Left Atrial Strain Performance and its Application in Clinical Practice

Incremental prognostic value of left atrial and biventricular feature tracking in dilated cardiomyopathy: a long-term study

BACKGROUND

Despite the use of cardiovascular magnetic resonance (CMR) feature tracking (FT) imaging to detect myocardial deformation, the optimal strain index in dilated cardiomyopathy (DCM) is unclear. This study aimed to determine whether atrial and biventricular strains can provide the greatest or joint incremental prognostic value in patients with DCM over a long follow-up period.

METHODS

Four hundred-twelve DCM patients were included retrospectively. Comprehensive clinical evaluation and imaging investigations were obtained, including measurements of CMR-FT derived left atrial (LA) reservoir, conduit, booster strain (εs, εe, εa); left ventricular (LV) and right ventricular (RV) global longitudinal, radial, circumferential strain (GLS, GRS, GCS). All patients were followed up for major adverse cardiac events (MACE) including all-cause mortality, heart transplantation, and implantable cardioverter defibrillator discharge. The predictors of MACE were examined with univariable and multivariable Cox regression analysis. Subsequently, nested Cox regression models were built to evaluate the incremental prognostic value of strain parameters. The incremental predictive power of strain parameters was assessed by Omnibus tests, and the model performance and discrimination were evaluated by Harrell C-index and integrated discrimination improvement (IDI) analysis. Patient survival was illustrated by Kaplan-Meier curves and differences were evaluated by log-rank test.

RESULTS

During a median follow-up of 5.0 years, MACE were identified in 149 (36%) patients. LAεe, LVGLS, and RVGLS were the most predictive strain parameters for MACE (AUC: 0.854, 0.733, 0.733, respectively). Cox regression models showed that the predictive value of LAεe was independent from and incremental to LVGLS, RVGLS, and baseline variables (HR 0.74, 95% CI 0.68-0.81, P < 0.001). In reclassification analysis, the addition of LAεe provided the best discrimination of the model (χ2 223.34, P < 0.001; C-index 0.833; IDI 0.090, P < 0.001) compared with LVGLS and RVGLS models. Moreover, LAεe with a cutoff of 5.3% further discriminated the survival probability in subgroups of patients with positive LGE or reduced LVEF (all log-rank P < 0.001).

CONCLUSION

LAεe provided the best prognostic value over biventricular strains and added incremental value to conventional clinical predictors for patients with DCM.

Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023

Central Illustration : Position Statement on the Use of Myocardial Strain in Cardiology Routines by the Brazilian Society of Cardiology's Department Of Cardiovascular Imaging - 2023 Proposal for including strain in the integrated diastolic function assessment algorithm, adapted from Nagueh et al.67 Am: mitral A-wave duration; Ap: reverse pulmonary A-wave duration; DD: diastolic dysfunction; LA: left atrium; LASr: LA strain reserve; LVGLS: left ventricular global longitudinal strain; TI: tricuspid insufficiency. Confirm concentric remodeling with LVGLS. In LVEF, mitral E wave deceleration time < 160 ms and pulmonary S-wave < D-wave are also parameters of increased filling pressure. This algorithm does not apply to patients with atrial fibrillation (AF), mitral annulus calcification, > mild mitral valve disease, left bundle branch block, paced rhythm, prosthetic valves, or severe primary pulmonary hypertension.

Left atrial strain as a predictor of left ventricular filling pressures in coronary artery disease with preserved ejection fraction: a comprehensive study with left ventricular end-diastolic and pre-atrial contraction pressures

