Echocardiographic Measurement of Left Atrial Strain - A Key Requirement in Clinical Practice

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.

Left atrial reservoir strain is a marker of atrial fibrotic remodeling in patients undergoing cardiovascular surgery: Analysis of gene expression

Left atrial strain (LAS) measured by two-dimensional speckle tracking echocardiography (2DSTE) is considered to be a marker of LA structural remodeling, but it remains unsettled. We investigated the potential usefulness and clinical relevance of LAS to detect atrial remodeling including fibrosis by analyzing gene expression in cardiovascular surgery patients. Preoperative 2DSTE was performed in 131 patients (92 patients with sinus rhythm [SR] patients including paroxysmal AF [PAF], 39 atrial fibrillation [AF]) undergoing cardiovascular surgery. Atrial samples were obtained from the left atrial appendages, and mRNA expression level was analyzed by real-time reverse transcription polymerase chain reaction (RT-PCR) in 59 cases (24 PAF, 35 AF). Mean value of left atrial reservoir strain (mLASr) correlated with left atrial volume index (LAVI), and left atrial conduit strain (mLAScd). mLASr also correlated with left atrial contractile strain (mLASct) in SR patients including PAF. mLASr was significantly lower, and LAVI was higher, in the AF group, compared with SR patients including PAF. The expression of COL1A1 mRNA encoding collagen type I α1 significantly increased in AF patients (p = 0.031). mLASr negatively correlated with COL1A1 expression level, and multivariate regression analysis showed that mLASr was an independent predictor of atrial COL1A1 expression level, even after adjusting for age, sex, and BMI. But, neither mLAScd / mLASct nor LAVI (bp) correlated with COL1A1 gene expression. The expression level of COL1A1 mRNA strongly correlated with ECM-related genes (COL3A1, FN1). It also correlated ECM degradation-related genes (MMP2, TIMP1, and TIMP2), pro-fibrogenic cytokines (TGFB1 encoding TGFβ1, END1, PDGFD, CTGF), oxidant stress-related genes (NOX2, NOX4), ACE, inflammation-related genes (NLRP, IL1B, MCP-1), and apoptosis (BAX). Among the fibrosis-related genes examined, univariable regression analysis showed that log (COL1A1) was associated with log (TGFB1) (adjusted R2 = 0.685, p<0.001), log (NOX4) (adjusted R2 = 0.622, p<0.001), log (NOX2) (adjusted R2 = 0.611, p<0.001), suggesting that TGFB1 and NOX4 was the potent independent determinants of COL1A1 expression level. mLASr negatively correlated with the ECM-related genes, and fibrosis-related gene expression level including TGFB1, NOX2, and NLRP3 in PAF patients. PAF patients with low mLASr had higher expression of the fibrosis-related gene expression, compared with those with high mLASr. These results suggest that LASr correlates with atrial COL1A1 gene expression associated with fibrosis-related gene expression. Patients with low LASr exhibit increased atrial fibrosis-related gene expression, even those with PAF, highlighting the utility of LAS as a marker for LA fibrosis in cardiovascular surgery patients.

Left atrial strain in neonates with congenital diaphragmatic hernia and length of stay in pediatric intensive care unit

Introduction

The role of cardiac left ventricle (LV) dysfunction in children with congenital diaphragmatic hernia (CDH) has gained increasing attention. The hernia allows abdominal mass to enter thorax and subsequently both dislocating and compressing the heart. The pressure on vessels and myocardium alters blood flow and may interfere with normal development of the LV. A dysfunctional LV is concerning and impacts the complex pathophysiology of CDH. Hence, assessing both the systolic and diastolic LV function in the newborn with CDH is important, and it may add value for medical treatment and prognostic factors as length of stay (LOS) in pediatric intensive care unit (PICU). LV strain is considered an early marker of systolic dysfunction used in the pediatric population. Left atrial (LA) strain is an echocardiographic marker of LV diastolic dysfunction used in the adult population. When filling pressure of the LV increases, the strain of the atrial wall is decreased. We hypothesized that reduced LA strain and LV strain are correlated with the LOS in the PICU of newborns with CDH.

Methods

This retrospective observational cohort study included data of 55 children born with CDH between 2018 and 2020 and treated at Karolinska University Hospital, Sweden. Overall, 46 parents provided consent. Echocardiograms were performed in 35 children <72 h after birth. The LA reservoir strain (LASr), LV global longitudinal strain, LV dimensions, and direction of blood flow through the patent foramen ovale (PFO) were retrospectively assessed using the echocardiograms.

