Ventricular arrhythmias represent one of the leading causes of cardiovascular mortality and constitute an area of intense clinical and research interest. To develop safer and more effective therapeutic strategies for managing these cardiac rhythm disorders, research is increasingly focusing on innovative approaches to modulate myocardial electrical activity. In this context, Pulsed Field Ablation (PFA) emerges as a promising non-thermal ablative technique based on the application of high-voltage, short-duration electrical pulses, with the potential to treat cardiac arrhythmias. Applying PFA to ventricular tissue, the site of potentially lethal arrhythmias, presents an intriguing challenge and remains an active field of study in preclinical animal research. To gain deeper insight into PFA's effects on ventricular electrical activity, this thesis focused on analyzing the Spatial Ventricular Gradient (SVG), a three-dimensional vector that reflects global myocardial electrical heterogeneity by combining the vectorial contributions of ventricular depolarization (QRS complex) and repolarization (T wave). The main objective of this thesis was to evaluate changes in the SVG vector following PFA application in an animal model. The study utilized electrocardiographic (ECG) signals previously acquired from five experimental animals included in a preclinical study of PFA. In a preliminary phase, custom codes were developed and implemented to identify QRS complex peaks and determine the integration boundaries necessary for calculating areas under individual heartbeats. However, due to limitations in reproducibility, accuracy, and computational efficiency, the research opted to use software specifically developed for SVG analysis in human electrocardiographic data from standard 12-lead ECGs. Using this software, was analyzed the magnitude, azimuthal angle, and elevation angle of the SVG at different timepoints: before the procedure, immediately after, and at the end of the electrocardiographic recording. The results of this SVG analysis suggest that PFA induces transient changes in ventricular electrical activity. Specifically, was observed a notable decrease in SVG vector intensity immediately following PFA application (p = 0.01 with repeated measures ANOVA), an effect that appears to resolve spontaneously over time, with a return to pre-procedure values by the end of the recording. A more in-depth analysis, focused on PFA dosage intensity, revealed that specific treatment regimens characterized by the application of 8 and 16 pulses are associated with significant variations in SVG magnitude over time (p = 0.03 and p = 0.048 respectively with repeated measures ANOVA, with confirmed significance for the 8-pulse dosage even after Holm-Sidak correction, p < 0.05). Interestingly, despite these variations in intensity, the overall direction of ventricular electrical activity, assessed through the azimuthal and elevation angles of the SVG, showed no statistically relevant changes in response to PFA.

Ventricular arrhythmias represent one of the leading causes of cardiovascular mortality and constitute an area of intense clinical and research interest. To develop safer and more effective therapeutic strategies for managing these cardiac rhythm disorders, research is increasingly focusing on innovative approaches to modulate myocardial electrical activity. In this context, Pulsed Field Ablation (PFA) emerges as a promising non-thermal ablative technique based on the application of high-voltage, short-duration electrical pulses, with the potential to treat cardiac arrhythmias. Applying PFA to ventricular tissue, the site of potentially lethal arrhythmias, presents an intriguing challenge and remains an active field of study in preclinical animal research. To gain deeper insight into PFA's effects on ventricular electrical activity, this thesis focused on analyzing the Spatial Ventricular Gradient (SVG), a three-dimensional vector that reflects global myocardial electrical heterogeneity by combining the vectorial contributions of ventricular depolarization (QRS complex) and repolarization (T wave). The main objective of this thesis was to evaluate changes in the SVG vector following PFA application in an animal model. The study utilized electrocardiographic (ECG) signals previously acquired from five experimental animals included in a preclinical study of PFA. In a preliminary phase, custom codes were developed and implemented to identify QRS complex peaks and determine the integration boundaries necessary for calculating areas under individual heartbeats. However, due to limitations in reproducibility, accuracy, and computational efficiency, the research opted to use software specifically developed for SVG analysis in human electrocardiographic data from standard 12-lead ECGs. Using this software, was analyzed the magnitude, azimuthal angle, and elevation angle of the SVG at different timepoints: before the procedure, immediately after, and at the end of the electrocardiographic recording. The results of this SVG analysis suggest that PFA induces transient changes in ventricular electrical activity. Specifically, was observed a notable decrease in SVG vector intensity immediately following PFA application (p = 0.01 with repeated measures ANOVA), an effect that appears to resolve spontaneously over time, with a return to pre-procedure values by the end of the recording. A more in-depth analysis, focused on PFA dosage intensity, revealed that specific treatment regimens characterized by the application of 8 and 16 pulses are associated with significant variations in SVG magnitude over time (p = 0.03 and p = 0.048 respectively with repeated measures ANOVA, with confirmed significance for the 8-pulse dosage even after Holm-Sidak correction, p < 0.05). Interestingly, despite these variations in intensity, the overall direction of ventricular electrical activity, assessed through the azimuthal and elevation angles of the SVG, showed no statistically relevant changes in response to PFA.

