Left Atrial Strain and the Risk of Atrial Arrhythmias From Extended Ambulatory Cardiac Monitoring: MESA

Atrial Strain and Strain Rate in a General Population: Do These Measures Improve the Assessment of Elevated NT-proBNP Levels?

Background

Noninvasive assessment of elevated filling pressure in the left ventricle (LV) remains an unresolved problem. Of the many echocardiographic parameters used to evaluate diastolic pressure, the left atrial strain and strain rate (LA S/SR) have shown promise in clinical settings. However, only a few previous studies have evaluated LA S/SR in larger populations.

Methods

A total of 2033 participants from Norwegian (Tromsø 7) and Russian (Know Your Heart) population studies, equally distributed by age and sex, underwent echocardiography, including atrial and ventricular S/SR and NT-proBNP measurements. Of these, 1069 were identified as healthy (without hypertension (HT), atrial fibrillation (AF), or structural cardiac disease) and were used to define the age- and sex-adjusted normal ranges of LA S/SR. Furthermore, the total study population was divided into groups according to ejection fraction (EF) ≥50%, EF <50%, and AF. In each group, uni- and multiple regression and receiver operating characteristic curve analyses were performed to test LA and LV functional parameters as potential indicators of NT-proBNP levels above 250 ng/ml.

Results

The mean LA S/SR values in this study were higher than those in previous large studies, whereas the lower references were comparable. In normal hearts, atrial total strain (ATS) and mitral valve E deceleration time (MV DT) were independent factors indicating elevated NT-proBNP levels, whereas in hearts with reduced EFs, the independent indicators were peak atrial contraction strain (PACS) and LV stroke volume. The areas under the curve for these significant indicators to discriminate elevated NT-proBNP levels were 0.639 (95% confidence interval (CI): 0.577-0.701) for normal EF and 0.805 (CI: 0.675-0.935) for reduced EF.

Conclusion

The results confirm good intrastudy reproducibility, with mean values in the upper range of previous meta-analyses. In the future, automated border-detection algorithms may be able to generate highly reproducible normal values. Furthermore, the study showed atrial S/SR as an additional indicator of elevated NT-proBNP levels in the general population, demonstrating the incremental value of both ATS and PACS in addition to conventional and ventricular strain echocardiography. Thus, the LA S/SR may be regarded as an important addition to the multiparametric approach used for evaluating LV filling.

Beyond Blood Sugar: How Left Atrium Strain Predicts Cardiac Outcomes in Type 2 Diabetes

Speckle tracking echocardiography is an innovative imaging technique that evaluates myocardial motion, including the function of the left atrium (LA). The assessment of the left atrium's function across its dimensions can have diagnostic and prognostic roles in various cardiovascular conditions. Left atrial strain has been recognized as a valuable predictor of mortality and cardiovascular incidents in the general population across various conditions. For individuals with type 2 diabetes mellitus (T2DM), left atrial dysfunction, as gauged by speckle tracking echocardiography, appears particularly prognostic. Parameters such as peak atrial longitudinal strain (PALS) and left atrial stiffness have been linked with heightened risks of severe cardiovascular events, including atrial fibrillation (AF), heart failure (HF) hospitalizations, or mortality. Consequently, recognizing left atrial dysfunction early is crucial for accurate diagnosis, guiding treatment choices, comprehensive patient management, and prognosis evaluation. Using two-dimensional (2D) speckle tracking echocardiography, results from recent studies report that treatment with empagliflozin significantly enhanced LA function in patients with type 2 diabetes mellitus, improving left atrial strain (LAS) contraction and reservoir values. Furthermore, treatments with glucagon-like peptide-1 (GLP)-1 receptor agonists and sodium-glucose cotransporter-2 (SGLT-2) inhibitors were shown to improve LA reservoir strain more effectively than insulin alone, suggesting their potential in reducing cardiovascular complications in T2DM patients. This narrative review further addresses ongoing challenges and potential enhancements needed to boost the clinical value of left atrium strain, emphasizing its significance in managing and improving outcomes for diabetic patients.

