Short- and long-term associations of atrial fibrillation catheter ablation with left atrial structure and function: A cardiac magnetic resonance study.

BACKGROUND: The effects of atrial fibrillation (AF) catheter ablation on the left atrium (LA) are poorly understood. OBJECTIVES: To examine short- and long-term associations of AF catheter ablation with LA function using cardiac magnetic resonance (CMR). METHODS: Fifty-one AF patients (mean age 56 ± 8 years) underwent CMR at baseline, 1 day (n = 17) and 11 ± 2 months after ablation (n = 38). LA phasic volumes, emptying fractions (LAEF), and longitudinal strain were measured using feature-tracking CMR. LA fibrosis was quantified using late gadolinium enhancement (LGE). RESULTS: There were no acute changes in volume; however, active, total LAEF, and peak LA strain decreased significantly compared to the baseline. During long-term follow-up, there was a decrease in maximum but not minimum LA volume (from 99 ± 5.2 ml to 89 ± 4.7 ml; p = .009) and a decrease in total LAEF (from 43 ± 1.8% to 39 ± 2.0%; p = .001). In patients with AF recurrence, LA volumes were unchanged. However, total LAEF decreased from 38 ± 3% to 33 ± 3%; p = .015. Patients without AF recurrence had no changes in LA functional parameters during follow-up. The amount of LA LGE at long-term follow-up was higher compared to the baseline, however, was significantly less compared to immediately post-procedure (37 ± 1.9% vs. 47 ± 2.8%; p = .015). A higher increase in LA LGE extent compared to the baseline was associated with a greater decrease in total LAEF (r = -.59; p < .001). CONCLUSIONS: LA function is impaired acutely following AF catheter ablation. However, long-term changes of LA function are associated positively with the successful restoration of sinus rhythm and inversely with increased LA LGE.

Radiofrequency ablation: technological trends, challenges, and opportunities.

More than three decades have passed since utilization of radiofrequency (RF) ablation in the treatment of cardiac arrhythmias. Although several limitations and challenges still exist, with improvements in catheter designs and delivery of energy the way we do RF ablation now is much safer and more efficient. This review article aims to give an overview on historical advances on RF ablation and challenges in performing safe and efficient ablation.

Clinical predictors of cardiac magnetic resonance late gadolinium enhancement in patients with atrial fibrillation.

AIMS: This study aims to examine the association of clinical co-morbidities with the presence of left atrial (LA) late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR). Previous studies have established the severity of LA LGE to be associated with atrial fibrillation (AF) recurrence following AF ablation. We sought to determine whether baseline clinical characteristics were associated with LGE extent among patients presenting for an initial AF ablation. METHODS AND RESULTS: The cohort consisted of 179 consecutive patients with no prior cardiac ablation procedures who underwent pre-procedure LGE-CMR. The extent of LA LGE for each patient was calculated using the image intensity ratio, normalized to the mean blood pool intensity, corresponding to a bipolar voltage ≤0.3 mV. The association of LGE extent with baseline clinical characteristics was examined using non-parametric and multivariable models. The mean age of the cohort was 60.9 ± 9.6 years and 128 (72%) were male. In total, 56 (31%) patients had persistent AF. The mean LA volume was 118.4 ± 41.6 mL, and the mean LA LGE extent was 14.1 ± 10.4%. There was no association with any clinical variables with LGE extent by quartiles in the multivariable model. Extent of LGE as a continuous variable was positively, but weakly associated with LA volume in a multivariable model adjusting for age, body mass index, AF persistence, and left ventricular ejection fraction (1.5% scar/mL, P = 0.038). CONCLUSION: In a cohort of patients presenting for initial AF ablation, the presence of pre-ablation LA LGE extent was weakly, but positively associated with increasing LA volume.

Left atrial structure and functional quantitation using cardiovascular magnetic resonance and multimodality tissue tracking: validation and reproducibility assessment.