Results

Children with LASr <33% (n = 27) had longer stays in the PICU than children with LA strain ≥33% (n = 8) (mean: 20.8 vs. 8.6 days; p < 0.002). The LASr was correlated with the LOS in the PICU (correlation coefficient: -0.378; p = 0.025). The LV dimension was correlated with the LOS (correlation coefficient: -0.546; p = 0.01). However, LV strain was not correlated to LOS.

Conclusion

Newborns with CDH and a lower LASr (<33%) had longer stays in the PICU than children with LASr ≥33%. LASr is a feasible echocardiographic marker of diastolic LV dysfunction in newborns with CDH and may indicate the severity of the condition.

Coronary microvascular dysfunction and atrial reservoir function

BACKGROUND

Coronary microvascular dysfunction (CMD) refers to structural and functional abnormalities of the coronary microcirculation, which may be diagnosed using invasive coronary physiology. CMD is responsible for impaired diastolic cardiac function. It has recently been suggested that left atrial strain (LASr) represents a highly sensitive tool for detecting cardiac diastolic function abnormalities. Accordingly, the aim of this study was to investigate the relationship between CMD and LASr.

METHODS

Consecutively enrolled patients with non-obstructed coronary arteries (NOCA) underwent CMD and LASr evaluation by invasive thermodilution and noninvasive echocardiography, respectively.

RESULTS

Forty-two (42) patients were included, out of which 26 presented with CMD. There were no significant differences between CMD-positive and negative patients in terms of clinical and echocardiographic characteristics. LASr was significantly reduced in patients with CMD (24.6% ± 6.1 vs. 30.3 ± 7.8%, p = 0.01). A moderate correlation was observed between coronary flow reserve and LAsr (r = 0.47, p = 0.002). A multivariate logistic regression analysis demonstrated that CMD was independently associated with LASr (OR = 0.88, 95%CI 0.78-0.99.135, p = 0.04). A LASr cut-off of 25.5% enabled an optimal classification of patients with or without CMD.

CONCLUSION

Patients with NOCA and CMD had a significantly reduced LASr compared with patients without CMD, suggesting the early impairment of diastolic function in these patients.

Impact of left atrial appendage flow velocity on thrombus resolution and clinical outcomes in patients with atrial fibrillation and silent left atrial thrombi: insights from the LAT study

AIMS

Blood stasis is crucial in developing left atrial (LA) thrombi. LA appendage peak flow velocity (LAAFV) is a quantitative parameter for estimating thromboembolic risk. However, its impact on LA thrombus resolution and clinical outcomes remains unclear.

METHODS AND RESULTS

The LAT study was a multicentre observational study investigating patients with atrial fibrillation (AF) and silent LA thrombi detected by transoesophageal echocardiography (TEE). Among 17 436 TEE procedures for patients with AF, 297 patients (1.7%) had silent LA thrombi. Excluding patients without follow-up examinations, we enrolled 169 whose baseline LAAFV was available. Oral anticoagulation use increased from 85.7% at baseline to 97.0% at the final follow-up (P < 0.001). During 1 year, LA thrombus resolution was confirmed in 130 (76.9%) patients within 76 (34-138) days. Conversely, 26 had residual LA thrombi, 8 had thromboembolisms, and 5 required surgical removal. These patients with failed thrombus resolution had lower baseline LAAFV than those with successful resolution (18.0 [15.8-22.0] vs. 22.2 [17.0-35.0], P = 0.003). Despite limited predictive power (area under the curve, 0.659; P = 0.001), LAAFV ≤ 20.0 cm/s (best cut-off) significantly predicted failed LA thrombus resolution, even after adjusting for potential confounders (odds ratio, 2.72; 95% confidence interval, 1.22-6.09; P = 0.015). The incidence of adverse outcomes including ischaemic stroke/systemic embolism, major bleeding, or all-cause death was significantly higher in patients with reduced LAAFV than in those with preserved LAAFV (28.4% vs. 11.6%, log-rank P = 0.005).

CONCLUSION

Failed LA thrombus resolution was not rare in patients with AF and silent LA thrombi. Reduced LAAFV was associated with failed LA thrombus resolution and adverse clinical outcomes.