Assessing left ventricular (LV) filling pressure (LVFP) is challenging in patients with coronary artery disease (CAD) and preserved LV ejection fraction (LVEF). We aimed to correlate left atrial strain (LAS) with two invasive complementary parameters of LVFP and compared its accuracy to other echocardiographic data to predict high LVFP. This cross-sectional, single-center study enrolled 81 outpatients with LVEF > 50% and significant CAD from a database. Near-simultaneous echocardiography and invasive measurements of both LV end-diastolic pressure (LVEDP) and LV pre-atrial contraction (pre-A) pressure were performed in each patient, based on the definition of LVEDP > 16 mmHg and LV pre-A > 12 mmHg as high LVFP. A moderate to strong correlation was observed between LAS reservoir (LASr), contractile strain, and LVEDP (r: 0.67 and 0.62, respectively; p < 0.001); the same was true for LV pre-A (r: 0.65 and 0.63, respectively; p < 0.001). LASr displayed good diagnostic performance to identify elevated LVFP, which was higher when compared to traditional parameters. Median value of LASr was higher for an isolated increase of LVEDP than for simultaneously high LV pre-A. The cutoff found to predict high LVFP was lower for LV pre-A than that one for LVEDP. In the current study, LASr did not provide an additional contribution to the 2016 diastolic function algorithm. LAS is a valuable tool for predicting LVFP in patients with CAD and preserved LVEF. The choice of LVEDP or LV pre-A as the representative marker of LVFP leads to different cutoffs to predict high pressures. The best strategy for adding this tool to a multiparametric algorithm requires further investigation.

Association of Atrial Fibrillation With Stroke and Dementia Accounting for Left Atrial Function and Size

BACKGROUND

Atrial fibrillation (AF) is associated with higher risks of ischemic stroke (IS) and dementia. Whether alterations in left atrial (LA) function or size-atrial myopathy-confound these associations remains unknown.

OBJECTIVES

The purpose of this study was to examine the association of prevalent and incident AF with ischemic stroke and dementia in the ARIC (Atherosclerosis Risk In Communities) study, adjusting for LA function and size.

METHODS

Participants at visit 5 (2011-2013) with echocardiographic LA function (reservoir, conduit, contractile strain, and emptying fraction) and size (maximal, minimal volume index) data, and without prevalent stroke or dementia were followed through 2019. For analysis, we used time-varying Cox regression.

RESULTS

Among 5,458 participants (1,193 with AF, mean age of 76 years) in the stroke analysis and 5,461 participants (1,205 with AF, mean age of 75 years) in the dementia analysis, 209 participants developed ischemic stroke, and 773 developed dementia over 7.1 years (median). In a demographic and risk factor-adjusted model, AF was significantly associated with ischemic stroke (HR, 1.63; 95% CI: 1.11-2.37) and dementia (HR: 1.38, 95% CI: 1.13-1.70). After additionally adjusting for LA reservoir strain, these associations were attenuated and no longer statistically significant (stroke [HR: 1.33, 95% CI: 0.88-2.00], dementia [HR: 1.15, 95% CI: 0.92-1.43]). Associations with ischemic stroke and dementia were also attenuated and not statistically significant after adjustment for LA contractile strain, emptying fraction, and minimal volume index.

CONCLUSIONS

AF-ischemic stroke and AF-dementia associations were not statistically significant after adjusting for measures of atrial myopathy. This proof-of-concept analysis does not support AF as an independent risk factor for ischemic stroke and dementia.

Left Atrial Strain Derived From Cardiac Magnetic Resonance Imaging Can Predict Outcomes of Patients With Acute Myocarditis

OBJECTIVE

There is increasing recognition that left atrial (LA) strain can be a prognostic marker of various cardiac diseases. However, its prognostic value in acute myocarditis remains unclear. Therefore, this study aimed to evaluate whether cardiovascular magnetic resonance (CMR)-derived parameters of LA strain can predict outcomes in patients with acute myocarditis.

MATERIALS AND METHODS

We retrospectively analyzed the data of 47 consecutive patients (44.2 ± 18.3 years; 29 males) with acute myocarditis who underwent CMR in 13.5 ± 9.7 days (range, 0-31 days) of symptom onset. Various parameters, including feature-tracked CMR-derived LA strain, were measured using CMR. The composite endpoints included cardiac death, heart transplantation, implantable cardioverter-defibrillator or pacemaker implantation, rehospitalization following a cardiac event, atrial fibrillation, or embolic stroke. The Cox regression analysis was performed to identify associations between the variables derived from CMR and the composite endpoints.

