Coronary artery calcium and risk of atrial fibrillation (from the multi-ethnic study of atherosclerosis)

Arteriosclerotic Calcification and Atrial Fibrillation in the General Population: The Rotterdam Study

Limited population-based data on the gender differences and association between arteriosclerotic calcification at different sites and atrial fibrillation (AF) exist. We aimed to investigate the (gender-specific) associations between arteriosclerotic calcification at different sites with the risk of AF in the general population. Arteriosclerotic calcification was quantified using computed tomography examinations between 2003 and 2006 in 2,259 participants free of AF from the population-based Rotterdam Study. Cox proportional hazards models, adjusted for cardiovascular risk factors, were used to assess the associations of volumes of coronary artery calcification (CAC), aortic arch calcification (AAC), extracranial and intracranial carotid arteries, vertebrobasilar arteries, and the aortic valve with incident AF. During a median follow-up of 8.6 years, 182 incident AF cases occurred. A larger CAC was associated with incident AF (hazard ratio [HR], 95% confidence interval [CI] 1.25 1.09 to 1.44, p = 0.0019). The gender-stratified analyses showed that larger CAC in men (HR 1.43, 95% CI 1.10 to 1.86, p = 0.0068) and larger AAC in women were associated with incident AF (HR1.44, 95% CI 1.04 to 2.01, p = 0.0299). In conclusion, CAC in the general population, especially in men, and AAC in women were significantly associated with new-onset AF. Our findings imply that interventions to lower arteriosclerotic calcification, particularly, CAC, carry potential for the prevention of AF in the general population, especially in men.

Clinical impact of cardiovascular calcifications on stroke incidence in primary prevention: analysis in NADESICO study

The utility of assessment of cardiovascular calcifications for predicting stroke incidence remains unclear. This study assessed the relationship between cardiovascular calcifications including coronary artery calcification (CAC), aortic valve (AVC), and aortic root (ARC) assessed by coronary computed tomography (CT) and stroke incidence in patients with suspected CAD. In this multicenter prospective cohort study, 1187 patients suspected of CAD who underwent coronary CT were enrolled. Cardiovascular events including stroke were documented. Hazard ratio (HR) and confidence interval (CI) were assessed by Cox proportional hazard model adjusted for the Framingham risk score. C statistics for stroke incidence were also examined by models including cardiovascular calcifications. A total of 980 patients (mean age, 65 ± 7 years; females, 45.8%) were assessed by the CAC, AVC, and ARC Agatston scores. During a median follow-up of 4.0 years, 19 patients developed stroke. Cox proportional hazard model showed severe CAC (Agatston score ≥ 90th percentile [580.0 value]) and presence of AVC and ARC were associated with stroke incidence (HR; 10.33 [95% CI; 2.08-51.26], 3.08 [1.19-7.98], and 2.75 [1.03-7.30], respectively). C statistic in the model with CAC and AVC severity for predicting stroke incidence was 0.841 (95% CI; 0.761-0.920), which was superior to the model with CAC alone (0.762 [95% CI; 0.665-0.859], P < 0.01). CAC, AVC, and ARC were associated with stroke incidence in patients suspected of CAD. Assessment of both CAC and AVC may be useful for prediction of stroke incidence.

Predictors of low-voltage zones in patients with persistent atrial fibrillation eligible for catheter ablation: An observational study

INTRODUCTION

The presence of low-voltage zones (LVZs) in the left atrium (LA) is associated with the recurrence of atrial fibrillation (AF) following pulmonary vein isolation (PVI). However, there is variability and conflict in the data regarding predictors of LVZs as reported in previous studies. The objective of this study was to identify predictors for the presence of LVZs in a cohort of patients with persistent AF.

METHODS

The study prospectively enrolled 439 patients with persistent AF who were scheduled for ablation. Voltage map of the LA was collected using a multipolar catheter. An LVZ was defined as an area of ≥3 cm2 exhibiting a peak-to-peak bipolar voltage of <0.5 mV.

RESULTS

The mean age of the cohort was 65.3 ± 8.6 years and 26.4% were female. Additionally, 25.7% had significant LVZs, most frequently located in the anterior wall of the LA. Multivariable analysis identified the following independent predictors for LVZ: advanced age (OR [odds ratio] = 1.08, 95% CI [confidence interval] = 1.03-1.13, p = .002); female sex (OR = 4.83, 95% CI = 2.66-8.76, p < .001); coronary artery disease (CAD) (OR = 3.20, 95% CI = 1.32-7.77, p = .01) and enlarged LA diameter (OR = 1.10, 95% CI = 1.04-1.17, p = .001). The area under the curve (AUC) of the receiver operating characteristic (ROC) curve for the final model was 0.829.

CONCLUSION

Approximately 25% of the patients with persistent AF had LVZs. Advanced age, female sex, CAD, and a larger LA were independent predictors for LVZs with the model demonstrating a very good AUC for the ROC curve. These findings hold the potential to be used to tailor the ablation procedure for the individual patient.

Atrial Fibrillation and Dementia: Pathophysiological Mechanisms and Clinical Implications

Numerous longitudinal studies suggest a strong association between cardiovascular risk factors and cognitive impairment. Individuals with atrial fibrillation are at higher risk of dementia and cognitive dysfunction, as atrial fibrillation increases the risk of cerebral hypoperfusion, inflammation, and stroke. The lack of comprehensive understanding of the observed association and the complex relationship between these two diseases makes it very hard to provide robust guidelines on therapeutic indications. With this review, we attempt to shed some light on how atrial fibrillation is related to dementia, what we know regarding preventive interventions, and how we could move forward in managing those very frequently overlapping conditions.

The relationship between atrial fibrillation and coronary artery disease: Understanding common denominators

Atrial fibrillation (AF) and coronary artery disease (CAD) are highly prevalent cardiovascular conditions. The coexistence of both diseases is common as they share similar risk factors and common pathophysiological characteristics. Systemic inflammatory conditions are associated with an increased incidence of both AF and CAD. The presence of both entities increases the incidence of complications and adverse outcomes. Furthermore, their coexistence poses challenges for the management of patients, particularly with respect to anticoagulation and rhythm management. In this review, we aim to better understand the relationship between AF and CAD by detailing basic molecular pathophysiology, assessing therapeutic guidelines, and describing interactions between the two conditions.

