Virtual Electrophysiological Study in a 3-Dimensional Cardiac Magnetic Resonance Imaging Model of Porcine Myocardial Infarction

Ng, Jason; Jacobson, Jason T.; Ng, Justin; Gordon, David; Lee, Daniel; Carr, James C.; Goldberger, Jeffrey J.

doi:10.1016/j.jacc.2012.03.029

Cited by 36 publications

(33 citation statements)

References 33 publications

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“…Previous efforts in modelling of infarcted hearts have been limited to 2D representations [46] or lacked full characterization of the entire ventricles including specific fiber orientations [47]. The individualized infarcted canine ventricular model used in this study incorporated accurate geometry, infarct distribution, and fiber orientation obtained from high resolution ex-vivo MRI and DTMRI.…”

Section: Discussionmentioning

confidence: 99%

Tachycardia in Post-Infarction Hearts: Insights from 3D Image-Based Ventricular Models

et al. 2013

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Ventricular tachycardia, a life-threatening regular and repetitive fast heart rhythm, frequently occurs in the setting of myocardial infarction. Recently, the peri-infarct zones surrounding the necrotic scar (termed gray zones) have been shown to correlate with ventricular tachycardia inducibility. However, it remains unknown how the latter is determined by gray zone distribution and size. The goal of this study is to examine how tachycardia circuits are maintained in the infarcted heart and to explore the relationship between the tachycardia organizing centers and the infarct gray zone size and degree of heterogeneity. To achieve the goals of the study, we employ a sophisticated high-resolution electrophysiological model of the infarcted canine ventricles reconstructed from imaging data, representing both scar and gray zone. The baseline canine ventricular model was also used to generate additional ventricular models with different gray zone sizes, as well as models in which the gray zone was represented as different heterogeneous combinations of viable tissue and necrotic scar. The results of the tachycardia induction simulations with a number of high-resolution canine ventricular models (22 altogether) demonstrated that the gray zone was the critical factor resulting in arrhythmia induction and maintenance. In all models with inducible arrhythmia, the scroll-wave filaments were contained entirely within the gray zone, regardless of its size or the level of heterogeneity of its composition. The gray zone was thus found to be the arrhythmogenic substrate that promoted wavebreak and reentry formation. We found that the scroll-wave filament locations were insensitive to the structural composition of the gray zone and were determined predominantly by the gray zone morphology and size. The findings of this study have important implications for the advancement of improved criteria for stratifying arrhythmia risk in post-infarction patients and for the development of new approaches for determining the ablation targets of infarct-related tachycardia.

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Section: Discussionmentioning

confidence: 99%

Tachycardia in Post-Infarction Hearts: Insights from 3D Image-Based Ventricular Models

et al. 2013

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“…Consistent with the remote post-MI data, they demonstrated that infarct size at CMR, used in addition to LVEF, optimized arrhythmia risk prediction. Another potential utility of CMR is a technique of virtual EPS, described recently by Ng et al 101 in a porcine post-MI model. In this study, delayed-gadoliniumenhancement CMR images were used to create high-resolution 3-dimensional reconstructions of the LV.…”

Section: Cardiac Magnetic Resonance Imagingmentioning

confidence: 99%

“…Další možnost případného využití CMR představuje metoda virtuální EPS, kterou nedávno popsali Ng a spol. 101 u prasečího modelu po IM. V jejich studii byly CMR obrazy s pozdním zesílením kontrastu gadolinia použity k trojrozměrným rekonstrukcím (s vysokým rozlišením) LK.…”