Left atrial strain time integral evaluated by two-dimensional speckle tracking predicts left atrial appendage dysfunction in patients with acute ischemic stroke

Cardioembolic stroke is a serious disease with poor prognosis, whose main embolic source is the left atrial appendage (LAA). Left atrial (LA) strain evaluated by the two-dimensional (2D) speckle tracking technique has been proposed. However, the commonly used peak LA strain reflects only LA reservoir function. The LA strain also includes indicators of the other LA functions, such as booster pump function, which reflects active contraction of the LA. This study aimed to investigate whether a newly developed parameter, the left atrial strain time integral (LASTI), can evaluate LAA dysfunction more accurately in patients with acute stroke. We measured LA strain using a 2D speckle tracking method in 168 patients with acute stroke and 20 age-matched control subjects. LASTI was calculated as the area under the LA strain curve in one cardiac cycle. LAA dysfunction was defined as LAA thrombus and/or severe spontaneous echo contrast by transesophageal echocardiography. LASTI was significantly lower in patients with LAA dysfunction than those without. LASTI was a better correlation with LAA blood flow velocity measured by transesophageal echocardiography than peak LA strain. Multivariate logistic regression analysis showed that LASTI was an independent predictor of LAA dysfunction after adjustment for conventional risk factors. LASTI can be a feasible parameter for predicting LAA dysfunction in patients with acute stroke.

Biventricular performance in adults with a systemic right ventricle: new insights from myocardial work analysis

To evaluate biventricular mechanics by means of echo-derived myocardial work (MW) analysis in patients with a systemic right ventricle (sRV). Comprehensive echo data were collected in all patients with a sRV who underwent transthoracic echocardiography at our tertiary centre between 2020 and 2021 including sRV function indices, global longitudinal strain (GLS) of right and left ventricle (RV/LV), biventricular MW, and atrial strain in those with congenitally corrected transposition of the great arteries (ccTGA). Fifty-six patients (37 [30.97-45.87]years, 59% male) and 49 healthy individuals matched per age and sex were included for comparison. Global work index (GWI:1106 [869.80-1293.10] Vs 314.2 [281.5-358.2]mmHg%, p < 0.0001) and global constructive work(GCW: 1542.50 [1338.9-1718.50] Vs 416.4 [365.70-464]mmHg%, p < 0.0001) were both increased for sRV compared to normal RV, reflecting exposition to a systemic afterload, with a contemporary raise in wasted work (GWW:197 [138.50-322.20] Vs 26.09 [17.80-43.48]mmHg%, p < 0.0001) and impaired efficiency (GWE:89 [83-93.54] Vs 93.67 [91.67-96] %, p < 0.0001). Conversely, sRV showed reduced MW indices in comparison to normal LV(p < 0.0001 for all). Non-systemic LV demonstrated normal GLS values (19.51 ± 3.9%), but reduced GWI (479 [368-665] Vs 2172 [1978-2386]mmHg%, p < 0.0001) and GCW (708 [490-815]mmHg% Vs 86.5 [59.25-118], p < 0.0001). Nevertherless, non-systemic LV showed also impaired efficiency (91 [88-94] Vs 95 [94-97]%, p < 0.0001). LVGLS values were related to RVGLS (R = 0.5, p = 0.00019), suggesting a consistent interventricular dependency. Atrial strain could be assessed in 16 out of 20 (80%) patients with ccTGA: both atria had reduced strain values compared to their normal counterparts. Moreover, pulmonary atrial strain during the reservoir phase was related to LVGWE (R = 0.58, p = 0.047) and inversely related to LVGLS (R = - 0.71, p = 0.0043). MW analysis is feasible in sRV and may provide additional clinical data. In our cohort MW revealed biventricular impairment, in particular for non-systemic LV, in spite of normal GLS values.

Effect of volume infusion on left atrial strain in acute circulatory failure

BACKGROUND

Left atrial strain (LAS) is a measure of atrial wall deformation during cardiac cycle and reflects atrial contribution to cardiovascular performance. Pathophysiological significance of LAS in critically ill patients with hemodynamic instability has never been explored. This study aimed at describing LAS and its variation during volume expansion and to assess the relationship between LAS components and fluid responsiveness.

METHODS

This prospective observational study was performed in a French ICU and included patients with acute circulatory failure, for whom the treating physician decided to proceed to volume expansion (rapid infusion of 500 mL of crystalloid solution). Trans-thoracic echocardiography was performed before and after the fluid infusion. LAS analysis was performed offline. Fluid responsiveness was defined as an increase in velocity-time integral (VTI) of left ventricular outflow tract ≥ 10%.