Prognostic Impact of Atrial Fibrillation in Patients with Heavily Calcified Coronary Artery Disease Receiving Rotational Atherectomy

Background and Objectives: Although both rotational atherectomy (RA) and atrial fibrillation (AF) have a high thrombotic risk, there have been no previous studies on the prognostic impact of AF in patients who undergo percutaneous coronary intervention (PCI) using RA. Thus, the aim of the present study was to determine the prognostic impact of AF in patients undergoing PCI using RA. Materials and Methods: A total of 540 patients who received PCI using RA were enrolled between January 2010 and October 2019. Patients were divided into AF and sinus rhythm groups according to the presence of AF. The primary endpoint was net adverse clinical events (NACEs) defined as a composite outcome of all-cause death, myocardial infarction, target vessel revascularization, cerebrovascular accident, or total bleeding. Results: Although in-hospital adverse events showed no difference between those with AF and those without AF (in-hospital events, 54 (11.0%) vs. 6 (12.2%), p = 0.791), AF was strongly associated with an increased risk of NACE at 3 years (NACE: hazard ratio, 1.880; 95% confidence interval, 1.096-3.227; p = 0.022). Conclusions: AF in patients who underwent PCI using RA was strongly associated with poor clinical outcomes. Thus, more attention should be paid to thrombotic and bleeding risks.

Prevalence of coronary calcification on preoperative computed tomography and its management in thoracic surgery

PURPOSE

We investigated the preoperative assessment of coronary artery calcification using computed tomography for appropriate intraoperative management to reduce the risk of perioperative cardiac complications during pulmonary resection.

METHODS

Patients (n = 665) who underwent anatomical lung resection were examined. The extent of preoperative asymptomatic coronary artery stenosis or cardiac complications in patients with coronary artery calcification was assessed. In addition, the risk factors for perioperative cardiac complications were determined.

RESULTS

Coronary artery calcification was detected in 233 (35.0%) asymptomatic patients. Nineteen (8.2%) patients with coronary artery calcification had coronary artery stenosis ≥ 75%. Percutaneous coronary intervention was performed preoperatively (n = 3) and postoperatively (n = 10), and preoperative drug intervention was performed in 10 cases. One case of severe postoperative cardiac complications and 20 cases of mild postoperative cardiac complications, including those without coronary artery calcification, occurred. Patients with calcified coronary arteries were at risk of cardiovascular complications in the perioperative period. However, patients with coronary artery calcification who underwent preoperative cardiology intervention had no significant perioperative cardiovascular complications.

CONCLUSIONS

Coronary artery calcification detected on preoperative computed tomography is a risk factor for perioperative cardiovascular complications. Early intervention may reduce the risk of such complications.

Higher coronary artery calcium score is associated with increased risk of atrial fibrillation recurrence after catheter ablation

BACKGROUND

Coronary artery calcium score (CACS) is associated with an increased risk of atrial fibrillation (AF) development, but scarce data are available regarding the impact on AF recurrence. This study aims to assess the impact of CACS on AF recurrence following catheter ablation.

METHODS

Retrospective study of patients with AF undergoing cardiac computed tomography (CCT) before ablation (2017-2019). Patients with coronary artery disease (CAD), significant valvular heart disease and previous catheter ablation were excluded. A cut-off of CACS ≥ 100 was used according to literature.

RESULTS

A total of 311 patients were included (median age 57 [48, 64] years, 65% men and 21% with persistent AF). More than half of the patients had a CACS > 0 (52%) and 18% a CACS ≥ 100. Patients with CACS ≥ 100 were older (64 [59, 69] vs 55 [46, 63] years, p ​< ​0.001), had more frequently hypertension (68% vs 42%, p ​< ​0.001) and diabetes mellitus (21% vs 10%, p ​= ​0.020). During a median follow-up of 34 months (12-57 months), 98 patients (32%) had AF recurrence. CACS ≥ 100 was associated with increased risk of AF recurrence (unadjusted Cox regression: hazard ratio [HR] 2.0; 95% confidence interval [CI], 1.3-3.1, p ​= ​0.002). After covariate adjustment, CACS ≥ 100 and persistent AF remained independent predictors of AF recurrence (HR, 1.7; 95% CI, 1.0-2.8, p ​= ​0.039 and HR, 2.0; 95% CI, 1.3-3.2, p ​= ​0.004, respectively).

CONCLUSION

An opportunistic evaluation of CACS could be an important tool to improve clinical care considering that CACS ≥ 100 was independently associated with a 69% increase in the risk of AF recurrence after first catheter ablation.

Association of Sinoatrial Node Radiation Dose With Atrial Fibrillation and Mortality in Patients With Lung Cancer

Importance

Atrial fibrillation (AF) can develop following thoracic irradiation. However, the critical cardiac substructure responsible for AF has not been properly studied.

Objective

To describe the incidence of AF in patients with lung cancer and determine predictive cardiac dosimetric parameters.

Design, Setting, and Participants

This retrospective cohort study was performed at a single referral center and included 239 patients diagnosed with limited-stage small cell lung cancer (SCLC) and 321 patients diagnosed with locally advanced non-small cell lung cancer (NSCLC) between August 2008 and December 2019 who were treated with definitive chemoradiotherapy.

Exposures

Radiation dose exposure to cardiac substructures, including the chambers, coronary arteries, and cardiac conduction nodes, were calculated for each patient.

Main Outcomes and Measures

Main outcomes were AF and overall survival.

Results

Of the 239 and 321 patients with SCLC and NSCLC, the median (IQR) age was 68 (60-73) years and 67 (61-75) years, and 207 (86.6%) and 261 (81.3%) were men, respectively. At a median (IQR) follow-up time of 32.7 (22.1-56.6) months, 9 and 17 patients experienced new-onset AF in the SCLC and NSCLC cohorts, respectively. The maximum dose delivered to the sinoatrial node (SAN Dmax) exhibited the highest predictive value for prediction of AF. A higher SAN Dmax significantly predicted an increased risk of AF in patients with SCLC (adjusted hazard ratio [aHR], 14.91; 95% CI, 4.00-55.56; P < .001) and NSCLC (aHR, 15.67; 95% CI, 2.08-118.20; P = .008). However, SAN Dmax was not associated with non-AF cardiac events. Increased SAN Dmax was significantly associated with poor overall survival in patients with SCLC (aHR, 2.68; 95% CI, 1.53-4.71; P < .001) and NSCLC (aHR, 1.97; 95% CI, 1.45-2.68; P < .001).

Conclusions and Relevance

In this cohort study, results suggest that incidental irradiation of the SAN during chemoradiotherapy may be associated with the development of AF and increased mortality. This supports the need to minimize radiation dose exposure to the SAN during radiotherapy planning and to consider close follow-up for the early detection of AF in patients receiving thoracic irradiation.

