CLINICAL AND ELECTROPHYSIOLOGICAL PREDICTORS OF RECURRENT POSTINFARCTION VENTRICULAR TACHICARDIAS AFTER CATHETER ABLATION

Aim. To find out the clinical and electrophysiological predictors of recurrent ventricular tachyarrhythmias (VTA) after catheter homogenization of post-infarction scar areas.

Material and methods. Patients included, with myocardial infarction (MI) in anamnesis and documented sustained VTA, regardless effective treatment by implantable cardioverter-defibrillator. Totally, 72 patients included (mean age 64±13 y.o.), of those 63 males with postinfarction VTA. In 12 cases there were“electrical storms” demanded urgent catheter management. In such patients, the extended catheter homogenization of the scar was performed, that is ablation of all conduction channels, anomalous potentials and surrounding ablation of infarction zone.

Patients were selected to 2 groups according to recurrent VT in post-surgery period. First group included 27 (37%) VTA recurrent patients, mean age 62±10 y.o. Second group included 45 patients (63%) with non tachyarrhythmias recurrence, mean age 63±12 y.o. The evaluation was done, of the selected parameters with the aim to define predictors of rhythm disorders recurrence.

Results. Main clinical predictors of VTA recurrence after catheter ablation were the duration of post MI period and its anterior localization. Full area of the scar surface (bipolar voltage lower 1,5 mV) was comparable in patients with recurrent VT and with none (66±51 cm² vs 82±49 cm²). However the area of the dense scar (bipolar amplitude ≤0,5 mV) and percent of the dense scar in relation to entire scar was significantly smaller in the recurrence group (group 1 — 23±22 cm² and 24±18%, in group 2 — 41±22 cm² and 45±21%; p<0,05). The differences were found in the cycle length of clinical VTA assessment in groups 1 and 2 (290±62 and 330±93 ms, respectively, p<0,05).

Conclusion. The analysis that was done, made it to define the following variables and VT predictors: localization of the MI (anterior vs inferior), duration of ischemic anamnesis, cycle of clinical VT, non-homogeneity of the scar, area of the fractionized potentials and delayed potentials of electrograms, area of the dense scar.

1. Tilz R, Makimoto H, Lin T, et al. Electrical isolation of a substrate after myocardial infarction: a novel ablation strategy for unmappable ventricular tachycardias-feasibility and clinical outcome. Europace 2014; 16: 1040-52. DOI: 10.1093/europace/eut419.

2. Carbucicchio C, Raja Ahmad N, Di Biase L, et al. High-density substrate-guided ventricular tachycardia ablation: role of activation mapping in an attempt to improve procedural effectiveness. Heart Rhythm 2013; 10: 1850-58. DOI: 10.1016/j.hrthm.2013.09.059.

3. Arenal A, Pérez-David E, Avila P, et al. Noninvasive identification of epicardial ventricular tachycardia substrate by magnetic resonance-based signal intensity mapping. Heart Rhythm 2014; 11: 1456-64. DOI: 10.1016/j.hrthm.2014.04.022.

4. Stevens S, Tung R, Rashid S, et al. Device artifact reduction for magnetic resonance imaging of patients with implantable cardioverter-defibrillators and ventricular tachycardia: late gadolinium enhancement correlation with electroanatomic mapping. Heart Rhythm 2014; 11: 289-98. DOI: 10.1016/j.hrthm.2013.10.032.

5. Codreanu A, Odille F, Aliot E, et al. Electroanatomic characterization of post-infarct scars comparison with 3-dimensional myocardial scar reconstruction based on magnetic resonance imaging. J Am Coll Cardiol. 2008; 52: 839-842. DOI: 10.1016/j.jacc.2008.05.038.

6. Tatarskiy RB, Lebedev DS, Lebedeva VK, et al. Urgent catheter ablation of electrical storm in patients with implantable cardioverter-defibrillators. Russ J Cardiol 2015; 11;57-62. (In Russ.) Татарский Р.Б., Лебедев Д.С., Лебедева В.К. и др. Экстренная катетерная аблация электрического шторма у больных с имплантированными кардиовертерами-дефибрилляторами. Российский кардиологический журнал 2015; 11: 57-62. DOI: 10.15829/1560-4071-2015-11-57-62.

7. Schmidt A, Azevedo C, Cheng A, et al. Infarct tissue heterogeneity by magnetic resonance imaging identifies enhanced cardiac arrhythmia susceptibility in patients with left ventricular dysfunction. Circulation 2007; 115: 2006-14. DOI: 10.1161/CIRCULATIONAHA.106.653568.

8. Perez-David E, Arenal A, Rubio-Guivernau J, et al. Noninvasive identification of ventricular tachycardia-related conducting channels using contrast-enhanced magnetic resonance imaging in patients with chronic myocardial infarction: comparison of signal intensity scar mapping and endocardial voltage mapping. J Am Coll Cardiol 2011; 57: 184-94. DOI: 10.1016/j.jacc.2010.07.043.