RESULTS

Thirty-eight patients were included in the final analysis. Seventeen (45%) patients were fluid responders. LAS analysis had a good feasibility and reproducibility. Overall, LAS was markedly reduced in all its components, with values of 19 [15 - 32], -9 [-19 - -7] and - 9 [-13 - -5] % for LAS reservoir (LASr), conduit (LAScd) and contraction (LASct), respectively. LASr, LAScd and LASct significantly increased during volume expansion in the entire population. Baseline value of LAS did not predict fluid responsiveness and the changes in LAS and VTI during volume expansion were not significantly correlated.

CONCLUSIONS

LAS is severely altered during acute circulatory failure. LAS components significantly increase during fluid administration, but cannot be used to predict or assess fluid responsiveness.

Significant dependency of left atrial strain on left ventricular longitudinal motion

BACKGROUND

The effects of left ventricular longitudinal function on the left atrial strain, including the left atrial reservoir function, have not been adequately quantified.

METHODS

A total of 124 patients who underwent echocardiography were enrolled in this study. Left atrial strain analysis was performed using two-dimensional speckle tracking echocardiography, and the left atrial volume was derived using the modified Simpson's method. The peak left atrial strain (LAS) and left atrial expansion index (LAEI), as indices of left atrial reservoir function, were measured. The global longitudinal strain (GLS) and mitral annular plane systolic excursion (MAPSE), which are indices of contractile motion toward the left ventricular apex, were also measured. The correlation between LAS and candidate determinants, including left ventricular systolic longitudinal function, was evaluated, and multivariate regression analysis was performed.

RESULTS

A significant correlation was found between LAS and left ventricular systolic longitudinal functions, GLS (r = 0.63, p < 0.001), and MAPSE (r = 0.65, p < 0.001). Two models, which were selected by multiple regression analyses for LAS, included GLS or MAPSE as independent determinants. GLS and MAPSE were also the strongest predictors, among other factors.

CONCLUSION

LAS, when determined by evaluating the left atrial reservoir function, was significantly associated with left ventricular function, especially the systolic longitudinal function. Left ventricular function should be considered when assessing left atrial function by LAS.

Prognostic Role of Right Ventricular-Pulmonary Artery Coupling Assessed by TAPSE/PASP Ratio in Patients With Acute Heart Failure

BACKGROUND

Right ventricular (RV) dysfunction is a significant risk of major adverse cardiac events in patients with acute heart failure (AHF). In this study, we evaluated RV-pulmonary artery (PA) coupling, assessed by tricuspid annular plane systolic excursion (TAPSE)/pulmonary artery systolic pressure (PASP) and assessed its prognostic significance, in AHF patients.

METHODS

We measured the TAPSE/PASP ratio and analyzed its correlations with other echocardiographic parameters. Additionally, we assessed its prognostic role in AHF patients.

RESULTS

A total of 1147 patients were included in the analysis (575 men, aged 70.81 ± 13.56 years). TAPSE/PASP ratio exhibited significant correlations with left ventricular (LV) ejection fraction(r = 0.243, p < 0.001), left atrial (LA) diameter(r = -0.320, p < 0.001), left atrial global longitudinal strain (LAGLS, r = 0.496, p < 0.001), mitral E/E' ratio(r = -0.337, p < 0.001), and right ventricular fractional area change (RVFAC, r = 0.496, p < 0.001). During the median follow-up duration of 29.0 months, a total of 387 patients (33.7%) died. In the univariate analysis, PASP, TAPSE, and TAPSE/PASP ratio were significant predictors of mortality. After the multivariate analysis, TAPSE/PASP ratio remained a statistically significant parameter for all-cause mortality (hazard ratio [HR], 0.453; p = 0.037) after adjusting for other parameters. In the receiver operating curve analysis, the optimal cut-off level of TAPSE/PASP ratio for predicting mortality was 0.33 (area under the curve = 0.576, p < 0.001), with a sensitivity of 65% and a specificity of 47%. TAPSE/PASP ratio < 0.33 was associated with an increased risk of mortality after adjusting for other variables (HR, 1.306; p = 0.025).

CONCLUSIONS

In AHF patients, TAPSE/PASP ratio demonstrated significant associations with RVFAC, LA diameter and LAGLS. Moreover, a decreased TAPSE/PASP ratio < 0.33 was identified as a poor prognostic factor for mortality.

