Impact of Abandoned Leads on Cardiovascular Implantable Electronic Device Infections: A Propensity Matched Analysis of MEDIC (Multicenter Electrophysiologic Device Infection Cohort).

OBJECTIVES: This study sought to evaluate the impact of abandoned cardiovascular implantable electronic device (CIED) leads on the presentation and management of device-related infections. BACKGROUND: Device infection is a serious consequence of CIEDs and necessitates removal of all hardware for attempted cure. The merits of extracting or retaining presumed sterile but nonfunctioning leads is a subject of ongoing debate. METHODS: The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled patients with CIED infections at 10 institutions in the United States and abroad between January 1, 2009, and December 31, 2012. Within a propensity-matched cohort, relevant clinical information was compared between patients who had 1 or more abandoned leads at the time of infection and those who had none. RESULTS: Matching produced a cohort of 264 patients, including 176 with no abandoned leads and 88 with abandoned leads. The groups were balanced with respect to Charlson comorbidity index, oldest lead age, device type, sex, and race. At the time of admission, those with abandoned leads were less likely to demonstrate systemic signs of infection, including leukocytosis (p = 0.023) and positive blood cultures (p = 0.005). Conversely, patients with abandoned leads were more likely to demonstrate local signs of infections, including skin erosion (p = 0.031) and positive pocket cultures (p = 0.015). In addition, patients with abandoned leads were more likely to require laser extraction (p = 0.010). CONCLUSIONS: The results of a large prospective registry of CIED infections demonstrated that patients with abandoned leads may present with different signs, symptoms, and microbiological findings and require laser extraction more than those without abandoned leads.

Clinical presentation of CIED infection following initial implant versus reoperation for generator change or lead addition.

Objective: To explore differences in clinical manifestations and outcomes in those patients who develop infection after undergoing initial implantation versus reoperation. Methods: We compared cases of cardiac implantable electronic device (CIED) infection based on initial implantation versus reoperation from 11 centres. Results: There were 432 patients with CIED infection, 178 occurring after initial device placement and 254 after repeat reoperation. No differences were seen in age, sex or device type. Those with infection after initial implant had a higher Charlson Comorbidity Score (median 3 (IQR 2-6) vs 2 (IQR 1-4), p<0.001), shorter time since last procedure (median 8.9 months (IQR 0.9-33.3) vs 19.5 months (IQR 1.1-62.9), p<0.0001) and fewer leads (2.0±0.6vs 2.5±0.9, p<0.001). Pocket infections were more likely to occur after a reoperation (70.1%vs48.9%, p<0.001) and coagulase negative staphylococci (CoNS) was the most frequently isolated organism in this group (p=0.029). In contrast, initial implant infections were more likely to present with higher white cell count (10.5±5.1 g/dL vs 9.5±5.4 g/dL, p=0.025), metastatic foci of infection (16.9%vs8.7%, p=0.016) and sepsis (30.9%vs19.3%, p=0.006). There were no differences in in-hospital (7.9%vs5.2%, p=0.31) or 6-month mortality (21.9%vs14.0%, p=0.056). Conclusions: CIED infections after initial device implant occur earlier, more aggressively, and often due to Staphylococcus aureus. In contrast, CIED infections after reoperation occur later, are due to CoNS, and have more indolent manifestations with primary localisation to the pocket.

Attempted salvage of infected cardiovascular implantable electronic devices: Are there clinical factors that predict success?

BACKGROUND: Published guidelines mandate complete device removal in cases of cardiovascular implantable electronic device (CIED) infection. Clinical predictors of successful salvage of infected CIEDs have not been defined. METHODS: Data from the Multicenter Electrophysiologic Device Infection Collaboration, a prospective, observational, multinational cohort study of CIED infection, were used to investigate whether clinical predictors of successful salvage of infected devices could be identified. RESULTS: Of 433 adult patients with CIED infections, 306 (71%) underwent immediate device explantation. Medical management with device retention and antimicrobial therapy was initially attempted in 127 patients (29%). "Early failure" of attempted salvage occurred in 74 patients (58%) who subsequently underwent device explantation during the index hospitalization. The remaining 53 patients (42%) in the attempted salvage group retained their CIED. Twenty-six (49%) had resolution of CIED infection (successful salvage group) whereas 27 patients (51%) experienced "late" salvage failure. Upon comparing the salvage failure group, early and late (N = 101), to the group experiencing successful salvage of an infected CIED (N = 26), no clinical or laboratory predictors of successful salvage were identified. However, by univariate analysis, coagulase-negative staphylococci as infecting pathogens (P = 0.0439) and the presence of a lead vegetation (P = 0.024) were associated with overall failed salvage. CONCLUSIONS: In patients with definite CIED infections, clinical and laboratory variables cannot predict successful device salvage. Until new data are forthcoming, device explantation should remain a mandatory and early management intervention in patients with CIED infection in keeping with existing expert guidelines unless medical contraindications exist or patients refuse device removal.

