A bi-AT can develop when an AnL is created for PMF termination. Biatrial entrainment mapping facilitates diagnosis. Termination of the bi-AT is feasible when ablated from either RA or LA.
Introduction. Radiofrequency ablation (RFA) is an established treatment of post-myocardial infarction ventricular tachycardia (VT). Endocardial VT ablation can be insufficient for VT termination when the scar is intramural/epicardial.Purpose: to assess the extent of epicardial electrophysiological VT substrate in patients with remote myocardial infarction.Materials and methods. Thirteen patients with sustained postinfarction VT, who signed an informed consent, were included into the study. All patients underwent full clinical evaluation. Electroanatomical voltage bi- and unipolar mapping of endocardial and epicardial surfaces was performed. Maps were evaluated for the presence of low-voltage areas and local abnormal ventricular activity (LAVA). RFA was performed at LAVA sites. The end-point of the procedure was scar LAVA abolition and VT noninducibility (procedure success). VT recurrence was detected using an implantable cardioverter-defibrillator and/or ECG monitoring.Results. Epicardial access was successful in 12 patients. Epicardial access was performed at a first procedure in 7 patients, 4 patients had a history of previous endocardial ablation. Epicardial LAVA sites were detected in 9 patients. Endocardial and epicardial arrhythmogenic substrate localization coincided in 8 patients. One patient had only epicardial scar, 1 patient had only septal endocardial scar. In one patient LAVA sites had different localizations on epicardial and endocardial maps. Acute ablation success was noted in 12 patients.Conclusion. In our patient group transmural scar and epicardial electrophysiological arrhythmogenic substrate was detected in 82% of cases. Isolated endocardial ablation may be unsuccessful, in such cases epicardial mapping and ablation might be useful.
Background The majority of patients have a sub-epicardial scar as a substrate for VT episodes. Purpose We sought to compare the efficacy of endocardial (ENDO) and epicardial (EPI) substrate modification in patients with ARVC. Methods 20 consecutive ARVC patients (mean age 41,4±13,8, 70% males; ICD previously implanted in 10 patients) with indications to ventricular arrhythmia ablation (RFA) were included into a prospective observational study. The EPI group consisted of 10 patients with sustained ventricular tachycardia (VT) (definite diagnosis ARVC – 8 patients; borderline – 1, possible – 1) who signed an informed consent to epicardial access. The ENDO group included 10 patients (definite diagnosis ARVC – 9 patients), five of them demonstrated sustained VT and 5 patients had frequent symptomatic premature ventricular contractions (PVC). Epicardial access in the EPI group was obtained through subxyphoid puncture. Bi- and unipolar voltage mapping of endocardial and epicardial surfaces was performed. Maps were evaluated for the presence of local abnormal ventricular electrical activity (LAVA, low-voltage areas and sites with highly fractionated or late activity). Ablation was performed at sites of LAVA on either side of the ventricular wall. In the ENDO group endocardial only ablation at LAVA sites was performed. RF energy ablation was 40W at the epicardial surface and 40–50W at the endocardial surface. Results In the EPI group endocardially mapped area of unipolar endocardial low voltage zone (LVZ) significantly prevailed over bipolar endocardial area of LVZ: 75.4 cm2 [IQR: 23.2; 211.9] vs 6.7 cm2 [IQR: 4.4; 35.5](P=0.009). Epicardial bipolar LVZ area prevailed over unipolar epicardial LVZ area: 65.3 cm2 [IQR: 55.6; 91.3] vs 6.7 cm2 [IQR: 4.4; 35.3] (P=0.005). Endocardial unipolar LVZ area in the EPI group was larger than in the ENDO group (P>0,05). After ablation non-inducibility of any ventricular arrhythmia was achieved in 90% of patients in the EPI group and in 80% of cases in the ENDO group. During a mean follow-up period of 22.3±10.5 months freedom of ventricular arrhythmia recurrence was 70% in the EPI group and 100% in the control group. Conclusions Although epicardial area of abnormal potentials significantly prevails over endocardial area, endocardial unipolar mapping and higher RF ablation power allow performing successful ventricular arrhythmia treatment in the majority of ARVC patients. Funding Acknowledgement Type of funding source: None
Background and purpose The aim of this pilot study was to investigate the association between an extent of the atrial and ventricular electroanatomical substrate, serum fibrotic biomarkers and histological and immune-histochemical myocardial characteristics in ipatients with atrial fibrillation and heart failure. Methods We prospectively analyzed electroanatomical ultra-high density bipolar maps (HDBM) in 72 patients with AF and CHF, who underwent circular pulmonary veins (PVs) isolation. LA areas outside PVs ostia with bipolar signals ≤0.75mV, associated with local conduction velocity delay were considered as EAS and measured. Relative area of low voltage zones in right (RV) and left ventricles (RV) with bipolar signals in range of 0,5–1,5 mV were also consistently measured. Endomyocardial biopsy samples were taken from low, mediate and high septal areas of RV; histological and immune-histochemical staining was performed and an extent of myocardial interstitial fibrosis (MIF) was calculated. Before the operation we measured plasma MMP2, MMP9, TIMP, MMPs/TIMPs, galectin 3 (Gal3), TGF, soluble ST2 and the cross-linked collagen I/III synthesis and degradation product levels. The patients were divided into groups according to their ejection fraction Simpson (EF) (groups 1: EF≥50%, groups 2: EF 40–49%, and groups 3: EF<40%). Results The data of electroanatomical mapping, serum biomarkers and myocardial expression are presented in the table. According to results of correlation analysis, an extent of LA EAS were correlated with Gal3 and PIIICP plasma level and Gal3 myocardial expression and MIF extent (Rs=0,40, 0,45 and 0,42 respectively). The relative extent of LV EAS was correlated with MMP9 serum level (Rs=0,38); LV volume (LVV) was correlated with sST2 serum level and RVV was correlated with CD 133 myocardial expression (Rs=0,42) (picture 1). The patients with lower EF had larger extent of the LA EAS, (group 3: 28±12.4% vs. 1: 17.7±11.6%, p=0.03), an extent of LV EAS and LVV (group 3: 8,4±4,5% vs. 1: 5,1±3,8% p=0.02; group 3 vs group 1 p=0,05 relatively),higher Gal3 plasma level (group 1: 7,1±2 vs. group 2: 8,9±1,5, p=0.05) and higher MIF extent (group 2: 134±56 vs. 3: 151±30 p=0.04) (picture 2). Conclusion Our data suggest that relative extent of LA EAS in patients with atrial fibrillation is associated with Gal3 plasma level and Gal3 myocardial expression; severity of myocardial remodeling is connected to CD 3/133 myocardial expression and myocardial interstitial fibrosis extent, especially in patients with HF with restricted LV ejection fraction. Funding Acknowledgement Type of funding source: None
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