Echocardiographic Evaluation of Atrial Remodelling for the Prognosis of Maintaining Sinus Rhythm after Electrical Cardioversion in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common atrial tachyarrhythmia. One of the methods of AF treatment is direct current cardioversion (DCCV), but in the long-term follow-up we observe quite a high percentage of AF recurrences after this procedure. In order to assess the prognosis of DCCV effectiveness, we use clinical, biochemical and echocardiographic parameters. The objective of this review is to systematise the current knowledge on echocardiographic measurements in patients with persistent AF used to assess the progress of remodelling of the atrial wall, which affects the likelihood of maintaining sinus rhythm after DCCV. In this article, echocardiographic parameters for the evaluation of remodelling of the atrial wall are divided into groups referring to structural, mechanical, and electrical remodelling, as well as parameters for the evaluation of left ventricular filling pressure. The article aims to draw attention to the clinical value of echocardiographic measurements, which is the selection of patients who will maintain sinus rhythm after DCCV in the long-term follow-up, which will allow to avoid unnecessary risks associated with the procedure and enable the selection of the appropriate treatment strategy.

Prognostic Impact of Left Atrial Strain in Patients Hospitalized for Acute Heart Failure With Atrial Fibrillation

BACKGROUND

Patients with atrial fibrillation (AF) and heart failure (HF) have elevated left ventricular end-diastolic pressure in addition to decreased left atrial (LA) function, but there are few reports of useful prognostic indices that can be seen on echocardiography. In this study, we investigated the association between LA reservoir strain (LARS) and prognosis in this group of patients.

METHODS AND RESULTS

We retrospectively enrolled patients with acute HF complicated by AF who were consecutively admitted to hospital between January 2014 and December 2018. A total of 320 patients (mean age 79±12 years, 163 women) were included in the analysis. During a median follow-up of 473 days, 92 cardiovascular deaths and 113 all-cause deaths occurred. In the multivariate analysis, LARS was an independent predictor of all-cause death (hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.90-0.99, P=0.016). Multivariate analysis also showed that the patients in the lowest LARS tertile (<7.16%) had a significantly increased risk of cardiovascular death (HR 1.76, 95% CI 1.05-2.96; P=0.033) and all-cause death (HR 1.90, 95% CI 1.17-3.08; P=0.009) in comparison with patients in the highest LARS tertile (>10.52%).

CONCLUSIONS

We found a significant association between LARS and death in patients with AF and HF. Patients with reduced LARS had poor prognosis, suggesting the need for aggressive therapy to improve their LA dysfunction.

The Role of Echocardiography in Evaluating Cardiovascular Diseases in Patients with Diabetes Mellitus

Patients with diabetes mellitus are highly susceptible to cardiovascular complications, which are directly correlated with cardiovascular morbidity and mortality. In addition to coronary artery disease, there is growing awareness of the risk and prevalence of heart failure (HF) in patients with diabetes. Echocardiography is an essential diagnostic modality commonly performed in patients with symptoms suggestive of cardiovascular diseases (CVD), such as dyspnea or chest pain, to establish or rule out the cause of symptoms. Conventional echocardiographic parameters, such as left ventricular ejection fraction, are helpful not only for diagnosing CVD but also for determining severity, treatment strategy, prognosis, and response to treatment. Echocardiographic myocardial strain, a novel echocardiographic technique, enables the detection of early changes in ventricular dysfunction before HF symptoms develop. This article aims to review the role of echocardiography in evaluating CVD in patients with diabetes mellitus and how to use it in patients with suspected cardiac diseases.

Evaluation of the relationship between left atrial strain and exercise tolerance in patients with hypertrophic cardiomyopathy by treadmill stress echocardiography

Objective

The aim of this study is to evaluate the left atrial strain (LAS) in patients with hypertrophic cardiomyopathy (HCM) by treadmill exercise stress echocardiography, combined with three-dimensional speckle tracking technology, for predicting exercise tolerance.

Methods

A total of 97 patients with HCM who underwent treadmill exercise stress echocardiography were recruited in Sichuan Provincial People's Hospital between January 2018 and January 2021, and 30 control subjects were selected to be included in the normal group. HCM patients with their metabolic equivalents (METS) ≤ 6.0 were included in the HCM-1 group, while those with METS > 6.0 were included in the HCM-2 group. The LAS and exercise tolerance were analyzed. The ultrasound parameters that could predict a decrease in exercise tolerance were screened, and a predictive model was constructed.

Results

It was found that METS, Rest-LASr, Rest-LAScd, and Rest-LASct were significantly lower in HCM patients than those in normal controls. There was a significant difference in age, Target_HR, LVMI, LAVI, E/e'-Rest, E/e'-Peak, Rest-LASr, Rest-LAScd, and Rest-LASct between the HCM-1 and the HCM-2 groups. LASr is an independent resting echocardiographic predictor of METS ≤ 6.0. LASr remained significant for predicting different subtypes (AHCM, asymmetric HCM, and obstructive HCM). Rest-LASr (AUC 0.990) was better at predicting METS ≤ 6.0 than Peak-E/e' (AUC 0.753). A multivariate model (LASr + Age + Target_HR) was established for METS prediction.