Reimplantation and Repeat Infection After Cardiac-Implantable Electronic Device Infections: Experience From the MEDIC (Multicenter Electrophysiologic Device Infection Cohort) Database.

BACKGROUND: Infection is a serious complication of cardiovascular-implantable electronic device implantation and necessitates removal of all hardware for optimal treatment. Strategies for reimplanting hardware after infection vary widely and have not previously been analyzed using a large, multicenter study. METHODS AND RESULTS: The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled subjects with cardiovascular-implantable electronic device infections at multiple institutions in the United States and abroad between 2009 and 2012. Reimplantation strategies were evaluated overall, and every patient who relapsed within 6 months was individually examined for clinical information that could help explain the negative outcome. Overall, 434 patients with cardiovascular-implantable electronic device infections were prospectively enrolled at participating centers. During the initial course of therapy, complete device removal was done in 381 patients (87.8%), and 220 of them (57.7%) were ultimately reimplanted with new devices. Overall, the median time between removal and reimplantation was 10 days, with an interquartile range of 6 to 19 days. Eleven of the 434 patients had another infection within 6 months, but only 4 of them were managed with cardiovascular-implantable electronic device removal and reimplantation during the initial infection. Thus, the repeat infection rate was low (1.8%) in those who were reimplanted. Patients who retained original hardware had a 11.3% repeat infection rate. CONCLUSIONS: Our study findings confirm that a broad range of reimplant strategies are used in clinical practice. They suggest that it is safe to reimplant cardiac devices after extraction of previously infected hardware and that the risk of a second infection is low, regardless of reimplant timing.

Prevention, Diagnosis, and Treatment of Cardiac Implantable Electronic Device Infections.

Cardiac implantable electronic device (CIED) infections are complex medical problems that are increasingly encountered. They are associated with significant morbidity and mortality with tremendous economic cost. The current review will emphasize the prevention, diagnosis, and treatment of this clinical entity using the relatively limited evidence that is currently available. Because there is a paucity of high quality evidence regarding prevention, diagnosis, and treatment of CIED infections, this review will attempt to summarize the best evidence as well as to suggest, when possible, paradigms for care. The topic of CIED infections is a dynamic one as the scope of CIED continues to widen. Furthermore, there are promising advancements in CIED technology which may help reduce its occurrence the future. Unfortunately, significant gaps in knowledge remain, and definitive recommendations regarding CIED infections and future studies should be directed at improving our ability to prevent infections.

Atrial Fibrillation Ablation and Stroke.

Catheter ablation has become a widely available and accepted treatment to restore sinus rhythm in atrial fibrillation patients who fail antiarrhythmic drug therapy. Although generally safe, the procedure carries a non-negligible risk of complications, including periprocedural cerebral insults. Uninterrupted anticoagulation, maintenance of an adequate ACT during the procedure, and measures to avoid and detect thrombus build-up on sheaths and atheters during the procedure, appears useful to reduce the risk of embolic events. This is a review of the incidence, mechanisms, impact, and methods to reduce catheter ablation related cerebral insults.

Non-Vitamin K Antagonist Oral Anticoagulants and Antiplatelet Therapy for Stroke Prevention in Patients With Atrial Fibrillation: A Meta-Analysis of Randomized Controlled Trials.

