrequency catheter ablation targeting the monomorphic PVC causing polymorphic VT was performed. With an almost perfect pace map within the distal coronary sinus, ablation in this region did not abolish the PVC. Therefore, we antegradely mapped the LV via transseptal access. Endocardial mapping at the anterior mitral anulus using the reverse S-curve technique revealed the earliest bipolar activation in close proximity to the ablated region within the coronary sinus. Ablation at this site abolished the clinical PVC. ECG monitoring at 3, 6 and 12 months did not reveal any PVC, and no ICD discharges have occurred since ablation.