Density of Calcified Coronary Artery Plaque and Risk of Incident Atrial Fibrillation (from the Multiethnic Study of Atherosclerosis)

Elevated coronary artery calcium (CAC) score, as assessed by the Agatston method, is associated with incident atrial fibrillation (AF). We aimed to evaluate the associations of CAC volume and density with incident AF. Participants from the Multiethnic Study of Atherosclerosis without baseline AF and CAC >0 were included. The associations between baseline and progression (average annual change) of CAC measures and incident AF were evaluated using Cox proportional hazards models. CAC volume and Agatston scores were natural log (ln)-transformed, and hazard ratios (HRs) were calculated per standard deviation increment. The baseline analysis included 3,332 participants; 2,643 were included in the progression analysis. In multivariable models adjusted for cardiovascular risk factors, volume (HR 1.24, 95% confidence interval [CI] 1.14 to 1.36), density (HR 1.14, 95% CI 1.05 to 1.25), and Agatston score (HR 1.24, 95% CI 1.14 to 1.35) were associated with increased risk of incident AF. In models including both volume and density, the magnitude of association between volume and incident AF was unchanged, whereas the density association was eliminated (HR 0.99, 95% CI 0.89 to 1.11). Median time to follow-up CAC assessment was 1.9 (interquartile range 1.3, 3.0) years. Similar results were observed for the association of incident AF with annual change in volume and Agatston score. CAC volume, but not density, is associated with risk for incident AF when adjusting for both. In conclusion, our findings suggest that, although CAC may be a risk marker for AF, the association between CAC and AF appears to be independent of plaque density.

Nongated computed tomography predicts perioperative cardiovascular risk in lung cancer surgery

BACKGROUND

The coronary artery calcification score (CACS) is a strong predictor of cardiovascular events and mortality, which can be assessed by nongated chest computed tomography (CT). The study aimed to determine whether CACS based on nongated CT is predictive of perioperative cardiovascular events during intermediate-risk lung cancer surgery.

METHODS

In this retrospective, single-center study, we used nongated CT images to evaluate CACS in 4,491 lung cancer patients who underwent intermediate-risk surgeries. Perioperative cardiovascular events were defined as in-hospital cardiac death, nonfatal myocardial infarction (MI), heart failure, atrial and ventricular arrhythmia with hemodynamic compromise, and complete heart block. Risk factors of perioperative cardiovascular were identified using multivariate logistic regression analysis.

RESULTS

In total, 110 inpatients (2.5%) experienced perioperative cardiac events. Coronary calcification was observed on nongated CT in 1,070 (23.8%) patients. CACS was significantly associated with the incidence of cardiovascular events and longer hospital stays. According to receiver operating characteristic curve analysis, the CACS cutoff value was set to 1. In the multivariate analysis, CACS ≥1 (odds ratio (OR) = 1.75, 95% confidence interval (CI): 1.14-2.68, p = 0.011) or the number of calcified vessels (OR = 1.23, 95%CI: 1.01-1.50, p = 0.043), age, forced expiratory volume in one second/predicted, operation time, and thoracotomy were predictive of cardiovascular complications.

CONCLUSIONS

CACS is an independent predictor of severe perioperative cardiovascular risk in patients undergoing intermediate-risk lung cancer surgery. CACS may represent a valuable tool for preoperative risk assessments among these patients.

Atrial Fibrillation and Dementia: A Report From the AF-SCREEN International Collaboration

Growing evidence suggests a consistent association between atrial fibrillation (AF) and cognitive impairment and dementia that is independent of clinical stroke. This report from the AF-SCREEN International Collaboration summarizes the evidence linking AF to cognitive impairment and dementia. It provides guidance on the investigation and management of dementia in patients with AF on the basis of best available evidence. The document also addresses suspected pathophysiologic mechanisms and identifies knowledge gaps for future research. Whereas AF and dementia share numerous risk factors, the association appears to be independent of these variables. Nevertheless, the evidence remains inconclusive regarding a direct causal effect. Several pathophysiologic mechanisms have been proposed, some of which are potentially amenable to early intervention, including cerebral microinfarction, AF-related cerebral hypoperfusion, inflammation, microhemorrhage, brain atrophy, and systemic atherosclerotic vascular disease. The mitigating role of oral anticoagulation in specific subgroups (eg, low stroke risk, short duration or silent AF, after successful AF ablation, or atrial cardiopathy) and the effect of rhythm versus rate control strategies remain unknown. Likewise, screening for AF (in cognitively normal or cognitively impaired patients) and screening for cognitive impairment in patients with AF are debated. The pathophysiology of dementia and therapeutic strategies to reduce cognitive impairment warrant further investigation in individuals with AF. Cognition should be evaluated in future AF studies and integrated with patient-specific outcome priorities and patient preferences. Further large-scale prospective studies and randomized trials are needed to establish whether AF is a risk factor for cognitive impairment, to investigate strategies to prevent dementia, and to determine whether screening for unknown AF followed by targeted therapy might prevent or reduce cognitive impairment and dementia.

Relationship between Cardiovascular Calcium and Atrial Fibrillation

Coronary artery calcium score (CACS) is associated with increased risk of atrial fibrillation (AF). However, the relationship between the burden of CACS and extra-coronary calcium and the AF is unclear. This cross-sectional study retrospectively analyzed the data of 143,529 participants (74.9% men; mean age, 41.7 ± 8.6 years) who underwent health examination including non-contrast cardiac CT and electrocardiography, from 2010 to 2018 to evaluate the association between cardiac calcium and AF. AF was diagnosed in 679 participants. The prevalence of AF was significantly increased as the CACS increased (p < 0.01). Multivariable analysis adjusted for age, sex, body mass index, hypertension, diabetes, hyperlipidemia, smoking, alcohol, and history of coronary artery disease showed a significant association between a high CACS ≥1000 and AF (OR 2.26, 95% CI 1.07–4.77, p = 0.032). In a subgroup analysis of participants with a CACS ≥100, aortic valve and thoracic aorta calcium were significantly associated with AF (OR 3.49, 95% CI 1.57–7.77, p = 0.002 and OR 2.19, 95% CI 1.14–4.21, p = 0.01, respectively). High CACS was associated with AF, and extra-coronary atherosclerosis was associated with AF in participants with a moderate to very high CACS.

Cardiac computed tomographic evaluation of coronary artery calcification: A review

Vascular calcification is most commonly due to atherosclerosis. It has been well documented that absence of coronary calcification on a chest CT (CCT) is associated with low cardiovascular events and good prognosis. High CT calcium scores often result in a higher incidence of cardiovascular events and worse survival. In asymptomatic patients with an intermediate risk for coronary artery disease, numerous studies have shown Coronary Calcium Scoring (CCS) has prognostic relevance and incremental prognostic value over conventional risk stratification. CT detected calcium score plays important role in patient management. This article will review various CT based coronary artery calcium scoring methods.

Incidence of new-onset atrial fibrillation in COVID-19 is associated with increased epicardial adipose tissue

PURPOSE

Coronary artery calcium (CAC) and epicardial adipose tissue (EAT) can predict AF in the general population. We aimed to determine if CAC and EAT measured by computed tomographic (CT) scanning can predict new-onset AF in patients admitted with COVID-19 disease.