BACKGROUND: Left atrium (LA) strain, volume and function are important markers of cardiovascular disease and myocardial impairment. We aimed to assess the accuracy of LA biplane volume and function measured by Multimodality Tissue Tracking (MTT). Also we assessed the inter-study reproducibility for cardiovascular magnetic resonance (CMR) derived LA volume and function parameters. METHODS: Thirty subjects (mean age: 71.3 ± 8.7, 87% male) including twenty subjects with cardiovascular events and ten healthy subjects, with CMR were evaluated in the Multi-Ethnic Study of Atherosclerosis (MESA). LA volumes were computed by the modified biplane method from 2- and 4-chamber projections and the Simpson's method from short-axis slices using both methods - manual and semi-automated delineation using MTT. LA total, active and passive ejection fractions were calculated. Pearson's correlation and Bland-Altman analysis were used to compare the measurements. In a second sample of 25 subjects (age: 65.7 ± 7.1, 72% males) inter study, intra and inter reader reliability analysis was performed. The intra-class correlation coefficient (ICC) was evaluated. RESULTS: Left atrial MTT structural and functional parameters were not different from manual delineation, yet image analysis was only half as time consuming on average with MTT. Maximal volume MTT was not different between the Simpson's and Biplane methods, functional parameters, however were different. MTT allowed us to measure multiple LA parameters with good-excellent (ICC; 0.88- 0.98, p < 0.001) intra-and inter reader reproducibility and fair-good (ICC; 0.44-0.82, p < 0.05-0.001) inter study reproducibility. CONCLUSIONS: MTT derived LA biplane volume and function is accurate and reproducible and is suited for use in longitudinal studies.

Safety of novel oral anticoagulants compared with uninterrupted warfarin for catheter ablation of atrial fibrillation.

BACKGROUND: The novel oral anticoagulants (NOACs) are used for stroke prevention in atrial fibrillation (AF), but their safety and efficacy in the periablation period are not well established. Additionally, no standard procedure for managing periprocedural and intraprocedural anticoagulation has been established. OBJECTIVE: To evaluate the frequency of hemorrhagic and thrombotic events as well as periprocedural management strategies of NOACs compared with warfarin as anticoagulation therapy for AF ablation. METHODS: This was a retrospective cohort study from a prospective AF ablation registry maintained at a large, academic medical center. RESULTS: A total of 374 cases (173 warfarin, 123 dabigatran, 61 rivaroxaban, and 17 apixaban) were included in the analysis. The overall hemorrhagic/thrombotic event rate was 14.2 % (major hemorrhage 2.7%, minor hemorrhage 11.2%, thrombotic stroke 0.5%). The frequency of minor hemorrhage was significantly higher with warfarin compared with dabigatran (15% vs 5.7%, P = 0.012). The average heparin dose required to reach the goal activated clotting time (ACT) was 5600 units for warfarin, 12 900 units for dabigatran (P < 0.001), 15 100 units for rivaroxaban (P < 0.001), and 14 700 units for apixaban (P < 0.001). The average time in minutes to reach the goal ACT was significantly longer, compared with warfarin, for dabigatran (57 vs 28, P < 0.001), rivaroxaban (63 vs 28, P < 0.001), and apixaban (72 vs 28, P < 0.001). CONCLUSIONS: Compared with warfarin, periprocedural anticoagulation with dabigatran resulted in fewer minor hemorrhages and total adverse events after AF ablation. Patients anticoagulated with NOACs required larger doses of heparin and took longer to reach the goal ACT compared with patients anticoagulated with warfarin.

Multi-ethnic study of atherosclerosis: association between left atrial function using tissue tracking from cine MR imaging and myocardial fibrosis.