RESULTS

After a median follow-up of 37 months, 20 of the 47 (42.6%) patients experienced the composite events. In the multivariable Cox regression analysis, LA reservoir and conduit strains were independent predictors of the composite endpoints, with an adjusted hazard ratio per 1% increase of 0.90 (95% confidence interval [CI], 0.84-0.96; P = 0.002) and 0.91 (95% CI, 0.84-0.98; P = 0.013), respectively.

CONCLUSION

LA reservoir and conduit strains derived from CMR are independent predictors of adverse clinical outcomes in patients with acute myocarditis.

Speckle tracking echocardiography in early disease stages: a therapy modifier?

Echocardiography has been included as a first-line tool in several international guidelines for the management of patients with various cardiac diseases. Beyond diagnosis, echocardiographic examination helps in characterizing the severity of the condition since the very first stages. In particular, the application of second-level techniques, speckle tracking echocardiography in particular, can also reveal a subclinical dysfunction, while the standard parameters are in the normality range. The present review describes the potentialities of advanced echocardiography in different settings, including arterial hypertension, atrial fibrillation, diastolic dysfunction, and oncological patients, thus opening up potential starting points for its application as a clinical routine changer.

The Impact of Sonothrombolysis on Left Ventricular Diastolic Function and Left Atrial Mechanics Preventing Left Atrial Remodeling in Patients With ST Elevation Acute Myocardial Infarction

BACKGROUND

The diagnostic ultrasound-guided high mechanical index impulses during an intravenous microbubble infusion (sonothrombolysis) improve myocardial perfusion in acute ST segment elevation myocardial infarction, but its effect on left ventricular diastolic dysfunction (DD), left atrial (LA) mechanics and remodeling is unknown. We assessed the effect of sonothrombolysis on DD grade and LA mechanics.

METHODS

One hundred patients (59 ± 10 years; 34% women) were randomized to receive either high mechanical index impulses plus percutaneous coronary intervention (PCI) (therapy group) or PCI only (control group) (n = 50 in each group). Diastolic dysfunction grade and LA mechanics were assessed immediately before and after PCI and at 48 to 72 hours, 1 month, and 6 months of follow-up. Diastolic dysfunction grades were classified as grades I, II, and III. The LA mechanics was obtained by two-dimensional speckle-tracking echocardiography-derived global longitudinal strain (GLS).

RESULTS

As follow-up time progressed, increased DD grade was observed more frequently in the control group than in the therapy group at 1 month and 6 months of follow-up (all P < .05). The LA-GLS values were incrementally higher in the therapy group when compared with the control group at 48 to 72 hours, 24.0% ± 7.3% in the therapy group versus 19.6% ± 7.2% in the control group, P = .005; at 1 month, 25.3% ± 6.3% in the therapy group versus 21.5% ± 8.3% in the control group, P = .020; and at 6 months, 26.2% ± 8.7% in the therapy group versus 21.6% ± 8.5% in the control group, P = .015. The therapy group was less likely to experience LA remodeling (odds ratio, 2.91 [1.10-7.73]; P = .03). LA-GLS was the sole predictor of LA remodeling (odds ratio, 0.79 [0.67-0.94]; P = .006).

CONCLUSION

Sonothrombolysis is associated with better DD grade and LA mechanics, reducing LA remodeling.

Clinical utility of left atrial strain in predicting atrial fibrillation recurrence after catheter ablation: An up-to-date review

Rhythm control is the core part of the integrated management of atrial fibrillation (AF), especially in the early stages. Despite advances in catheter ablation (CA), the recurrence rate of AF after CA remains high. As a result, stratification and early management of AF recurrence after CA are critical. Currently, predictors of recurrence of AF after CA are mostly based on dysfunction caused by structural remodeling, apart from traditional risk factors. Atrial strain is a recently developed important parameter for detecting the deformability of atrial myocardium during the cardiac cycle prior to atrial remodeling. Although there is only preliminary evidence, atrial strain is still a promising parameter in predicting the recurrence of AF after CA at an early stage. This review focuses on the evaluation of atrial strain, the current applications of atrial strain in assessing atrial function, and predicting the recurrence of AF after CA. We summarize the contents related as follows: (1) CA for rhythm control in AF; (2) Evaluation methods of atrial strain; (3) Atrial strain in the remodeling and reverse remodeling of AF; and (4) Clinical applications of atrial strain in predicting the recurrence of AF after CA. Although there is accumulating evidence on the role of decreased atrial strain in the early prediction of AF recurrence, atrial strain is limited in clinical practice for lacking exact cut-off values and difficulty in distinguishing specific function phases of the atrium. More research is needed in the future to add strength to the early prediction value of atrial strain in AF recurrences.