Ischemic stroke and the emerging role of left atrial function

INTRODUCTION

Ischemic stroke is a leading cause of morbidity and mortality worldwide. Emerging evidence suggests that left atrial (LA) dysfunction could play a role in the pathophysiology of ischemic stroke, as a possible contributor and as a predictive biomarker.

AREAS COVERED

This narrative review details the intricate relationship between LA function, atrial fibrillation (AF), and ischemic stroke. We discuss imaging techniques used to assess LA function, the mechanisms by which impaired LA function may contribute to stroke, and its potential as a prognostic marker of stroke.

EXPERT OPINION

There is a lack of evidence-based treatments of LA dysfunction in both primary and secondary stroke prevention. This is partly due to the lack of a practical clinical definition and unanswered questions concerning the clinical implications of LA dysfunction in patients without AF. Until such questions are resolved, addressing well-known cardiovascular risk factors, like hypertension and obesity, should be prioritized for preventing AF and ischemic stroke. These risk factors are closely tied to atrial remodeling, emphasizing the importance of targeting primary modifiable factors for preventing future morbidity and mortality.

Correlation of epicardial adipose tissue and inflammatory indices in patients with STEMI and implications for atrial arrhythmias

BACKGROUND

Epicardial adipose tissue(EAT) is associated with inflammation in previous studies but is unknown in patients with ST-segment elevation myocardial infarction(STEMI).This study investigated the correlation between epicardial fat and inflammatory cells obtained by cardiac magnetic resonance (CMR) and the effect on atrial arrhythmias in patients with STEMI.

METHODS

This was a single-center, retrospective study. We consecutively selected patients who all completed CMR after Percutaneous Coronary Intervention (PCI) from January 2019 to December 2022 and then had regular follow-ups at 1, 3, 6, 9, and 12 months. The enrolled patients were grouped according to the presence or absence of atrial arrhythmia and divided into atrial and non-atrial arrhythmia groups.

RESULTS

White blood cell, neutrophil, lymphocyte, C-reactive protein, EATV, LVES, LVED were higher in the atrial arrhythmia group than in the non-atrial arrhythmia group, and LVEF was lower than that in the non-atrial arrhythmia group (p < 0.05); EATV was significantly positively correlated with each inflammatory indices (white blood cell: r = 0.415 p < 0.001, neutrophil:r = 0.386 p < 0.001, lymphocyte:r = 0.354 p < 0.001, C-reactive protein:r = 0.414 p < 0.001); one-way logistic regression analysis showed that risk factors for atrial arrhythmias were age, heart rate, white blood cell, neutrophil, lymphocyte, C-reactive protein, EATV, LVES, LVED; multifactorial logistic regression analysis showed that neutrophil, lymphocyte, C-reactive protein, EATV, and LVES were independent risk factors for atrial arrhythmias; ROC analysis showed that the area under the curve (AUC) for neutrophil was 0.862; the AUC for lymphocyte was 1.95; and the AUC for C-reactive protein was 0.862. reactive protein was 0.852; AUC for LVES was 0.683; and AUC for EATV was 0.869.

CONCLUSION

In patients with STEMI, EAT was significantly and positively correlated with inflammatory indices; neutrophil, lymphocyte, C-reactive protein, EATV, and LVES were independent risk factors for atrial arrhythmias and had good predictive value.

Left ventricular hypertrophy phenotype to predict incident atrial fibrillation: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIM

Left ventricular hypertrophy (LVH) has been shown to be associated with the occurrence of atrial fibrillation (AF). However, the predictive value of the LVH phenotype for incident AF remains uncertain. This study aimed to investigate the predictive value of LVH phenotype for incident AF.