PURPOSE: To investigate the association between left atrial ( LA left atrium ) function and left ventricular myocardial fibrosis using cardiac magnetic resonance (MR) imaging in a multi-ethnic population. MATERIALS AND METHODS: For this HIPAA-compliant study, the institutional review board at each participating center approved the study protocol, and all participants provided informed consent. Of 2839 participants who had undergone cardiac MR in 2010-2012, 143 participants with myocardial scar determined with late gadolinium enhancement and 286 age-, sex-, and ethnicity-matched control participants were identified. LA left atrium volume, strain, and strain rate were analyzed by using multimodality tissue tracking from cine MR imaging. T1 mapping was applied to assess diffuse myocardial fibrosis. The association between LA left atrium parameters and myocardial fibrosis was evaluated with the Student t test and multivariable regression analysis. RESULTS: The scar group had significantly higher minimum LA left atrium volume than the control group (mean, 22.0 ± 10.5 [standard deviation] vs 19.0 ± 7.8, P = .002) and lower LA left atrium ejection fraction (45.9 ± 10.7 vs 51.3 ± 8.7, P < .001), maximal LA left atrium strain ( Smax maximum LA strain ) (25.4 ± 10.7 vs 30.6 ± 10.6, P < .001) and maximum LA left atrium strain rate ( SRmax maximum LA strain rate ) (1.08 ± 0.45 vs 1.29 ± 0.51, P < .001), and lower absolute LA left atrium strain rate at early diastolic peak ( SRE LA strain rate at early diastolic peak ) (-0.77 ± 0.42 vs -1.01 ± 0.48, P < .001) and LA left atrium strain rate at atrial contraction peak ( SRA LA strain rate at atrial contraction peak ) (-1.50 ± 0.62 vs -1.78 ± 0.69, P < .001) than the control group. T1 time 12 minutes after contrast material injection was significantly associated with Smax maximum LA strain (ß coefficient = 0.043, P = .013), SRmax maximum LA strain rate (ß coefficient = 0.0025, P = .001), SRE LA strain rate at early diastolic peak (ß coefficient = -0.0016, P = .027), and SRA LA strain rate at atrial contraction peak LA strain rate at atrial contraction peak (ß coefficient -0.0028, P = .01) in the regression model. T1 time 25 minutes after contrast material injection was significantly associated with SRmax maximum LA strain rate (ß coefficient = 0.0019, P = .016) and SRA LA strain rate at atrial contraction peak (ß coefficient = -0.0022, P = .034). CONCLUSION: Reduced LA left atrium regional and global function are related to both replacement and diffuse myocardial fibrosis processes. Clinical trial registration no.: NCT00005487

Defining the blanking period, using continuous ECG monitoring, after cryoballoon pulmonary vein isolation.

BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. A blanking period (BP) of 3 months is used in clinical trials and practice. However, the optimal BP duration after PVI remains undefined. OBJECTIVE: The aim of this study was to objectively define, using continuous monitoring by an implantable loop recorder, the optimal BP duration after cryoballoon PVI. METHODS: We enrolled consecutive patients who had cryoballoon PVI and an implantable loop recorder. We determined the time of the last confirmed episode of AF within the blanking period. This was then correlated with AF recurrence in the first year after ablation. RESULTS: There were 210 patients (66 ± 9 years; 138 [66%] male; 116 [55%] paroxysmal AF; CHA2DS2-VASc score, 2.5 ± 1.6). We defined 4 distinct groups based on the last AF episode within the BP: no AF days 0-90 (n = 96 [46%]) and last AF 0-30 days (n = 46 [22%]), 31-60 days (n = 18 [9%]), and 61-90 days (n = 50 [24%]). After the 3-month BP, 101 (48%) patients had AF recurrence at 160 ± 86 days. Compared with patients with no AF in the BP, those with recurrent AF and AF burden >0% 30 days after ablation had a significantly greater AF recurrence during long-term follow-up (P = .001). CONCLUSION: Our data show that the approximately one-third of patients in whom AF occurs and who have a burden of >0% after the first month that follows PVI are at significantly higher risk of long-term recurrent AF. We therefore suggest that the blanking period be limited to a month after cryoballoon PVI.

Association between Left Atrial Late Gadolinium Enhancement and Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA).