Conclusion

Left atrial reservoir strain (LASr) has the strongest association with METS ≤ 6.0. The LASr is an independent resting predictor of METS ≤ 6.0 and has a good performance record in predicting different subtypes of HCM. Compared with the traditional parameters, Peak-E/e' and Rest-E/e', Rest-LASr is the best predictor. Rest-LASr can serve as a reliable method for HCM patients who are unable to undergo exercise testing but require an urgent evaluation of their METS, which provides a basis for clinical treatment decision-making and treatment effect evaluation.

Imaging in atrial fibrillation: A way to assess atrial fibrosis and remodeling to assist decision-making

The 2020 ESC atrial fibrillation (AF) guidelines suggest the novel 4S-AF scheme for the characterization of AF. Imaging techniques could be helpful for this objective in everyday clinical practice, and information derived from these techniques reflects basic aspects of the pathophysiology of AF, which may facilitate treatment decision-making, and optimal management of AF patients. The aim of this review is to provide an overview of the mechanisms associated with atrial fibrosis and to describe imaging techniques that may help the management of AF patients in clinical practice. Transthoracic echocardiography is the most common procedure given its versatility, safety, and simplicity. Transesophageal echocardiography provides higher resolution exploration, and speckle tracking echocardiography can provide incremental functional and prognostic information over conventional echocardiographic parameters. In addition, LA deformation imaging, including LA strain and strain rate, are related to the extent of fibrosis. On the other hand, multidetector-row computed tomography and cardiac magnetic resonance provide higher resolution data and more accurate assessment of the dimensions, structure, and spatial relationships of the LA. Imaging is central when deciding on catheter ablation or cardioversion, and helps in selecting those patients who will really benefit from these procedures. Moreover, imaging enhances the understanding of the underlying mechanisms of atrial remodeling and might assists in refining the risk of stroke, which help to select the best medical therapies/interventions. In summary, evaluation of LA enlargement, LA remodeling and fibrosis with imaging techniques adds clinical and prognostic information and should be assessed as a part of routine comprehensive AF evaluation.

Stacked machine learning models to classify atrial disorders based on clinical ECG features: a method to predict early atrial fibrillation

OBJECTIVES

Atrial Tachycardia (AT) and Left Atrial Enlargement (LAE) are atrial diseases that are significant precursors to Atrial Fibrillation (AF). There are ML models for ECG classification; clinical features-based classification is required. The suggested work aims to create stacked ML models that categorize Sinus Rhythm (SR), Sinus Tachycardia (ST), AT, and LAE signals based on clinical parameters for AF prognosis.

METHODS

The classification was based on thirteen clinical parameters, such as amplitude, time domain ECG aspects, and P-Wave Indices (PWI), such as the ratio of P-wave length and amplitude ((P (ms)/P (µV)), P-wave area (µV*ms), and P-wave terminal force (PTFV1(µV*ms). Apart from classifying the ECG signals, the stacked ML models prioritized the clinical features using a pie formula-based technique.

RESULTS

The Stack 1 model achieves 99% accuracy, sensitivity, precision, and F1 score, while the Stack 2 model achieves 91%, 91%, 94%, and 92% for identifying SR, ST, LAE, and AT, respectively. Both stack models obtained a computational time of 0.06 seconds. PTFV1 (µV*ms), P (ms)/P (µV)), and P-wave area (µV*ms) were ranked as crucial clinical features.

CONCLUSION

Clinical feature-based stacking ML models may help doctors obtain insight into important clinical ECG aspects for early AF prediction.

Assessment of left atrial deformation in patients with total anomalous pulmonary venous connection by two-dimensional speckle-tracking echocardiography

BACKGROUND

Total anomalous pulmonary venous connection (TAPVC) is a rare congenital heart disease of newborns characterized by impaired left ventricle growth and diastolic dysfunction. We hypothesized that the patients with TAPVC reduced blood flow into the left heart prenatally could affect left atrium (LA) not just growth but function. We compared the age-related changes in LA deformation using two-dimensional speckle-tracking echocardiography (2DSTE) in Patients with TAPVC.