METHODS

We performed a retrospective, post hoc analysis of all patients admitted to Montefiore Medical Center with a confirmed COVID-19 diagnosis from March 1st to June 23rd, 2020, who had a non-contrast CT of the chest within 5 years prior to admission. We determined ordinal CAC scores and quantified the EAT volume and examined their relationship with inpatient mortality.

RESULTS

A total of 379 patients were analyzed. There were 16 events of new-onset AF (4.22%). Patients who developed AF during the index admission were more likely to be male (75 vs 47%, p < 0.001) and had higher EAT (129.5 [76.3-197.3] vs 91.0 [60.0-129.0] ml, p = 0.049). There were no differences on age (68 [56-71] vs 68 [58-76] years; p = 0.712), BMI (28.5 [25.3-30.8] vs 26.9 [23.1-31.8] kg/m²; p = 0.283), ordinal CAC score (3 [1-6] vs 2 [0-4]; p = 0.482), or prevalence of diabetes (56.3 vs 60.1%; p = 0.761), hypertension (75.0 vs 87.3%, p = 0.153), or coronary artery disease (50.0 vs 39.4%, p = 0.396). Patients with new-onset AF had worse clinical outcomes (death/intubation/vasopressors) (87.5 vs 44.1%; p = 0.001).

CONCLUSION

Increased EAT measured by non-contrast chest CT identifies patients hospitalized with COVID-19 at higher risk of developing new-onset AF. Patients with new-onset AF have worse clinical outcomes.

Endothelial dysfunction and vascular maladaptation in atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia and is associated with worsened morbidity and mortality. The prevalence of AF is estimated to increase with an ageing population resulting in an ever-increasing burden on the healthcare system. Despite improvements in AF treatment, several questions remain unanswered in relation to the development and progression of AF. In this review, we discuss the evidence supporting the presence of vascular dysfunction in the development of AF, but also as a final common pathway explaining why AF constitutes a markedly increased risk of cardiovascular morbidity and mortality. Specifically, we summarise the work performed in humans related to the impact of AF on vascular structure and function, and whether measures of vascular function predict AF progression and the development of cardiovascular events. Subsequently, we discuss the potential mechanisms linking AF to the development of vascular dysfunction. Finally, we propose future perspectives of vascular health and AF, advocating a strong focus on regular exercise training as a safe and effective strategy to improve vascular function and, hence, reduce the risk for development and progression of AF and its associated risk for cardiovascular events.

Incorporating coronary calcification by computed tomography into CHA2DS2-VASc score: impact on cardiovascular outcomes in patients with atrial fibrillation

AIMS

CHA2DS2-VASc score is widely utilized for risk stratification and guiding anticoagulation in patients with atrial fibrillation (AF). Cardiac computed tomography (CCT) routinely performed for pulmonary vein isolation (PVI) can also identify coronary artery calcifications (CAC). We evaluated the frequency and outcomes of incorporating CAC into the CHA2DS2-VASc score in AF patients undergoing PVI.

METHODS AND RESULTS

Consecutive patients in a prospective PVI registry during 2014-18 having CCT within 1 year of PVI were studied. Reclassification of CHA2DS2-VASc score and associations between CAC as a binary variable detected on CCT with clinical characteristics, stroke as primary endpoint, death, myocardial infarction, and major adverse cardiovascular events (MACE) were analysed. Amongst 3604 AF patients, 2238 (62.1%) had CAC detected on CCT and was associated with most traditional cardiovascular risk factors. Coronary artery calcification was independently associated with all pre-specified endpoints adjusting for clinical parameters in multivariable analysis. Adjusting for CHA2DS2-VASc score, CAC was associated with stroke (hazards ratio 3.64, 95% confidence interval 1.25-10.6, P = 0.018), death (2.26, 1.29-3.98, P = 0.006), and MACE (2.08, 1.36-3.16, P = 0.001) during 2.8 ± 1.6-year follow-up. Incorporating CAC as a vascular disease parameter of CHA2DS2-VASc score, anticoagulation decision-making would be revised in 723 (20.1%) patients, including an additional 488 (13.5%) patients where anticoagulation would be now indicated.

CONCLUSION

Coronary artery calcification is prevalent in AF patients undergoing PVI and independently associated stroke, death and MACE even when adjusted for traditional CHA2DS2-VASc score. Adding CAC as vascular component to the CHA2DS2-VASc score requires further research as it potentially modified the anticoagulation management in 20% of our AF cohort.

The coronary artery calcium score correlates with left atrial low-voltage area: Sex differences

INTRODUCTION

In patients with coronary artery disease, a high coronary artery calcium score (CACS) correlates with atrial fibrillation (AF); however, the association between left atrial (LA) remodeling progression and coronary arteriosclerosis is unclear. This study aimed to evaluate the relationship between LA remodeling progression and the CACS.

METHODS

This retrospective study enrolled 148 patients with AF (paroxysmal AF, n = 94) who underwent catheter ablation. Voltage mapping for the left atrium and coronary computed tomography for CACS calculations were performed. The ratio of the LA low-voltage area (LA-LVA), defined by values less than 0.5 mV divided by the total LA surface without pulmonary veins, was calculated. Patients with LA-LVA (<0.5 mV) >5% and ≤5% were classified as the LVA (n = 30) and non-LVA (n = 118) groups, respectively. Patient characteristics and CACS values were compared between the two groups.

RESULTS

LA volume, age, CHA₂ DS₂ VASc score, and percentage of female patients were significantly higher, and the estimated glomerular filtration rate was lower in the LVA group than in the non-LVA group. The CACS was significantly higher in the LVA group (248.4 vs. 13.2; p = .001). Multivariate analysis identified the LA volume index and CACS as independent predictors of LA-LVA (<0.5 mV) greater than 5%. The areas under the receiver operating characteristic curves for predicting LA-LVA (<0.5 mV) greater than 5% with CACS were 0.695 in the entire population, 0.782 in men, and 0.587 in women.

CONCLUSION

Progression of LA remodeling and coronary artery calcification may occur in parallel. A high CACS may indicate advanced LA remodeling, especially in men.

