Successful catheter ablation of intraseptal ventricular tachycardia from the entrance side of the slow conduction zone

Key Teaching Points•Macroreentrant ventricular tachycardia (VT) with an intraseptal substrate exhibits a centrifugal spread, making it challenging to complete the delineation of circuit.•The localization slow conduction zone (SCZ) in intraseptum would be more convincingly elucidated when “entrance” and “exit” can identified on septum.•Manifest entrainment orthodromic capture earliest activation site indicate that pacing is proximal SCZ. When from limited area those findings, located entrance side SCZ.•Catheter ablation strategy targeting SCZ alternative method VT ablation, especially cases exit failure. •Macroreentrant Catheter established treatment for (VT). However, remains challenge mapping delivery radiofrequency energy.1Haqqani H.M. Tschabrunn C.M. Tzou W.S. et al.Isolated septal nonischemic dilated cardiomyopathy: incidence, characterization, implications.Heart Rhythm. 2011; 8: 1169-1176Abstract Full Text PDF PubMed Scopus (140) Google Scholar, 2Liang J.J. D’Souza B.A. Betensky B.P. al.Importance interventricular septum as part cardiomyopathy.JACC Clin Electrophysiol. 2018; 4: 1155-1162Crossref (18) 3Yoshida K. Yokokawa M. Desjardins B. al.Septal involvement patients post-infarction tachycardia: implications ablation.J Am Coll Cardiol. 58: 2491-2500Crossref (31) Scholar Recent advances high-resolution electroanatomic systems help us identify reentrant circuit. endocardial often spread during VT, Additionally, identification local electrograms critical difficult unless electrode catheters are inserted into perforators. Moreover, isolated substrates require emergent technologies experimental approaches such bipolar needle chemical ablation.4Berte Derval N. Sacher F. Yamashita S. Haïssaguerre Jaïs P. A case incessant intramural focus: ethanol or ablation?.HeartRhythm Case Rep. 2015; 1: 89-94Abstract These anatomical technical difficulties limit overall success catheter VTs, exploring techniques demanding. Here we present macroreentrant was successfully ablated by maneuvers. 69-year-old man cardiac sarcoidosis referred our hospital electrical storm repetitive appropriate implantable cardioverter defibrillator therapies. Hemodynamically stable monomorphic wide QRS 12-lead electrocardiography incessantly observed emergency room. The rate 108 beats per minute (tachycardia cycle length [TCL] = 560 ms), morphology right bundle branch block configuration left axis deviation (Figure 1B), suggesting inferior ventricle. Physical examination, laboratory data, echocardiographic data revealed no evidence acute coronary syndrome myocarditis. Hypokinetic motion thinning (4 mm) (LV) basal remained unchanged, LV ejection fraction 42%. Treatment using medications (i.e., amiodarone 200 mg, carvedilol 20 sacubitril/valsartan prednisone 5mg) could not completely prevent occurrence VT. After obtaining informed consent, performed multipolar (EP star Fix AIV; Japan Lifeline, Tokyo, Japan) placed distal great vein. Another multielectrode (PentaRay; Biosense Webster, Diamond Bar, CA) ventricle via transseptal approach. Subsequently, heparin administered achieve activated clotting time 250–300 seconds. Electroanatomic CARTO3 system (Biosense CA). First, voltage (RV) PentaRay catheter. Low-voltage areas, defined electrogram amplitude <0.5 mV, were found septum, coinciding areas at 1C). Programmed stimulation lengths 600 400 ms repeatedly induced clinical Constant fusion progressive overdrive supported mechanism. Activation demonstrated (EAS) septum. total within endocardium 322 ms, which much shorter than TCL ms. Ventricular LV-EAS exhibited near-concealed fusion, postpacing interval (PPI) equal stimulus 28 2A). findings suggested Radiofrequency energy range 35–40 W initially delivered irrigated tip (ThermoCool ST SF; did modify placing LV-EAS, checked contralateral RV Low-amplitude fragmented site; however, precede onset. manifest QRS, PPI–TCL 102 indicated location outside recorded orthodromically captured 2B), indicating approximately 2 cm2 3A). Pacing ≥100 antidromic LV-EAS. Although itself circuit, estimated between We applied 40 SCZ, terminated 7.6 still inducible until index reached 500. procedure completed without any complications after confirmation noninducibility patient discharged 3 days continuation (100 mg/day). During 10 months post occurred this report written. Successful scar-related relies controlled modification arrhythmogenic where commonly distributed but access 3D system. “entrance side" concealed entrainment, respectively. applications probably owing modifications deep inside 3B). Entrainment important increasing awareness nature circuits. Concealed PPI strongly suggests circuit.5Stevenson W.G. Friedman P.L. Sager P.T. al.Exploring postinfarction mapping.J 1997; 29: 1180-1189Crossref (316) Manifest EAS demonstrate SCZ.6Okumura Olshansky Henthorn R.W. Epstein A.E. Plumb V.J. Waldo A.L. Demonstration presence sustained man: use transient tachycardia.Circulation. 1987; 75: 369-378Crossref Scholar,7Yamabe H. Okumura Morihisa al.Demonstration circuit verapamil-sensitive atrial originating vicinity atrioventricular node.Heart 2012; 9: 1475-1483Abstract (32) Certainly, theoretically occur fixed rate, stimuli continuously reset tachycardia. wavefront tachycardia, whereas (N) collides preceding (N-1). Antidromic occurs impulse arrives before directly activates EAS. Conversely, if reaches impulse, passing through relative significantly impacts whether antidromically rate. Orthodromic close (Supplemental Figure 1). If EAS, believed closer adjacent sites. In case, only (2 cm2) proven, provide supportive information sites Several limitations should acknowledged. modifier influence result pacing. might have expanded penetration, been antidromically, even same observed. Second, necessary measure accurate determination entrance. time, aimed ablate intraventricular allow approach Third, detailed risk dislodging cardioverter-defibrillator lead. absence diastolic potentials prolonged minimal contribution Finally, useful VTs. procedures available hospitals. correct may minimize tissue destruction created energy. This highlights usefulness detection exact boundaries reentry defined, Ablation they refractory ablation.