Purpose: To determine the prevalence and correlates of left atrial (LA) late gadolinium enhancement (LGE) at cardiac MRI and its association with atrial fibrillation (AF) in a population-based sample from the Multi-Ethnic Study of Atherosclerosis (MESA). Materials and Methods: In this secondary post hoc analysis of the MESA cohort (ClinicalTrials.gov no. NCT00005487), participants without AF underwent LGE cardiac MRI at the fifth examination (2010-2012). LA LGE burden was quantified using the image intensity ratio technique on biplane long-axis two-dimensional (2D) LGE images without fat saturation. Survival analysis was performed with log-rank testing and Cox regression. Results: Of 1697 participants (mean age, 67 years ± 9 [SD]; 872 men), 1035 (61%) had LA LGE, and 75 (4.4%) developed AF during follow-up (median, 3.95 years). At univariable analysis, LA LGE was associated with age (ß = .010 [95% CI: .005, .015], P < .001), diastolic blood pressure (ß = .005 [95% CI: .001, .009], P = .02), HbA1c level (ß = .06 [95% CI: .02, .11], P = .009), heart failure (ß = .60 [95% CI: .11, 1.08], P = .02), LA volume (ß = .008 [95% CI: .004, .012], P < .001), and LA function (emptying fraction, LA global longitudinal strain, LA early diastolic peak longitudinal strain rate, and LA late diastolic peak strain rate; all P < .05). After adjusting for the variables in the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) AF score, LA LGE independently helped predict incident AF (hazard ratio = 1.46 [95% CI: 1.13, 1.88], P = .003). The highest tertile (LGE > 2%) was twice as likely to develop AF. Conclusion: Although limited by the 2D LGE technique employed, LA LGE was associated with adverse atrial remodeling and helped predict AF in a multiethnic population-based sample.Clinical trial registration no. NCT00005487Keywords: MR Imaging, Cardiac, Epidemiology Supplemental material is available for this article. © RSNA, 2023.

Association of Pro-B-Type Natriuretic Peptide With Cardiac Magnetic Resonance-Measured Global and Regional Cardiac Function and Structure Over 10 Years: The MESA Study.

Background NT-proBNP (N-terminal pro-B-type natriuretic peptide) is widely used to diagnose and manage patients with heart failure. We aimed to investigate associations between NT-proBNP levels and development of global and regional myocardial impairment, dyssynchrony, and risk of developing myocardial scar over time. Methods and Results We included 2416 adults (45-84 years) without baseline clinical cardiovascular disease from MESA (Multi-Ethnic Study of Atherosclerosis). NT-proBNP was assessed at baseline (2000-2002). Cardiac magnetic resonance-measured left ventricular parameters were assessed at baseline and year 10 (2010-2012). Tagged cardiac magnetic resonance and myocardial dyssynchrony were assessed. We used linear and logistic regression models to study the relationships between quartiles of NT-proBNP levels and outcome variables. Left ventricular parameters decreased over time. After 10-year follow-up and adjusting for cardiovascular disease risk factors, people in the highest quartile had significantly greater decline in left ventricular ejection fraction (-1.60%; 95% CI, -2.26 to -0.94; P<0.01) and smaller decline in left ventricular end systolic volume index (-0.47 mL/m2; 95% CI, -1.18 to 0.23; P<0.01) compared with those in the lowest quartile. Individuals in the highest quartile had more severe risk factor adjusted global, mid, and apical regional dyssynchrony compared with those in the lowest, second, and third quartiles (all P-trend<0.05). Compared with the lowest-quartile group, the adjusted odds ratios for having myocardial scar was 1.3 (95% CI, 0.7-2.2) for quartile 2; 1.2 (95% CI, 0.6-2.3) for quartile 3; and 2.7 (95% CI, 1.4-5.5) for quartile 4 (P-trend=0.012) for the total sample. Conclusions Among participants without baseline clinical cardiovascular disease, higher baseline NT-proBNP concentration was significantly associated with subclinical changes in developing myocardial dysfunction, more severe cardiac dyssynchrony, and higher odds of having myocardial scar over a 10-year period independent of traditional cardiovascular disease risk factors.

Association of Longitudinal Changes in NT-proBNP With Changes in Left Atrial Volume and Function: MESA.

