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ObjectiveTo demonstrate the feasibility of utilizing spectroscopic photoacoustic (sPA) imaging to detect radiofrequency (RF) ablation-induced necrosis in anin vivoenvironment where cardiac motion is present. Additionally, a framework for mapping the necrotic lesion using cardiac-gated sPA (CG-sPA) imaging was introduced to provide intraoperative monitoring of the extent of ablation-induced necrosis. The proposed framework aimed to overcome the challenging lack of intraoperative monitoring with conventional RF procedures, which are a minimally invasive therapy for heart arrhythmia, including atrial fibrillation (A-fib).MethodsThe sPA imaging method was used to differentiate ablated tissue from non-ablated tissue by measuring PA spectrum variation. The degree of necrosis, or necrotic extent (NE), was computed by dividing the quantified ablated tissue contrast by the total contrast from both ablated and non-ablated tissues. The necrotic area and extent were visualized using a continuous colormap. To compensate for tissue motion during the cardiac cycle, cardiac-gating was applied to the sPA data based on image similarity.ResultsIn vivovalidation of the concept was conducted in a swine model. The ablationinduced necrotic lesion at the surface of the beating heart was successfully depicted throughout the cardiac cycle through CG-sPA imaging.ConclusionThe results suggest that the introduced CG-sPA imaging frame is capable of detecting ablation-induced lesions on the beating heart.SignificanceThe proposed framework has great potential to be incorporated into clinical workflow to guide ablation procedures intraoperatively and improve operative outcomes.

Background Early during the current coronavirus disease 19 (COVID-19) pandemic, hydroxychloroquine (HCQ) received a significant amount of attention as a potential antiviral treatment, such that it became one of the most commonly prescribed medications for COVID-19 patients. However, not only has the effectiveness of HCQ remained questionable, but mainly based on preclinical and a few small clinical studies, HCQ is known to be potentially arrhythmogenic, especially as a result of QT prolongation. Objective The purpose of this study was to investigate the arrhythmic effects of HCQ, as the heightened risk is especially relevant to COVID-19 patients, who are at higher risk for cardiac complications and arrhythmias at baseline. Methods An optical mapping technique utilizing voltage-sensitive fluorescent dyes was used to determine the arrhythmic effects of HCQ in ex vivo guinea pig and rabbit hearts perfused with the upper therapeutic serum dose of HCQ (1000 ng/mL). Results HCQ markedly increased action potential dispersion, resulted in development of repolarization alternans, and initiated polymorphic ventricular tachycardia. Conclusion The study results further highlight the proarrhythmic effects of HCQ.

Better models to identify individuals at low risk of ventricular arrhythmia (VA) are needed for implantable cardioverter-defibrillator (ICD) candidates to mitigate the risk of ICD-related complications. We designed the CERTAINTY study (CinE caRdiac magneTic resonAnce to predIct veNTricular arrhYthmia) with deep learning for VA risk prediction from cine cardiac magnetic resonance (CMR). Using a training cohort of primary prevention ICD recipients (n = 350, 97 women, median age 59 years, 178 ischemic cardiomyopathy) who underwent CMR immediately prior to ICD implantation, we developed two neural networks: Cine Fingerprint Extractor and Risk Predictor. The former extracts cardiac structure and function features from cine CMR in a form of cine fingerprint in a fully unsupervised fashion, and the latter takes in the cine fingerprint and outputs disease outcomes as a cine risk score. Patients with VA (n = 96) had a significantly higher cine risk score than those without VA. Multivariate analysis showed that the cine risk score was significantly associated with VA after adjusting for clinical characteristics, cardiac structure and function including CMR-derived scar extent. These findings indicate that non-contrast, cine CMR inherently contains features to improve VA risk prediction in primary prevention ICD candidates. We solicit participation from multiple centers for external validation.