METHODS AND RESULTS

This study utilized the Multi-Ethnic Study of Atherosclerosis (MESA) data. LVH was defined by cardiac magnetic resonance measured LV mass index. Isolated LVH was determined as LVH without elevated cardiac biomarker and malignant LVH was determined as LVH with at least 1 elevated biomarker. Receiver-operating characteristic (ROC) analysis was performed to calculate areas under the curves (AUC) for predicting AF. A total of 4983 community-dwelling participants were included, with a mean age of 61.5 years. 279 (5.6 %) had isolated LVH, and 222 (4.5 %) had malignant LVH. During a median follow-up of 8.5 years, 272 incident AF was observed. Compared to participants without LVH and elevated cardiac biomarkers, those with isolated LVH (HR, 1.82; 95 % CI, 1.03-3.20) and malignant LVH (HR, 4.13; 95 % CI, 2.77-6.16) had a higher risk of incident AF. Malignant LVH carried a 1.5-fold increased risk of AF compared to isolated LVH (HR: 2.48, 95 % CI: 1.30-4.73). Including the LVH phenotype in the CHARGE-AF model improved model discrimination (AUC increase: 0.03, p < 0.001).

CONCLUSIONS

The risks of AF incidence varied across LVH phenotypes. Malignant LVH carried the highest risk among LVH phenotypes. LVH phenotype provides incremental predictive value over the variables included in the CHARGE-AF model.

Spironolactone improves left atrial function and atrioventricular coupling in patients with resistant hypertension

To determine the blood pressure independent effects of spironolactone on left atrial (LA) size and function in patients with resistant hypertension (RHTN). Patients with RHTN (n = 36, mean age 55 ± 7) were prospectively recruited. Spironolactone was initiated at 25 mg/day and increased to 50 mg/day after 4 weeks. Other antihypertensives were withdrawn to maintain constant blood pressure. Cardiac magnetic resonance imaging was performed at baseline and after 6 months of spironolactone treatment and changes in LA functional metrics were assessed. LA size and function parameters were improved (p < 0.05) from baseline to month-6: LA volumes indexed to body surface area (LAVI) were reduced (LAVImaximum 41.4 ± 12 vs. 33.2±9.7 mL/m2; LAVIpre-A 32.6 ± 9.8 vs. 25.6 ± 8.1 mL/m2; median LAVIminimum 18.5 [13.9-24.8] vs. 14.1 [10.9-19.2] mL/m2); left atrioventricular coupling index was reduced (28.2 ± 11.5 vs. 22.7 ± 9.2%); LA emptying fractions (LAEF) were increased (median total LAEF 52.4 [48.7-60.3] vs. 55.9 [50.3-61.1] %; active LAEF 40.2 ± 8.6 vs. 43.1 ± 7.8%). LA global longitudinal strain in the active phase was increased (16.3 ± 4.1 vs. 17.8 ± 4.2%). The effect of spironolactone was similar in patients with high (N = 18) and normal (N = 18) aldosterone status (defined by plasma renin activity and 24-h urine aldosterone). Treatment of RHTN with spironolactone is associated with improvements in LA size and function, and atrioventricular coupling, regardless of whether aldosterone levels were normal or high at baseline. This study suggests the need for larger prospective studies examining effects of mineralocorticoid receptor antagonists on atrial function and atrioventricular coupling.

AI-enabled Left Atrial Volumetry in Cardiac CT Scans Improves CHARGE-AF and Outperforms NT-ProBNP for Prediction of Atrial Fibrillation in Asymptomatic Individuals: Multi-Ethnic Study of Atherosclerosis

Background

Coronary artery calcium (CAC) scans contain actionable information beyond CAC scores that is not currently reported.

Methods

We have applied artificial intelligence-enabled automated cardiac chambers volumetry to CAC scans (AI-CAC), taking on average 21 seconds per CAC scan, to 5535 asymptomatic individuals (52.2% women, ages 45-84) that were previously obtained for CAC scoring in the baseline examination (2000-2002) of the Multi-Ethnic Study of Atherosclerosis (MESA). We used the 5-year outcomes data for incident atrial fibrillation (AF) and compared the time-dependent AUC of AI-CAC LA volume with known predictors of AF, the CHARGE-AF Risk Score and NT-proBNP (BNP). The mean follow-up time to an AF event was 2.9±1.4 years.