METHOD

This single-center, retrospective cohort study was conducted on consecutive isolated TAPVC patients who underwent neonatal surgery between January 1, 2009 and January 1, 2022. The LA datasets in TAPVC patients were analyzed before surgery (n = 28) and follow-ups at 1-2 (n = 24) and 5-7 years of age (n = 13) and compared with those of age-matched healthy controls (January 2009-2022). The LA strain (ε), indicating LA function, was analyzed using QLAB represented by reservoir (εR), conduit (εCD), and contractile (εCT) strains. LA pressure was evaluated by periodic follow-up catheterization after repair.

RESULTS

Compared to the controls, the TAPVC patients had significantly smaller LA maximum volume preoperatively, and with age, the LA maximal volumes reached normal levels, while the LA minimal volumes were larger. All 2DSTE-determined LA strains showed significant reductions at all time points in the TAPVC group compared to those in the control (median εR, εCD, and εCT; before surgery: 17.0% vs. 26.0%, 12.9% vs. 15.9%, and 6.3% vs. 10.4%; follow-up at 1-2 years: 30.0% vs. 45.7%, 23.2% vs. 29.6%, and 6.1% vs. 16.3%; follow-up at 5-7 years: 31.2% vs. 43.1%, 25.0% vs. 31.2%, and 5.2% vs. 10.8%, respectively; p < 0.05). Only εCT did not represented a significant change over time even though after correction of blood flow (median εCT: 6.0% → 5.9%). Patients with pulmonary venous obstruction (PVO) at birth showed significantly decreased εR and εCD and higher LA pressure compared to those without PVO.

CONCLUSION

This study showed that nevertheless maximum volume of LA was recovered within the normal range, reduced LA strains, especially contractile function lasted from birth even after repair in Patients with TAPVC.

Predictive value of left atrial strain analysis in adverse clinical events in patients with hypertrophic cardiomyopathy: a CMR study

BACKGROUND

A subset of patients with hypertrophic cardiomyopathy (HCM) will experience adverse clinical events such as heart failure (HF), cardiovascular death, and new-onset atrial fibrillation (AF). Current risk stratification methods are imperfect and limit the identification of patients at high risk for HCM. This study aimed to evaluate the role of cardiac magnetic resonance (CMR)-derived left atrial strain parameters in the occurrence of adverse clinical events in patients with HCM.

METHODS

Left atrial (LA) structural, functional, and strain parameters were evaluated in 99 patients with HCM and compared with 89 age-, sex-, and BMI-matched control subjects. LA strain parameters were derived from CMR two- and four-chamber cine images by a semiautomatic method. LA strain parameters include global longitudinal strain (GLS) and global circumferential strain (GCS). The LA GLS includes reservoir strain (GLS reservoir), conduit strain (GLS conduit), and booster strain (GLS booster). Three LA GLS strain rate (SR) parameters were derived: SR reservoir, SR conduit, and SR booster. The primary endpoint was set as a composite of adverse clinical events, including SCD, new-onset or worsening to hospitalized HF, new-onset AF, thromboembolic events, and fatal ventricular arrhythmias.

RESULTS

LA GLS, GLS SR and GCS were impaired in HCM patients compared to control subjects (all p < 0.001). After a mean follow-up of 37.94 ± 23.69 months, 18 HCM patients reached the primary endpoint. LA GLS, GLS SR, and GCS were significantly lower in HCM patients with adverse clinical events than in those without adverse clinical events (all p < 0.05). In stepwise multiple Cox regression analysis, LV SV, LA diameter, pre-contraction LAV (LAV pre-ac), passive LA ejection fraction (EF), and LA GLS booster were all independent determinants of adverse clinical events. LA GLS booster ≤ 8.9% was the strongest determinant (HR = 8.9 [95%CI (1.951, 40.933)], p = 0.005). Finally, LA GLS booster provided predictive adverse clinical events value (AUC = 0.86 [95%CI 0.77-0.98]) that exceeded traditional outcome predictors.

CONCLUSION

LA strain assessment, a measure of LA function, provides additional predictive information for established predictors of HCM patients. LA GLS booster was independently associated with adverse clinical events in patients with HCM.

Left atrial strain predicts risk and prognosis in patients with acute coronary syndrome: A retrospective study with external validation

Objectives

To explore the association between left atrial (LA) strain and the GRACE score in patients with acute coronary syndrome (ACS) and to investigate the utility of LA function in predicting short-term adverse cardiovascular events post ACS.