BACKGROUND: The mechanism of left atrial (LA) remodeling is poorly understood. The aim of this longitudinal study was to investigate whether changes in NT-proBNP levels relate to alterations of LA structure and function over time in a multiethnic population. METHODS: From the prospective cohort study, the Multi-Ethnic Study of Atherosclerosis, our analysis included 1,838 participants who underwent cardiac magnetic resonance imaging at the baseline and 10-year examinations, had NT-proBNP levels available at both time points, and did not develop heart failure, myocardial infarction, and/or atrial fibrillation. Multivariable linear regression was used to analyze the association between NT-proBNP level (log-transformed) at the 2 time points and change in LA volumes, LA emptying fractions (total, active, and passive), and LA longitudinal strain. Log NT-proBNP was categorized into Low-Low (N = 681), Low-High (N = 238), High-Low (N = 237), and High-High (N = 682) based on the median value at both time points. RESULTS: With the Low-Low group as the reference group, the High-High group experienced a greater increase in LA maximum and minimum indexed volumes: 3.1 ml/m2 (95% confidence interval 1.98, 4.20) and 2.7 ml/m2 (1.89, 3.51), respectively. The High-High group also experienced a greater decrease in LA total, passive, active emptying fraction, and longitudinal strain: -3.3% (-4.46, -2.11), -0.9% (-1.80, -0.02), -4.2% (-5.55, -2.76), and -2.3% (-3.80, -0.72), respectively. The Low-High group had similar associations, but the effect sizes were not as high. CONCLUSIONS: Adverse LA remodeling over 10 years of follow-up strongly correlates with prolonged elevated levels of intracardiac stress, as assessed by NT-proBNP levels.

References Values for Left Atrial Volumes, Emptying Fractions, Strains, and Strain Rates and Their Determinants by Age, Gender, and Ethnicity: The Multiethnic Study of Atherosclerosis (MESA).

RATIONALE AND OBJECTIVES: Left Atrial (LA) adverse remodeling is an important predictor of morbidity and mortality in several cardiovascular (CV) diseases. Our goals were to quantify and provide reference ranges for LA structure and function using feature tracking cine cardiac magnetic resonance. MATERIALS AND METHODS: 2526 participants of the Multiethnic Study of Atherosclerosis study who had feature tracking cine cardiac magnetic resonance derived LA data and were free of atrial fibrillation/flutter and prior CV events at year five follow-up examination (2010-2012) were included in this study. LA phasic indexed volumes: maximum (LAVi max), minimum (LAVi min), and preatrial contraction (LAVi preA); LA empty fractions: total, passive, and active (LAtEF, LApEF, and LAaEF); LA longitudinal strain: maximum and preatrial contraction (S max and S preA); and LA longitudinal strain rate: systolic (SR max) and early/late diastolic (SR e and SR a) were measured. Age, gender, and race/ethnicity-specific reference ranges were identified. Also, reference values in a select subgroup of healthy participants free of traditional CV risk factors at the time of exam date were reported. RESULTS: The mean ± SD for LAVi max, LAVi min, LAVi preA, S max, SR e, and SR a were in the 45-65-year-old participants: (33.8 ± 10 mL/m2), (14.5 ± 6.4 mL/m2), (24.8 ± 8.2 mL/m2), (34.6 ± 13.8 %), (-1.4 ± 0.7 s-1), (-2.1 ± 1 s-1) and in the ≥ 65-year-old participants: (35 ± 11.5 mL/m2), (16.6 ± 8.3 mL/m2), (27.6 ± 9.9 mL/m2), (31.2 ± 14.3 %), (-1 ± 0.6 s-1), (-2.1 ± 1 s-1) respectively. Younger individuals had Powered by Editorial Manager and ProduXion Manager from Aries Systems Corporation smaller LA volumes and better LA function compared to their older counterparts. Similar findings were observed in Chinese-Americans as compared to Whites. CONCLUSION: This study provides reference values of LA structure and function parameters from a healthy multiethnic community-based population aged 53-94 years evaluated by FTMRI.

Unacceptable results with an accepted soft tissue filler: polyacrylamide hydrogel.

