Application of cardiac MRI - PowerPoint Presentation

1. Application of cardiac MRI in cardiac electrophysiologyMohammad Vahid Jorat, MD.Interventional Electrophysiologist

2. Cardiac diseases leading to cardiac arrhythmiaNormal heart structure:Long QT, Short QT, CPVT, ER, Brugada Sx?Ventricular arrhythmia are dominantly polymorphic and can occur in any cardiac chamber but mostly occurs in the ventricles A focal trigger may be found that can tend to PVT or sustained VTRe-entrant circuit is common in SVTStructural heart diseaseIschemic heart disease and non-ischemic heart diseaseType of arrhythmia is dominantly monomorphic and ventricularPVC (occasional, repetitive)VT (non-sustained, Sustained)Supraventricular arrhythmia

3. Mechanism of Cardiac Arrhythmia, Re-entry

4. Techniques for ablation of scar related VT

5. Ischemic vs Non-ischemic heart diseaseDirect damageMIViral infectionothersRemodeling (neurohormonal mechanisms)Remodeling (neurohormonal mechanisms)Direct damageUnknownGeneticViral infectionIschemiaothersTime

6. Arrhythmia in cardiac arrhythmiaDirect damage(CAD) MIViral infectionothersRemodeling (neurohormonal mechanisms)Direct damageUnknownGeneticViral infectionIschemiaothersRemodeling (neurohormonal mechanisms)TimeCardiac ArrhythmiaElectrophysiology interventions

7. Application of CMRI in ablation of cardiac arrhythmia

8. Cardiac imaging and electrophysiologyInitial eventTypeExtentConsequenceFixed scarChannelsSlow conduction areaMaking an image before the procedure and during the procedure mostly used in AF ablation, focal AT, AFL and structural VTheterogeneity may be as a surrogative clue

9. Cardiac MRI Tissue Characterization Late Gadolinium Enhancement Late gadolinium enhanced (LGE) CMRI imaging has become the standard for imaging myocardial fibrosis. Gadolinium washout rapid in normal tissue, slow in areas of myocardial fibrosis The volume of abnormal tissue can be quantified manually or automatedT1 Mapping T1 values are increased by tissue edema and fibrosis, and are reduced by lipid overload (e.g. in Anderson-Fabry disease) and iron overload ECV measurement through T mapping pre and post contrast injectionHigher ECV values are seen with expansion of the interstitium due to fibrosis or deposition and therefore correlate well with fibrotic changes at endomyocardial biopsy.

10. Cardiac MRI Tissue Characterization Channels diameter 100-200µmLGE image resolution: 1.4 × 1.4 × 10 mm (the 10 mm distance is the gap between slices T1 image resolution: 1.4 × 1.9 × 6 mm (Less than LGE)Still need to be confirmed by EAM

11. Comparison of Myocardial Tissue Characterisation Techniques

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13. Cardiac imaging in AF ablationPreprocedural Anticipate and plan for technical difficulties due to left atrial and pulmonary vein structural variation: (CTA=CMR)Prognostication of long-term success; LA size and tissue characterization: (CMR>CT>TEE,ICE)Simulations to identify AF reentrant drivers (CMR-LGE + machine learning)Tissue characterization of the left atrium through the evaluation of fibrosis in LGE. (UTAH classification, only CMR) Left atrial appendage thrombus: (TEE=CTA)>CMR

14. Variations in pulmonary venous anatomy A: Two left pulmonary veins and 2 right pulmonary veins. B: One common left pulmonary vein and 2 right pulmonary veins.C: Two left pulmonary veins with early branching and 2 right pulmonary veins. D: Two left pulmonary veins and 3 right pulmonary veins.

15. Late gadolinium enhancement sequences depicting a left atrial scar UTAH ClassificationUtah 1: no or minimal fibrosis. (< 5%)Utah2: (5%-20%) fibrosisUtah 3: (21%-35%) fibrosisUtah 4: (>35% fibrosis)in the atria A: Utah I—5.1% fibrosis. B: Utah II—18.2% fibrosis.C: Utah III—24.5% fibrosis.D: UtahIII—35.4% fibrosis. Increased LGE uptake in the left atrium has been associated with a greater likelihood of recurrent atrial arrhythmia after AF ablation in both long-term and short-term follow-up studies

16. Cardiac imaging in AF ablationIntraproceduralFor image integration ( pre procedural CT & CMR) (intraoperative ICE)Interatrial septostomy (ICE) (Zero ablation radiation) Pericardial effusion and monitoring of other complication (ICE)Post procedural (recurrence)To differentiate between inadequate homogenization and reconnection (only CMR)Degree of pulmonary vein stenosis (comparing with pre-procedural data)

17. Supraventricular tachycardia and typical atrial flutter ablation For selection of type of catheter and curve of the sheath (TEE, CTA, CMR)For detail of anatomy in complex situation like congenital heart disease or post operation status (CTA, CMR)Intraoperative anatomy of CTI (ICE)Large pouch or a prominent Eustachian ridge Zero-radiation procedure (ICE)

18. Ventricular arrhythmia (VT or PVC) ablation Pre-procedural and Intra-procedural imaging

19. Preprocedural imaging:To delineate areas of myocardial scar and the border zone (CMR with contrast>>CT)Inflammation area (PET)Survivors of sudden cardiac arrest with an inconclusive diagnosis (CMR)up to 67% of revealed evidence of structural abnormalities in 38% of patients, led to a new or alternate diagnosis In patients with idiopathic PVCs or VTCMR can also visualize areas of scarring during an otherwise normal structural in TTECan guide EAM and delineate areas of potential substrate for ablation targeting. No significant difference in the procedural time Significant improvement in VT-free survival as well as overall survival.

