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Post-myocardial infarction ventricular tachycardia (VT) is due to re-entry through surviving conductive myocardial corridors across infarcted tissue. However, not all conductive corridors participate in re-entry.This study sought to test the hypothesis that critical VT corridors are more likely to traverse near lipomatous metaplasia (LM) and that current loss is reduced during impulse propagation through such corridors.Among 30 patients in the Prospective 2-center INFINITY (Intra-Myocardial Fat Deposition and Ventricular Tachycardia in Cardiomyopathy) study, potential VT-viable corridors within myocardial scar or LM were computed from late gadolinium enhancement cardiac magnetic resonance images. Because late gadolinium enhancement highlights both scar and LM, LM was distinguished from scar by using computed tomography. The SD of the current along each corridor was measured.Scar exhibited lower impedance than LM (median Z-score -0.22 [IQR: -0.84 to 0.35] vs -0.07 [IQR: -0.67 to 0.54]; P lt; 0.001). Among all 381 corridors, 84 were proven to participate in VT re-entry circuits, 83 (99%) of which traversed or were adjacent to LM. In comparison, only 13 (4%) non-VT corridors were adjacent to LM. Critical corridors adjacent to LM displayed lower SD of current compared with noncritical corridors through scar but distant from LM (2.0 [IQR: 1.0 to 3.4] μA vs 8.4 [IQR: 5.5 to 12.8] μA; P lt; 0.001).Corridors critical to VT circuitry traverse infarcted tissue through or near LM. This association is likely mediated by increased regional resistance and reduced current loss as impulses traverse corridors adjacent to LM.

Nonischemic cardiomyopathies encompass a broad spectrum of myocardial disorders with mechanical or electrical dysfunction without evidence of ischemia. There are five broad variants of nonischemic cardiomyopathies; hypertrophic cardiomyopathy (Variant 1), restrictive or infiltrative cardiomyopathy (Variant 2), dilated or unclassified cardiomyopathy (Variant 3), arrhythmogenic cardiomyopathy (Variant 4), and inflammatory cardiomyopathy (Variant 5). For variants 1, 3, and 4, resting transthoracic echocardiography, MRI heart function and morphology without and with contrast, and MRI heart function and morphology without contrast are the usually appropriate imaging modalities. For variants 2 and 5, resting transthoracic echocardiography and MRI heart function and morphology without and with contrast are the usually appropriate imaging modalities. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Chest pain is a frequent cause for emergency department visits and inpatient evaluation, with particular concern for acute coronary syndrome as an etiology, since cardiovascular disease is the leading cause of death in the United States. Although history-based, electrocardiographic, and laboratory evaluations have shown promise in identifying coronary artery disease, early accurate diagnosis is paramount and there is an important role for imaging examinations to determine the presence and extent of anatomic coronary abnormality and ischemic physiology, to guide management with regard to optimal medical therapy or revascularization, and ultimately to thereby improve patient outcomes. A summary of the various methods for initial imaging evaluation of suspected acute coronary syndrome is outlined in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Background It is unknown whether sex-specific differences in mortality observed in HCM are due to older age of women at presentation, or whether women have greater degree of LV myopathy than men. Methods We retrospectively compared clinical/imaging characteristics and outcomes between women and men in our overall cohort composed of 728 HCM patients, and in an age-matched subgroup comprised of 400 age-matched patients. We examined sex-specific differences in LV myopathy, and dissected the influence of age and sex on outcomes. LV myopathy was assessed by measuring LV mass, LVEF, global peak longitudinal systolic strain (LV-GLS), diastolic function (E/A, E/e′), late gadolinium enhancement (LV-LGE) and myocardial blood flow (MBF) at rest/stress. The primary endpoint was a composite outcome, comprising heart failure (HF), atrial fibrillation (AFib), ventricular tachycardia/fibrillation (VT/VF) and death; individual outcomes were defined as the secondary endpoint. Results Women in the overall cohort were older by 6 years. Women were more symptomatic and more likely to have obstructive HCM. Women had smaller LV cavity size, stroke volume and LV mass, higher indexed maximum wall thickness (IMWT), more hyperdynamic LVEF and higher/similar LV-GLS. Women had similar LV-LGE and E/A, but higher E/e′ and rest/stress MBF. Female sex was independently associated with the composite outcome in the overall cohort, and with HF in the overall cohort and age-matched subgroup after adjusting for obstructive HCM, LA diameter, LV-GLS. Conclusions Our results suggest that sex-specific differences in LV geometry, hyper-contractility and diastolic function, not greater degree of LV myopathy, contribute to a higher, age-independent risk of diastolic HF in women with HCM.