BACKGROUND: Polyacrylamide hydrogel, considered a safe and biocompatible soft tissue filler, is widely used in cosmetic procedures. Its use for facial contouring and breast augmentation in Iran has increased dramatically in recent years. Most patients and many doctors are unaware of possible and reported adverse effects related to its administration. METHODS: This study enrolled 98 patients experiencing unsatisfactory results and complications of polyacrylamide hydrogel. Adverse effects related to gel administration were documented for all the patients. Lab values were requested together with related medical care and surgical treatments, and gel was extracted by incision, milking, and irrigation. RESULTS: The most common findings at the time of presentation were inflammation (n = 51), asymmetry (n = 31), irregularity (n = 18), infection and abscess formation (n = 11), and gel migration (n = 8). In one patient, severe anaphylactoid reaction was observed 1 week after gel injection, which led to significant complications for the patient. Histologic findings showed granuloma formation (n = 17), fat necrosis (n = 9), and fibrosis (n = 17). Macroscopic gel-related complications resolved after extraction of the injected material, except for skin necrosis and hyperpigmentation, which remained unchanged. For eight patients, the gel could not be extracted by squeezing and irrigation entirely. Three patients experienced gel reaccumulation after seemingly complete removal of the gel. CONCLUSIONS: A wide range of complications seen among our patients showed that polyacrylamide hydrogel may not be as safe and biocompatible as it was thought previously. Both patients and physicians must be aware of the potential side effects of polyacrylamide hydrogel before gel administration.

Utility of Cardiac MRI in Atrial Fibrillation Management.

Advances in cardiac magnetic resonance (CMR) techniques and image acquisition have made it an excellent tool in the assessment of atrial myopathy. Remolding of the left atrium is the mainstay of atrial fibrillation (AF) development and its progression. CMR can detect phasic atrial volumes, atrial function, and atrial fibrosis using cine, and contrast-enhanced or non-contrast-enhanced images. These abilities make CMR a versatile and extraordinary tool in management of patients with AF including for risk stratification, ablation prognostication and planning, and assessment of stroke risk. We review the latest advancements in utility of CMR in management of patients with AF.

Cardiac magnetic resonance-derived right atrial functional analysis in patients with atrial fibrillation and typical atrial flutter.

BACKGROUND: Typical atrial flutter (AFL) often occurs in patients with atrial fibrillation (AF). Decision-making tools for application of prophylactic cavo-tricuspid isthmus (CTI) ablation at the time of AF ablation may improve outcomes. In this study, we sought to define the right atrial (RA) functional characteristics of AF patients with documented typical AFL. METHODS: Consecutive patients that underwent cardiac magnetic resonance (CMR) prior to initial AF ablation in the Johns Hopkins Hospital were enrolled. The AF database was reviewed to identify prevalent and incident documented typical AFL. Feature tracking CMR analysis during sinus rhythm was utilized to quantify RA longitudinal strain and strain rate, as well as RA passive and active emptying fractions derived from phasic RA volumes. RESULTS: A total of 115 patients were analyzed (mean age 59.1 ± 11.4 years, 78.3% male, 74.8% paroxysmal AF). Of all patients, 30 (26.1%) had typical AFL. Clinical characteristics and AF type did not differ among groups defined by the absence or presence of typical AFL. In contrast, RA longitudinal strain (41.6 ± 16.8% vs. 55.8 ± 17.1%, p ≤ 0.001), systolic strain rate (1.71 ± 0.85 s-1 vs. 2.33 ± 0.93 s-1, p = 0.002), and late diastolic strain rate (1.78 ± 1.02 s-1 vs. 2.50 ± 0.91 s-1 p ≤ 0.001) were significantly lower in patients with typical AFL. Although RA passive emptying fraction was similar among groups (18.9 ± 8.1 vs. 19.5 ± 8.0, p = 0.75), RA active emptying fraction was lower in patients with typical AFL (34.8 ± 12.3 vs. 40.8 ± 12.1, p = 0.02). CONCLUSIONS: The reservoir and pump function of the RA is significantly reduced in patients with typical AFL. Prophylactic CTI ablation warrants further study as adjunctive therapy to AF catheter ablation in selected patients with RA dysfunction.