Introduction: Computational modeling-guided, personalized electrophysiology (EP) intervention for atrial fibrillation (AF) is an emerging paradigm of precision medicine. In the published models, advanced imaging and invasive mapping achieve personalization of cardiac anatomy. However, EP cellular personalization is less developed, and parameters are often assumed to be uniform across individual patients Hypothesis: Anatomical personalization alone is not sufficient to recapitulate the individual clinical features of AF in personalized models. Methods: For each of 57 patients (66±10 yr, 30 persistent) referred for catheter ablation of AF, we constructed a personalized 3-D model using pre-ablation CT, invasive mapping, and Courtemanche-Ramirez-Nattel atrial cell model. In the pre-ablation model, we performed virtual ramp pacing with cycle lengths at 200-120ms within the coronary sinus to induce AF. AF was defined as being inducible when it persists for >15s. Simulation was repeated for 5 different published sets of EP parameters of ionic currents. In total, >10k simulations were performed on an NVIDIA V100 GPU cluster, using the Lattice Boltzmann method with spatial resolution of 0.5mm and temporal resolution of 0.05ms, achieving a runtime of 24s per 1s of simulation ( Fig. A ). Results: While 100% AF inducibility was expected in the personalized pre-ablation models, AF inducibility varied between 27% and 96% depending on the set of ionic parameters used ( Fig. B ). The large variability of AF inducibility indicates that those models are highly sensitive to EP parameters, therefore anatomical personalization alone cannot adequately constrain the individual features of AF. Conclusions: The patient-specificity of the current paradigm of modeling-guided, personalized EP intervention is limited. There is an unmet clinical need for incorporation of personalized EP as well as anatomical parameters to achieve true precision medicine.

Radiofrequency (RF) ablation is an effective minimally invasive therapy for diseases including cancer and cardiac arrhythmia by heating the problematic lesions using an electric current. RF procedures lack direct, intraoperative, realtime feedback on the size and extent of ablation-induced necrosis, making the assessment of procedure completeness difficult. Previous studies have suggested that photoacoustic (PA) imaging can detect ablated lesions based on their PA spectrum difference from that of non-ablated tissues. In this work, we introduce a PA-based necrotic region mapping, focusing on visualizing the extent of ablation-induced necrosis and its lesion distribution. Real-time visual feedback on the growth of the ablation necrotic region is expected to reduce recurrence and procedural complications by avoiding incomplete and excessive ablation, respectively. The extent of necrosis is quantified based on the contribution from the ablated spectra intensity with respect to the total intensity combining with non-ablated spectra. We visualized it with continuous colormap to present the necrotic lesion size and extent. A PA image-guided ablation system consists of a side-firing linear array transducer, a laser pulse illuminating fiber bundle, and an RF ablation catheter. Three wavelengths (700nm, 740nm, and 760nm) were used for continuous illumination. The necrotic region mapping computation was applied to identify the growth of necrotic lesions over time. We applied continuous PA imaging to an ex-vivo swine liver tissue during the RF ablation. The growth of the necrotic region area was visualized through the ablation. Direct comparison between the acquired image and gross pathology demonstrated the system could monitor necrotic region size. The measured necrotic region was 5.93 mm in width, matching with the actual width of 6.2 mm. The ablated area was measured as 2.81 mm2 after the ablation. The results suggest that PA image-guided ablation system has the potential to be incorporated into clinical practice to guide ablation procedures.

Background:People living with human immunodeficiency virus (HIV+) have greater risk for sudden arrhythmic death than HIV-uninfected (HIV–) individuals. HIV-associated abnormal cardiac repolarization may contribute to this risk. We investigated whether HIV serostatus is associated with ventricular repolarization lability by using the QT variability index (QTVI), defined as a log measure of QT-interval variance indexed to heart rate variance.Methods:We studied 1123 men (589 HIV+ and 534 HIV–) from MACS (Multicenter AIDS Cohort Study), using the ZioXT ambulatory electrocardiography patch. Beat-to-beat analysis of up to 4 full days of electrocardiographic data per participant was performed using an automated algorithm (median analyzed duration [quartile 1–quartile 3]: 78.3 [66.3–83.0] hours/person). QTVI was modeled using linear mixed-effects models adjusted for demographics, cardiac risk factors, and HIV-related and inflammatory biomarkers.Results:Mean (SD) age was 60.1 (11.9) years among HIV– and 54.2 (11.2) years among HIV+ participants (PConclusions:HIV+ men have greater beat-to-beat variability in QT interval (QTVI) than HIV– men, especially in the setting of HIV viremia and heightened inflammation. Among HIV+ men, higher QTVI suggests ventricular repolarization lability, which can increase susceptibility to arrhythmias, whereas lower heart rate variability signals a component of autonomic dysfunction.