Objective To examine differences in image quality of the coronary arteries when performing high-pitch non-electrocardiography (ECG)-gated scans on the second-generation (2G) and third-generation (3G) dual-source CT scanners. Methods We retrospectively examined patients with high-pitch non-ECG-gated CT angiography (CTA) of the chest or chest/abdomen/pelvis. Outpatient scans from 59 patients in the 3G high-pitch group and 53 patients in the 2G high-pitch group were included. Two blinded cardiac imagers independently scored the coronary image quality using a 4-point Likert scale (from completely diagnostic to completely non-diagnostic) and evaluated the presence of coronary artery disease. Results Diagnostic image quality of the coronaries in high-pitch CTA exams using 3G scanner was improved compared to 2G scanner, both on a per-vessel basis (45–94% versus 23–86%) and on a per-study basis (34% versus 14%). The 3G group showed a statistically significant improvement in image quality when evaluating the left main coronary, right coronary, and overall coronary arteries. Coronary artery disease was detected in 65% of high-pitch scans. Radiation doses in terms of CTDIvol and DLP were lower for 3G high-pitch scans (7.5 mGy and 491 mGy∗cm) compared to 2G high-pitch scans (14.8 mGy and 911 mGy∗cm). Conclusions We found a higher proportion of diagnostic image quality of the coronary arteries in high-pitch non-ECG-gated CTA exams using a 3G dual-source CT scanner, compared to 2G. In scans with diagnostic image quality, underlying coronary artery disease may be confidently diagnosed and should prompt considerations for further management in the appropriate clinical setting.

Cardiac magnetic resonance (CMR) and cardiac CT (CCT) have evolved into powerful diagnostic tools in the evaluation of patients with cardiovascular diseases. However, the use of these imaging techniques poses potential safety concerns for patients with implanted cardiac devices. These concerns result from the potential for electromagnetic interaction between the device and the CMR field or CCT x-ray radiation, which could lead to device heating, malfunction, or dislocation. Additionally, the presence of cardiac devices may induce significant image artifacts due to local magnetic field inhomogeneities (CMR) or photon starvation/beam hardening (CCT). In this review summarizes the safety issues regarding imaging in patients with cardiac devices. Optimization strategies to mitigate image artifacts and to improve imaging efficacy are discussed.

OBJECTIVES This study hypothesized that paroxysmal atrial fibrillation (PAF) reflects the presence of a more severe cardiac hypertrophic cardiomyopathy (HCM) phenotype.BACKGROUND HCM is characterized by myocyte hypertrophy, fibrosis, and a high prevalence of PAF. It is currently unresolved whether atrial fibrillation (AF) is a marker or a mediator of adverse outcomes in HCM.METHODS This study retrospectively examined 45 HCM patients who underwent cardiovascular magnetic resonance (CMR) imaging in sinus rhythm. The function of all 4 cardiac chambers was assessed, as well as late gadolinium enhancement (LGE) in the left atrium (LA) and left ventricle (LV), as indicators of fibrosis. A fat-saturated, 3-dimensional inversion recovery-prepared, fast-spoiled, gradient-recalled echo sequence, and the image intensity ratio method were used to measure LA-LGE; LGE in the LV was quantified using a semi-automated threshold technique.RESULTS HCM patients (n = 45) were divided into 2 groups (PAF, no AF) based on history of PAF. All HCM patients had LGE in the LA posterior wall. The PAF group (n = 18) had higher LA volume, a lower LA ejection fraction, a lower global peak longitudinal LA strain (PLAS), and a higher amount of LA-LGE compared with the no AF group (n = 27). A modest inverse association was noted between the LA ejection fraction, PLAS, and LA-LGE; a positive association was present between LV-LGE and LA-LGE. The PAF group had lower ejection fractions in the LV, right atrium, and right ventricle compared with those in the no AF group.CONCLUSIONS PAF is associated with a greater degree of structural LA remodeling and global myopathy, which suggests a more severe cardiac HCM phenotype. (c) 2019 The Authors. Published by Elsevier on behalf of the American College of Cardiology Foundation. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Chronic chest pain (CCP) of a cardiac etiology is a common clinical problem. The diagnosis and classification of the case of chest pain has rapidly evolved providing the clinician with multiple cardiac imaging strategies. Though scintigraphy and rest echocardiography remain as appropriate imaging tools in the diagnostic evaluation, new technology is available. Current evidence supports the use of alternative imaging tests such as coronary computed tomography angiography (CCTA), cardiac MRI (CMRI), or Rb-82 PET/CT. Since multiple imaging modalities are available to the clinician, the most appropriate noninvasive imaging strategy will be based upon the patient's clinical presentation and clinical status. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