Utility of Cardiac Magnetic Resonance Imaging Versus Cardiac Positron Emission Tomography for Risk Stratification for Ventricular Arrhythmias in Patients With Cardiac Sarcoidosis.

Abnormalities on cardiac magnetic resonance imaging (CMR) and positron emission tomography (PET) predict ventricular arrhythmias (VA) in patients with cardiac sarcoidosis (CS). Little is known whether concurrent abnormalities on CMR and PET increases the risk of developing VA. Our aim was to compare the additive utility of CMR and PET in predicting VA in patients with CS. We included all patients treated at our institution from 2000 to 2018 who (1) had probable or definite CS and (2) had undergone both CMR and PET. The primary endpoint was VA at follow up, which was defined as sustained ventricular tachycardia, sudden cardiac death, or any appropriate device tachytherapy. Fifty patients were included, 88% of whom had a left ventricular ejection fraction >35%. During a mean follow-up 4.1 years, 7/50 (14%) patients had VA. The negative predictive value of LGE for VA was 100% and the negative predictive value of FDG for VA was 79%. Among groups, VA occurred in 4/21 (19%) subjects in the LGE+/FDG+ group, 3/14 (21%) in the LGE+/FDG- group, and 0/15 (0%) in the FDG+/LGE- group. There were no LGE-/FDG- patients. In conclusion, CMR may be the preferred initial clinical risk stratification tool in patients with CS. FDG uptake without LGE on initial imaging may not add additional prognostic information regarding VA risk.

Atrial fibrillation catheter ablation: an updated review of current guidelines and expert consensus documents.

Although atrial fibrillation (AF) is the most common cardiac arrhythmia, its management remains complex and depends on several variables. Over the past decade, catheter ablation has been widely used as an effective method for rhythm control in AF patients. Therefore, AF ablation has been the focus of many studies in recent years. Given the complexity of AF management and catheter ablation, several guidelines have been developed to regulate and direct management of AF patients. The European Society of Cardiology (ESC), together with the European Heart Rhythm Association (EHRA) and the European Association of Cardiothoracic Surgeons (EACTS), has been regulating the European guidelines, while the American Heart Association (AHA), along with the American College of Cardiology (ACC) and the Heart Rhythm Society (HRS), is publishing the US guidelines. Additionally, HRS, EHRA, and the Society of Thoracic Surgeons, along with representatives from heart rhythm societies from different parts of the world, have developed an "expert consensus statement on catheter and surgical ablation of AF." This article reviews and compares the most recent guidelines and consensus document on AF catheter ablation.

Predictors and Incidence of Atrial Flutter After Catheter Ablation of Atrial Fibrillation.

Atrial flutter (AFL) is a common form of arrhythmia recurrence after atrial fibrillation (AF) ablation. We aimed to define (1) the incidence of AFL and (2) the clinical factors associated with cavo-tricuspid isthmus dependent (typical) and atypical AFL, after AF ablation. The retrospective cohort consisted of 1,029 patients that underwent initial radiofrequency AF ablation from May 2005 to December 2013 at a single academic center. Patients with missing follow-up data, history of AFL ablation, and those with undocumented AFL were excluded. Atrial volumes were measured using three-dimensional cardiac computed tomography or magnetic resonance imaging. A total of 607 patients were included in the final cohort (age 59.2 ± 10.6 years, 76.0% men, 58.7% paroxysmal AF). During a median follow-up of 845 days (interquartile range 389 to 1,597 days), 122 (20.1%) patients developed AFL. Of these, 17 had typical AFL, 98 had atypical AFL, and 7 patients had both circuits. In the multivariable Cox regression analysis, only right atrial volume index (hazard ratio [HR] 1.25 per 10 ml/m2, confidence interval [CI] 95% 1.10 to 1.42) was associated with incident typical AFL; whereas persistent AF (HR 1.59, CI 95% 1.06 to 2.40), linear lesions (HR 1.58, CI 95% 1.02 to 2.46) and left atrial volume index (HR 1.17 per 10 ml/m2, CI 95% 1.07 to 1.27) were associated with incident atypical AFL. In conclusion, noninvasive measures of right and left atrial remodeling are strongly associated with incident AFL after AF ablation. Strategies to prevent incident AFL using these measures after index ablation warrant further investigation.