INTRODUCTION Ablation of atrial vagal ganglia has been associated with improved pulmonary vein isolation (PVI) outcomes. Disruption of vagal reflexes results in heart rate (HR) increase. We investigated the association between HR change after PVI and freedom from atrial fibrillation (AF) at 1 year. METHODS AND RESULTS Patients who underwent PVI for paroxysmal AF were identified from the Johns Hopkins Hospital AF registry. Electrocardiograms taken pre-PVI and post-PVI were used to determine the change in HR. Patients followed-up at 3, 6, and 12 months. Of 257 patients (66% male, age 59+/-11 years), 134 (52%) remained free from AF at 1 year. The average HR increased from 60.6 ± 11.3 beats per minute (bpm) pre-PVI to 70.7 ± 12.0 bpm post-PVI. Patients with recurrence of AF had lower post-PVI HR than those who remained free from AF (67.8 ± 0.2 vs 73.3 ± 13.0 bpm; P

The purpose of this study was to evaluate the usefulness of intra-atrial dyssynchrony as a marker of underlying left atrial (LA) remodeling to predict recurrence after the first atrial fibrillation (AF) ablation.Catheter ablation for AF remains far from curative with relatively high recurrence rates. One of the causes of recurrence is poor patient selection out of a diverse patient population with different degrees of LA remodeling.We included 208 patients with a history of AF (59.4 ± 10.0 years of age; 26.0% nonparoxysmal AF) referred for catheter ablation of AF who underwent pre-ablation cardiac magnetic resonance in sinus rhythm. Clinical follow-up was 20 ± 6 months. Using tissue tracking cardiac magnetic resonance, we measured the LA longitudinal strain in each of 12 equal-length segments in 2- and 4-chamber views. We defined intra-atrial dyssynchrony as the standard deviation of the time to the peak longitudinal strain corrected by the cycle length (SD-time to peak strain [TPS], %).Patients with AF recurrence after ablation (n = 101) had significantly higher SD-TPS than those without (n = 107; 3.9% vs. 2.2%; p 0.001). Multivariable cox analysis showed that SD-TPS was associated with recurrence after adjusting for clinical risk factors, AF type, LA structure and function, and fibrosis (p 0.001). Furthermore, receiver-operating characteristics analysis showed SD-TPS improved prediction of recurrence better than clinical risk factors, LA structure and function, and fibrosis.Intra-atrial dyssynchrony during sinus rhythm is an independent predictor of recurrence after the first catheter ablation of paroxysmal or persistent AF. Assessment of intra-atrial dyssynchrony may improve ablation outcomes by refining patient selection.

Aims Mapping data of human ventricular fibrillation (VF) are limited. We performed detailed mapping of the activities underlying the onset of VF and targeted ablation in patients with structural cardiac abnormalities. Methods and results We evaluated 54 patients (50 ± 16 years) with VF in the setting of ischaemic (n = 15), hypertrophic (n = 8) or dilated cardiomyopathy (n = 12), or Brugada syndrome (n = 19). Ventricular fibrillation was mapped using body-surface mapping to identify driver (reentrant and focal) areas and invasive Purkinje mapping. Purkinje drivers were defined as Purkinje activities faster than the local ventricular rate. Structural substrate was delineated by electrogram criteria and by imaging. Catheter ablation was performed in 41 patients with recurrent VF. Sixty-one episodes of spontaneous (n = 10) or induced (n = 51) VF were mapped. Ventricular fibrillation was organized for the initial 5.0 ± 3.4 s, exhibiting large wavefronts with similar cycle lengths (CLs) across both ventricles (197 ± 23 vs. 196 ± 22 ms, P = 0.9). Most drivers (81%) originated from areas associated with the structural substrate. The Purkinje system was implicated as a trigger or driver in 43% of patients with cardiomyopathy. The transition to disorganized VF was associated with the acceleration of initial reentrant activities (CL shortening from 187 ± 17 to 175 ± 20 ms, P Conclusions The onset of human VF is sustained by activities originating from Purkinje and structural substrate, before spreading throughout the ventricles to establish disorganized VF. Targeted ablation results in effective reduction of VF burden. Key question The initial phase of human ventricular fibrillation (VF) is critical as it involves the primary activities leading to sustained VF and arrhythmic sudden death. The origin of such activities is unknown. Key finding Body-surface mapping shows that most drivers (≈80%) during the initial VF phase originate from electrophysiologically defined structural substrates. Repetitive Purkinje activities can be elicited by programmed stimulation and are implicated as drivers in 37% of cardiomyopathy patients. Take-home message The onset of human VF is mostly associated with activities from the Purkinje network and structural substrate, before spreading throughout the ventricles to establish sustained VF. Targeted ablation reduces or eliminates VF recurrence.

