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Cardiovascular magnetic resonance (CMR) is a proven imaging modality for informing diagnosis and prognosis, guiding therapeutic decisions, and risk stratifying surgical intervention. Patients with a cardiac implantable electronic device (CIED) would be expected to derive particular benefit from CMR given high prevalence of cardiomyopathy and arrhythmia. While several guidelines have been published over the last 16 years, it is important to recognize that both the CIED and CMR technologies, as well as our knowledge in MR safety, have evolved rapidly during that period. Given increasing utilization of CIED over the past decades, there is an unmet need to establish a consensus statement that integrates latest evidence concerning MR safety and CIED and CMR technologies. While experienced centers currently perform CMR in CIED patients, broad availability of CMR in this population is lacking, partially due to limited availability of resources for programming devices and appropriate monitoring, but also related to knowledge gaps regarding the risk-benefit ratio of CMR in this growing population. To address the knowledge gaps, this SCMR Expert Consensus Statement integrates consensus guidelines, primary data, and opinions from experts across disparate fields towards the shared goal of informing evidenced-based decision-making regarding the risk-benefit ratio of CMR for patients with CIEDs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

OBJECTIVE. Patients with cardiac implantable electronic devices (CIEDs) require cardiac MRI (CMRI) for a variety of reasons. The purpose of this study is to review and evaluate the value and safety of CMRI for patients with in situ CIEDs. CONCLUSION. Late gadolinium enhancement CMRI is the reference standard for assessing myocardial viability in patients with ventricular tachycardia before ablation of arrhythmogenic substrates. The use of late gadolinium enhancement CMRI for patients with CIEDs is safe as long as an imaging protocol is in place and precaution measures are taken.

OBJECTIVE. An important application of late gadolinium enhancement (LGE) cardiac MRI is accurate assessment of myocardial scar before ablation. However, this is often limited in patients with cardiac implantable electronic devices (CIEDs) because of metal device-induced artifacts. The purpose of this study was to determine whether a modified wideband inversion recovery (IR) LGE MRI technique decreases artifact volume to allow the assessment of myocardial scar. SUBJECTS AND METHODS. Fifty patients (17 women and 33 men; mean age ± SD, 61 ± 12 years; mean ejection fraction ± SD, 35.9% ± 13.3%) with CIEDs underwent cardiac MRI using conventional and modified wideband IR LGE techniques before ablation. The volume of device-induced artifact was quantified and stratified by tertiles on mild, moderate, and severe. Ordinal logistic regression analysis assessed the association between artifact volume on conventional and wideband images adjusted for patients' demographics. RESULTS. Conventional LGE MRI resulted in device-induced hyperintense artifacts that obscured ventricular segments in 32 of 50 (64%) cases. Wideband LGE MRI significantly reduced severe artifact volume ( p < 0.0001) and completely resolved all mild and most moderate artifacts. Overall, wideband techniques resulted in a 56% reduction in total artifact volume for the cohort ( p < 0.0001). The wideband LGE MRI sequence minimized artifacts in the most commonly obscured segments on the conventional LGE MRI sequence, with persistent artifacts in seven, eight, and four of 32 cases at the basal anterior, midventricular anterior, and midventricular anteroseptal segments, respectively. CONCLUSION. The modified wideband IR technique completely resolves mild and moderate device-induced hyperintense artifacts and significantly reduces the volume of severe artifact to allow accurate identification of myocardial scar in patients with CIEDs before ablation.

Aims: Magnetic resonance imaging (MRI) has been reported to be safe in patients with cardiac implantable electronic devices (CIED) provided a specific protocol is followed. The objective of this study was to assess whether this is also true for patients excluded from published protocols., Methods and Results: A total of 160 MRIs were obtained in 142 consecutive patients with CIEDs [106 patients had an implantable cardioverter defibrillator (ICD) and 36 had a pacemaker implanted] using an adapted, pre-specified protocol. A cardiac MRI was performed in 95 patients, and a spinal/brain MRI was performed in 47 patients. Forty-six patients (32%) had either abandoned leads (n = 10), and/or were pacemaker dependent with an implanted ICD (n = 19), had recently implanted CIEDs (n = 1), and/or had a CIED device with battery depletion (n = 2), and/or a component of the CIED was recalled or on advisory (n = 32). No major complications occurred. Some device parameters changed slightly, but significantly, right after or at 1-week post-MRI without requiring any reprogramming. In one patient with an ICD on advisory, the pacing rate changed inexplicably during one of his two MRIs from 90 to 50 b.p.m., Conclusion: Using a pre-specified protocol, cardiac and non-cardiac MRIs were performed in CIED patients with pacemaker dependency, abandoned leads, or depleted batteries without occurrence of major adverse events. Patients with devices on advisory need to be monitored carefully during MRI, especially if they are pacemaker dependent., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