While there is no single diagnostic test for heart failure (HF), imaging plays a supportive role beginning with confirmation of HF, especially by detecting ventricular dysfunction ( Variant 1 ). Ejection fraction (EF) is important in HF classification, and imaging plays a subsequent role in differentiation between HF with reduced EF (HFrEF) versus preserved EF (HFpEF) ( Variant 2 ). Once HFrEF is identified, distinction between ischemic and nonischemic etiologies with imaging support ( Variant 3 ) facilitates further planning. Imaging approaches which are usually appropriate include: both resting transthoracic echocardiography (TTE) and chest radiography for Variant 1 ; resting TTE and/or MRI (including functional, without absolute need for contrast) for Variant 2 ; and for Variant 3 , a. Coronary CTA or coronary arteriography (if high pretest probability/symptoms for ischemic disease) for coronary assessment; b. Rest/vasodilator stress SPECT/CT, PET/CT, or MRI for myocardial perfusion assessment; c. Rest/exercise or inotropic stress TTE for myocardial contraction assessment; or d. MRI (including morphologic with contrast) for myocardial characterization. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Background Ablation-induced left atrial (LA) edema may result in procedural failure due to reversible pulmonary vein isolation. Conventional T2-weighted magnetic resonance edema imaging is limited by low spatial resolution. Objective The purpose of this pilot study was to optimize and validate a 3-dimensional (3D) sampling perfection with application-optimized contrasts using different flip-angle evolution (SPACE) sequence for quantification of T2 signal in the LA, and to apply it in recently ablated patients, comparing myocardial edema on T2-SPACE to tissue damage on late gadolinium enhancement (LGE) imaging. Methods Phantom studies were performed to identify 3D-SPACE parameters for optimal contrast between normal and edematous myocardium. Fourteen AF patients were imaged with both 3D-SPACE and dark-blood turbo-spin echo (DB-TSE) to compare image quality and signal intensity between the 2 techniques. Eight patients underwent pre- and postablation 3D-SPACE and 3D-LGE imaging. Ablation points were co-registered with corresponding myocardial sectors, and ablation-induced changes in T2 and LGE signal intensities were measured. Results Signal-to-noise ratio and contrast-to-noise ratio were higher on SPACE vs DB-TSE (65.5 ± 33.9 vs 35.7 ± 17.9; P = .01; and 59.4 ± 33.0 vs 32.9 ± 17.7; P = .04, respectively). T2-signal correlated well on 3D-SPACE and DB-TSE, such that each unit increase in TSE intensity correlated with a 0.69-unit increase in SPACE intensity (95% confidence interval 0.56–0.82; P Conclusion T2-SPACE can be used to map the extent of acute postablation edema in the thin LA myocardium, with improved resolution and lower artifact compared to traditional DB-TSE.

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

Background Exercise intolerance is the most common symptom in hypertrophic cardiomyopathy (HCM). We examined whether inability to augment myocardial mechanics during exercise would influence functional performance and clinical outcomes in HCM. Methods Ninety-five HCM patients (32 nonobstructive, 32 labile-obstructive, 31 obstructive) and 26 controls of similar age and gender distribution were recruited prospectively. They underwent rest and treadmill stress strain echocardiography, and 61 of them underwent magnetic resonance imaging. Mechanical reserve (MRES) was defined as percent change in systolic strain rate (SR) immediately postexercise. Results Global strain and SR were significantly lower in HCM patients at rest (strain: nonobstructive, −15.6 ± 3.0; labile-obstructive, −15.9 ± 3.0; obstructive, −13.8 ± 2.9; control, −17.7% ± 2.1%, P −1 , P = .002); and immediately postexercise (strain: nonobstructive, −15.6 ± 3.0; labile-obstructive, −17.6 ± 3.6; obstructive, −15.6 ± 3.6; control, −19.2 ± 3.1%; P = .001; SR: nonobstructive, −1.41 ± 0.37; labile-obstructive, −1.64 ± 0.38; obstructive, −1.32 ± 0.29; control, −1.82 ± 0.29 s −1 , P P = .001, respectively). Postexercise SR and MRES were associated with exercise capacity ( r = 0.47 and 0.42, P r = 0.74, P = .003). Postexercise SR was correlated with extent of late gadolinium enhancement ( r = 0.34, P = .03). By Cox regression, exercise SR and MRES predicted ventricular tachycardia/ventricular fibrillation (VT/VF) even after adjustment for age, gender, family history of sudden cardiac death, septum ≥ 3 cm and abnormal blood pressure response ( P = .04 and P = .046, respectively). Conclusions Nonobstructive and obstructive patients have reduced MRES compared with labile-obstructive and controls. Postexercise SR correlates with LGE and exercise capacity. Exercise SR and MRES predict VT/VF.