Non-vitamin K antagonist oral anticoagulants (NOACs) are frequently used to prevent stroke in patients with atrial fibrillation. These patients are often also on aspirin or other antiplatelet agents. It is possible that treatment with both NOACs and aspirin or other antiplatelet drug may be effective in decreasing stroke, but data are sparse regarding the efficacy and safety of using both agents for stroke prevention. To address these issues, data were pooled from the 4 recent randomized, controlled trials of NOACs: apixaban, rivaroxaban, dabigatran, and edoxaban, which included 42,411 patients; 14,148 (33.4%) were also on aspirin or other antiplatelet drug. The number of thromboembolic events among participants on NOAC and aspirin/antiplatelet was compared with the number of events in patients on NOAC alone. Bleeding rates were also compared between those on NOAC + aspirin/antiplatelet and on NOAC alone. These results were compared with thromboembolic and bleeding events in the warfarin + aspirin/antiplatelet versus warfarin alone. No greater risk for thromboembolism was seen in patients on NOACs compared with patients on both NOACs and aspirin/antiplatelet drug. In this nonrandomized comparison, there was initially a signal toward higher thromboembolic rates among NOAC users also on aspirin/antiplatelet drugs (relative risk, 1.16; 95% confidence intervals, 1.05, 1.29) when compared with NOAC alone. This likely reflected the higher CHADS2 scores of those on aspirin/antiplatelet drugs. When the analysis was limited to studies that included aspirin rather than other antiplatelet drugs, no difference was seen for thromboembolic rates comparing dual therapy to NOAC alone (relative risk, 1.02; 95% confidence intervals, 0.90, 1.15). Higher rates of bleeding were seen with aspirin/antiplatelet drug in conjunction with NOAC. In this meta-analysis and nonrandomized comparison of aspirin/antiplatelet users and nonusers also on anticoagulation, there was no additional benefit seen of anticoagulation and antiplatelet therapy for stroke prevention when compared with anticoagulation alone. There was, however, an increased risk of bleeding. Careful assessment of the indications for antiplatelet drugs in patients with atrial fibrillation who are also receiving oral anticoagulants is warranted, and future randomized comparisons are needed.

Atrioesophageal fistula following ablation procedures for atrial fibrillation: systematic review of case reports.

BACKGROUND: Atrioesophageal fistula (AEF) is a rare but serious adverse event of atrial fibrillation (AF) ablation. OBJECTIVE: To identify the clinical characteristics of AEF following ablation procedures for AF and determine the associated mortality. METHODS: A systematic review of observational cases of AEF following ablation procedures for AF was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol. RESULTS: 53 cases were identified. Mean age was 54±13 years; 73% (39/53) of cases occurred in males. Mean interval between procedure and presentation was 20±12 days, ranging from 2 to 60 days. AEF was observed in 12 patients who underwent surgical radiofrequency ablation (RFA) and in 41 patients with percutaneous RFA. Fever was the most common presenting symptom (n=44) followed by neurological deficits (n=27) and haematemesis (n=19). CT of the chest (n=27) was the preferred diagnostic test. Patients who did not receive a primary esophageal repair were more likely to have a deadly outcome (34% vs 83%; p<0.05). No difference in mortality rate was found between patients who underwent surgical RFA when compared with percutaneous RFA (58% vs 56%; p=0.579). No association was found between onset of symptoms and mortality (19±10 vs 23±14 days; p=0.355). CONCLUSIONS: AEF following ablation procedures for AF is a serious complication with high mortality rates. Presenting symptoms most often include a triad of fever, neurological deficit and/or haematemesis within 60 days of procedure. The preferred diagnostic test is CT of the chest. The treatments of choice is surgical repair.

Myocardial scar imaging by standard single-energy and dual-energy late enhancement CT: Comparison with pathology and electroanatomic map in an experimental chronic infarct porcine model.

BACKGROUND: Myocardial scar is a substrate for ventricular tachycardia and sudden cardiac death. Late enhancement CT imaging can detect scar, but it remains unclear whether newer late enhancement dual-energy (LE-DECT) acquisition has benefit over standard single-energy late enhancement (LE-CT). OBJECTIVE: We aim to compare late enhancement CT using newer LE-DECT acquisition and single-energy LE-CT acquisitions with pathology and electroanatomic map (EAM) in an experimental chronic myocardial infarction (MI) porcine study. METHODS: In 8 pigs with chronic myocardial infarction (59 ± 5 kg), we performed dual-source CT, EAM, and pathology. For CT imaging, we performed 3 acquisitions at 10 minutes after contrast administration: LE-CT 80 kV, LE-CT 100 kV, and LE-DECT with 2 postprocessing software settings. RESULTS: Of the sequences, LE-CT 100 kV provided the best contrast-to-noise ratio (all P ≤ .03) and correlation to pathology for scar (ρ = 0.88). LE-DECT overestimated scar (both P = .02), whereas LE-CT images did not (both P = .08). On a segment basis (n = 136), all CT sequences had high specificity (87%-93%) and modest sensitivity (50%-67%), with LE-CT 100 kV having the highest specificity of 93% for scar detection compared to pathology and agreement with EAM (κ = 0.69). CONCLUSIONS: Standard single-energy LE-CT, particularly 100 kV, matched better to pathology and EAM than dual-energy LE-DECT for scar detection. Larger human trials as well as more technical studies that optimize varying different energies with newer hardware and software are warranted.