Background: Ventricular tachycardia (VT) in patients with cardiomyopathy originates in scar tissue. Intramural or epicardial scar may result in ineffective ablation if mapping and ablation are limited to the endocardium. The purpose of this study was to investigate whether preprocedural magnetic resonance imaging (MRI) is beneficial in patients with failed endocardial VT ablations in determining an appropriate ablation strategy., Methods and Results: A cardiac MRI was performed in 20 patients with a failed ablation procedure and cardiomyopathy (nonischemic n = 12, ischemic n = 8). A subsequent ablation strategy was determined by a delayed enhanced MRI (DE-MRI) and an epicardial subxyphoid access was planned only in patients with epicardial or intramural free-wall scar. MRIs were performed in all patients with or without an implanted cardioverter defibrillator (ICD). The location of scar tissue in the MRI predicted the origin of VT in all patients. In 9/20 patients an epicardial procedure was performed based on the result of the MRI. An endocardial procedure was performed in the remaining 11 patients who had either endocardial or septal scarring and one patient in whom the MRI only showed artifact. Five patients remained inducible postablation and four patients had VT recurrence within a follow-up period of 17 ± 22 months. All of the latter patients had an intramural scar pattern., Conclusions: Imaging with DE-MRI prior to VT ablation in patients with previously failed endocardial ablation procedures is beneficial in identifying an ablation strategy, helps to focus on an area of interest intraprocedurally, and provides valuable outcomes information., (© 2015 Wiley Periodicals, Inc.)

Background: The purpose of this study was to assess whether delayed enhancement (DE) on MRI is associated with ventricular tachycardia (VT)/ventricular fibrillation or death in patients with cardiac sarcoidosis and left ventricular ejection fraction >35%., Methods and Results: Fifty-one patients with cardiac sarcoidosis and left ventricular ejection fraction >35% underwent DE-MRI. DE was assessed by visual scoring and quantified with the full-width at half-maximum method. The patients were followed for 48.0 ± 20.2 months. Twenty-two of 51 patients (63%) had DE. Forty patients had no prior history of VT (primary prevention cohort). Among those, 3 patients developed VT and 2 patients died. DE was associated with risk of VT/ventricular fibrillation or death (P=0.0032 for any DE and P<0.0001 for right ventricular DE). The positive predictive values of the presence of any DE, multifocal DE, and right ventricular DE for death or VT/ventricular fibrillation at mean follow-up of 48 months were 22%, 48%, and 100%, respectively. Among the 11 patients with a history of VT before the MRI, 10 patients had subsequent VTs, 1 of whom died., Conclusions: RV DE in patients with cardiac sarcoidosis is associated with a risk of adverse events in patients with cardiac sarcoidosis and preserved ejection fraction in the absence of a prior history of VT. Patients with DE and a prior history of VT have a high VT recurrence rate. Patients without DE on MRI have a low risk of VT., (© 2014 American Heart Association, Inc.)

Purpose: This study aims to determine the impact of preprocedural imaging using computerized tomography (CT) or magnetic resonance imaging (MRI) with 3-D reconstruction on procedural efficiency, efficacy, complications and clinical outcome in patients who undergo radiofrequency catheter ablation (RFA) to eliminate atrial fibrillation (AF)., Methods: In this registry, a CT (n = 161) or MRI (n = 37) was obtained prior to RFA in 198 of 333 consecutive patients (age 61 ± 10 years) with paroxysmal (172) or persistent (161) AF. Antral pulmonary vein isolation was performed in all patients using an open-irrigation-tip catheter with a 3-D electroanatomical navigation system. Procedural and clinical outcomes were compared among patients who underwent RFA with and without preprocedural imaging., Results: The mean duration of the procedure (246 ± 47 vs. 242 ± 40 min, P = 0.55), fluoroscopy (47 ± 13 vs. 50 ± 10 min, P = 0.16), and total RF application (83 ± 27 vs. 78 ± 23 min, P = 0.17) were similar among patients who did and did not have preprocedural imaging. The likelihood of a complication also was similar (5/198 [3%] vs. 4/135 [3%], P = 1.0). A repeat ablation was performed in 95/198 (48%) and 61/135 (45%) of the patients who did and did not have imaging study, respectively (P = 0.62). At 22 ± 9 months, after a mean of 2 ± 1 procedures, 140/198 (71%) and 101/135 (75%) of the patients who did and did not have preprocedural imaging were in sinus rhythm (P = 0.4)., Conclusions: Preprocedural awareness of pulmonary venous and left atrial anatomy does not appear to have an effect on procedural efficiency or clinical outcomes in patients who undergo catheter ablation for AF.