ObjectivesTestosterone usage (T-use) may alter risk factors for sudden cardiac death in men living with HIV (MLWH). Electrocardiographic QT interval prolongation, which could potentiate ventricular arrhythmias, has previously been associated with HIV infection and, separately, with low testosterone levels. We investigated whether T-use shortens the QT interval duration in MLWH and HIV-uninfected men.MethodsWe utilized data from the Multicenter AIDS Cohort Study, a prospective, longitudinal study of HIV infection among men who have sex with men. Multivariable linear regression analyses were used to evaluate associations between T-use and corrected QT interval (QTc) duration.ResultsTestosterone usage was more common in MLWH compared with HIV-uninfected men (19% vs. 9%). In a multivariable regression analysis, T-use was associated with a 5.7ms shorter QT interval [95% confidence interval (CI): -9.5 to -1.9; P=0.003). Furthermore, stronger associations were observed for prolonged duration of T-use and recent timing of T-use.ConclusionsThis study is the first known analysis of T-use and QTc interval in MLWH. Overall, our data demonstrate that recent T-use is associated with a shorter QTc interval. Increased T-use duration above a threshold of ≥50% of visits in the preceding 5years was associated with a shorter QTc interval while lesser T-use duration was not.

Systems and methods for personalized sudden cardiac death risk prediction that generates fingerprints of imaging features of cardiac structure and function. One or more fingerprints and clinical data may be used to generate a risk score. The output risk score may be used to predict the time of death in order to select high-risk patients for implantable cardioverter-defibrillator treatment.

Aims Clinical observations suggest that the Purkinje network can be part of anatomical re-entry circuits in monomorphic or polymorphic ventricular arrhythmias. However, significant conduction delay is needed to support anatomical re-entry given the high conduction velocity within the Purkinje network. Methods and results We investigated, in computer models, whether damage rendering the Purkinje network as either an active lesion with slow conduction or a passive lesion with no excitable ionic channel, could explain clinical observations. Active lesions had compromised sodium current and a severe reduction in gap junction coupling, while passive lesions remained coupled by gap junctions, but modelled the membrane as a fixed resistance. Both types of tissue could provide significant delays of over 100 ms. Electrograms consistent with those obtained clinically were reproduced. However, passive tissue could not support re-entry as electrotonic coupling across the delay effectively increased the proximal refractory period to an extremely long interval. Active tissue, conversely, could robustly maintain re-entry. Conclusion Formation of anatomical re-entry using the Purkinje network is possible through highly reduced gap junctional coupling leading to slowed conduction.

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.

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±5.2ml to 89±4.7ml, p=0.009) and a decrease in total LAEF (from 43±1.8% to 39±2.0%, p=0.001). In patients with AF recurrence, LA volumes were unchanged. However, total LAEF decreased from 38±3% to 33±3%; p=0.015. 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=0.015). A higher increase in LA LGE extent compared to the baseline was associated with a greater decrease in total LAEF (r=-0.59, p Conclusions LA function is impaired acutely following AF catheter ablation. However, long-term changes of LA function are associated positively with successful restoration of sinus rhythm and inversely with increased LA LGE. This article is protected by copyright. All rights reserved.