Fragmented sinoatrial dynamics in the prediction of atrial fibrillation: the Multi-Ethnic Study of Atherosclerosis

Heart rate fragmentation (HRF), a marker of abnormal sinoatrial dynamics, was shown to be associated with incident cardiovascular events in the Multi-Ethnic Study of Atherosclerosis (MESA). Here, we test the hypothesis that HRF is also associated with incident atrial fibrillation (AF) in the MESA cohort of participants who underwent in-home polysomnography (PSG) and in two high-risk subgroups: those ≥70 yr taking antihypertensive medication and those with serum concentrations of NH₂-terminal prohormone B-type natriuretic peptide (NT-proBNP) >125 pg/ml (top quartile). Heart rate time series (n = 1,858) derived from the ECG channel of the PSG were analyzed using newly developed HRF metrics, traditional heart rate variability (HRV) indices and two widely used nonlinear measures. Eighty-three participants developed AF over a mean follow-up period of 3.83 ± 0.87 yr. A one-standard deviation increase in HRF was associated with a 31% (95% CI: 3-66%) increase in risk of incident AF, in Cox models adjusted for age, height, NT-proBNP, and frequent premature supraventricular complexes. Furthermore, HRF added value to the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE)-AF models. Traditional HRV and nonlinear indices were not significantly associated with incident AF. In the two high-risk subgroups defined above, HRF was also significantly associated with incident AF in unadjusted and adjusted models. These findings support the translational utility of HRF metrics for short-term (∼4-yr) prediction of AF. In addition, they support broadening the concept of atrial remodeling to include electrodynamical remodeling, a term used to refer to pathophysiological alterations in sinus interbeat interval dynamics.NEW & NOTEWORTHY This study is the first demonstration that heart rate fragmentation (HRF), a marker of anomalous sinoatrial dynamics, is an independent predictor of atrial fibrillation (AF). Traditional measures of heart rate variability and two widely used nonlinear measures were not associated with incident AF in the Multi-Ethnic Study of Atherosclerosis. Fragmentation measures added value to the strongest contemporary predictors of AF, including ECG-derived parameters, coronary calcification score, serum concentrations of NH₂-terminal prohormone B-type natriuretic peptide, and supraventricular ectopy. The computational algorithms for quantification of HRF could be readily incorporated into wearable ECG monitoring devices.

Subclinical atherosclerosis is associated with incident atrial fibrillation: a systematic review and meta-analysis

Aims

Coronary artery disease is an established risk factor for incident atrial fibrillation (AF), but it is unclear whether subclinical atherosclerosis also increases the risk of incident AF. Therefore, the aim was to assess the association between subclinical atherosclerosis, defined by increased carotid intima-media thickness (cIMT) or coronary artery calcium score (CACS), and incident AF.

Methods and results

A systematic review of MEDLINE, EMBASE, and Cochrane was done to find all cohort studies investigating the association between subclinical atherosclerosis, defined by increased cIMT or CACS, and incident AF. Eligible articles had to be available in an English full-text version; include adults over the age of 18 years; include ≥100 participants; and have a follow-up period ≥12 months. Data on cIMT were pooled using a fixed-effects model, while data on CACS (I2 &gt;25) were pooled using a random-effects model. Five studies on cIMT including 36 333 patients and two studies on CACS including 34 603 patients were identified. All studies investigating the association between increased cIMT and incident AF showed a significant association, with an overall hazard ratio (HR) of 1.43 [95% confidence interval (CI) 1.27–1.59]. The two studies investigating the association between increased CACS and AF also showed a significant association with an overall HR of 1.07 (95% CI 1.02–1.12).

Conclusion

Data from seven observational studies suggest that subclinical atherosclerosis defined by increased cIMT or CACS is associated with an increased risk of incident AF. These findings emphasize the need for further research investigating whether treatment of subclinical atherosclerosis should be a part of the initiatives to prevent AF.

Atrial fibrillation and cardiac fibrosis: A review on the potential of extracellular matrix proteins as biomarkers

The involvement of fibrosis as an underlying pathology in heart diseases is becoming increasingly clear. In recent years, fibrosis has been granted a causative role in heart diseases and is now emerging as a major contributor to Atrial Fibrillation (AF) pathogenesis. AF is the most common arrhythmia encountered in the clinic, but the substrate for AF is still being debated. Consensus in the field is a combination of cardiac tissue remodeling, inflammation and genetic predisposition. The extracellular matrix (ECM) is subject of growing investigation, since measuring circulatory biomarkers of ECM formation and degradation provides both diagnostic and prognostic information. However, fibrosis is not just fibrosis. Each specific collagen biomarker holds information on regulatory mechanisms, as well as information about which section of the ECM is being remodeled, providing a detailed description of cardiac tissue homeostasis. This review entails an overview of the implication of fibrosis in AF, the different collagens and their significance, and the potential of using biomarkers of ECM remodeling as tools for understanding AF pathogenesis and identifying patients at risk for further disease progression.

Evaluation of Risk Prediction Models of Atrial Fibrillation (from the Multi-Ethnic Study of Atherosclerosis [MESA])

Atrial fibrillation (AF) is prevalent and strongly associated with higher cardiovascular disease (CVD) risk. Machine learning is increasingly used to identify novel predictors of CVD risk, but prediction improvements beyond established risk scores are uncertain. We evaluated improvements in predicting 5-year AF risk when adding novel candidate variables identified by machine learning to the CHARGE-AF Enriched score, which includes age, race/ethnicity, height, weight, systolic and diastolic blood pressure, current smoking, use of antihypertensive medication, diabetes, and NT-proBNP. We included 3,534 participants (mean age, 61.3 years; 52.0% female) with complete data from the prospective Multi-Ethnic Study of Atherosclerosis. Incident AF was defined based on study electrocardiograms and hospital discharge diagnosis ICD-9 codes, supplemented by Medicare claims. Prediction performance was evaluated using Cox regression and a parsimonious model was selected using LASSO. Within 5 years of baseline, 124 participants had incident AF. Compared with the CHARGE-AF Enriched model (c-statistic, 0.804), variables identified by machine learning, including biomarkers, cardiac magnetic resonance imaging variables, electrocardiogram variables, and subclinical CVD variables, did not significantly improve prediction. A 23-item score derived by machine learning achieved a c-statistic of 0.806, whereas a parsimonious model including the clinical risk factors age, weight, current smoking, NT-proBNP, coronary artery calcium score, and cardiac troponin-T achieved a c-statistic of 0.802. This analysis confirms that the CHARGE-AF Enriched model and a parsimonious 6-item model performed similarly to a more extensive model derived by machine learning. In conclusion, these simple models remain the gold standard for risk prediction of AF, although addition of the coronary artery calcium score should be considered.

Comparison of Framingham risk score and chest-CT identified coronary artery calcification in breast cancer patients to predict cardiovascular events

BACKGROUND

In breast cancer patients, coincidental detection of CAC at chest CT may be important in determining cardiovascular (CV) outcomes and facilitate CV disease primary prevention strategies.