Resting Heart Rate, Short-Term Heart Rate Variability and Incident Atrial Fibrillation (from the Multi-Ethnic Study of Atherosclerosis (MESA)).

Evidence suggests an association between autonomical nervous system (ANS) function and atrial fibrillation (AF) development. We sought to examine the association of baseline resting heart rate (RHR) and short-term heart rate variability (HRV) as surrogates of (ANS) with incident AF in individuals without previous cardiovascular disease. A total of 6,261 participants of the Multi-Ethnic Study of Atherosclerosis who were free of AF and diagnosed cardiovascular disease were enrolled. Three standard 10-second, 12-lead electrocardiograms (ECG) were used to measure RHR, the standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences in RR intervals (RMSSD). Cox proportional hazards models adjusted for demographics, atrioventricular nodal agents, and known cardiovascular risk factors were used to examine the association of baseline RHR, and log transformed SDNN and RMSDD with incident AF. Over a mean follow-up of 11.3 ± 3.7 years, 754 (12%) participants developed AF. Spline curve analysis revealed a nonlinear association between RHR, HRV, and incident AF. In fully adjusted models higher (but not lower) baseline RHR (RHR >76 beats/min) was associated with incident AF (hazard ratio 1.48 95% confidence interval 1.18 to 1.86). Additionally, lower values of RMSDD and SDNN and higher values of RMSDD were independently associated with incident AF. In conclusion, cardiac ANS dysregulation indicated as higher RHR and lower HRV is associated with incident AF independent of known cardiovascular risk factors.

Left Atrial Mechanical Function and Incident Ischemic Cerebrovascular Events Independent of AF: Insights From the MESA Study.

OBJECTIVES: This study sought to assess the association of baseline left atrial (LA) phasic function measured with cardia magnetic resonance (CMR) and incident ischemic cerebrovascular events (CVE). BACKGROUND: LA remodeling is a known predictor of atrial fibrillation (AF), which is a risk factor for ischemic CVE. Despite studies showing an association between LA remodeling and ischemic CVE, the association of LA mechanical function with ischemic CVE in a population free of known cardiovascular disease is not fully studied. METHODS: Phasic LA volumes; total, passive, and active LA emptying fractions (LAEF); and peak longitudinal LA strain were measured using feature-tracking CMR in 4,261 MESA (Multi-Ethnic Study of Atherosclerosis) participants (61 ± 10 years of age; 48% male). All individuals were free of clinical cardiovascular disease at baseline. Participants were followed for 11.6 ± 3.5 years for the diagnosis of incident ischemic CVE, defined as ischemic stroke or transient ischemic attack adjudicated by vascular neurologists. RESULTS: During the follow-up, 193 (1.26 per 1,000 person-years) ischemic CVE (134 ischemic strokes and 59 TIAs) occurred. Individuals with incident ischemic CVE had larger LA volumes and lower passive, active, and total LAEFs at baseline. In multivariate analysis adjusted for known CVE risk factors, left ventricular mass and interim AF, total LAEF was associated with incident ischemic CVE (hazard ratio [HR]: 0.85 per SD; 95% confidence interval [CI]: 0.74 to 0.98; p = 0.027). The unadjusted HR for the lowest tertile of total LAEF compared to the highest tertile was 2.0 (95% CI: 1.43 to 2.79; p < 0.001), and the adjusted HR was 1.47 (95% CI: 1.04 to 2.05; p = 0.031). Addition of total LAEF to known clinical risk factors of CVE and left ventricular mass resulted in an improved predictive accuracy (C statistic of 0.76 vs. 0.73, respectively; p = 0.039). CONCLUSIONS: Reduced total LAEF was associated with incident ischemic CVE independent of known cerebrovascular risk factors and incident AF. Assessment of LA function may add further information in stratifying asymptomatic individuals at risk for ischemic stroke.