Section: Metody Stratifi Kace Rizika V čAsné Primární Prevenci Nssunclassified

Sudden Cardiac Death Early After Myocardial Infarction

2014

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The issue of SCD primary prevention early after MI remains unresolved. The focus is now firmly centered on the elucidation of risk stratification tests that effectively select patients at high risk of SCD who benefit from early ICD implantation. Zaman and Kovoor Primary Prevention of SCD Early After MI 2429A summary of major risk stratification tests currently used to identify patients at high risk of SCD is given in Table 2. LV DysfunctionImpaired LVEF, one of the most powerful predictors of survival, 64 has been shown to identify patients who derive a mortality benefit from an ICD when implanted predominantly in the remote period after MI. 16,65 However, there are major concerns with the use of LVEF alone as a risk stratifier to guide ICD implantation. One such concern is the low specificity of LVEF for selecting patients who experience arrhythmic versus nonarrhythmic death. In the MADIT II trial, the use of LVEF ≤30% alone to stratify patients for an ICD resulted in relatively small absolute improvement in mortality with low therapeutic efficiency (15-17 defibrillators per life saved). 66 Another concern is the sensitivity of LVEF, given that a large proportion of SCDs still occur in patients with preserved LV function. VALIANT demonstrated that, although the risk of SCD is greatest in patients with severe dysfunction (LVEF ≤30%), almost half of all sudden deaths occur in patients with a higher ejection fraction (LVEF, 31%-40%). 5 The use of LVEF as a risk stratification tool has been tested in the early post-MI stage in the DINAMIT and IRIS trials, which selected patients with LVEF ≤35% and ≤40%, respectively, and failed to show a benefit of early ICD implantation. 12,17 The major limitation with the use of an early LVEF cutoff is the phenomenon of myocardial stunning with variable and unpredictable recovery of LV function after MI. This is especially relevant in the contemporary era of primary PCI for STEMI. Of STEMI patients with LVEF ≤40% at day 3, 24% will improve to have an LVEF >40% at 6 months with a mean 6% relative improvement. 67 Hence, although LV function will invariably be incorporated into risk stratification models for the prevention of SCD, it is clear that other tests are required to adequately select high-risk patients early after MI. RV DysfunctionAlthough impaired LV function has been studied extensively as a predictor of mortality and arrhythmic death, RV dysfunction has been largely overlooked. We know from the VALIANT study that almost 50% of arrhythmic deaths occur in patients with a preserved LVEF.5 RV involvement in inferior MI has been shown to be a predictor of morbidity and mortality, with a higher rate of serious arrhythmias in patients with inferior MI and RV dysfunction. 68,69 In addition, RV dysfunction has been correlated with increased inducibility of VT at EPS. 70 Although there is no current evidence to support the role of early RV assessment to guide ICD implantation, these findings highlight the inadequacy of LVEF alone as a risk stratification tool for the prevention...

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“…Zhu et al [138] showed that models of the heart can be used to carry out non-invasive localization of accessory pathways in patients with Wolff-Parkinson-White syndrome. Ng et al [87] demonstrated the feasibility of using simulations to predict VT circuits. Relan et al [99] used a hy-brid X-ray and MR environment to image a patient heart, which was further personalized with voltage measurements.…”

Section: Clinical Applications Of Simulation-based Arrhythmia Researchmentioning

confidence: 99%

Cardiac Arrhythmias: Mechanistic Knowledge and Innovation from Computer Models

Trayanova

Boyle

2015

MS&A

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Computational simulation is increasingly recognized as an integral aspect of modern cardiovascular research. Realistic and biophysically detailed models of the cardio-circulatory system can help interpret complex experimental observations, dissect underlying mechanisms, and explain emerging organ-scale phenomena resulting from subtle changes at the tissue, cellular, and/or sub-cellular scales. This chapter provides an overview of recent advances in the simulation of cardiac electrical behavior, focusing specifically on detailed models of the initiation, perpetuation, and termination of ventricular arrhythmias, including fibrillation. The development and validation of such models has opened several noteworthy avenues of research, including close scrutiny of arrhythmia dynamics in healthy and diseased hearts, dissection of arrhythmogenic and cardioprotective properties of specialized cardiac tissue regions such as the Purkinje system, and exploration of emerging paradigms for anti-arrhythmia treatment, such as optogenetics. Excitingly, the clinical community is currently taking the first steps towards using patient-specific ventricular models to stratify arrhythmia risk, personalize treatment planning, and optimize device placement for difficult or unusual procedures.

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Virtual Electrophysiological Study in a 3-Dimensional Cardiac Magnetic Resonance Imaging Model of Porcine Myocardial Infarction

Cited by 36 publications

References 33 publications

Tachycardia in Post-Infarction Hearts: Insights from 3D Image-Based Ventricular Models

Tachycardia in Post-Infarction Hearts: Insights from 3D Image-Based Ventricular Models

Sudden Cardiac Death Early After Myocardial Infarction

Cardiac Arrhythmias: Mechanistic Knowledge and Innovation from Computer Models

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