Hypertrophic cardiomyopathy (HCM) is frequently associated with exercise-related sudden death. One possible contributor to arrhythmias is pathologic hypertrophy, which can lead to QTc prolongation. Since beta-adrenergic stimulation increases inward ionic currents and can increase spatial repolarization heterogeneity, we hypothesized that exercise would prolong QTc and predispose to arrhythmias in HCM patients. We tested this hypothesis by measuring QTc at rest and peak exercise, and examining ECGs for arrhythmias during exercise/recovery in 163 patients with a clinical diagnosis of HCM. Since hypertrophy and fibrosis are risk factors for arrhythmias in HCM, left ventricular (LV) mass and cardiac fibrosis were quantified using cardiac magnetic resonance imaging. Exercise led to an increase in QTc interval (436 +/- 37 to 482 +/- 45, p < 0.001), QRS duration (100 +/- 9 to 109 +/- 12, p < 0.001) and ST-T abnormalities. The proportion of patients with QTc prolongation (>470 ms) increased from 28% at rest, to 58% at peak exercise. An inverse correlation was detected between the approximated T1 relaxation time (using the Look Locker sequence) and rest-QTc (r = -0.68, p < 0.001); this association was increased during exercise (r = -0.81, p < 0.001). Late gadolinium enhancement (LGE) and LV mass were weakly associated with exercise-QTc. A weak inverse correlation was also observed between approximated T1 relaxation time and rest/exercise-QRS duration. A trend for association with arrhythmia (non-sustained ventricular tachycardia on Holler) was observed for rest-QTc >470 ms (OR = 3.0;p = 0.06). We conclude that exercise leads to QTc prolongation in a subset of HCM patients. The association between the approximated T1 relaxation time and QTc interval may reflect concomitant electrical and structural remodeling in HCM.

Objective We sought to derive and validate a model for identifying suspected ACS patients harboring undiagnosed significant coronary artery disease (CAD). Methods This was a secondary analysis of data from a randomized control trial (RCT). Patients randomized to the CTA arm of an RCT examining a CTA-based strategy for ruling-out acute coronary syndrome (ACS) constitute the derivation cohort, which was randomly divided into a training dataset (2/3, used for model derivation) and a test dataset (1/3, used for internal validation (IV)). ED patients from a different center receiving CTA to evaluate for suspected ACS constitute the external validation (EV) cohort. Primary outcome was CTA-assessed significant CAD (stenosis of ≥50% in a major coronary artery). Results In the derivation cohort, 11.2% (76/679) of subjects had CTA-assessed significant CAD, and in the EV cohort, 8.2% of subjects (87/1056) had CTA-assessed significant CAD. Age was the strongest predictor of significant CAD among the clinical risk factors examined. Predictor variables included in the derived logistic regression model were: age, sex, tobacco use, diabetes, and race. This model exhibited an area under the receiver operating characteristic curve (ROC AUC) of 0.72 (95% CI: 0.61–0.83) based on IV, and 0.76 (95% CI: 0.70, 0.82) based on EV. The derived random forest model based on clinical risk factors yielded improved but not sufficient discrimination of significant CAD (ROC AUC = 0.76 [95% CI: 0.67–0.85] based on IV). Coronary artery calcium score was a more accurate predictor of significant CAD than any combination of clinical risk factors (ROC AUC = 0.85 [95% CI: 0.76–0.94] based on IV; ROC AUC = 0.92 [95% CI: 0.88–0.95] based on EV). Conclusions Clinical risk factors, either individually or in combination, are insufficient for accurately identifying suspected ACS patients harboring undiagnosed significant coronary artery disease.

Prognostic significance of left atrial (LA) function in patients with atrial fibrillation (AF) is poorly defined.To examine the association of LA function measured with cardiac magnetic resonance (CMR) feature-tracking and AF recurrence following catheter ablation.One hundred and twenty-one AF patients (72% paroxysmal, mean age 59 ± 10 years) were enrolled. Baseline LA function was measured by calculating passive, active, and total emptying fractions (LAEF) and analysis of global longitudinal strain and strain rates. Patients were followed up for recurrence of AF or atrial tachycardia (AT). Hazard ratios for recurrence were calculated using Cox proportional models adjusted for potential clinical confounders, type of AF, left ventricular ejection fraction, AF duration, LA volume, and late gadolinium enhancement (LGE).During a mean follow-up of 18 ± 9 months, 52 patients (43%) experienced recurrent AF/AT. Patients with recurrent AF/AT had higher baseline LA volume index and lower LA passive, and total LAEF (P.05 for all). The baseline peak LA strain and strain rates in all phases of LA function were lower in the AF/AT recurrence group (P.01 for all). In multivariable analysis total LAEF, peak LA strain, and systolic and late diastolic strain rates were associated with recurrence. Both peak LA strain and total LAEF improved prediction of recurrent AT/AF compared to the baseline clinical model, including LA LGE (C statistic 0.82 vs 0.77, P.05 for both total LAEF and peak LA strain).LA reservoir function was independently associated with recurrent AF/AT after PVI and can additionally improve risk stratification in patients undergoing PVI.