Introduction Advanced interatrial block (IAB) on a 12‐lead electrocardiogram (ECG) is a predictor of stroke, incident atrial fibrillation (AF), and AF recurrence after catheter ablation. The objective of this study was to determine which features of IAB structural remodeling is associated with left atrium (LA) magnetic resonance imaging structure and function. Methods/Results We included 152 consecutive patients (23% nonparoxysmal AF) who underwent preprocedural ECG and cardiac magnetic resonance (CMR) in sinus rhythm before catheter ablation of AF. IAB was defined as P‐wave duration ≥120 ms, and was considered partial if P‐wave was positive and advanced if P‐wave had a biphasic morphology in inferior leads. From cine CMR and late gadolinium enhancement, we derived LA maximum and minimum volume indices, strain, LA fibrosis, and LA dyssynchrony. A total of 77 patients (50.7% paroxysmal) had normal P‐wave, 52 (34.2%) partial IAB, and 23 (15.1%) advanced IAB. Patients with advanced IAB had significantly higher LA minimum volume index (25.7 vs 19.9 mL/m2, P = .010), more LA fibrosis (21.9% vs 13.1%, P = .020), and lower LA maximum strain rate (0.99 vs 1.18, P = .007) than those without. Advanced IAB was independently associated with LA (minimum [P = .032] and fibrosis [P = .009]). P‐wave duration was also independently associated with LA fibrosis (β = .33; P = .049) and LA mechanical dyssynchrony (β = 2.01; P = .007). Conclusion Advanced IAB is associated with larger LA volumes, lower emptying fraction, and more fibrosis. Longer P‐wave duration is also associated with more LA fibrosis and higher LA mechanical dyssynchrony. Sin financiación 2.871 JCR (2020) Q3, 79/142 Cardiac & Cardiovascular Systems 1.193 SJR (2020) Q1, 72/349 Cardiology and Cardiovascular Medicine No data IDR 2020 UEM

Background: Characterizing myocardial conduction velocity (CV) in patients with ischemic cardiomyopathy (ICM) and ventricular tachycardia (VT) is important for understanding the patient-specific proarrhythmic substrate of VTs and therapeutic planning. The objective of this study is to accurately assess the relation between CV and myocardial fibrosis density on late gadolinium–enhanced cardiac magnetic resonance imaging (LGE-CMR) in patients with ICM. Methods: We enrolled 6 patients with ICM undergoing VT ablation and 5 with structurally normal left ventricles (controls) undergoing premature ventricular contraction or VT ablation. All patients underwent LGE-CMR and electroanatomic mapping (EAM) in sinus rhythm (2960 electroanatomic mapping points analyzed). We estimated CV from electroanatomic mapping local activation time using the triangulation method that provides an accurate estimate of CV as it accounts for the direction of wavefront propagation. We evaluated the association between LGE-CMR intensity and CV with multilevel linear mixed models. Results: Median CV in patients with ICM and controls was 0.41 m/s and 0.65 m/s, respectively. In patients with ICM, CV in areas with no visible fibrosis was 0.81 m/s (95% CI, 0.59–1.12 m/s). For each 25% increase in normalized LGE intensity, CV decreased by 1.34-fold (95% CI, 1.25–1.43). Dense scar areas have, on average, 1.97- to 2.66-fold slower CV compared with areas without dense scar. Ablation lesions that terminated VTs were localized in areas of slow conduction on CV maps. Conclusions: CV is inversely associated with LGE-CMR fibrosis density in patients with ICM. Noninvasive derivation of CV maps from LGE-CMR is feasible. Integration of noninvasive CV maps with electroanatomic mapping during substrate mapping has the potential to improve procedural planning and outcomes. Visual Overview: A visual overview is available for this article.

Objectives The aim of the current investigation is to examine whether use of high-frequency jet ventilation (HFJV) during pulmonary vein isolation (PVI) performed with force-sensing catheters is associated with improved outcomes. Background Catheter ablation is well established as therapy for symptomatic atrial fibrillation (AF). Reconnection following PVI is commonly observed during repeat ablation procedures. Technologies that may optimize catheter stability and lesion delivery include both force-sensing ablation catheters and HFJV. Methods Patients undergoing PVI at Johns Hopkins Hospital were prospectively enrolled in a registry. The study compared procedural characteristics, adverse event rates, and 1-year procedural outcomes in patients undergoing PVI supported either by standard ventilation or HFJV. Patient and procedural aspects were otherwise constant. Results Eighty-four HFJV patients and 84 matched control patients with 1-year outcome data were identified. Atrial arrhythmia recurrence occurred in 26 of 84 HFJV patients (31%) and 42 of 84 control patients (50%; p = 0.019). In patients with paroxysmal AF, arrhythmia recurrence in HFJV and control patients was 27.3% and 47.3%, respectively (p = 0.045). In patients with persistent AF, arrhythmia recurrence rates were not significantly different (37.9% in HFJV patients, 55.2% in control patients; p = 0.184). On multivariate analysis, HFJV was independently associated with improved freedom from arrhythmia recurrence. Vasopressor use during HFJV cases was significantly higher than during standard ventilation (79.7% vs. 22.4%; p = 0.001). Indices of catheter stability and contact force adequacy were significantly higher in the HFJV patients than in control patients. Complication rates in the 2 groups were similarly low. Conclusions Use of HFJV in patients undergoing PVI with radiofrequency force-sensing catheters is associated with improved outcomes, without appreciable increase in adverse procedural events.

