Banca de QUALIFICAÇÃO: JOSE CARLOS GOMES JUNIOR

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : JOSE CARLOS GOMES JUNIOR
Data: 11/12/2025
HORA: 15:00
LOCAL: Sala 107 Bloco Zeta Campus São Bernardo do Campo
TÍTULO:

Electrophysiological characterization of the epicardium in the rabbit animal model through voltage mapping technique

PÁGINAS: 100
RESUMO:

Cardiovascular diseases remain the leading cause of death worldwide, with cardiac arrhythmias playing a central role in this scenario due to their high lethality and clinical impact, for certain cases. Electroanatomic voltage mapping is an essential tool for the characterization and identification of arrhythmogenic substrates. However, the voltage cut-off values employed in clinical practice remain largely empirical and vary according to the mapping system, electrode configuration, and related cardiac chamber tissue. In this study, electroanatomic voltage mapping was applied to a rabbit animal model in order to perform electrophysiological characterization in isolated hearts perfused using the Langendorff system. Epicardial unipolar and bipolar electrogram were acquired through multi-electrode arrays (MEAs) composed of electrodes made of different materials: silver (Ag), platinum/iridium (Pt/Ir), and platinum (Pt). Eletrograms were initially filtered by a band-passs filter to remove baseline wandering and high frequency noise, followed by calculating peak-to-peak and statistical analysis. Regarding electrophysiological characterization through voltage mapping, voltage cut-off values were determined for healthy epicardial tissue in atrial and ventricular chambers by applying the 95th percentile. Additionally, amplitude variability between different cardiac rhythms was analyzed, along with histological assessment of the hearts corresponding to each rhythm. Comparison among electrode materials demonstrated significant differences, with median amplitudes of 26.9 mV for Pt, 20.6 mV for Pt/Ir, and 9.09 mV for Ag (H = 38.98; P < 0.001[JS1] ), which reflected in the voltage cut-off values determined for healthy tissue: for Ag electrodes, unipolar and bipolar signals were 2.8 mV and 1.0 mV (atrium), and 9.2 mV and 4.9 mV (ventricle), respectively; for Pt/Ir electrodes, unipolar and bipolar signals were 2.4 mV and 2.5 mV in the atrial region; and for Pt electrodes, unipolar and bipolar signals reached 4.5 mV and 1.9 mV in the atrium, and 16.8 mV and 11.9 mV in the ventricle, respectively. Comparison between rhythms revealed significant amplitude reductions during arrhythmia: in atrial tachyarrhythmia (AT), amplitude in the left atrium decreased by approximately 80% (from 32.6 mV to 6.8 mV; p = 0.002), while in ventricular fibrillation (VF), reductions reached 60%. Histological analysis of the hearts corresponding to the cardiac rhythms studied confirmed the correlation between reduced electrical amplitude and structural tissue remodeling. The voltage thresholds obtained for healthy tissue are consistent with reference values reported in the literature for larger animal models (swine and ovine) and human clinical studies (≥1.5 mV for bipolar mapping and >8.3 mV for unipolar), demonstrating the translational applicability of the model. In the rhythm comparison analysis, the correspondence between low-amplitude arrhythmic signals and higher structural disorganization scores of the corresponding epicardial tissue validates the causal relationship between the anatomical substrate and electrophysiological behavior. This analysis is also translational, as it was performed using signals collected through Pt-based MEAs, the same electrode material employed in commercial catheters for clinical analyses. Thus, the present study establishes epicardial reference values for unipolar and bipolar signals in isolated rabbit hearts, contributing to the standardization of future experimental investigations and to the refinement of electroanatomic mapping methodologies used in translational studies of cardiac arrhythmias in animal models.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1188948 - JOAO LAMEU DA SILVA JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - OMER BERENFELD
Membro Titular - Examinador(a) Externo à Instituição - ROSANA ALMADA BASSANI - UNICAMP
Membro Suplente - Examinador(a) Interno ao Programa - 2123676 - OLAVO LUPPI SILVA
Membro Suplente - Examinador(a) Externo à Instituição - RODRIGO WEBER DOS SANTOS - UFJF
Membro Suplente - Examinador(a) Externo à Instituição - MATHEUS CARDOSO MORAES - UNIFESP