scholarly journals Analyzing the Role of Repolarization Gradients in Post-infarct Ventricular Tachycardia Dynamics Using Patient-Specific Computational Heart Models

2021 ◽  
Vol 12 ◽  
Author(s):  
Eric Sung ◽  
Adityo Prakosa ◽  
Natalia A. Trayanova
Keyword(s):  
Ventricular Tachycardia ◽  
Cardiac Magnetic Resonance ◽  
Conduction Block ◽  
Magnetic Resonance Images ◽  
Border Zone ◽  
Patient Specific ◽  
Rapid Pacing ◽  
Infarct Border Zone ◽  
Infarct Border

Aims: Disease-induced repolarization heterogeneity in infarcted myocardium contributes to VT arrhythmogenesis but how apicobasal and transmural (AB-TM) repolarization gradients additionally affect post-infarct VT dynamics is unknown. The goal of this study is to assess how AB-TM repolarization gradients impact post-infarct VT dynamics using patient-specific heart models.Method: 3D late gadolinium-enhanced cardiac magnetic resonance images were acquired from seven post-infarct patients. Models representing the patient-specific scar and infarct border zone distributions were reconstructed without (baseline) and with repolarization gradients along both the AB-TM axes. AB only and TM only models were created to assess the effects of each ventricular gradient on VT dynamics. VTs were induced in all models via rapid pacing.Results: Ten baseline VTs were induced. VT inducibility in AB-TM models was not significantly different from baseline (p>0.05). Reentry pathways in AB-TM models were different than baseline pathways due to alterations in the location of conduction block (p<0.05). VT exit sites in AB-TM models were different than baseline VT exit sites (p<0.05). VT inducibility of AB only and TM only models were not significantly different than that of baseline (p>0.05) or AB-TM models (p>0.05). Reentry pathways and VT exit sites in AB only and TM only models were different than in baseline (p<0.05). Lastly, repolarization gradients uncovered multiple VT morphologies with different reentrant pathways and exit sites within the same structural, conducting channels.Conclusion: VT inducibility was not impacted by the addition of AB-TM repolarization gradients, but the VT reentrant pathway and exit sites were greatly affected due to modulation of conduction block. Thus, during ablation procedures, physiological and pharmacological factors that impact the ventricular repolarization gradient might need to be considered when targeting the VTs.

scholarly journals Myofibroblast Senescence Promotes Arrhythmogenic Remodeling in the Aged Infarcted Rabbit Heart

2021 ◽  
Author(s):  
Brett Baggett ◽  
Kevin Murphy ◽  
Elif Sengun ◽  
Eric Mi ◽  
Yueming Cao ◽  
...  
Keyword(s):  
Cardiac Arrhythmias ◽  
Conduction Block ◽  
Rabbit Heart ◽  
Border Zone ◽  
Infarct Zone ◽  
Inflammatory Signaling ◽  
Large Animals ◽  
Infarct Border Zone ◽  
Infarct Border

Progressive tissue remodeling after myocardial infarction (MI) promotes cardiac arrhythmias. This process is well studied in young animals, but little is known about pro-arrhythmic changes in aged animals. Senescent cells accumulate with age and accelerate age-associated diseases. Senescent cells interfere with cardiac function and outcome post-MI with age, but studies have not been performed in large animals, and the mechanisms are unknown. Here, we investigated the role of senescence in regulating inflammation, fibrosis, and arrhythmogenesis in young and aged infarcted rabbits. Aged rabbits exhibited increased peri-procedural mortality and arrhythmogenic electrophysiological remodeling at the infarct border zone (IBZ) compared to young rabbits. Studies of the aged infarct zone revealed persistent myofibroblast senescence and increased inflammatory signaling over a twelve-week timecourse. Senescent IBZ myofibroblasts in aged rabbits appear to be coupled to myocytes, and our computational modeling showed that senescent myofibroblast-cardiomyocyte coupling prolongs action potential duration (APD) and facilitates conduction block permissive of arrhythmias. Aged infarcted human ventricles show levels of senescence consistent with aged rabbits, and senescent myofibroblasts also couple to IBZ myocytes. Our findings suggest that senolytic drugs may mitigate arrhythmias post-MI.