Post-infarction arrhythmias are most often confined to scar tissue. Scar can be detected by delayed-enhanced cardiac magnetic resonance. The purpose of this study was to assess the feasibility of pre-procedural scar identification and intraprocedural real-time image registration with an electroanatomical map in 23 patients with previous infarction and ventricular arrhythmias (VAs). Registration accuracy and cardiac magnetic resonance/electroanatomical map correlations were assessed, and critical areas for VA were correlated with the presence of scar. With a positional registration error of 3.8 ± 0.8 mm, 86% of low-voltage points of the electroanatomical map projected onto the registered scar. The delayed-enhanced cardiac magnetic resonance-defined scar correlated with the area of low voltage (R = 0.82, p < 0.001). All sites critical to VAs projected on the registered scar. Selective identification and extraction of delayed-enhanced cardiac magnetic resonance defined scar followed by registration into a real-time mapping system are feasible and help to identify and display the arrhythmogenic substrate in post-infarction patients with VAs., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Cardiac magnetic resonance imaging (MRI) has a central role in the management of patients with ventricular arrhythmias. Cardiac MRIs help to identify patients with risk for life-threatening arrhythmias. Delayed enhancement identifies scar tissue within the heart. Because scar harbors the arrhythmic substrate in patients with structural heart disease, areas of delayed enhancement can be targeted in order to eliminate ventricular arrhythmias with catheter ablation procedures. In this article, we will discuss the role of MRI in diagnosing different forms of non-ischemic cardiomyopathy and its role in risk stratification. Furthermore, we will discuss the role of MRI in imaging of the arrhythmogenic substrate in patients with structural heart disease.

Background: Structural factors contributing to the development of postinfarction ventricular tachycardia (VT) are unclear. The purpose of this study was to analyze infarct architecture and electrogram characteristics in patients with and without inducible VT and to identify correlates of postinfarction VT., Methods and Results: Twenty-four postinfarction patients (median age, 64 [53, 70] years) were referred for radiofrequency catheter ablation of VT (n = 12) or frequent symptomatic premature ventricular contractions (PVCs) (n = 12). Delayed-enhanced (DE) MRI was obtained before ablation. Electroanatomical mapping was performed and scar area and electrogram characteristics of the scar tissue compared in patients with and without inducible VT. The median ejection fraction in patients with and without inducible VT was 27% (22%, 43%) and 43% (40%, 47%), respectively (P = 0.085). Subendocardial infarct area determined by DE-MRI was larger in patients with inducible VT (43 [38, 62] cm(2)) than in those with noninducible VT (8 [4, 11] cm(2); P = 0.002), and unipolar and bipolar voltages on electroanatomical maps were significantly lower in patients with inducible VT (both P<0.05). An infarct volume of >14% identified 11 of 12 patients with inducible VT (area under the curve, 0.94; P = 0.007). On electroanatomical mapping, distinct sites with isolated potentials (IPs) were more prevalent in patients with inducible VT than in those without (13.2% versus 1.1% of points within scar; P < 0.001). The number of inducible VTs correlated with the number of distinct sites with IPs (R = 0.87; P<0.0001)., Conclusions: Scar tissue in postinfarction patients with inducible VT shows quantitative and qualitative differences from scars in patients without inducible VT. Scar size and IPs are correlated with VT inducibility.

Background: Delayed enhanced magnetic resonance imaging (DE-MRI) can be used for the exact assessment of myocardial infarct scar. Electroanatomic (EA) mapping can identify the subendocardial extension of infarcts and is used to identify and eliminate areas critical for postinfarction ventricular arrhythmias., Objectives: The purpose of this study was to correlate DE-MRI with EA mapping in postinfarction patients with ventricular arrhythmias to assess myocardial infarct architecture and its relationship to postinfarction ventricular arrhythmias., Methods: EA mapping during sinus rhythm was performed in 14 postinfarction patients (10 men; age 64 +/- 10 years; ejection fraction 0.33 +/- 0.12) referred for ablation of ventricular arrhythmias. All patients underwent prior DE-MRI. Both DE-MRI and EA mapping data were registered in three-dimensional space. Presence of scar and its transmurality as well as scar core versus gray zone were assessed on DE-MRI and correlated with EA maps; furthermore, the electrogram characteristics of the EA map were correlated with the DE-MRI., Results: Scar areas as assessed by bipolar and unipolar voltages in the EA map both correlated well with the scar as defined by DE-MRI. The best cutoff value to differentiate subendocardial scar from normal myocardium was 1.0 mV for bipolar voltage and 5.8 mV for unipolar voltage. Areas with DE had distinct electrophysiologic characteristics compared with nonenhancing sites. All identified sites that were critical for postinfarction ventricular tachycardia (31/31) and premature ventricular complexes (5/5) were located within areas of DE, with most (71%) being located in the core area of the scar., Conclusions: DE-MRI can accurately predict the EA characteristics of corresponding subendocardial locations. Critical sites of postinfarction arrhythmias were confined to areas of DE. The scar information on MRI can be selectively imported into an EA mapping system to facilitate the mapping and ablation procedure.