METHODS

408 consecutive breast cancer patients referred to cardiac oncology clinic were included in the study. 256 patients without a prior history of coronary artery disease had undergone a chest CT. CT images were reviewed to detect CAC. Framingham risk score (FRS) was calculated and patient electronic medical records were interrogated to document the incidence of a composite clinical end point of all-cause mortality and cardiac events (coronary revascularization, heart failure hospitalization and de novo atrial fibrillation). Prevalence of statin prescribing was also collected.

RESULTS

Patients were followed for a median of 6.5 years. 112 clinical events occurred. Clinical follow up was 98%. CAC was found in 26% of patients. On multivariable analysis, CAC and advance cancer stage, but not FRS predicted the composite clinical end point (OR for CAC 2.59, p < 0.01). CAC but not FRS also predicted the incidence of cardiac events (OR for CAC 4.90, p < 0.01). CAC was present in 7.3% of patients with low FRS; none had been prescribed a statin. In patients with CAC and FRS ≥ 10%, 45% were not on a statin.

CONCLUSION

CAC is a common coincidental finding at CT chest in breast cancer patients referred to cardiac oncology. CAC but not FRS was predictive of composite clinical events and cardiac events. Detection of CAC at chest CT could alter the prescribing of primary prevention strategies to help prevent future cardiac events in breast cancer patients.

Effect of Systemic Hypertension With Versus Without Left Ventricular Hypertrophy on the Progression of Atrial Fibrillation (from the Euro Heart Survey)

Hypertension is a risk factor for both progression of atrial fibrillation (AF) and development of AF-related complications, that is major adverse cardiac and cerebrovascular events (MACCE). It is unknown whether left ventricular hypertrophy (LVH) as a consequence of hypertension is also a risk factor for both these end points. We aimed to assess this in low-risk AF patients, also assessing gender-related differences. We included 799 patients from the Euro Heart Survey with nonvalvular AF and a baseline echocardiogram. Patients with and without hypertension were included. End points after 1 year were occurrence of AF progression, that is paroxysmal AF becoming persistent and/or permanent AF, and MACCE. Echocardiographic LVH was present in 33% of 379 hypertensive patients. AF progression after 1 year occurred in 10.2% of 373 patients with rhythm follow-up. In hypertensive patients with LVH, AF progression occurred more frequently as compared with hypertensive patients without LVH (23.3% vs 8.8%, p = 0.011). In hypertensive AF patients, LVH was the most important multivariably adjusted determinant of AF progression on multivariable logistic regression (odds ratio 4.84, 95% confidence interval 1.70 to 13.78, p = 0.003). This effect was only seen in male patients (27.5% vs 5.8%, p = 0.002), while in female hypertensive patients, no differences were found in AF progression rates regarding the presence or absence of LVH (15.2% vs 15.0%, p = 0.999). No differences were seen in MACCE for hypertensive patients with and without LVH. In conclusion, in men with hypertension, LVH is associated with AF progression. This association seems to be absent in hypertensive women.

Genetics of Subclinical Coronary Atherosclerosis

Purpose of Review

This review highlights recent findings regarding genetics of coronary artery calcification (CAC), a marker of subclinical atherosclerosis burden, that is a precursor of clinical coronary artery disease.

Recent findings

CAC quantity is heritable. Genome wide association studies of common single nucleotide polymorphisms have identified genomic regions explaining ~2.4% of CAC heritability. Low frequency and rare variants explain additional variation in CAC. Evidence suggests that there may be different genetic etiologies for variation in CAC progression than for cross-sectional measures of CAC. Studies integrating multiple -omics data are providing new insights into the pathobiology of subclinical coronary atherosclerosis.

Summary

The future is promising for innovative studies utilizing whole genome sequencing data as well as other -omics such as epigenomic modifications of genes and gene expression. These studies may provide multiple sources of data pointing to the same gene or pathway, thus providing greater confidence in findings.

Associations of Lipoprotein(a) Levels With Incident Atrial Fibrillation and Ischemic Stroke: The ARIC (Atherosclerosis Risk in Communities) Study

Background

Lipoprotein(a) (Lp[a]) is proatherosclerotic and prothrombotic, causally related to coronary disease, and associated with other cardiovascular diseases. The association of Lp(a) with incident atrial fibrillation (AF) and with ischemic stroke among individuals with AF remains to be elucidated.

Methods and Results

In the community‐based ARIC (Atherosclerosis Risk in Communities) study cohort, Lp(a) levels were measured by a Denka Seiken assay at visit 4 (1996–1998). We used multivariable‐adjusted Cox models to compare AF and ischemic stroke risk across Lp(a) levels. First, we evaluated incident AF in 9908 participants free of AF at baseline. AF was ascertained by electrocardiography at study visits, hospital International Statistical Classification of Diseases, 9th Revision (ICD‐9) codes, and death certificates. We then evaluated incident ischemic stroke in 10 127 participants free of stroke at baseline. Stroke was identified by annual phone calls, hospital ICD‐9 Revision codes, and death certificates. The baseline age was 62.7±5.6 years. Median Lp(a) levels were 13.3 mg/dL (interquartile range, 5.2–39.7 mg/dL). Median follow‐up was 13.9 and 15.8 years for AF and stroke, respectively. Lp(a) was not associated with incident AF (hazard ratio, 0.98; 95% confidence interval, 0.82–1.17), comparing those with Lp(a) ≥50 with those with Lp(a) <10 mg/dL. High Lp(a) was associated with a 42% relative increase in stroke risk among participants without AF (hazard ratio, 1.42; 95% confidence interval, 1.07–1.90) but not in those with AF (hazard ratio, 1.06; 95% confidence interval, 0.70–1.61 [P interaction for AF=0.25]). There were no interactions by race or sex. No association was found for cardioembolic stroke subtype.

Conclusions

High Lp(a) levels were not associated with incident AF. Lp(a) levels were associated with increased ischemic stroke risk, primarily among individuals without AF but not in those with AF.

Adult Height, Prevalent Coronary Artery Calcium Score, and Incident Cardiovascular Disease Outcomes in a Multiethnic Cohort

We assessed the relationships among adult height, coronary artery calcium (CAC) score, incident atherosclerotic cardiovascular disease (ASCVD) events, and atrial fibrillation (AFib) in a multiethnic cohort. We used race/ethnicity-specific height (dichotomized by median value and in quartiles) as the predictor variable within the 4 racial/ethnic groups in the Multi-Ethnic Study of Atherosclerosis (n = 6,814). After a mean of 10.2 years of follow-up (2000-2012), 556 ASCVD events (8.2%) and 539 AFib events (7.9%) occurred. Adult height was not associated with prevalent CAC score (ln(CAC + 1) or categories). Tall stature (i.e., race/ethnicity-specific height ≥median) had a significant but opposite association with future ASCVD and AFib (hazard ratios were 0.72 (95% confidence interval: 0.56, 0.92) and 1.38 (95% confidence interval: 1.07, 1.79), respectively). We observed a gradient-response but opposite association between quartiles of race/ethnicity-specific height and ASCVD/AFib events in our multivariable models. A formal test of interaction between race/ethnicity-specific height and sex was not significant in the ASCVD model (P = 0.78) but was significant in the AFib model (P = 0.03). Tall stature was associated (in a gradient-response fashion) with reduced risk of ASCVD events and increased risk of AFib. Adult height may signal interactions between genetic and environmental factors and may provide risk information independent of current traditional risk factors and CAC score.

