Case presentation: The 62-year-old man had a history of anterior myocardial infarction 30 years ago, severe left ventricle (LV) systolic dysfunction due to apical scar and aneurysmal apical anterior wall in LV, with cardiac resynchronisation therapy with defibrillator in 2013 for primary prevention, atrial fibrillation and transient ischemic attack. He presented with an episode of ventricular tachycardia (VT) besides multiple anti-tachycardia pacing despite being on 2 antiarrhythmic drugs (AADs) – amiodarone and bisoprolol. He was listed for an urgent procedure as he required lidocaine infusion, which was stopped 24 hours prior to the procedure, besides other AADs. His last international normalised ratio was 3 due to warfarin. Written informed consent was obtained. Right femoral vein and arterial access was obtained using ultrasound guidance. Two 8-French sheaths were placed into the vein and a 5-French sheath was placed into the artery. A quadripolar catheter was placed into the right ventricular (RV) apex. SL0 and BRK needles were used for a transseptal puncture using fluoroscopy guidance. The sheaths were then exchanged with a large curve Agilis. Heparin was given to keep the activated clotting time to >300 s throughout the procedure.
Mapping of VT: An HD Grid catheter was used for topographic, voltage and propagation mapping of the LV using EnSite X electro anatomical mapping system. The patient had a spontaneous induction of six different VT morphologies, four of them had a high bundle branch block configuration with superior and inferior axis, and most of them had lateral and anterior exit. Tachycardia cycle lengths varied from 380 ms to 320 ms and all of them had stable haemodynamics, with systolic blood pressure between 80–100. We used substrate mapping with RV pacing using omnipolar mapping technique as well, and we managed to complete activation mapping of two of the six different VT episodes. The map revealed large anterior and apical scar with areas of slow conduction and mid diastolic potentials across the region. An FJ TACTICATH irrigated tip catheter was used to target the critical isthmus of tachycardia along with the late potential signals. We used 40–45 watts, 10–20 g aiming at LSI of 6. We successfully ablated and eliminated all the late potentials and conducting channels within the scar. Further programmed ventricular stimulation revealed two different VT circuits with multiple apical exits. We had noted some apical late potential within the apical aneurysm; therefore, further radiofrequency ablation targeted all these signals. At the end of the procedure, aggressive VT stimulation did not lead to any sustained arrhythmia. This was accepted as an endpoint. Protamine was given, sheaths were removed, and Z suture was applied for haemostasis and Angioseal for the right femoral artery access.
Learning points: Mapping multiple morphologies of VT is a challenge, but it can be due to a single re-entry utilising a single isthmus. It is very critical to target the isthmus to achieve abolition of VT. Isolation of late potentials by ablation can improve the outcome.
Conclusion: This is an interesting case of VT with multiple morphologies but using two discreet isthmuses. Identifying the critical isthmus and ablation of late potentials demonstrated successful control of cardiac arrhythmias. ❑