Left Atrial Function Predicts Outcome in Dilated Cardiomyopathy: Fast Long-Axis Strain Analysis Derived from MRI

Background There is increasing recognition that left atrial (LA) function is prognostically important in cardiovascular disease. LA strain is a sensitive parameter to describe complex LA phasic function. However, the prognostic value of LA strain in participants with idiopathic dilated cardiomyopathy (DCM) remains unclear. Purpose To evaluate the prognostic value of LA strain derived from cardiac MRI in study participants with idiopathic DCM. Materials and Methods Participants with idiopathic DCM who underwent cardiac MRI between June 2012 and November 2018 were prospectively enrolled. The fast long-axis strain MRI method was performed to assess LA strain. The primary end point was all-cause mortality and heart transplant, and the secondary end point was a combination of primary end point, heart failure readmission, and aborted sudden cardiac death. Cox regression analyses and Kaplan-Meier survival analysis were performed to identify the association between variables and outcomes. Results There were 497 participants (mean age, 47 years ± 14 [standard deviation]; 357 men) evaluated. During a median follow-up of 36 months (interquartile range, 26-54 months), 113 participants reached primary end points and 203 participants reached secondary end points. LA reservoir, conduit and booster strain, and strain rate were lower in participants with primary end points (P < .001). In multivariable Cox regression analysis, LA reservoir strain and conduit strain were independent predictors for primary end point (hazard ratio [HR] per 1% increase, 0.95 [95% CI: 0.91, 0.99; P = .008] and 0.92 [95% CI: 0.87, 0.98; P = .010], respectively) and secondary end points (HR per 1% increase, 0.95 [95% CI: 0.93, 0.97; P < .001] and 0.93 [95% CI: 0.89, 0.97; P < .001], respectively). In addition, LA reservoir strain and conduit strain added incremental prognostic value to clinical risk factors and late gadolinium enhancement presence (all, P < .05). Conclusion Left atrial reservoir and conduit strain, derived from cardiac MRI by using the fast long-axis method, were independent predictors of adverse clinical outcomes in idiopathic dilated cardiomyopathy. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Ambale-Venkatesh in this issue.

Clinical Utility of Echocardiographic Strain and Strain Rate Measurements

PURPOSE OF REVIEW

Assessment of left ventricular function is pivotal in many decisions, but ejection fraction has fundamental limitations for assessment of mild dysfunction, and especially for repeated assessments. Myocardial deformation imaging using speckle-tracking is widely available on modern echocardiography systems, and is now feasible as a clinical, rather than purely a research tool. Strain can be measured in all cardiac chambers, most commonly as a systolic parameter, although it can be measured in diastole. Generally, speckle tracking is more effective at measuring strain than strain-rate, which requires a higher temporal resolution. The purpose of this review is to help clinicians understand the main situations where strain provides incremental value to standard echocardiographic measurements.

RECENT FINDINGS

The normal range of LV global longitudinal strain (GLS) has now been defined as -18% and lower (ie more negative), abnormal as -16% or higher (ie less negative), with -16 to -18% being borderline. The variation between different vendors is now small for global parameters, but regional strain measurement remains unreliable - and therefore its use for stress echocardiography remains problematic. The most valuable indications for measuring strain are subclinical LV dysfunction (eg., GLS in HFpEF, stage B heart failure, aortic stenosis, mitral regurgitation), RV dysfunction (RV strain in pulmonary hypertension), atrial fibrillation (LA strain) and sequential follow-up (cardiotoxicity). Strain measurements have clinical utility in a number of settings and should be considered as part of the standard echocardiogram.