Objectives: The purpose of this study was to assess the value of delayed-enhanced magnetic resonance imaging (DE-MRI) to guide ablation of ventricular arrhythmias in patients with nonischemic cardiomyopathy (NIC)., Background: In patients with NIC, ventricular arrhythmias often are associated with scar tissue. DE-MRI can be used to precisely define scar tissue., Methods: DE-MRI was performed in 29 consecutive patients (mean age 50 +/- 15 years) with NIC (mean ejection fraction 37 +/- 9%) referred for catheter ablation of ventricular tachycardia (VT) or premature ventricular complexes (PVCs). Scar was extracted from DE-MRIs and was then integrated into the electroanatomic map. Mapping data were correlated with respect to the localization of scar tissue., Results: Scar was identified by DE-MRI in 14 of 29 patients. Nine of these patients had VT and 5 had PVCs. In 5 of the patients there was predominantly endocardial scar, and mapping and ablation of arrhythmias was effectively performed from the endocardium in all 5 patients. In 2 patients scar was either intramural or epicardial with extension to the endocardium. In both patients with partial endocardial scar extension, the ablation was effective in eliminating some but not all arrhythmias. In 2 patients most of the scar tissue was confined to the epicardium; mapping identified and eliminated an epicardial origin in both patients. No effect on arrhythmias could be achieved in the other 5 patients with predominantly intramural scar., Conclusions: DE-MRI in patients without prior infarctions can help to identify the arrhythmogenic substrate; furthermore, it helps to plan an appropriate mapping and ablation strategy.

Introduction: Bicuspid aortic valves (BAV) are the most common congenital heart defects and the extent of ventricular arrhythmias (VA) in patients with BAV is unclear. The objective of this study is to describe VAs and late gadolinium enhancement cardiac magnetic resonance imaging (LGE‐CMR) in patients with BAV. Methods: A total of 19 patients with BAV (18 males, age: 58 ± 13 years) were referred for VA ablation procedures. Ten patients had BAVs at the time of ablation, nine patients had prior aortic valve replacement for a BAV. All but one patient had LGE‐CMR and all patients underwent programmed ventricular stimulation at the time of the ablation. Results: Frequent PVCs were the targeted VAs in 17/19 patients and VT in 2/19 patients. Monomorphic ventricular tachycardia (VT) was inducible in 6 patients. A total of 15 VTs were inducible (2.5 ± 1.0 VTs per patient with a mean cycle length of 322 ± 83 msec). LGE was present in 13 patients. Patients with inducible VT had larger borderzone and core scar compared to non‐inducible patients (7.8 ± 2.1 cm3 vs. 2.5 ± 3.1 cm3 and 5.1 ± 2.6 cm3 vs. 1.9 ± 3.0 cm3, p‐value <.05 for both). PVCs and VTs were mapped to the periaortic valve area in 12 patients and 4 patients, respectively. The PVC burden was reduced from 27 ± 13 to 3 ± 6 (p <.001) and the ejection fraction improved from 49 ± 13% to 55 ± 9% (p =.005). Conclusions: VAs in patients with BAV often originate from the perivalvular area and patients often have LGE and inducible VT. LGE may be due to ventricular remodeling secondary to the presence of BAV and harbors the arrhythmogenic substrate for VT. [ABSTRACT FROM AUTHOR]