Spatial Ventricular Gradient for quantification of ECG changes after pulsed field ablation in the left ventricle of swine hearts

MONTI, ALESSANDRA SILVIA
2024/2025

Abstract

Ventricular arrhythmias represent one of the leading causes of cardiovascular mortality and constitute an area of intense clinical and research interest. To develop safer and more effective therapeutic strategies for managing these cardiac rhythm disorders, research is increasingly focusing on innovative approaches to modulate myocardial electrical activity. In this context, Pulsed Field Ablation (PFA) emerges as a promising non-thermal ablative technique based on the application of high-voltage, short-duration electrical pulses, with the potential to treat cardiac arrhythmias. Applying PFA to ventricular tissue, the site of potentially lethal arrhythmias, presents an intriguing challenge and remains an active field of study in preclinical animal research. To gain deeper insight into PFA's effects on ventricular electrical activity, this thesis focused on analyzing the Spatial Ventricular Gradient (SVG), a three-dimensional vector that reflects global myocardial electrical heterogeneity by combining the vectorial contributions of ventricular depolarization (QRS complex) and repolarization (T wave). The main objective of this thesis was to evaluate changes in the SVG vector following PFA application in an animal model. The study utilized electrocardiographic (ECG) signals previously acquired from five experimental animals included in a preclinical study of PFA. In a preliminary phase, custom codes were developed and implemented to identify QRS complex peaks and determine the integration boundaries necessary for calculating areas under individual heartbeats. However, due to limitations in reproducibility, accuracy, and computational efficiency, the research opted to use software specifically developed for SVG analysis in human electrocardiographic data from standard 12-lead ECGs. Using this software, was analyzed the magnitude, azimuthal angle, and elevation angle of the SVG at different timepoints: before the procedure, immediately after, and at the end of the electrocardiographic recording. The results of this SVG analysis suggest that PFA induces transient changes in ventricular electrical activity. Specifically, was observed a notable decrease in SVG vector intensity immediately following PFA application (p = 0.01 with repeated measures ANOVA), an effect that appears to resolve spontaneously over time, with a return to pre-procedure values by the end of the recording. A more in-depth analysis, focused on PFA dosage intensity, revealed that specific treatment regimens characterized by the application of 8 and 16 pulses are associated with significant variations in SVG magnitude over time (p = 0.03 and p = 0.048 respectively with repeated measures ANOVA, with confirmed significance for the 8-pulse dosage even after Holm-Sidak correction, p < 0.05). Interestingly, despite these variations in intensity, the overall direction of ventricular electrical activity, assessed through the azimuthal and elevation angles of the SVG, showed no statistically relevant changes in response to PFA.
2024
Spatial Ventricular Gradient for quantification of ECG changes after pulsed field ablation in the left ventricle of swine hearts
Ventricular arrhythmias represent one of the leading causes of cardiovascular mortality and constitute an area of intense clinical and research interest. To develop safer and more effective therapeutic strategies for managing these cardiac rhythm disorders, research is increasingly focusing on innovative approaches to modulate myocardial electrical activity. In this context, Pulsed Field Ablation (PFA) emerges as a promising non-thermal ablative technique based on the application of high-voltage, short-duration electrical pulses, with the potential to treat cardiac arrhythmias. Applying PFA to ventricular tissue, the site of potentially lethal arrhythmias, presents an intriguing challenge and remains an active field of study in preclinical animal research. To gain deeper insight into PFA's effects on ventricular electrical activity, this thesis focused on analyzing the Spatial Ventricular Gradient (SVG), a three-dimensional vector that reflects global myocardial electrical heterogeneity by combining the vectorial contributions of ventricular depolarization (QRS complex) and repolarization (T wave). The main objective of this thesis was to evaluate changes in the SVG vector following PFA application in an animal model. The study utilized electrocardiographic (ECG) signals previously acquired from five experimental animals included in a preclinical study of PFA. In a preliminary phase, custom codes were developed and implemented to identify QRS complex peaks and determine the integration boundaries necessary for calculating areas under individual heartbeats. However, due to limitations in reproducibility, accuracy, and computational efficiency, the research opted to use software specifically developed for SVG analysis in human electrocardiographic data from standard 12-lead ECGs. Using this software, was analyzed the magnitude, azimuthal angle, and elevation angle of the SVG at different timepoints: before the procedure, immediately after, and at the end of the electrocardiographic recording. The results of this SVG analysis suggest that PFA induces transient changes in ventricular electrical activity. Specifically, was observed a notable decrease in SVG vector intensity immediately following PFA application (p = 0.01 with repeated measures ANOVA), an effect that appears to resolve spontaneously over time, with a return to pre-procedure values by the end of the recording. A more in-depth analysis, focused on PFA dosage intensity, revealed that specific treatment regimens characterized by the application of 8 and 16 pulses are associated with significant variations in SVG magnitude over time (p = 0.03 and p = 0.048 respectively with repeated measures ANOVA, with confirmed significance for the 8-pulse dosage even after Holm-Sidak correction, p < 0.05). Interestingly, despite these variations in intensity, the overall direction of ventricular electrical activity, assessed through the azimuthal and elevation angles of the SVG, showed no statistically relevant changes in response to PFA.
ECG
Signal Processing
SVG
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12608/85225