Predictive value of CHADS2 and CHA2DS2-VASc scores for acute myocardial infarction in patients with atrial fibrillation

The presence of acute myocardial infarction (AMI) confers a poor prognosis in atrial fibrillation (AF), associated with increased mortality dramatically. This study aimed to evaluate the predictive value of CHADS₂ and CHA₂DS₂-VASc scores for AMI in patients with AF. This retrospective study enrolled 5140 consecutive nonvalvular AF patients, 300 patients with AMI and 4840 patients without AMI. We identified the optimal cut-off values of the CHADS₂ and CHA₂DS₂-VASc scores each based on receiver operating characteristic curves to predict the risk of AMI. Both CHADS₂ score and CHA₂DS₂-VASc score were associated with an increased odds ratio of the prevalence of AMI in patients with AF, after adjustment for hyperlipidaemia, hyperuricemia, hyperthyroidism, hypothyroidism and obstructive sleep apnea. The present results showed that the area under the curve (AUC) for CHADS₂ score was 0.787 with a similar accuracy of the CHA₂DS₂-VASc score (AUC 0.750) in predicting “high-risk” AF patients who developed AMI. However, the predictive accuracy of the two clinical-based risk scores was fair. The CHA₂DS₂-VASc score has fair predictive value for identifying high-risk patients with AF and is not significantly superior to CHADS₂ in predicting patients who develop AMI.

The Implication of Coronary Artery Calcium Testing for Cardiovascular Disease Prevention and Diabetes

Over the last two decades coronary artery calcium (CAC) scanning has emerged as a quick, safe, and inexpensive method to detect the presence of coronary atherosclerosis. Data from multiple studies has shown that compared to individuals who do not have any coronary calcifications, those with severe calcifications (i.e., CAC score >300) have a 10-fold increase in their risk of coronary heart disease events and cardiovascular disease. Conversely, those that have a CAC of 0 have a very low event rate (~0.1%/year), with data that now extends to 15 years in some studies. Thus, the most notable implication of identifying CAC in individuals who do not have known cardiovascular disease is that it allows targeting of more aggressive therapies to those who have the highest risk of having future events. Such identification of risk is especially important for individuals who are not on any therapies for coronary heart disease, or when intensification of treatment is being considered but has an uncertain role. This review will highlight some of the recent data on CAC testing, while focusing on the implications of those findings on patient management. The evolving role of CAC in patients with diabetes will also be highlighted.

Linkage of a Population-Based Cohort With Primary Data Collection to Medicare Claims: The Reasons for Geographic and Racial Differences in Stroke Study

We described the linkage of primary data with administrative claims using the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study and Medicare. REGARDS study data were linked with Medicare claims by use of Social Security numbers. We compared REGARDS participants by Medicare linkage status, having fee-for-service (FFS) coverage or not, and with a 5% sample of Medicare beneficiaries who had FFS coverage in 2005, overall, by age (45-64 and ≥65 years), and by race. Among REGARDS participants who were ≥65 years of age, 80% had data linked to Medicare on their study-visit date (64% with FFS coverage). No differences except race and sex were present between REGARDS participants without Medicare linkage and those with data linked to Medicare with and without FFS coverage. After the age-sex-race adjustment, comorbid conditions and health-care utilization were similar for those with FFS coverage in the REGARDS study and the 5% sample of Medicare beneficiaries. Among REGARDS participants aged 45-64 years, 11% had FFS coverage on their study-visit date. In this age group, differences were present between participants with and without FFS coverage and the Medicare 5% sample with FFS coverage. In conclusion, REGARDS participants aged ≥65 years with FFS coverage are representative of the study cohort and the US population aged ≥65 years with FFS coverage.

Biomarkers and the prediction of atrial fibrillation: state of the art

Atrial fibrillation (AF) is the most common sustained arrhythmia encountered in clinical practice, and it places a substantial burden on the health care system. Despite improvements in our understanding of AF pathophysiology, we have yet to develop targeted preventive therapies. Recently, numerous biological markers have been identified to aid in the prediction of future AF events. Subclinical markers of atrial stress, inflammation, endothelial dysfunction, kidney dysfunction, and atherosclerosis have been linked to AF. The connection between these markers and AF is the identification of subclinical states in which AF propagation is likely to occur, as these conditions are associated with abnormal atrial remodeling and fibrosis. Additionally, several risk scores have been developed to aid in the identification of at-risk patients. The practicing clinician should be aware of these subclinical markers, as several of these markers improve the predictive abilities of current AF risk scores. Knowledge of these subclinical markers also provides clinicians with a better understanding of AF risk factors, and the opportunity to reduce the occurrence of AF by incorporating well-known cardiovascular disease risk factor modification strategies. In this review, we highlight several novel biological markers that have improved our understanding of AF pathophysiology and appraise the utility of these markers to improve our ability to predict future AF events.

Carotid Intima-Media Thickness and Arterial Stiffness and the Risk of Atrial Fibrillation: The Atherosclerosis Risk in Communities (ARIC) Study, Multi-Ethnic Study of Atherosclerosis (MESA), and the Rotterdam Study

BACKGROUND

We evaluated the association of carotid intima-media thickness (cIMT), carotid plaque, carotid distensibility coefficient (DC), and aortic pulse wave velocity (PWV) with incident atrial fibrillation (AF) and their role in improving AF risk prediction beyond the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE)-AF risk score.

METHODS AND RESULTS

We analyzed data from 3 population-based cohort studies: Atherosclerosis Risk in Communities (ARIC) Study (n=13 907); Multi-Ethnic Study of Atherosclerosis (MESA; n=6640), and the Rotterdam Study (RS; n=5220). We evaluated the association of arterial indices with incident AF and computed the C-statistic, category-based net reclassification improvement (NRI), and relative integrated discrimination improvement (IDI) of incorporating arterial indices into the CHARGE-AF risk score (age, race, height weight, systolic and diastolic blood pressure, antihypertensive medication use, smoking, diabetes, previous myocardial infarction, and previous heart failure). Higher cIMT (meta-analyzed hazard ratio [95% CI] per 1-SD increment, 1.12 [1.08-1.16]) and presence of carotid plaque (1.30 [1.19-1.42]) were associated with higher AF incidence after adjustment for CHARGE-AF risk-score variables. Lower DC and higher PWV were associated with higher AF incidence only after adjustment for the CHARGE-AF risk-score variables excepting height, weight, and systolic and diastolic blood pressure. Addition of cIMT or carotid plaque marginally improved CHARGE-AF score prediction as assessed by the relative IDI (estimates, 0.025-0.051), but not when assessed with the C-statistic and NRI.