Background: Programed ventricular stimulation (PVS) is a risk stratification tool in patients at risk for adverse arrhythmia outcomes. Patients with negative PVS may yet be at risk for adverse arrhythmia‐related events, particularly in the presence of symptomatic ventricular arrhythmias (VA). Objective: To investigate the long‐term outcomes of real‐world patients with symptomatic VA without indication for device therapy and negative PVS, and to examine the role of cardiac scaring on arrhythmia recurrence. Methods: Patients with symptomatic VA, and late gadolinium enhancement cardiac magnetic resonance imaging (LGE‐CMR), and negative PVS testing were included. All patients underwent placement of implantable cardiac monitors (ICM). Survival analysis was performed to investigate the impact of LGE‐CMR findings on survival free from adverse arrhythmic events. Results: Seventy‐eight patients were included (age 60 ± 14 years, women n = 36 (46%), ejection fraction 57 ± 9%, cardiomyopathy n = 26 (33%), mitral valve prolapse [MVP] n = 9 (12%), positive LGE‐CMR scar n = 49 (62%), history of syncope n = 23 (29%)) including patients with primarily premature ventricular contractions (n = 21) or nonsustained VA (n = 57). Patients were followed for 1.6 ± 1.5 years during which 14 patients (18%) experienced VA requiring treatment (n = 14) or syncope due to bradycardia (n = 2). Four/9 patients (44%) with MVP experienced VA (n = 3) or syncope (n = 1). Baseline characteristics between those with and without adverse events were similar (p > 0.05); however, the presence of cardiac scar on LGE‐CMR was independently associated with an increased risk of adverse events (hazard ratio: 5.6 95% confidence interval: [1.2–27], p = 0.03, log‐rank p = 0.03). Conclusions: In a real‐world cohort with long‐term follow‐up, adverse arrhythmic outcomes occurred in 18% of patients with symptomatic VA despite negative PVS, and this risk was significantly greater in patients with positive DE‐CMR scar. Long term‐monitoring, including the use of ICM, may be appropriate in these patients. [ABSTRACT FROM AUTHOR]

Introduction: Variants of cardiomyopathy genes in patients with nonischemic cardiomyopathy (NICM) generate various phenotypes of cardiac scar and delayed enhancement cardiac magnetic resonance (DE‐CMR) imaging which may impact ventricular tachycardia (VT) management. Methods: The objective was to compare the findings of cardiomyopathy genetic testing on DE‐CMR imaging and long‐term outcomes among patients with NICM undergoing VT ablation procedures. Image phenotyping and genotyping were performed in a consecutive series of patients referred for VT ablation and correlated to survival free of VT. Scar depth index (SDI) (% of scar at 0‐3 mm, 3‐5 mm and >5 mm projected on the closest endocardial surface) was determined. Results: Forty‐three patients were included (11 women, 55 ± 14 years, ejection fraction (EF) 45 ± 16%) and were followed for 3.4 ± 2.9 years. Pathogenic variants (PV) were identified in 16 patients (37%) in the following genes: LMNA (n = 5), TTN (n = 5), DSP (n = 2), AMLS1 (n = 1), MYBPC3 (n = 1), PLN (n = 1), and SCN5A (n = 1). A ring‐like septal scar (RLSS) pattern was more often seen in patients with pathogenic variants (66% vs 15%, p =.001). RLSS was associated with deeper seated scars (SDI >5 mm 30.6 ± 22.6% vs 12.4 ± 16.2%, p =.005), and increased VT recurrence (HR 5.7 95% CI[1.8‐18.4], p =.003). After adjustment for age, sex, EF, and total scar burden, the presence of a PV remained independently associated with worse outcomes (HR 4.7 95% CI[1.22‐18.0], p =.02). Conclusions: Preprocedural genotyping and scar phenotyping is beneficial to identify patients with a favorable procedural outcome. Some PVs are associated with an intramural, deeper seated scar phenotype and have an increase of VT recurrence after ablation. [ABSTRACT FROM AUTHOR]

Background: Intramural ventricular arrhythmias (VAs) can originate in patients with or without structural heart disease. Electrogram (EGM) recordings from intramural sources of VA have not been described thoroughly. Objective: We hypothesized that the presence of scar may be linked to the site of origin (SOO) of focal, intramural VAs. Methods: In a series of 21 patients (age: 55 ± 11 years, 12 women, mean ejection fraction 43 ± 14%) in whom the SOO of intramural VAs was identified, we analyzed bipolar EGM characteristics at the SOO and compared the findings with the endocardial breakout site. The patients were from a pool of 86 patients with intramural VAs referred for ablation. Results: In 16/21 patients intramural scarring was detected by cardiac magnetic resonance (CMR) imaging In patients in whom the intramural SOO was reached, intramural bipolar EGMs showed a lower voltage and had broader EGMs compared to the endocardial breakout sites (0.97 ± 0.56 vs. 2.28 ± 0.15 mV, p =.001; and 122.3 ± 31.6 vs. 96.5 ± 26.3 ms, p <.01). All intramural sampled sites at the SOO had either low voltage or broad abnormal EGMs. The activation time was significantly earlier at the intramural SOO than at breakout sites (−36.2 ± 11.8 vs. −23.2 ± 9.1 ms, p <.0001). Conclusions: Sites of origin of intramural VAs with scar by CMR display EGM characteristics of scarring, supporting that scar tissue localizes to the SOO of intramural outflow tract arrhythmias in some patients. Scarring identified by CMR may be helpful in planning ablation procedures in patients with suspected intramural VAs. [ABSTRACT FROM AUTHOR]