The P-wave terminal force in lead V1 (PTFV1) on the 12-lead electrocardiogram (ECG) quantifies left atrial (LA) structural and electrophysiologic abnormalities. We aimed to evaluate the association between PTFV1 and cerebrovascular accident (CVA) as well as LA structure and function in patients with atrial fibrillation (AF). We conducted a cross-sectional study of 229 patients with AF (60 ± 10years, 72% men) with (n = 21) and without (n = 208) a history of CVA, who underwent preablation ECG and cardiac magnetic resonance in sinus rhythm. PTFV1 was defined as the duration (in milliseconds) of the downward deflection of the P wave in lead V1 multiplied by the absolute value of its amplitude (in microvolts) on ECG. PTFV1 is associated with LA minimum volume (Vmin) and left ventricular ejection fraction but not associated with the extent of LA fibrosis quantified by cardiac magnetic resonance late gadolinium enhancement. In addition, PTFV1 is associated with CVA independent of the CHA2DS2-VASc score and LA Vmin (odds ratio 1.23; 95% confidence interval 1.08 to 1.40; p = 0.002). Furthermore, PTFV1 has an incremental value over the CHA2DS2-VASc score as a marker of CVA (p

Objectives The aim of this study was to examine atrial fibrillation (AF) substrate using different modalities (point-by-point [PBP], fast anatomic mapping [FAM], and late gadolinium enhancement [LGE] magnetic resonance imaging [MRI] mapping) in patients presenting for AF ablation. Background Bipolar voltage mapping, as part of AF ablation, is traditionally performed in a PBP approach using single-tip ablation catheters. Alternative techniques for fibrosis delineation include FAM with multi-electrode circular catheters and LGE MRI. The correlation between PBP, FAM, and LGE-MRI fibrosis assessment is unknown. Methods LGE MRI was performed pre-ablation in 26 patients (73% men, mean age 63 ± 8 years). Local image intensity ratio (IIR) was used to normalize myocardial intensities. PBP and FAM voltage maps were acquired, in sinus rhythm, prior to ablation and coregistered with LGE MRI. Results The mean bipolar voltage for all 19,087 FAM voltage points was 0.88 ± 1.27 mV, and the average IIR was 1.08 ± 0.18. In an adjusted mixed-effects model, each unit increase in local IIR was associated with a 57% decrease in bipolar voltage (p 0.74 corresponded to a bipolar voltage Conclusions LGE-MRI, FAM, and PBP mapping showed good correlation in delineating electroanatomic AF substrate. Each approach has fundamental technical characteristics, the awareness of which allows proper assessment of atrial fibrosis.

Background Longitudinal change in left atrial (LA) structure and function could be helpful in predicting risk for incident AF. We used cardiac magnetic resonance (CMR) imaging to explore the relationship between change in LA structure and function and incident AF in a multi-ethnic population free of clinical cardiovascular disease at baseline. Methods and results In the Multi-Ethnic Study of Atherosclerosis (MESA), 2338 participants, free at baseline of clinically recognized AF and cardiovascular disease, had LA volume and function assessed with CMR imaging, at baseline (2000–02), and at Exam 4 (2005–07) or 5 (2010–12). Free of AF, 124 participants developed AF over 3.8±0.9 years (to 2015) following the second imaging. In adjusted Cox regression models, an average annualized change in all LA parameters were significantly associated with an increased risk of AF. An annual decrease of 1–SD unit in total LA emptying fractions (LAEF) was most strongly associated with risk of AF after adjusting for AF clinical risk factors, baseline LA parameters and left ventricular mass-to-volume ratio (hazard ratio per SD=1.91,95% confidence interval=1.53–2.38, P Model discrimination, NRI and IDI Model: CHARGE-AF risk factors# + Baseline LA variable + ΔLA variable CHARGE-AF ΔLAVImin (mL/m2/y) ΔTotal LAEF (%/y) ΔPeak LA Strain (%/y) C-statistic (95% CI) 0.757 (0.721–0.794) 0.787 (0.749–0.824) 0.779 (0.737–0.820) 0.770 (0.732–0.808) NRI† (p-value) – 0.000 (0.991) 0.107 (0.017) 0.017 (0.634) IDI (p-value) – 0.049 (5%. *Model calibration: Grønnesby and Borgan's modified Hosmer-Lemeshow chi-square statistic for survival analysis. Kaplan-Meier curves of ΔTotal LAEF Conclusion In this multi-ethnic study population free of clinical cardiovascular disease at baseline, a greater increase in LA volumes and decrease in LA function were associated with incident AF. The addition of change in total LAEF to risk prediction models for AF improved model discrimination and reclassification of AF risk. Acknowledgement/Funding This research was supported by contracts HHSN2682015ehz745.01623I,N01-HC-95159-69 from the NHLBI and UL1-TR-ehz745.016240,UL1-TR-001079,R01-HL-127659 from NIH