Abstract 14985: Presence of Repolarization Gradients Reverses Post-infarct Ventricular Tachycardia Exit and Entrance Sites in Personalized Digital Hearts

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Eric Sung ◽  
Adityo Prakosa ◽  
Natalia Trayanova
Keyword(s):  
Border Zone ◽  
Non Invasive ◽  
Cycle Lengths ◽  
Rapid Pacing ◽  
Vt Ablation ◽  
Right Ventricular Apex ◽  
The Right ◽  
Ventricular Tachycardias ◽  
Infarct Border Zone ◽  
Infarct Border

Introduction: Post-infarct ventricular tachycardias (VT) arise due to structural remodeling (scarring). Physiological repolarization gradients (apicobasal and transmural) exist in the human heart, but the effects on post-infarct VT dynamics are unknown. Hypothesis: We hypothesized that incorporation of repolarization gradients in personalized digital hearts of post-infarct patients impacts VT exit sites without altering the location of the VTs. Methods: 3D late-gadolinium enhanced CMR images were acquired from 7 post-infarct patients. Personalized image-based computational heart models (digital hearts) representing scar and infarct border zone distributions were constructed. Apicobasal (AB) and transmural (TM) repolarization gradients were incorporated using a validated method (Fig A). VTs were induced at baseline (no repolarization gradient) via rapid pacing in the right ventricular apex, using two pacing cycle lengths, mimicking non-invasive programmed stimulation. Pacing protocols that induced baseline VTs were repeated under AB and TM conditions. Results: Ten VTs were induced in baseline digital hearts. 8 AB VTs and 8 TM VTs were induced; the remaining 2 VTs for both AB and TM digital hearts could not be induced. 5/8 induced AB VTs had VT exit sites matching baseline VT exit sites; the remaining 3/8 AB VTs had reversed VT exit and entrance sites from the corresponding baseline VTs (Fig B, VT 1 & 2). 4/8 induced TM VTs had exit sites that matched those at baseline; the remaining TM VTs had exit and entrance sites reversed from those of baseline VTs (Fig B, VT 1, 2 & 3). All 8 AB VTs and 8 TM VTs had the same location as corresponding baseline VTs. Conclusion: AB and TM repolarization gradients can act to reverse VT entrance and exit sites without changing VT location. Thus, incorporation of physiological repolarization gradients into personalized digital hearts may not impact VT ablation targeting but may affect accurate prediction of VT exit or entrance sites.

scholarly journals Model of Bipolar Electrogram Fractionation and Conduction Block Associated With Activation Wavefront Direction at Infarct Border Zone Lateral Isthmus Boundaries

2014 ◽  
Vol 7 (1) ◽  
pp. 152-163 ◽  
Author(s):  
Edward J. Ciaccio ◽  
Hiroshi Ashikaga ◽  
James Coromilas ◽  
Bruce Hopenfeld ◽  
Daniel O. Cervantes ◽  
...  
Keyword(s):  
Conduction Block ◽  
Border Zone ◽  
Infarct Border Zone ◽  
Infarct Border

scholarly journals Model of unidirectional block formation leading to reentrant ventricular tachycardia in the infarct border zone of postinfarction canine hearts

2015 ◽  
Vol 62 ◽  
pp. 254-263 ◽  
Author(s):  
Edward J. Ciaccio ◽  
James Coromilas ◽  
Hiroshi Ashikaga ◽  
Daniel O. Cervantes ◽  
Andrew L. Wit ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Border Zone ◽  
Unidirectional Block ◽  
Block Formation ◽  
Infarct Border Zone ◽  
Infarct Border

P6555A self-adaptive approach to antitachycardia pacing - a head to head comparison using advanced computational modeling

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
D Swenson ◽  
J Blauer ◽  
R Taepke ◽  
E Kwan ◽  
E Ghafoori ◽  
...  
Keyword(s):  
Ventricular Arrhythmias ◽  
Border Zone ◽  
Patient Specific ◽  
Programmed Electrical Stimulation ◽  
Antitachycardia Pacing ◽  
Cardiac Arrythmias ◽  
Modeling Software ◽  
Excitable Gap ◽  
Infarct Border Zone ◽  
Infarct Border