Background The extent of left atrial (LA) late gadolinium enhancement (LGE), as a surrogate for fibrosis, has been associated with atrial fibrillation (AF) recurrence after catheter ablation. Furthermore, there is ex vivo evidence that islands of fibrosis may anchor fibrillatory rotors. Objective The purpose of this study was to examine the anatomical association of AF rotors with LA and right atrial (RA) LGE on cardiac magnetic resonance. Methods The cohort included 9 patients with persistent AF (mean age 61.1 ± 9.7 years) who underwent LGE cardiac magnetic resonance before AF ablation using the focal impulse and rotor modulation system. The extent of LA and RA LGE was quantified globally and in each of the 7 sectors: LA posterior/inferior wall, anterior wall, roof, left and right pulmonary vein antra, and RA lateral and septal regions. The multivariable association of rotor incidence with global and per sector LGE extent was examined using multivariable Bernoulli logistic regression estimated by generalized estimating equations. Results The mean RA and LA volumes were 113.2 ± 37.31 and 143.03 ± 58.25 mL, respectively. The mean RA and LA LGE burden was 17.2% ± 11.0% and 17.4% ± 14.4%, respectively. A total of 18 LA rotors and 9 RA rotors were identified in all patients. No univariable or multivariable association was observed between global or per sector LGE extent and focal impulse and rotor modulation rotor incidence. Conclusion In this cohort of patients, there was no association between AF rotor incidence and the global or regional extent of RA and LA LGE.

Purpose Right ventricular (RV) function is best represented by the ratio of RV contractility to pulmonary arterial (PA) load (RV-PA coupling). Gold standard measurement of RV-PA coupling, using multi-beat pressure-volume (P-V) loop to obtain the ratio of end-systolic elastance (Ees) to effective arterial elastance (Ea), is costly and invasive. Therefore, we sought to identify clinical surrogates of reduced Ees/Ea and RV-PA uncoupling. Methods We prospectively studied 35 patients suspected to have pulmonary hypertension (PH) with same day echocardiography, cardiac magnetic resonance imaging (CMR), right heart catheterization, and supine bicycle submaximal cardiopulmonary exercise testing. Multi-beat RV P-V loop measurements were also performed. Ees/Ea Results Of 35 patients, 26 had resting PH while 9 did not (20/26 had group I PH). Average age was 57±13 years; 30 were women. Compared with baseline Ees/Ea ≥ 1.0, Ees/Ea Conclusion Readily attainable clinical variables correspond to the gold standard Ees/Ea. We identified a novel parameter, exercise change in ΔESV/ΔESP, a marker of RV reserve, which had the best ability to predict RV-PA uncoupling. Future studies will investigate RV ΔESV/ΔESP and other markers of RV reserve.

The aims of this study were to: 1) use a novel method of late gadolinium enhancement (LGE) quantification that uses normalized intensity measures to confirm the association between LGE extent and atrial fibrillation (AF) recurrence following ablation; and 2) examine the presence of interaction and effect modification between LGE and AF persistence.Recurrent AF after catheter ablation has been reported to associate with the baseline extent of left atrial LGE on cardiac magnetic resonance. Traditional methods for measurement of intensity lack an objective threshold for quantification and interpatient comparisons of LGE.The cohort included 165 participants (mean age 60.0 ± 10.2 years, 77% men, 57% with persistent AF) who underwent initial AF ablation. The association of baseline LGE extent with AF recurrence was examined using multivariable Cox proportional hazards models. Multiplicative and additive interactions between AF type and LGE extent were examined.During 10.2 ± 5.7 months of follow-up, 63 patients (38.2%) experienced AF recurrence. Baseline LGE extent was independently associated with AF recurrence after adjusting for confounders (hazard ratio: 1.5 per 10% increased LGE; p 0.001). The hazard ratio for AF recurrence progressively increased as a function of LGE. The magnitude of association between LGE35% and AF recurrence was greater among patients with persistent AF (hazard ratio: 6.5 [p = 0.001] vs. 3.6 [p = 0.001]); however, there was no evidence for statistical interaction.Regardless of AF persistence at baseline, participants with LGE ≤35% have favorable outcomes, whereas those with LGE35% have a higher rate of AF recurrence in the first year after ablation. These findings suggest a role for: 1) patient selection for AF ablation using LGE extent; and 2) substrate modification in addition to pulmonary vein isolation in patients with LGE extent exceeding 35% of left atrial myocardium.

