Low vitamin D levels predict left atrial thrombus in nonvalvular atrial fibrillation

External validation and comparison of CHA2DS2-VASc-RAF and CHA2DS2-VASc-LAF scores for predicting left atrial thrombus and spontaneous echo contrast in patients with non-valvular atrial fibrillation

PURPOSE

CHA₂DS₂-VASc-RAF (R is renal dysfunction, and AF is atrial fibrillation type) and CHA₂DS₂-VASc-LAF (L is left atrial diameter, and AF is atrial fibrillation type) scores have been developed to estimate the risk of left atrial thrombus (LAT) and spontaneous echo contrast (SEC) in patients with non-valvular atrial fibrillation (NVAF). However, few external validations have been conducted to assess their accuracy. Thus, this study aimed to validate and compare the two modified scores for predicting LAT/SEC in patients with NVAF.

METHODS

This study included 399 patients with NVAF who underwent transesophageal echocardiography. Risk factors related to LAT/SEC were identified through logistic regression analysis, and predictive value and diagnostic efficiency were evaluated using receiver operating characteristic (ROC) curve.

RESULTS

Approximately 9.8% (39/399) of the patients with NVAF had LAT/SEC. Multivariate logistic regression analysis showed that history of stroke/transient ischemic attack, congestive heart failure, non-paroxysmal atrial fibrillation, lack of anticoagulation therapy, enlarged left atrial diameter, enlarged left ventricular end diastolic diameter, decreased left ventricular ejection fraction, decreased left atrial appendage emptying velocity, and decreased estimated glomerular filtration rate were independent risk factors for LAT/SEC. The CHA₂DS₂-VASc-LAF (area under the ROC curve [AUC] = 0.839) and CHA₂DS₂-VASc-RAF (AUC = 0.829) scores showed larger predictive values than the CHA₂DS₂-VASc (AUC = 0.737) and CHADS₂ (AUC = 0.736) scores. The AUC of the CHA₂DS₂-VASc-RAF score was similar to that of the CHA₂DS₂-VASc-LAF score (Z = 0.432; P = 0.666).

CONCLUSION

This study validated that the CHA₂DS₂-VASc-RAF and CHA₂DS₂-VASc-LAF scores are useful prognostic scoring systems for predicting LAT/SEC in patients with NVAF.

The Pathogenesis of Cardiac Arrhythmias in Vitamin D Deficiency

The global prevalence of vitamin D deficiency is more than 20%, and the main causes include insufficient intake, reduced absorption, abnormal metabolism, or resistance to its effects. The levels of serum vitamin D appear to influence cardiovascular risk, and the mechanism involved is linked to the transient outward current and the ultrarapid delayed rectifier K+ current densities, activated through the nuclear vitamin D receptor and Akt pathway. A significant number of studies have correlated vitamin D deficiency with an increased risk of developing cardiac arrhythmias and sudden cardiac death. For this reason, the purpose of this review is to analyze the relation between vitamin D deficiency and the pathogenesis of cardiac arrhythmias. Atrial fibrillation, increased QT interval, and QT dispersion were the most common findings associated with vitamin D deficiency. Due to the heterogeneity among existing studies, further research is necessary to confirm the existing data and to analyze its relationship with other types of arrhythmias.

[Independent risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation and low CHA2DS2-VASc scores]

OBJECTIVE

To explore the risk factors of atrial thrombosis in patients with nonvalvular atrial fibrillation(NVAF)with low CHA₂DS₂-VASc scores at admission (≤1 for male and ≤2 for female patients).

METHODS

We retrospectively analyzed the clinical data of 10 382 patients with NVAF undergoing transesophageal echocardiography in our hospital from 2009 to 2019, and enrolled 48 NVAF patients with thrombosis as the observation group and another 240 NVAF patients without thrombosis as the control group.The baseline characteristics, biochemical indicators, and echocardiographic findings of the patients were analyzed using univariate analysis, multivariate logistic regression analysis and Pearson correlation analysis.

RESULTS

The baseline data did not differ significantly between the two groups (P > 0.05).Compared with those in the control group, the patients with atrial thrombosis had an increased left atrial diameter (LAD; P < 0.001), a greater likelihood of hypertrophic cardiomyopathy (HCM; P < 0.001), significantly higher levels of C-reactive protein (CRP; P < 0.05) and uric acid (P < 0.001), and greater standard deviation of red blood cell distribution width(RDW-SD; P < 0.001).LAD(P < 0.001), HCM(P < 0.05)and CRP(P < 0.05) were identified as the independent factors affecting the occurrence of atrial thrombosis in patients with low CHA₂DS₂-VASc scores.

CONCLUSIONS

LAD enlargement, HCM, and an elevated CRP level are independent risk factors for atrial thrombosis in NVAF patients with low CHA₂DS₂-VASc scores.Active anticoagulation therapy should be administered for these patients once these risk factors are detected to prevent the occurrence of stroke.

Prevalence of Left Atrial Thrombus in Anticoagulated Patients With Atrial Fibrillation

BACKGROUND

The prevalence of left atrial (LA) thrombus in patients with atrial fibrillation (AF) or atrial flutter (AFL) on guideline-directed anticoagulation is not well known, yet this may inform transesophageal echocardiogram (TEE) use before cardioversion or catheter ablation.

OBJECTIVES

The purpose of this study was to quantify LA thrombus prevalence among patients with AF/AFL on guideline-directed anticoagulation and to identify high-risk subgroups.

METHODS

EMBASE, MEDLINE, and CENTRAL were systematically searched from inception to July 2020 for studies reporting on LA thrombus prevalence among patients with AF/AFL undergoing TEE following at least 3 weeks of continuous therapeutic oral anticoagulation with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs). Meta-analysis was performed using random effects models.

RESULTS

Thirty-five studies describing 14,653 patients were identified. The mean-weighted LA thrombus prevalence was 2.73% (95% confidence interval [CI]: 1.95% to 3.80%). LA thrombus prevalence was similar for VKA- and DOAC-treated patients (2.80%; 95% CI: 1.86% to 4.21% vs. 3.12%; 95% CI: 1.92% to 5.03%; p = 0.674). Patients with nonparoxysmal AF/AFL had a 4-fold higher LA thrombus prevalence compared with paroxysmal patients (4.81%; 95% CI: 3.35% to 6.86% vs. 1.03%; 95% CI: 0.52% to 2.03%; p < 0.001). LA thrombus prevalence was higher among patients undergoing cardioversion versus ablation (5.55%; 95% CI: 3.15% to 9.58% vs. 1.65%; 95% CI: 1.07% to 2.53%; p < 0.001). Patients with CHA₂DS₂-VASc scores ≥3 had a higher LA thrombus prevalence compared with patients with scores ≤2 (6.31%; 95% CI: 3.72% to 10.49% vs. 1.06%; 95% CI: 0.45% to 2.49%; p < 0.001).

CONCLUSIONS

LA thrombus prevalence is high in subgroups of anticoagulated patients with AF/AFL, who may benefit from routine pre-procedural TEE use before cardioversion or catheter ablation.