20. Preprocedural imaging: (continue)Scar area definition (Dense scar and semi-viable area) EAM vs LGE-CMRBetter delineation of scar by CMR, compared EAM to LGE-CMRLarger scar was associated with clinical recurrence after catheter ablation Some scar locations in NICMP with poor prognosisPredominantly anteroseptal scar and predominantly inferolateral scar. Transmural extension of scar (endocardial vs epicardial scar) especially in NICMPBetter guidance of EAM to find critical isthmus Difficulty of ECG to predict epicardial isthmus in NICMP or post myocarditisLocalization of isthmus by LGE-CMRSeptal VT occurred in areas of high signal intensity on LGE-CMR Delayed-enhancement border zone areas have good correlation with conduction channels visualized through EAM. To define isthmus, area with >75% transmural scars contained most of critical isthmus sites for VT in both ICMP and NICMP

21. A:Ventricular tachycardia (VT) ablation performed without magnetic resonance imaging (MRI)– derived scar integration. B: Ablation performed with MRI-derived scar integration in ARVC

22. Preprocedural imaging: (continue)Myocarditis:For patients with myocarditis undergoing VT ablation due to medication-refractory VTActive myocarditis using the MRI Lake Louise Criteria or by endomyocardial biopsy has been associated with longer-term VT recurrence.It is suggested that these patients may not benefit from VT ablation and should be managed medically if possible until they enter the post-myocarditis phase.

23. Preprocedural imaging: (continue)Combination of CMR with other modalities123I-MIBG SPECT + EAM + cardiac MRI to help delineate scarring123I-MIBG SPECT is used to image areas of sympathetic innervation to the heart. In one study, a VT channel and exit sites were found to be localized to areas with both cardiac MRI-LGE and 123I-MIBG SPECT abnormal innervation. Cardiac MRI and cardiac CTA used to guide trans-arterial coronary ethanol ablation in a small case series

24. Preprocedural imaging: (continue)- Area of gowingThe potential of imaging-based computational simulations to guide catheter ablation by identifying potential targets. These methods, as described by Trayanova et al., use finite element models derived from LGE-MRI sequences to simulate pacing maneuver–induced arrhythmogenicity in the model ventricle.These methods have been utilized to accurately predict ablation targets found during EAM in 9 of 11 patients with primarily ischemic VT in the study by Ashikaga et al.This technique can add to other non-invasive technique of ablation such as stereotactic body radiotherapy in the future.

25. Intraprocedural imaging (image integration into the EAM system and real-time imaging during ablation)Integration of contrast-enhanced cardiac MRI into the EAM:Increase the likelihood of non-inducibility and freedom from VT recurrence in substrate modification approach Intraprocedural real-time MRI:Is an experimental technique, mostly used in animal model, in human only used for simple procedure like AFLICE is commonly used in the real-time proceduresCMRI has used in Non-invasive cardiac ablation with stereotactic body radiation therapy (SBRT)

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27. MRI and CIED

28. MRI and Cardiac Pacemakers(AHA guideline,2018-ESC guideline, 2021) Pacemaker implantationFor finding partially treatable conditionsLike Amyloidosis, myocarditis, hemochromatosis, sarcoidosis, CHD, sinus of Valsalva aneurysm, aortic dissection, arrhythmogenic right ventricular cardiomyopathyIs helpful for diagnosis of Lamin A/C disease by finding of intramyocardial fibrosisIn selected patients with LBBB in whom structural heart disease is suspected and echocardiogram is unrevealing, advanced imaging (e.g., cardiac MRI, computed tomography, or nuclear studies) is reasonable to find causes like sarcoidosis, amyloidosis,…Conductive system pacing (was not mentioned)Safety issues

29. MRI and ICD(AHA guideline,2017)MRI allow for evaluation of structural heart disease and assessment of LV and RV function Cardiac MRI can be useful in the evaluation for myocardial scar and infiltrative processes evident as late gadolinium enhancement.Cardiac MRI also provides high-quality assessment of LV and RV function, size, and degree of fibrosis and is particularly useful in ARVC and HCM.Sustained monomorphic VT due to NICM is most often due to scar-related reentry. Cardiac MRI often indicates scar location, which tends to be basal along the mitral annulus or in the septum.The VT substrate can be subendocardial, subepicardial, or intramyocardial, and all locations may be affected and require endocardial and epicardial ablation.

30. MRI and ICD (AHA guideline,2017)ARVC: Cardiac MRI provides high-quality assessment of ventricular function, size, regional wall motion abnormalities, and extent of scar and fibrosis (late gadolinium enhancement, seen in 30% to 95% of patients with the clinical ARVC).Cardiac MRI detects biventricular involvement in 34% to 56% of patients, with isolated LV involvement noted in 4% to 9% of patients.

31. MRI and ICD (AHA guideline 2017)MRI and HCMRisk modifiers: Age <30 y, late gadolinium enhancement on cardiac MRI, LVOT obstruction, LV aneurysm, syncope >5 y.

32. MRI and ICD(AHA guideline 2017)MRI and SarcoidosisCardiac involvementLVEFExtend of myocardial fibrosis

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