Symptomatic left atrial (LA) flutter (LAFL) is common after atrial fibrillation (AF) ablation.The purpose of this study was to examine the association of baseline LA function with incident LAFL after AF ablation.The source cohort included 216 patients with cardiac magnetic resonance (CMR) before initial AF ablation between 2010 and 2013. Patients who underwent cryoballoon or laser ablation, patients with AF during CMR, and those with suboptimal CMR, or missing follow-up data were excluded. Baseline LA volume and function were assessed by feature-tracking CMR analysis.The final cohort included 119 patients (mean age 58.9 ± 11 years; 76.5% men; 70.6% patients with paroxysmal AF). During a median follow-up of 421 days (interquartile range 235-751 days), 22 patients (18.5%) had incident LAFL. Baseline LA volume was similar between the 2 groups. In contrast, baseline reservoir, conduit, and contractile function of the LA were significantly impaired in patients with incident LAFL. Baseline global peak longitudinal atrial strain (PLAS)22.65% predicted incident LAFL with 86% sensitivity and 68% specificity (C statistic 0.76). In a multivariable model adjusting for age, heart failure, and LA volume, PLAS (hazard ratio 0.9 per % increase in PLAS; P = .003) and LA linear lesions (hazard ratio 2.94; P = .020) were independently associated with incident LAFL. The coexistence of PLAS22.65% and linear lesions was associated with 9-fold increased hazard of incident LAFL.Baseline LA function and linear lesions were independently associated with incident LAFL after AF ablation. Linear lesions should be limited to selected cases, especially in patients with impaired LA function.

Rationale and Objectives To analyze the statistical biases in the studies used to derive cardiac magnetic resonance–based major and minor criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC). Materials and Methods ARVC is a rare disorder of the heart that can lead to sudden death in young adults. Cardiac magnetic resonance imaging (CMR) plays a role in the diagnosis by contributing to the criteria set by experts. The original criteria emphasized qualitative analysis of CMR. The criteria were modified in 2010 to provide quantitative cutoffs. Results We apply the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool for systematic review of diagnostic accuracy to the studies cited in the guidelines written in 1994 and revised in 2010. We use the signaling questions in QUADAS-2 to identify different types of statistical bias. Conclusions The studies have understandable biases that affect the sensitivity and specificity of CMR in the diagnosis of ARVC, as well as the truth of the disease state. There is potential to overdiagnose ARVC particularly in low prevalence populations.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a rare inherited cardiomyopathy characterized by fibrofatty replacement of the right ventricular myocardium and risk of sudden death from ventricular tachyarrhythmias. Cardiac magnetic resonance (MR) imaging plays an important role in the diagnostic evaluation of patients and family members suspected of having ARVC/D. This article discusses the epidemiology and pathophysiology of ARVC/D, reviews typical MR imaging findings and diagnostic criteria, and summarizes potential pitfalls in the MR imaging evaluation of patients suspected of having ARVC/D.

Cardiac magnetic resonance (CMR) is a standard of reference for cardiac structure and function. Recent advances in T1 mapping and spectroscopy also provide assessment of myocardial tissue composition. However, the reference ranges of left ventricular parameters have rarely been assessed in an African-American (AA) population without known cardiac disease. To estimate the reference values of myocardial structure, function, and tissue composition by CMR and to explore their relationships to serologic factors and cardiovascular risk factors in asymptomatic AAs with low Framingham risk, between November 2010 and June 2012, 92 healthy AAs aged ≥21 years, from Baltimore, MD, were enrolled in an observational study. CMR examination was performed on a 3T scanner. Proton magnetic resonance spectroscopy was performed to noninvasively quantify myocardial triglyceride content. Native T1 values were obtained from modified Look-Locker inversion recovery sequence. The median age was 37 (interquartile range IQR 27 to 44) years (41% men). The median native T1 time of the myocardium was 1,228 ms (IQR 1,200 to 1,263) with no gender difference. The median myocardial fat content was 0.6% (IQR 0.7% to 4.6%). Native T1 time was not influenced by age, sex, and body mass index. Among the factors investigated, myocardial fat and elevated C-reactive protein (>2.0 mg/dL) were independently associated with T1 relaxation time. Native T1 time was also independently associated with left ventricular end-diastolic volume indexed to body surface area. In conclusion, this study of asymptomatic AAs provides reference ranges for cardiovascular structure, function, and tissue composition. Alterations in myocardial fat are associated with native T1 time, a CMR measure of interstitial fibrosis.