Background: Late gadolinium enhancement cardiac magnetic resonance (LGE‐CMR) imaging distinguishes between intrinsic postinfarction scar and radiofrequency ablation lesion related scar (dark core lesions [DCLs]) in patients with prior ventricular tachycardia (VT) ablation procedures. Objective: To combine LGE‐CMR and electroanatomic mapping data to describe the relationship between DCLs and recurrent VT among patients undergoing repeat ablations for postinfarction VT. Methods: Consecutive patients with repeat ablation for postinfarct VT with LGE‐CMR before the repeat procedures were studied. Prior ablation procedures and implantable cardiac defibrillator electrograms were analyzed to determine new versus previously documented VT. DCLs were identified on preprocedure LGE‐CMR and registered to electroanatomic maps. A control group of patients undergoing repeat ablation procedures without imaging was included. Results: Nineteen study patients and 14 control patients were followed for 2.6 (1.6–5.6) years (31 [94%] men, age 65.8 ± 8.4 years, ejection fraction 24.7 ± 10.3, p > 0.10 for all). DCLs corresponded to unexcitable tissue during repeat procedures (area 22.4 ± 15.1 vs. 22.9 ± 16.8 cm3, correlation coefficient =.93). Most VT target sites (39/50 [78%]) were in close proximity (<1 cm) to DCLs. Most DCL related VTs 32/39 (82%) were new VTs. Patients with LGE‐CMR imaging incorporated into their ablation procedures had improved 24‐month survival from VT (64% vs. 38%, log rank p < 0.02). Conclusion: LGE‐MRI can identify prior ablation lesions corresponding to nonexcitable tissue during repeat ablation procedures for postinfarction VT. VT target sites are often located in close proximity to the DCL area that may function as a fixed border for reentry circuits. Registration of DCL from prior ablation may facilitate repeat ablation procedures. [ABSTRACT FROM AUTHOR]

Introduction: In patients with structural heart disease presenting with ventricular tachycardia (VT), detection of ventricular thrombi and subsequent management can be challenging. This study aimed to assess the value of multimodality imaging with cardiac magnetic resonance imaging (CMR), contrast‐enhanced transthoracic echocardiography (TTE), and computed tomography (CT) for thrombus detection as well as a management algorithm geared towards anticoagulation and deferred ablation for patients referred for VT ablation. Methods and results: A total of 154 consecutive patients referred for VT ablation underwent preprocedural multimodality imaging with CMR, CT, and TTE. In 9 patients (6%) a new ventricular thrombus was detected and anticoagulation was initiated. Thrombi were detected by CMR in nine patients, by CT in seven patients, and by TTE in two patients. Five patients eventually underwent endocardial VT ablation procedures 6.0 ± 2.0 months after initiation of anticoagulation with one patient also requiring an epicardial approach. Two patients died while on anticoagulation, unrelated to ventricular arrhythmia. Four of five patients were rendered non‐inducible and no testing was performed in 1/5 patients. Areas containing left ventricular thrombi were non‐excitable with pacing. Six of thirty‐two inducible VTs were mapped in close vicinity of ventricular thrombi. No clinical embolic events occurred during the ablation procedures. Conclusions: Ventricular thrombus was detected in 6% of consecutive patients with structural heart disease undergoing VT ablation. CMR was the most sensitive modality, while contrast‐enhanced TTE failed to detect the majority of thrombi. Anticoagulation followed by ablation can be safely and successfully performed in patients with ventricular thrombi. [ABSTRACT FROM AUTHOR]

Introduction: Left ventricular noncompaction (LVNC) is associated with ventricular arrhythmias (VA) including premature ventricular complexes, and ventricular tachycardia (VT). The value of imaging with delayed enhancement cardiac magnetic resonance (DE‐CMR) and programmed ventricular stimulation (PVS) for risk stratification in patients with VA and LVNC is unknown. The purpose of this study was to determine whether DE‐CMR and PVS are beneficial for risk stratification and whether CMR helps to identify VA target sites. Methods and Results: Consecutive patients with LVNC undergoing ablation for VAs were included, all patients had preprocedure DE‐CMR. A total of 23 patients (7 women, 46 ± 14 years, ejection fraction 35 ± 14) were included and followed for 2.9 ± 2.2 years. DE‐CMR scar was present in 12/23 patients (52%). PVS was performed in 20/23 patients, 8/10 patients (80%) with scar were inducible for VT compared to 0/10 (0%) patients without scar (p <.001). VA target sites in patients with scarring were located adjacent to areas of scarring in all but 1 patient and ablation was successful in 15/23 patients (65%). Patients with scar had worse survival free of VT than those without scar (log rank p =.01) and patients with inducible VT had worse survival free of VT than those who were noninducible (log rank p <.001). Conclusions: The presence of CMR defined scar in patients with LVNC was associated with inducible VT and worse outcomes. Inducibility for VT was associated with VT recurrence. Furthermore, CMR is beneficial in localizing the arrhythmogenic substrate in LVNC and therefore can aid in procedural planning. [ABSTRACT FROM AUTHOR]