Author(s): Wu, Katherine C; Bhondoekhan, Fiona; Haberlen, Sabina A; Ashikaga, Hiroshi; Brown, Todd T; Budoff, Matthew J; D'Souza, Gypsyamber; Magnani, Jared W; Kingsley, Lawrence A; Palella, Frank J; Margolick, Joseph B; Martinez-Maza, Otoniel; Altekruse, Sean F; Soliman, Elsayed Z; Post, Wendy S | Abstract: BackgroundThe total QT interval comprises both ventricular depolarization and repolarization currents. Understanding how HIV serostatus and other risk factors influence specific QT interval subcomponents could improve our mechanistic understanding of arrhythmias.MethodsTwelve-lead electrocardiograms (ECGs) were acquired in 774 HIV-infected (HIV+) and 652 HIV-uninfected (HIV-) men from the Multicenter AIDS Cohort Study. Individual QT subcomponent intervals were analyzed: R-onset to R-peak, R-peak to R-end, JT segment, T-onset to T-peak, and T-peak to T-end. Using multivariable linear regressions, we investigated associations between HIV serostatus and covariates, including serum concentrations of inflammatory biomarkers such as interleukin-6 (IL-6), and each QT subcomponent.ResultsAfter adjustment for demographics and risk factors, HIV+ versus HIV- men differed only in repolarization phase durations with longer T-onset to T-peak by 2.3 ms (95% CI 0-4.5, p l .05) and T-peak to T-end by 1.6 ms (95% CI 0.3-2.9, p l .05). Adjusting for inflammation attenuated the strength and significance of the relationship between HIV serostatus and repolarization. The highest tertile of IL-6 was associated with a 7.3 ms (95% CI 3.2-11.5, p l .01) longer T-onset to T-peak. Age, race, body mass index, alcohol use, and left ventricular hypertrophy were each associated with up to 2.2-12.5 ms longer T-wave subcomponents.ConclusionsHIV seropositivity, in combination with additional risk factors including increased systemic inflammation, is associated with longer T-wave subcomponents. These findings could suggest mechanisms by which the ventricular repolarization phase is lengthened and thereby contribute to increased arrhythmic risk in men living with HIV.

Background: Previous studies showed that the quantity of the left atrial (LA) periatrial fat tissue predicts recurrence after catheter ablation of atrial fibrillation (AF). We hypothesized that the quality of the LA periatrial fat tissue, measured by the mean computed tomography attenuation, predicts recurrence after AF ablation independent of the quantity of the LA periatrial fat tissue. Methods: We included 143 consecutive patients with drug-refractory AF referred for the first catheter ablation of AF (62.2±10 years, 40% nonparoxysmal AF). All participants had a preablation cardiac computed tomography. We measured the quantity of the LA periatrial fat tissue by the area (millimeter square) and the quality by the mean computed tomography attenuation (Hounsfield units) in a standard 4-chamber view. Results: Patients with AF recurrence after ablation (n=57) had a significantly larger fat area (167.6 [interquartile range, 124.1–255] versus 145.4 [95.6–229.3] mm 2 ; P =0.018) and a higher fat attenuation (−92.0±9.8 versus −96.5±9.4 Hounsfield units; P =0.006) than those without recurrence (controls). LA fat attenuation was correlated with LA fat volume and LA bipolar voltage by invasive mapping and was associated with AF recurrence after adjusting for clinical risk factors, including body mass index, AF type, LA dimension, and fat area (hazard ratio, 2.65; P =0.001). Conclusions: The quality of the LA periatrial fat tissue is an independent predictor of recurrence after the first AF ablation. Assessment of LA periatrial fat attenuation can improve AF ablation outcomes by refining patient selection.