Late gadolinium enhancement among survivors of sudden cardiac arrest.

OBJECTIVES: The aim of this study was to describe the role of contrast-enhanced cardiac magnetic resonance (CMR) in the workup of patients with aborted sudden cardiac arrest (SCA) and in the prediction of long-term outcomes. BACKGROUND: Myocardial fibrosis is a key substrate for SCA, and late gadolinium enhancement (LGE) on a CMR study is a robust technique for imaging of myocardial fibrosis. METHODS: We performed a retrospective review of all survivors of SCA who were referred for CMR studies and performed follow-up for the subsequent occurrence of an adverse event (death and appropriate defibrillator therapy). RESULTS: After a workup that included a clinical history, electrocardiogram, echocardiography, and coronary angiogram, 137 patients underwent CMR for workup of aborted SCA (66% male; mean age 56 ± 11 years; left ventricular ejection fraction 43 ± 12%). The presenting arrhythmias were ventricular fibrillation (n = 105 [77%]) and ventricular tachycardia (n = 32 [23%]). Overall, LGE was found in 98 patients (71%), with an average extent of 9.9 ± 5% of the left ventricular myocardium. CMR imaging provided a diagnosis or an arrhythmic substrate in 104 patients (76%), including the presence of an infarct-pattern LGE in 60 patients (44%), noninfarct LGE in 21 (15%), active myocarditis in 14 (10%), hypertrophic cardiomyopathy in 3 (2%), sarcoidosis in 3, and arrhythmogenic cardiomyopathy in 3. In a median follow-up of 29 months (range 18 to 43 months), there were 63 events. In a multivariable analysis, the strongest predictors of recurrent events were the presence of LGE (adjusted hazard ratio: 6.7; 95% CI: 2.38 to 18.85; p < 0.001) and the extent of LGE (hazard ratio: 1.15; 95% CI: 1.11 to 1.19; p < 0.001). CONCLUSIONS: Among patients with SCA, CMR with contrast identified LGE in 71% and provided a potential arrhythmic substrate in 76%. In follow-up, both the presence and extent of LGE identified a group at markedly increased risk of future adverse events.

Outcomes of patients with definite and suspected isolated cardiac sarcoidosis treated with an implantable cardiac defibrillator.

PURPOSE: Cardiac sarcoidosis (CS) patients are at increased risk for sudden death. Isolated CS is rare and can be difficult to diagnose. METHODS: In this multicenter retrospective review, patients with CS and an implantable cardiac defibrillator (ICD) were identified. RESULTS: Of 235 patients with CS and ICD, 13 (5.5 %) had isolated CS, including 7 (3.0 %) with definite isolated CS (biopsy or necropsy-proven) and 6 (2.6 %) with suspected isolated CS based on a constellation of clinical, ECG, and imaging findings. Among 13 patients with isolated CS, 10 (76.9 %) were male, mean age was 53.8 ± 7.6 years, and mean left ventricular ejection fraction was 38.3 ± 16.5. Diagnosis was made by cardiac magnetic resonance (CMR) (n = 2), biopsy (n = 3), CMR and biopsy (n = 2), CMR and positron emission tomography (PET) (n = 2), PET (n = 1), late enhanced cardiac CT (n = 1), pathology at heart transplant (n = 1), and autopsy (n = 1). Eight of 13 (61.5 %) patients with isolated CS had a secondary prevention indication (VT in 6 and VF in 2) vs. 80 of 222 (36.0 %) with sarcoidosis in other organs (p = 0.04). Over a mean of 4.2 years, 9 of 13 (69.2 %) patients with isolated CS received appropriate ICD therapy, including anti-tachycardia pacing (ATP) and/or shock, compared with 75 of 222 (33.8 %) patients with cardiac and extracardiac sarcoidosis (p = 0.0150). Six of 7 (85.7 %) patients with definite isolated CS received appropriate ICD intervention, compared with 78 of 228 patients (34.2 %) without definite isolated CS (p = 0.0192.) CONCLUSIONS: In this retrospective study, patients with isolated CS had very high rates of appropriate ICD therapy. Prospective, long-term follow-up of consecutive patients with isolated CS is needed to determine the true natural history and rates of ventricular arrhythmias in this rare and difficult-to-diagnose disease.