Introduction: Intramural scarring is a risk factor for sudden cardiac death. The objective of this study was to determine the value of scar quantification for risk stratification in patients with nonischemic cardiomyopathy (NICM) undergoing ablation procedures for ventricular arrhythmias (VA). Methods and Results: Cardiac late gadolinium‐enhanced magnetic resonance imaging was performed in patients with NICM referred for ablation of premature ventricular complexes or ventricular tachycardia (VT). Only patients with intramural delayed enhancement were included. Scar volume was measured and correlated with immediate and long‐term outcomes. Receiver operator curves, Wilcoxon signed‐rank testing, and logistic regression were used to compare patient characteristics. The study consisted of 99 patients (74 males, mean age: 59.6 [54.0‐68.1] years, ejection fraction [EF]: 46.0 [35.0‐60.0]%). Patients without clinical VT or inducible VT had smaller total and core scar size compared to patients with a history of VT or inducible VT (total scar 1.12 [0.74‐1.79] cm3 vs 7.45 [4.16‐12.21] cm3, P <.001). A total scar volume of greater than or equal to 2.78 cm3 was associated with inducibility of VT (AUC 0.94, 95% CI [0.89‐0.98], sensitivity 85%, specificity 90%). Scar volume was associated with VT inducibility independent of a prior history of VT or the preprocedure EF (adjusted OR 1.67 [1.24‐2.24]/cm3, P <.01). Conclusion: Quantification of scar size in patients with intramural scarring is useful for risk stratification in patients with NICM and VA independent of the EF or a prior history of VT. Scar characteristics of patients without a history of VT who have inducible VT are similar to patients with a history of VT. [ABSTRACT FROM AUTHOR]

Background: Knowledge of complex arrhythmogenic substrates can help plan ventricular tachycardia (VT) ablation in patients with idiopathic dilated cardiomyopathy (DCM).Objective: The purpose of this study was to assess whether preprocedural late gadolinium enhancement magnetic resonance imaging (LGE-MRI) can improve ablation outcomes in DCM.Methods: Consecutive patients (N = 96) with idiopathic DCM underwent VT ablation with open-irrigated catheters (2006-2016). Before 2012, LGE-MRI was not performed at our institution in patients with implanted devices, but it has been performed routinely in all patients after implementation of a new MRI protocol in 2012. We retrospectively compared acute and long-term outcomes of initial VT ablation procedures in patients with (n = 41) and those without (n = 55) preprocedural LGE-MRI. Procedural outcome was classified as successful if VT was not inducible postablation.Results: The 2 groups had a similar mean age and ejection fraction, comorbidities, and frequency of epicardial ablation. Preablation LGE-MRI was independently associated with improved procedural success (63% vs 24%) by logistic regression analysis (adjusted odds ratio [OR] 7.86, P <.001). This result was consistent even when patients with nondiagnostic MRIs due to artifact were included in the imaging group (OR 4.87, P = .005). Preablation imaging was also associated with improved survival free of the composite endpoint of VT recurrence, heart transplantation, or death, which was met by 11 (27%) and 33 (60%) patients in the imaging and no imaging groups, respectively, after median 7.6 months of follow-up (unadjusted log-rank P = .02). However, there was no association with long-term outcomes after adjustment for other covariates.Conclusion: Preprocedural imaging with LGE-MRI may be associated with improved outcomes of VT ablation in DCM. [ABSTRACT FROM AUTHOR]

Aims: Magnetic resonance imaging (MRI) has been reported to be safe in patients with cardiac implantable electronic devices (CIED) provided a specific protocol is followed. The objective of this study was to assess whether this is also true for patients excluded from published protocols.Methods and Results: A total of 160 MRIs were obtained in 142 consecutive patients with CIEDs [106 patients had an implantable cardioverter defibrillator (ICD) and 36 had a pacemaker implanted] using an adapted, pre-specified protocol. A cardiac MRI was performed in 95 patients, and a spinal/brain MRI was performed in 47 patients. Forty-six patients (32%) had either abandoned leads (n = 10), and/or were pacemaker dependent with an implanted ICD (n = 19), had recently implanted CIEDs (n = 1), and/or had a CIED device with battery depletion (n = 2), and/or a component of the CIED was recalled or on advisory (n = 32). No major complications occurred. Some device parameters changed slightly, but significantly, right after or at 1-week post-MRI without requiring any reprogramming. In one patient with an ICD on advisory, the pacing rate changed inexplicably during one of his two MRIs from 90 to 50 b.p.m.Conclusion: Using a pre-specified protocol, cardiac and non-cardiac MRIs were performed in CIED patients with pacemaker dependency, abandoned leads, or depleted batteries without occurrence of major adverse events. Patients with devices on advisory need to be monitored carefully during MRI, especially if they are pacemaker dependent. [ABSTRACT FROM AUTHOR]