Background Treatment decisions for ascending aortic aneurysms are guided by measurements from CT angiograms. Objective The aim was to evaluate the reproducibility of these measurements by using manual techniques and advanced imaging software. Methods Two radiologists measured maximal ascending aorta diameter on CT angiograms in 30 subjects at 4 separate reading sessions—2 with manual techniques and 2 with semiautomated software analysis. Interobserver and intraobserver variabilities were assessed with Bland-Altman plots and Spearman correlation coefficients. Results Interobserver variability was smaller for the software-assisted method. Limits of agreement for the manual method were −4.2 mm and 9.2 mm compared with −4.0 mm and 4.6 mm for the software-assisted method; coefficients of repeatability were 6.8 mm and 4.3 mm. Intraobserver variability was inconsistent between readers. Strong correlation was found between observers who used both methods ( R 2 = 0.8078–0.9881; P Conclusion The use of an advanced imaging software for measurement of ascending aortic aneurysm reduces interobserver variability.

Cardiac steatosis is common in patients with diabetes or obesity, and cardiac steatosis may result in cardiomyopathy. However, factors associated with cardiac steatosis have not been reported in healthy individuals without diabetes and hypertension. The objectives of this study were to explore factors associated with myocardial triglyceride levels, and to examine the association between myocardial triglyceride and regional left ventricular (LV) function in healthy African Americans (AAs).Between November 2010 and June 2012, 92 healthy AAs aged 21 years or older, without clinical evidence of cardiac dysfunction, coronary artery disease, diabetes, or hypertension from Baltimore, Maryland, were enrolled in an observational proton magnetic resonance spectroscopy and imaging study investigating factors associated with cardiac steatosis, and the relationships between cardiac steatosis and LV volumes and LV function.Among the participants, all had a low Framingham risk; 31 had a normal BMI, 23 were overweight and 38 were obese. The median myocardial triglyceride content was 0.5% (IQR: 0.3-1.0%). Among the factors investigated, BMI (R2=0.43, p=0.0001) was independently associated with myocardial triglyceride. Overall, myocardial triglyceride was not associated with LV EF/structure, but may be associated with regional LV function.In healthy AA adults, obesity is associated with cardiac steatosis. In contrast to studies in patients with diabetes suggesting a link between cardiac steatosis and LV dysfunction, this study found no relationship between cardiac steatosis and left ventricular volumes or EF, though there is some evidence suggesting that cardiac steatosis may be associated with LV regional function in healthy AA women.

Atrial fibrillation (AF) is associated with left atrial (LA) systolic and diastolic dysfunction. LA diastolic functions are related with outcomes of catheter ablation for atrial fibrillation. This study is designed to correlate the diastolic functions measured by left atrial stiffness index (LASI)

Background The measurement of late gadolinium–enhanced magnetic resonance imaging (LGE-MRI) intensity in arbitrary units limits the objectivity of thresholds for focal scar detection and interpatient comparisons of scar burden. Objective To develop and validate a normalized measure, the image intensity ratio (IIR), for the assessment of left atrial (LA) scar on LGE-MRI. Methods Electrocardiogram- and respiratory-gated 1.5 Tesla LGE-MRI was performed in 75 patients (75% men; 62 ± 8 years) before atrial fibrillation ablation. The local IIR was defined as LA myocardial signal intensity for each of the 20 sectors on contiguous axial image planes divided by the mean LA blood pool image intensity. Intracardiac point-by-point sampled electroanatomic map points were coregistered with the corresponding image sectors. Results The average bipolar voltage for all 8153 electroanatomic map points was 0.9 ± 1.1 mV. In a mixed effects model accounting for within patient clustering, and adjusting for age, LA volume, mass, body mass index, sex, CHA 2 DS 2 -VASc score, atrial fibrillation type, history of previous ablations, and contrast delay time, each unit increase in local IIR was associated with 91.3% decrease in bipolar LA voltage ( P 0.97 and >1.61 corresponded to bipolar voltage Conclusions Normalization of LGE-MRI intensity by the mean blood pool intensity results in a metric that is closely associated with intracardiac voltage as a surrogate of atrial fibrosis.