Effect of the 2010 task force criteria on reclassification of cardiovascular magnetic resonance criteria for arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: We sought to evaluate the effect of application of the revised 2010 Task Force Criteria (TFC) on the prevalence of major and minor Cardiovascular Magnetic Resonance (CMR) criteria for Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) versus application of the original 1994 TFC. We also assessed the utility of MRI to identify alternative diagnoses for patients referred for ARVC evaluation. METHODS: 968 consecutive patients referred to our institution for CMR with clinical suspicion of ARVC from 1995 to 2010, were evaluated for the presence of major and minor CMR criteria per the 1994 and 2010 ARVC TFC. CMR criteria included right ventricle (RV) dilatation, reduced RV ejection fraction, RV aneurysm, or regional RV wall motion abnormalities. When quantitative measures of RV size and function were not available, and in whom abnormal size or function was reported, a repeat quantitative analysis by 2 qualified CMR physicians in consensus. RESULTS: Of 968 patients, 220 (22.7%) fulfilled either a major or a minor 1994 TFC, and 25 (2.6%) fulfilled any of the 2010 TFC criterion. Among patients meeting any 1994 criteria, only 25 (11.4%) met at least one 2010 criterion. All patients who fulfilled a 2010 criteria also satisfied at least one 1994 criterion. Per the 2010 TFC, 21 (2.2%) patients met major criteria and 4 (0.4%) patients fulfilled at least one minor criterion. Eight patients meeting 1994 minor criteria were reclassified as satisfying 2010 major criteria, while 4 patients fulfilling 1994 major criteria were reclassified to only minor or no criteria under the 2010 TFC.Eighty-nine (9.2%) patients had alternative cardiac diagnoses, including 43 (4.4%) with clinically significant potential ARVC mimics. These included cardiac sarcoidosis, RV volume overload conditions, and other cardiomyopathies. CONCLUSIONS: Application of the 2010 TFC resulted in reduction of total patients meeting any diagnostic CMR criteria for ARVC from 22.7% to 2.6% versus the 1994 TFC. CMR identified alternative cardiac diagnoses in 9.2% of patients, and 4.4% of the diagnoses were potential mimics of ARVC.

Influence of vegetation size on the clinical presentation and outcome of lead-associated endocarditis: results from the MEDIC registry.

OBJECTIVES: The purpose of this study was to determine whether the clinical presentation of lead-associated endocarditis (LAE) is related to the size of lead vegetations and how size is related to bacteriology and clinical outcomes. BACKGROUND: Cardiac implantable electronic device (CIED) infection may present as either local pocket infection or bloodstream infection with or without LAE. LAE is associated with significant morbidity and mortality. METHODS: The clinical presentation and course of LAE were evaluated by the MEDIC (Multicenter Electrophysiologic Device Cohort) registry, an international registry enrolling patients with CIED infection. Consecutive LAE patients enrolled in the MEDIC registry between January 1, 2009 and December 31, 2012 were analyzed. The clinical features and outcomes of 2 groups of patients were compared based on the size of the lead vegetation detected by echocardiography (> or <1 cm in diameter). RESULTS: There were 129 patients with LAE enrolled into the MEDIC registry. Of these, 61 patients had a vegetation <1 cm in diameter (Group I) whereas 68 patients had a vegetation ≥1 cm in diameter (Group II). Patients in Group I more often presented with signs of local pocket infection, whereas Group II patients presented with clinical evidence of systemic infection. Staphylococcus aureus was the organism most often responsible for LAE, whereas infection with coagulase-negative staphylococci was associated with larger vegetations. Outcomes were improved among those who underwent complete device removal. However, major complications were associated with an open surgical approach for device removal. CONCLUSIONS: The clinical presentation of LAE is influenced by the size of the lead vegetation. Prompt recognition and management of LAE depends on obtaining blood cultures and echocardiography, including transesophageal echocardiography, in CIED patients who present with either signs of local pocket or systemic infection.

Variability in clinical features of early versus late cardiovascular implantable electronic device pocket infections.