Methods

This retrospective study included ACS patients who underwent coronary angiography (CAG) in two independent cohorts from October 2020 to July 2022. The patients were classified into low-intermediate risk group and high-risk group based on the GRACE score. All participants underwent a transthoracic echocardiogram, with LA strain analysis before CAG. Correlation analysis was used to determine the relationship between LA strain and the GRACE score. The predictive value of LA strain was examined utilizing the area under the curve (AUC). Participants were followed for 10.5 ± 2.9 months for the primary endpoint of major adverse cardiovascular events (MACE).

Results

A total of 229 patients were included in this study, including 196 in the primary group and 33 in the validation group. Spearman’s correlation analysis showed there was a moderate negative correlation between the GRACE and left atrial reservoir strain (LASr) in both the primary (r = −0.63, P < 0.001) and validation (r = −0.73, P < 0.001) cohorts. Receiver operator characteristic (ROC) curve analysis showed that the AUC of LASr for prediction of the high-risk group was 0.86. Taking LASr 19.6% as the cut-off value, the sensitivity and specificity were 0.71 and 0.92, respectively. The cut-off value of 19.6% remains good at identifying high-risk group in the validation group (AUC = 0.87, sensitivity: 77.8%, specificity: 95.8%). Furthermore, 49 patients reached the endpoint in the primary cohort during the follow-up. On multivariable regression analysis, LASr (P = 0.03) was the independent echocardiographic predictor for the primary endpoint, rather than left atrial volume index (LAVI).

Conclusions

LASr can identify high-risk patients with ACS as defined by the GRACE score and may be superior to Max LAVI in predicting incidents of MACE in the short-term following ACS.

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LA function parameters significantly correlate with the GRACE score.

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Impaired LASr has high specificity in identifying high-risk patients with ACS.

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LASr may be superior to Max LAVI in predicting an adverse prognosis following ACS.

Putative protective effects of sodium-glucose cotransporter 2 inhibitors on atrial fibrillation through risk factor modulation and off-target actions: potential mechanisms and future directions

Atrial fibrillation, the most common cardiac arrhythmia, results in substantial morbidity and mortality related to its increased risks of stroke, heart failure, and impaired cognitive function. The incidence and prevalence of atrial fibrillation in the general population is rising, making atrial fibrillation treatment and management of its risk factors highly relevant clinical targets. One well-studied risk factor for the development of atrial fibrillation is diabetes mellitus. Inhibitors of sodium-glucose cotransporter 2 (SGLT2), common medications used to treat diabetes mellitus, have been observed to decrease the incidence of atrial fibrillation. This review discusses the SGLT2 and its role in glucose homeostasis, molecules inhibiting the transporter, possible physiological mechanisms responsible for the decreased incident atrial fibrillation in patients treated with SGLT2 inhibitors and proposes mechanistic studies to further our understanding of the biological processes involved.

Decreased Peak Left Atrial Longitudinal Strain Is Associated with Persistent Pulmonary Hypertension Associated with Left Heart Disease

Pulmonary hypertension (PH) associated with left heart disease (PH-LHD) is the most common form of PH and has significantly higher morbidity and mortality. We estimated the prevalence of PH-LHD on the follow-up echocardiography and the role of left atrial (LA) function in PH-LHD. From the STRATS-AHF registry composed of 4312 acute heart failure (HF) patients, we analyzed peak atrial longitudinal strain (PALS) in 1729 patients with follow-up echocardiographic examinations during mean 18.1 ± 13.5 months. PH was determined by the maximal velocity of tricuspid regurgitation (TR Vmax ≥ 3.4 m/s). Persistent PH was found in 373 patients (21.6%). The PH-LHD group was significantly older, and the prevalence of atrial fibrillation (AF), hypertension, diabetes, and heart failure with preserved ejection fraction were higher compared with the no PH-LHD group. Baseline left ventricular end-systolic volume and PALS were lower, and LA diameter, mitral E/E’ ratio, and TR Vmax were higher in the PH-LHD group. In the multivariate analysis, PALS (HR = 1.024, p = 0.040) was a significant variable after adjustment of LA diameter and mitral E/E’. A decreased PALS of <12.5% was the best cutoff value in the prediction of persistent PH-LHD (AUC = 0.594, sensitivity = 65.3%, specificity = 46.1%). PH-LHD was associated with increased HF hospitalization (HR = 2.344, p < 0.001) and mortality (HR = 2.015, p < 0.001) after adjusting for age and sex. In conclusion, persistent PH-LHD was found in 21.6% in the follow-up echocardiography and was associated with decreased PALS (<12.5%). PH-LHD persistence was associated with poor clinical outcomes. Thus, AHF patients with decreased PALS, especially <12.5%, should be followed with caution.