Research Information System
35th Turkish Cardiology Congress with International Participation, Antalya, Turkey, 3 - 06 October 2019, vol.22, pp.43, (Full Text)
Background and Aim: There is limited data in the literature regarding the effect of scar tissue on left ventricular (LV) repolarization process in patients with cardiomyopathy. The aim of present study is to evaluate the
acute effect of ventricular tachycardia (VT) ablation on dispersion of LV repolarization which is suggested to
play a role in initiating and sustaining arrhythmia.
Methods: A total of 27 consecutive patients with ischemic cardiomyopathy who had undergone VT ablation
constituted our study population. Endocardial mapping was perfomed to all patients and epicardial mapping
was performed when endocardial mapping failed to identify desired ablation sites. Substrate mapping was
performed using Ensite Precision 3D mapping system (St Jude Medical, Inc., Minnesota, USA). Normal tissue was defined as tissue with bipolar voltage >1.5 mV, dense scar was defined as bipolar voltage <0.5 mV
and scar borderzone was defined as a bipolar voltage 0.5-1.5 mV on voltage mapping. Late systolic potentials
and local abnormal ventricular activities (LAVA) during sinus rhythm and mid diastolic potentials during VT
were tagged as the potential ablation sites (Figure-1). Entrainment maneuvers were performed to identify
isthmus if VT was hemodynamically tolerated. Irrigated tip catheters were used during ablation.Electrocardiographic recordings obtained at the time of hospitalization and after the procedure were retrospectively
evaluated for the QTc dispersion, Tp-Te interval and Tp-Te/QT ratio which are suggested to be noninvasive
markers of dispersion of ventricular repolarization. Significance of difference between electrocardiographic
parameters obtained before and after VT ablation was evaluated.
Results: There was 23 males (82.1%) in the study population and mean age of the patients was 35.0±12.7
years. Mean ejection fraction was 34.2±9.9. 19 patients (67.9%) were hypertensive and 12 patients (42.9%)
were diabetic. There was no significant difference between pre- and post ablation state regarding QTc
dispersion Tp-Te interval and Tp-Te/QT ratio (Table-1)).
Conclusions: VT ablation did not alter electrocardiographic parameters that are assumed to represent heterogeneity and transmural dispersion of repolarization in the immediate post procedure state. Results of
prospective studies are needed to evaluate the chronic effect of VT ablation on myocardial repolarization
abnormalities that has the potential to increase tendency for VT initiation.