Background: Frequent idiopathic premature ventricular complexes (PVC) are associated with a reversible form of cardiomyopathy. The effect of frequent PVCs on left ventricular function has not been evaluated in post-infarction patients. Objective: This study sought to evaluate the value of post-infarction PVC ablation and possible determinants of a reversible cardiomyopathy. Methods: Thirty consecutive patients (24 men, age 61 ± 12, left ventricular ejection fraction [LVEF] 0.36 ± 0.12) with remote myocardial infarction referred for implantable cardioverter-defibrillator (ICD) implantation for primary prevention of sudden death or for management of symptomatic ventricular tachycardia or PVCs were evaluated. Fifteen patients with a high PVC burden (≥5% of all QRS complexes on 24-h Holter monitor) underwent mapping and ablation of PVCs before ICD implantation. The remaining 15 patients served as a control group. LVEF was assessed by echocardiography, and scar burden was assessed by cardiac magnetic resonance imaging with delayed enhancement (DE-MRI) in both groups. Results: PVC ablation was successful in 15 of 15 patients and reduced the mean PVC burden from 22 ± 12% to 2.6 ± 5.0% (P <.001). After the procedure, LVEF increased significantly from 0.38 ± 0.11 to 0.51 ± 0.09 in the PVC ablation group (P = .0001). In the control group, LVEF remained unchanged within the same time frame (0.34 ± 0.14 vs. 0.33 ± 0.15; P = .6). Patients with frequent PVCs had a significantly smaller scar burden by DE-MRI compared with control patients. Five of the patients with frequent PVCs underwent ICD implantation. Conclusion: Post-infarction patients with frequent PVCs may have a reversible form of cardiomyopathy. DE-MRI may identify patients in whom the LVEF may improve after ablation of frequent PVCs. [Copyright &y& Elsevier]

Mapping and ablation of ventricular tachycardia (VT) in patients with nonischemic cardiomyopathy can be challenging. In this article, we describe the approach to VT in patients with nonischemic cardiomyopathy that we use at the University of Michigan. Imaging, especially with delayed enhanced cardiac magnetic resonance imaging, plays a central role in planning a mapping and ablation procedure. During the mapping procedure, pace-mapping in conjunction with voltage maps focusing on areas with isolated potentials helps to identify scar areas that are critical for VT in these patients. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to define the role of papillary muscles (PAPs) in post-infarction ventricular arrhythmias. Background: Papillary muscles have been implicated in arrhythmogenesis; however, their role in post-infarction ventricular arrhythmias has not been well-defined. Methods: In a series of 9 patients (age 65 ± 9 years, ejection fraction 0.36 ± 0.1) with post-infarction ventricular arrhythmias, electroanatomic mapping in conjunction with intracardiac echocardiography demonstrated that 1 of the PAPs was involved in the arrhythmia. Magnetic resonance imaging with delayed enhancement (DEMRI) was performed in all patients without contraindications. A consecutive series of 9 patients (age 64 ± 8 years, ejection fraction 0.32 ± 0.14) with ventricular arrhythmias that did not originate from the PAP served as a control group and also underwent DEMRI. Results: Heterogeneous uptake of gadolinium during magnetic resonance imaging was observed more frequently in arrhythmogenic PAPs than in PAPs that were not involved in ventricular arrhythmias (p = 0.01). The PAPs in the control patients did not take up contrast or show homogeneous contrast uptake. Radiofrequency ablation eliminated all arrhythmias originating from PAPs. Echocardiography after the ablation showed no new or worsened mitral regurgitation. Conclusions: Papillary muscles that lie within an infarct zone might give rise to ventricular arrhythmias. Heterogeneous uptake of gadolinium in magnetic resonance images might be predictive of arrhythmogenic PAPs. Radiofrequency catheter ablation of ventricular tachycardia and ventricular ectopy arising in a PAP has a high success rate. [Copyright &y& Elsevier]

An abstract of the article "Detection of intramural scar by electroanatomic mapping versus MRI in patients with nonischemic cardiomyopathy," by Benoit Desjardins, Fred Morady and Frank Bogun is presented.