Cardiac magnetic resonance (CMR) T1 mapping is an emerging tool for objective quantification of myocardial fibrosis.To (a) establish the feasibility of left atrial (LA) T1 measurements, (b) determine the range of LA T1 values in patients with atrial fibrillation (AF) vs healthy volunteers, and (c) validate T1 mapping vs LA intracardiac electrogram voltage amplitude measures.CMR imaging at 1.5 T was performed in 51 consecutive patients before AF ablation and in 16 healthy volunteers. T1 measurements were obtained from the posterior LA myocardium by using the modified Look-Locker inversion-recovery sequence. Given the established association of reduced electrogram amplitude with fibrosis, intracardiac point-by-point bipolar LA voltage measures were recorded for the validation of T1 measurements.The median LA T1 relaxation time was shorter in patients with AF (387 [interquartile range 364-428] ms) compared to healthy volunteers (459 [interquartile range 418-532] ms; P.001) and was shorter in patients with AF with prior ablation compared to patients without prior ablation (P = .035). In a generalized estimating equations model, adjusting for data clusters per participant, age, rhythm during CMR, prior ablation, AF type, hypertension, and diabetes, each 100-ms increase in T1 relaxation time was associated with 0.1 mV increase in intracardiac bipolar LA voltage (P = .025).Measurement of the LA myocardium T1 relaxation time is feasible and strongly associated with invasive voltage measures. This methodology may improve the quantification of fibrotic changes in thin-walled myocardial tissues.

Exposure to radiation as a result of medical imaging is currently in the spotlight, receiving attention from Congress as well as the lay press. Although scanner manufacturers are moving toward including effective dose information in the Digital Imaging and Communications in Medicine headers of imaging studies, there is a vast repository of retrospective CT data at every imaging center that stores dose information in an image-based dose sheet. As such, it is difficult for imaging centers to participate in the ACR's Dose Index Registry. The authors have designed an automated extraction system to query their PACS archive and parse CT examinations to extract the dose information stored in each dose sheet. First, an open-source optical character recognition program processes each dose sheet and converts the information to American Standard Code for Information Interchange (ASCII) text. Each text file is parsed, and radiation dose information is extracted and stored in a database which can be queried using an existing pathology and radiology enterprise search tool. Using this automated extraction pipeline, it is possible to perform dose analysis on the >800,000 CT examinations in the PACS archive and generate dose reports for all of these patients. It is also possible to more effectively educate technologists, radiologists, and referring physicians about exposure to radiation from CT by generating report cards for interpreted and performed studies. The automated extraction pipeline enables compliance with the ACR's reporting guidelines and greater awareness of radiation dose to patients, thus resulting in improved patient care and management.

Background Recurrence of atrial fibrillation (AF) after catheter ablation has been associated with left atrial (LA) fibrosis. However, arbitrary units of measure limit the interpatient comparison of delayed enhancement intensity. We sought to quantify LA fibrosis using a novel normalized measure: the image intensity ratio (IIR) of late-gadolinium enhanced magnetic resonance imaging (LGE-MRI). Methods LGE-MRI images (1.5 Tesla) were obtained in 30 patients (37% female, mean age 62 ± 8) prior to first (60%), second (23%), or third (17%) ablation procedure for AF. Multiplanar reformatted images were reconstructed from the stack of 3-D axial image data. Epicardial and endocardial contours were manually drawn around LA myocardium. The IIR, defined as local LA myocardial signal intensity divided by the mean LA blood pool image intensity, was measured for each of 20 sectors created on contiguous axial planes through the LA. Electroanatomic map (EAM) points were registered to the corresponding LGE-MRI images using custom software. Results A total of 2569 EAM points were analyzed. The average bipolar voltage was 0.9 ± 1.0 mV (0.5 between and 0.9 within patient standard deviation). Local IIR was strongly associated with bipolar voltage (Figure, P P Conclusions Higher IIR values were observed in areas with lower bipolar voltage on EAM. The IIR obtained from LGE-MRI may improve the quantification of LA fibrosis

Background Left atrial (LA) late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) has varying protocols, which may limit interstudy comparisons. This study evaluates whether changes in image acquisition and reconstruction parameters affect quantification of LA LGE MRI. Methods A total of 200 LGE MRI scans were prepared using various techniques from 5 subjects. 3D respiratory and ECG-gated LGE images were acquired at 15, 20, 25, and 30 minutes after contrast. Multiplanar reconstructions (MPR) and maximum intensity projections (MIP) were created from 3D data at various slice thicknesses. LA LGE was quantified with image intensity ratio (IIR, atrial wall signal intensity divided by blood pool). Mean IIR was calculated for the entire LA as a metric of LGE burden. Additionally, in 42 consecutive preablation patients, local IIR values from 3.5-mm MPR and MIP reconstructions were separately registered to LA electroanatomic voltage maps (EAM) obtained prior to ablation procedure. Results Multitime point LGE-MRI showed a rise in baseline mean IIR of 0.5% ± 0.1% per minute ( P P P P Conclusions Variations in timing of acquisition, image reconstruction methods, and slice thickness result in changes in LA LGE quantity.