Results

At 1,2,3,4, and 5 years follow-up 36, 77, 123, 182, and 236 cases of AF were identified, respectively. The AUC for AI-CAC LA volume was significantly higher than CHARGE-AF or BNP at year 1 (0.836, 0.742, 0.742), year 2 (0.842, 0.807,0.772), and year 3 (0.811, 0.785, 0.745) (p<0.02), but similar for year 4 (0.785, 0.769, 0.725) and year 5 (0.781, 0.767, 0.734) respectively (p>0.05). AI-CAC LA volume significantly improved the continuous Net Reclassification Index for prediction of AF over years 1-5 when added to CAC score (0.74, 0.49, 0.53, 0.39, 0.44), CHARGE-AF Risk Score (0.60, 0.28, 0.32, 0.19, 0.24), and BNP (0.68, 0.44, 0.42, 0.30, 0.37) respectively (p<0.01).

Conclusion

AI-CAC LA volume enabled prediction of AF as early as one year and significantly improved on risk classification of CHARGE-AF Risk Score and BNP.

Impact of rs1805127 and rs55742440 Variants on Atrial Remodeling in Hypertrophic Cardiomyopathy Patients with Atrial Fibrillation: A Romanian Cohort Study

Atrial fibrillation (AFib) is characterized by a complex genetic component. We aimed to investigate the association between variations in genes related to cardiac ion handling and AFib in a cohort of Romanian patients with hypertrophic cardiomyopathy (HCM). Forty-five unrelated probands with HCM were genotyped by targeted next-generation sequencing (NGS) for 24 genes associated with cardiac ion homeostasis. Subsequently, the study cohort was divided into two groups based on the presence (AFib+) or absence (AFiB-) of AFib detected during ECG monitoring. We identified two polymorphisms (rs1805127 located in KCNE1 and rs55742440 located in SCN1B) linked to AFib susceptibility. In AFib+, rs1805127 was associated with increased indexed left atrial (LA) maximal volume (LAVmax) (58.42 ± 21 mL/m2 vs. 32.54 ± 6.47 mL/m2, p < 0.001) and impaired LA strain reservoir (LASr) (13.3 ± 7.5% vs. 24.4 ± 6.8%, p < 0.05) compared to those without respective variants. The rs55742440 allele was less frequent in patients with AFib+ (12 out of 25, 48%) compared to those without arrhythmia (15 out of 20, 75%, p = 0.05). Also, AFib+ rs55742440 carriers had significantly lower LAVmax compared to those who were genotype negative. Among patients with HCM and AFib+, the rs1805127 variant was accompanied by pronounced LA remodeling, whereas rs55742440's presence was related to a milder LA enlargement.

Atrial strain and occult atrial fibrillation in cryptogenic stroke patients: a systematic review and meta-analysis

BACKGROUND

Cryptogenic stroke (CS) remains a significant cause of morbidity. Failure to identify the underlying pathology increases the rate of recurrence. Atrial fibrillation (AF) seems to be responsible for a substantial proportion of CS. Thus, there is an unmet need to identify and properly treat those with silent AF.

PURPOSE

To investigate the association between left atrial strain and newly diagnosed AF in CS patients.

OBJECTIVES

We searched major electronic databases for articles assessing the relationship between either peak left atrial longitudinal (PALS) or peak contractile (PACS) strain-quantified using speckle tracking echocardiography-and the incidence of occult AF during the diagnostic work-up of CS patients.

RESULTS

Eleven studies (two thousand and eighty-one patients) were analyzed. Incidence of occult AF was 19%. Both PALS and PACS were significantly lower in patients with newly diagnosed AF (MD - 8.6%, 95%CI - 10.7 to - 6.4, I2 86.4% and MD - 5.5, 95%CI - 6.8 to - 4.2, I2 80.8%). According to the diagnostic accuracy meta-analysis, PALS < 20% present 71% (95%CI 47-87%) sensitivity and 71% (95%CI 60-81%) specificity for the diagnosis of occult AF, assuming a prevalence of 20%. The corresponding values for PACS < 11% are 83% (95%CI 57-94%) and 78% (95%CI 56-91%).

CONCLUSION

Both PALS and PACS are significantly lower in patients with CS and silent AF. It seems that the cut-off values mentioned above could help physicians in identifying patients who may benefit more from prolonged rhythm monitoring. More studies are needed to confirm these findings.