Abstract Background Antitachycardia pacing (ATP) for monomorphic VT (MVT) reduces painful defibrillation shocks. Most ICD-treated ventricular arrhythmias are MVT, suggesting an opportunity for improved ATP to decrease shocks. We report on a new algorithm (Yee, Circ AE 2017) that uses electrophysiologic (EP) first-principles to design ATP sequences in real-time. Heart-rate history is used to design the first ATP sequence, and failed ATP post-pacing interval is used to design later sequences. Purpose The purpose of this modeling study was to understand how this new ATP algorithm would perform in a head-to-head comparison with traditional burst ATP. Modeling allows direct comparison of the two algorithms in identical, realistic, patient-derived cardiac arrythmias. Methods Patient-specific late gadolinium enhanced MRI and EP data were used to build an adjudicated cohort of realistic numerical heart models with varied EP, infarct, border zone. Publicly available EP modeling software CARPentry was used to calculate sustained reentrant VT initiated with the programmed electrical stimulation used to induce VT clinically. The VTs were physician-adjudicated to validate models. Burst ATP was 3 sequences of 8 pulses at 88% of VT cycle length, each decremented by 10ms. The new ATP was limited to 3 automatically designed sequences. Results Three hundred unique VT scenarios were generated from 6 human hearts with multiple VT circuits, 5 electrophysiologic states, and 10 pacing locations. Burst ATP terminated 168/300 VTs (56%) and accelerated 2.7%. The new ATP terminated 234/300 VTs (78%) with the same acceleration. The two dominant ATP failure mechanisms were identified as 1) insufficient prematurity to close the excitable gap, and 2) failure to reach the critical isthmus of the VT circuit. For these mechanisms, the new ATP algorithm reduce failures from 64 to 28 (44% reduction) without increasing acceleration. Conclusion The new automated ATP algorithm successfully adapted ATP sequences for VT episodes that burst ATP failed to terminate. The new ATP was successful even with complex scar geometries and electrophysiology heterogeneity as seen in the real world.

scholarly journals Model of reentrant ventricular tachycardia based on infarct border zone geometry predicts reentrant circuit features as determined by activation mapping

Heart Rhythm ◽  
2007 ◽  
Vol 4 (8) ◽  
pp. 1034-1045 ◽  
Author(s):  
Edward J. Ciaccio ◽  
Hiroshi Ashikaga ◽  
Riyaz A. Kaba ◽  
Daniel Cervantes ◽  
Bruce Hopenfeld ◽  
...  
Keyword(s):  
Ventricular Tachycardia ◽  
Border Zone ◽  
Infarct Border Zone ◽  
Activation Mapping ◽  
Infarct Border ◽  
Reentrant Circuit

Abstract 14725: Image-based Virtual-heart Predictions Co-localize With ECG-based Automated Localization of Scar-related Ventricular Tachycardias

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Shijie Zhou ◽  
Eric Sung ◽  
Adityo Prakosa ◽  
Jonathan Chrispin ◽  
Amir AbdelWahab ◽  
...  
Keyword(s):  
Border Zone ◽  
Patient Specific ◽  
Heart Arrhythmia ◽  
Surface Ecg ◽  
Improve Accuracy ◽  
Endocardial Surface ◽  
Ventricular Tachycardias ◽  
Ecg Leads ◽  
Infarct Border Zone ◽  
Infarct Border

Introduction: We previously developed an LGE-MRI-based virtual-heart arrhythmia ablation targeting (VAAT) methodology to non-invasively determine potential ablation targets for infarct-related VT. However, it is unknown whether VAAT’s predictions correspond with surface ECG predictions. Hypothesis: We hypothesized that the VAAT predicted VT circuits and potential ablation lesions would co-localize with ECG-based VT-exit predictions from a previously validated population-derived automated VT exit localization (PAVEL) system. Methods: We retrospectively enrolled 5 post-infarct patients who underwent LV endocardial VT ablation and had pre-procedural 2D LGE-MRIs. The PAVEL system based on a population-derived statistical method was used to localize VT-exit sites onto one of 238 triangles on the patient-specific virtual-heart LV endocardial surface using 8 independent ECG leads (I, II, V1-V6). The VAAT methodology incorporating patient-specific scar and infarct border zone distributions was used to identify potential VT circuits and find ablation lesions. Results: Eleven induced VTs were analyzed. Ten VT-exit sites were localized onto the patient-specific virtual-heart LV endocardial surface by the PAVEL system, and were used for the comparisons. One VT-exit site was too basal to be localized onto the virtual-heart geometry. The spatial resolution of the 10 predicted VT-exit sites was 13.8 ± 1.8 mm. VAAT-predicted VT circuits and ablation lesions correlated well with all 10 predicted VT-exit sites. Lastly, VAAT ablation lesions fell within the regions ablated clinically. Conclusions: The VAAT-predicted VT circuits and ablation lesions matched VT-exit sites predicted by the surface ECG-based PAVEL system. Combining these two complementary technologies may improve accuracy for non-invasively identifying optimal ablation targets to increase ablation efficacy.

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