CONCLUSIONS

Higher cIMT, presence of carotid plaque, and greater arterial stiffness are associated with higher AF incidence, indicating that atherosclerosis and arterial stiffness play a role in AF etiopathogenesis. However, arterial indices only modestly improve AF risk prediction.

Coronary Artery Calcium Progression and Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Coronary artery calcium (CAC) measured at a single time point has been associated with an increased risk for atrial fibrillation (AF). It is unknown whether CAC progression over time carries a similar risk.

METHODS AND RESULTS

This analysis included 5612 participants (mean age: 62±10; 52% women; 39% whites; 27% blacks; 20% Hispanics; 12% Chinese Americans) from the Multi-Ethnic Study of Atherosclerosis. Phantom-adjusted Agatston scores for baseline and follow-up measurements were used to compute change in CAC per year (≤0, 1-100, 101-300, and >300 U/year). AF was ascertained by review of hospital discharge records and from Medicare claims data through December 31, 2010. Cox regression was used to compute hazard ratios (HR) and 95% confidence intervals (CI) for the association between CAC progression and AF. Over a median follow-up of 5.6 years (25th, 75th percentiles=5.1, 6.8), a total of 203 (3.6%) incident AF cases were detected. Any CAC progression (>0/year) was associated with an increased risk for AF (HR=1.55, 95% CI=1.10, 2.19), and the risk increased with higher levels of CAC progression (≤0/year: HR=1.0 [reference]; 1-100/year: HR=1.47, 95% CI=1.03, 2.09; 101-300/year: HR=1.92, 95%CI=1.15, 3.20; >300/year: HR=3.23, 95%CI=1.48, 7.05). An interaction was observed by age with the association of CAC progression with AF being stronger for younger (<61 years: HR=3.53, 95% CI=1.29, 9.69) compared with older (≥61 years: HR=1.42, 95% CI=0.99, 2.04) participants (P interaction=0.037).

CONCLUSIONS

CAC progression during an average of 5 to 6 years of follow-up is associated with an increased risk for AF.

Prevalence and Spectrum of TBX5 Mutation in Patients with Lone Atrial Fibrillation

Atrial fibrillation (AF), the most common type of cardiac rhythm disturbance encountered in clinical practice, is associated with substantially increased morbidity and mortality. Aggregating evidence demonstrates that abnormal cardiovascular development is involved in the pathogenesis of AF. A recent study has revealed that the TBX5 gene, which encodes a T-box transcription factor key to cardiovascular development, was associated with AF and atypical Holt-Oram syndrome. However, the prevalence and spectrum of TBX5 mutation in patients with lone AF remain unclear. In this study, the coding regions and splicing junction sites of TBX5 were sequenced in 192 unrelated patients with lone AF and 300 unrelated ethnically-matched healthy individuals used as controls. The causative potential of the identified TBX5 variation was evaluated by MutationTaster and PolyPhen-2. The functional effect of the mutant TBX5 was assayed by using a dual-luciferase reporter assay system. As a result, a novel heterozygous TBX5 mutation, p.H170D, was identified in a patient, with a mutational prevalence of approximately 0.52%. This mutation, which was absent in the 300 control individuals, altered the amino acid completely conserved evolutionarily across species, and was predicted to be disease-causing. Functional deciphers showed that the mutant TBX5 was associated with significantly reduced transcriptional activity when compared with its wild-type counterpart. Furthermore, the mutation significantly decreased the synergistic activation between TBX5 and NKX2-5 or GATA4. The findings expand the mutational spectrum of TBX5 linked to AF and provide new evidence that dysfunctional TBX5 may contribute to lone AF.

Prevalence and Implications of Subclinical Coronary Artery Disease in Patients With Atrial Fibrillation

The objective of this study was to examine prevalence and clinical implications of subclinical coronary artery disease (CAD) detected by coronary artery calcium score (CACS) testing in patients with atrial fibrillation (AF). CACS was assessed in patients without history of CAD undergoing catheter ablation of AF. Age- and gender-matched patients with normal sinus rhythm (NSR) presenting with chest pain served as controls. Predicted arterial age using the Multi-Ethnic Study of Atherosclerosis registry was also compared to the chronologic age. A total of 860 patients (430 AF and 430 NSR, age 63 ± 10 years, 65% men) were included. Subclinical CAD prevalence (CACS >0) was 74% (319 of 430) in the AF group. Compared to the patients with NSR, patients with AF had higher prevalence of Subclinical CAD (74% vs 63%; p <0.001). In multivariate analysis, AF was independently associated with Subclinical CAD (hazard ratio 1.60; p = 0.002) but only with persistent AF (hazard ratio 2.28; p <0.001). Predicted arterial age was greater than chronologic age in patients with AF (69 ± 12 vs 64 ± 9 years). CACS-diagnosed subclinical CAD identified new potential candidates for statin therapy (12%; 33 of 267) and for oral anticoagulation (19%; 40 of 206) by addition of subclinical CAD to the CHA2DS2-VASc scores. In conclusion, in patients without known history of CAD, prevalence of subclinical CAD was significantly higher in those with persistent AF than those with NSR. AF was associated with subclinical CAD independently and complimentarily to clinical risk factors. Identifying subclinical CAD has potential clinical indications for prevention of CAD progression and stroke.

Coronary artery calcium screening: does it perform better than other cardiovascular risk stratification tools?

Coronary artery calcium (CAC) has been advocated as one of the strongest cardiovascular risk prediction markers. It performs better across a wide range of Framingham risk categories (6%-10% and 10%-20% 10-year risk categories) and also helps in reclassifying the risk of these subjects into either higher or lower risk categories based on CAC scores. It also performs better among population subgroups where Framingham risk score does not perform well, especially young subjects, women, family history of premature coronary artery disease and ethnic differences in coronary risk. The absence of CAC is also associated with excellent prognosis, with 10-year event rate of 1%. Studies have also compared with other commonly used markers of cardiovascular disease risk such as Carotid intima-media thickness and highly sensitive C-reactive protein. CAC also performs better compared with carotid intima-media thickness and highly sensitive C-reactive protein in prediction of coronary heart disease and cardiovascular disease events. CAC scans are associated with relatively low radiation exposure (0.9-1.1 mSv) and provide information that can be used not only for risk stratification but also can be used to track the progression of atherosclerosis and the effects of statins.