BACKGROUND: Cardiovascular implantable electronic device (CIED) pocket infections are often related to recent CIED placement or manipulation, but these infections are not well characterized. The clinical presentation of CIED pocket infection, based on temporal onset related to last CIED procedure, deserves further study. METHODS: The MEDIC (Multicenter Electrophysiologic Device Infection Cohort) prospectively enrolled subjects with CIED infection. Subjects were stratified into those whose infection occurred <12 months (early) or ≥ 12 months (late) since their last CIED-related procedure. RESULTS: There were 132 subjects in the early group and 106 in the late group. There were more females (P = 0.009) and anticoagulation use (P = 0.039) in the early group. Subjects with early infections were more likely to have had a generator change or lead addition as their last procedure (P = 0.03) and had more prior CIED procedures (P = 0.023). Early infections were more likely to present with pocket erythema (P < 0.001), swelling (P < 0.001), and pain (P = 0.007). Late infections were more likely to have pocket erosion (P = 0.005) and valvular vegetations (P = 0.009). In bacteremic subjects, early infections were more likely healthcare-associated (P < 0.001). In-hospital and 6-month mortality were equivalent. CONCLUSION: A total of 45% of patients with CIED pocket infection presented >12 months following their last CIED-related procedure. Patients with early infection were more likely to be female, on anticoagulation, and present with localized inflammation, whereas those with late infection were more likely to have CIED erosion or valvular endocarditis.

Management of refractory atrial fibrillation post surgical ablation.

Over the past two decades, invasive techniques to treat atrial fibrillation (AF) including catheter-based and surgical procedures have evolved along with our understanding of the pathophysiology of this arrhythmia. Surgical treatment of AF may be performed on patients undergoing cardiac surgery for other reasons (concomitant surgical ablation) or as a stand-alone procedure. Advances in technology and technique have made surgical intervention for AF more widespread. Despite improvements in outcome of both catheter-based and surgical treatment for AF, recurrence of atrial arrhythmias following initial invasive therapy may occur.Atrial arrhythmias may occur early or late in the post-operative course after surgical ablation. Early arrhythmias are generally treated with prompt electrical cardioversion with or without antiarrhythmic therapy and do not necessarily represent treatment failure. The mechanism of persistent or late occurring atrial arrhythmias is complex, and these arrhythmias may be resistant to antiarrhythmic drug therapy. The characterization and management of recurrent atrial arrhythmias following surgical ablation of AF are discussed below.

Navigated DENSE strain imaging for post-radiofrequency ablation lesion assessment in the swine left atria.

AIMS: Prior work has demonstrated that magnetic resonance imaging (MRI) strain can separate necrotic/stunned myocardium from healthy myocardium in the left ventricle (LV). We surmised that high-resolution MRI strain, using navigator-echo-triggered DENSE, could differentiate radiofrequency ablated tissue around the pulmonary vein (PV) from tissue that had not been damaged by radiofrequency energy, similarly to navigated 3D myocardial delayed enhancement (3D-MDE). METHODS AND RESULTS: A respiratory-navigated 2D-DENSE sequence was developed, providing strain encoding in two spatial directions with 1.2 × 1.0 × 4 mm(3) resolution. It was tested in the LV of infarcted sheep. In four swine, incomplete circumferential lesions were created around the right superior pulmonary vein (RSPV) using ablation catheters, recorded with electro-anatomic mapping, and imaged 1 h later using atrial-diastolic DENSE and 3D-MDE at the left atrium/RSPV junction. DENSE detected ablation gaps (regions with >12% strain) in similar positions to 3D-MDE (2D cross-correlation 0.89 ± 0.05). Low-strain (<8%) areas were, on average, 33% larger than equivalent MDE regions, so they include both injured and necrotic regions. Optimal DENSE orientation was perpendicular to the PV trunk, with high shear strain in adjacent viable tissue appearing as a sensitive marker of ablation lesions. CONCLUSIONS: Magnetic resonance imaging strain may be a non-contrast alternative to 3D-MDE in intra-procedural monitoring of atrial ablation lesions.

Cerebrovascular Complications Related to Atrial Fibrillation Ablation and Strategies for Periprocedural Stroke Prevention.

Transcatheter treatment of atrial fibrillation (AF) is a complex intervention performed in patients who are at inherently increased risk of a thromboembolic complication, including stroke. It is therefore not surprising that cerebrovascular accidents have been among the most feared complications since the inception of AF ablation. While improvements have been made to limit the incidence of thromboembolic events during catheter ablation of AF, the optimal strategy to minimize such complications has yet to be determined. It is hoped that larger trials using periprocedural anticoagulation strategies can be undertaken to definitively address these important concerns.

Catheter-based Epicardial Closure of the Left Atrial Appendage.

This article reviews novel techniques in stroke prevention based on epicardial closure of the left atrial appendage, illustrating the features of the first endo-epicardial device currently available and those of devices still in development. It also provides further information about early clinical experience with the endo-epicardial device.