Aims Longitudinal change in left atrial (LA) structure and function could be helpful in predicting risk for incident atrial fibrillation (AF). We used cardiac magnetic resonance (CMR) imaging to explore the relationship between change in LA structure and function and incident AF in a multi-ethnic population free of clinical cardiovascular disease at baseline. Methods and results In the Multi-Ethnic Study of Atherosclerosis (MESA), 2338 participants, free at baseline of clinically recognized AF and cardiovascular disease, had LA volume and function assessed with CMR imaging, at baseline (2000–02), and at Exam 4 (2005–07) or 5 (2010–12). Free of AF, 124 participants developed AF over 3.8 ± 0.9 years (2015) following the second imaging. In adjusted Cox regression models, an average annualized change in all LA parameters were significantly associated with an increased risk of AF. An annual decrease of 1-SD unit in total LA emptying fractions (LAEF) was most strongly associated with risk of AF after adjusting for clinical risk factors for AF, baseline LA parameters, and left ventricular mass-to-volume ratio (hazard ratio per SD = 1.91, 95% confidence interval = 1.53–2.38, P Conclusion In this multi-ethnic study population free of clinical cardiovascular disease at baseline, a greater increase in LA volumes and decrease in LA function were associated with incident AF. The addition of change in total LAEF to risk prediction models for AF improved model discrimination and reclassification of AF risk.

ObjectiveHIV-infected (HIV+) individuals may be at increased risk for sudden arrhythmic cardiac death. Some studies have reported an association between HIV infection and prolongation of the electrocardiographic QT interval, a measure of ventricular repolarisation, which could potentiate ventricular arrhythmias. We aimed to assess whether HIV+ men have longer QT intervals than HIV-uninfected (HIV−) men and to determine factors associated with QT duration.MethodsWe performed resting 12-lead ECGs in 774 HIV+ and 652 HIV− men in the Multicenter AIDS Cohort Study (MACS). We used multivariable linear and logistic regression analyses to assess associations between HIV serostatus and Framingham corrected QT interval (QTc), after accounting for potential confounders. We also determined associations among QTc interval and HIV-related factors in HIV+ men. In a subgroup of participants, levels of serum markers of inflammation were also assessed.ResultsAfter adjusting for demographics and risk factors, QTc was 4.0 ms longer in HIV+ than HIV− men (pConclusionsHIV+ men had longer QTc, which was associated with higher levels of systemic inflammatory factors. This longer QTc may contribute to the increased risk for sudden arrhythmic cardiac death in some HIV+ individuals.

Ventricular tachycardia (VT), which can lead to sudden cardiac death, occurs frequently in patients with myocardial infarction. Catheter-based radiofrequency ablation of cardiac tissue has achieved only modest efficacy, owing to the inaccurate identification of ablation targets by current electrical mapping techniques, which can lead to extensive lesions and to a prolonged, poorly tolerated procedure. Here we show that personalized virtual-heart technology based on cardiac imaging and computational modelling can identify optimal infarct-related VT ablation targets in retrospective animal (5 swine) and human studies (21 patients) and in a prospective feasibility study (5 patients). We first assessed in retrospective studies (one of which included a proportion of clinical images with artifacts) the capability of the technology to determine the minimum-size ablation targets for eradicating all VTs. In the prospective study, VT sites predicted by the technology were targeted directly, without relying on prior electrical mapping. The approach could improve infarct-related VT ablation guidance, where accurate identification of patient-specific optimal targets could be achieved on a personalized virtual heart prior to the clinical procedure.

Atrial fibrillation (AF) leads to increased risk for stroke. Human immunodeficiency virus (HIV) is associated with cardiovascular disease (CVD), although it is unclear if HIV is associated with AF. The purpose of this study was to evaluate the association between HIV serostatus and the prevalence of AF in the Multicenter AIDS Cohort Study. A cross sectional study was conducted among 1674 HIV-infected (HIV+) and uninfected (HIV–) men who completed resting 12-lead electrocardiograms, and/or ambulatory electrocardiogram monitoring. Multivariable logistic regression was used to evaluate the association between AF, defined as the presence of either AF or atrial flutter, and HIV+ serostatus. Associations were adjusted for demographic variables, and then also for CVD risk factors. HIV+ men were younger than HIV– men (median 55.5 vs 61.7 years, P