Severity of aortic stenosis predicts early post-operative normalization of left atrial size and function detected by myocardial strain

Prognostic value of left ventricular and left atrial strain imaging in moderate to severe aortic stenosis: Insights from an Asian population

BACKGROUND

Data regarding the prognostic value of left atrial (LA) strain in aortic stenosis (AS) is scarce, especially in Asian population and moderate AS.

METHOD

Left ventricular global longitudinal strain (LVGLS), LA reservoir strain (LASr), conduit strain (LAScd), and contractile strain (LASct) were measured using automated speckle-tracking echocardiography in consecutive patients with moderate or severe AS. The primary endpoint was a composite of all-cause death (ACD) and major adverse cardiovascular events (MACE; myocardial infarction, syncope, and heart failure hospitalization).

RESULTS

Of 712 patients (mean age, 78 ± 12 years; 370 [52%] moderate AS; 342 [48%] severe AS), average LV ejection fraction (LVEF) was 68 with SD of 12%. At a median follow-up of 18 months (interquartile range, 11-26 months), the primary endpoint occurred in 93 patients (60 deaths and 35 MACEs) and 221 patients underwent surgical or transcatheter aortic valve replacement (AVR). In the entire cohort, separate multivariable models adjusted for age, Charlson index, symptomatic status, time-dependent AVR, AS-severity, LA volume index and LVEF demonstrated that only LASr was associated with MACE+ACD (Hazard ratio, 0.97; P = 0.014). Subgroup analysis for MACE+ACD demonstrated consistent prognostication for LASr in moderate and severe AS; LVGLS was prognostic only in severe AS (all P ≤ 0.023). The optimal MACE+ACD cutoff for LASr from spline curves was 21.3%. Adjusted Kaplan-Meier curves demonstrated better event-free survival in patients with LASr >21.3% versus those with LASr ≤21.3% (P = 0.04).

CONCLUSIONS

In both moderate and severe AS, only LASr robustly predicted outcomes; thus, including LASr in the AS staging algorithm should be considered.

Mechanisms of myocardial reverse remodelling and its clinical significance: A scientific statement of the ESC Working Group on Myocardial Function

Cardiovascular disease (CVD) is the leading cause of morbimortality in Europe and worldwide. CVD imposes a heterogeneous spectrum of cardiac remodelling, depending on the insult nature, that is, pressure or volume overload, ischaemia, arrhythmias, infection, pathogenic gene variant, or cardiotoxicity. Moreover, the progression of CVD-induced remodelling is influenced by sex, age, genetic background and comorbidities, impacting patients' outcomes and prognosis. Cardiac reverse remodelling (RR) is defined as any normative improvement in cardiac geometry and function, driven by therapeutic interventions and rarely occurring spontaneously. While RR is the outcome desired for most CVD treatments, they often only slow/halt its progression or modify risk factors, calling for novel and more timely RR approaches. Interventions triggering RR depend on the myocardial insult and include drugs (renin-angiotensin-aldosterone system inhibitors, beta-blockers, diuretics and sodium-glucose cotransporter 2 inhibitors), devices (cardiac resynchronization therapy, ventricular assist devices), surgeries (valve replacement, coronary artery bypass graft), or physiological responses (deconditioning, postpartum). Subsequently, cardiac RR is inferred from the degree of normalization of left ventricular mass, ejection fraction and end-diastolic/end-systolic volumes, whose extent often correlates with patients' prognosis. However, strategies aimed at achieving sustained cardiac improvement, predictive models assessing the extent of RR, or even clinical endpoints that allow for distinguishing complete from incomplete RR or adverse remodelling objectively, remain limited and controversial. This scientific statement aims to define RR, clarify its underlying (patho)physiologic mechanisms and address (non)pharmacological options and promising strategies to promote RR, focusing on the left heart. We highlight the predictors of the extent of RR and review the prognostic significance/impact of incomplete RR/adverse remodelling. Lastly, we present an overview of RR animal models and potential future strategies under pre-clinical evaluation.

Prognostic value of left atrial strain in aortic stenosis: A systematic review

PURPOSE

Aortic stenosis (AS) is a common valvular heart disease with high morbidity and mortality. Recently, the association between peak atrial longitudinal strain (PALS) and AS clinical outcomes has been identified. This systematic review evaluates the prognostic value of PALS for adverse events in AS.

METHODS

We performed a systematic literature review to identify clinical studies that evaluated Speckle-Tracking Echocardiography (STE)-derived PALS to predict adverse outcomes in patients with AS. We excluded studies that compared echocardiography to computed tomography and studies that focused on diseases other than AS.

RESULTS

We included 18 studies reporting on 2660 patients. Patients with symptomatic AS had decreased PALS when compared to patients with asymptomatic AS. Patients with AS who had adverse events had decreased PALS when compared to patients with AS with no events. Each unit increase of PALS was independently associated with decreased risk for the primary endpoint. PALS cut-off values were associated with increased risk for the primary endpoint.

CONCLUSION

This systematic review suggests PALS as an independent predictor for cardiovascular events in patients with AS and highlights the importance of evaluating LA mechanics for AS prognosis.

Left Atrial Remodeling in Response to Aortic Valve Replacement: Pathophysiology and Myocardial Strain Analysis

Severe aortic stenosis (AS) is the most common valve disease in the elderly and is associated with poor prognosis if treated only medically. AS causes chronic pressure overload, concentric left ventricular (LV) hypertrophy, myocardial stiffness, and diastolic dysfunction. This adverse remodeling also affects the left atrium (LA), which dilates and develops myocardial fibrosis, with a reduction in intrinsic function and a consequent high risk of the development of atrial fibrillation. Speckle-tracking echocardiography is able to detect myocardial dysfunction before other conventional parameters, such as LV ejection fraction, and also predict clinical outcomes. This review aims at describing LV and LA remodeling in AS and before and after aortic valve replacement and the usefulness of myocardial strain analysis in this clinical setting.

Jujuboside A Ameliorates Myocardial Apoptosis and Inflammation in Rats with Coronary Heart Disease by Inhibiting PPAR-α Signaling Pathway

Background

Coronary heart disease (CHD) is a chronic disease caused by atherosclerosis (AS), which can cause myocardial ischemia, hypoxia, or necrosis, seriously threatening human health. There is an urgent need for effective treatments and drugs to reduce the various risk factors for coronary heart disease and relieve symptoms of angina pectoris and myocardial infarction in patients. Jujuboside A (JuA) is a triterpenoid saponin extracted from jujube seeds, which has various biological activities such as antioxidant, anti-inflammatory, antiapoptotic, and neuroprotective effects. We study the function of JuA in myocardial injury, dyslipidemia, and inflammation in the CHD rat model, to explore its potential mechanism of improving CHD.

Methods

A rat model of CHD was established by feeding a high-fat diet. The rats were randomly divided into 5 groups (n = 6): control group, CHD group, JuA 25 mg/kg group, JuA 50 mg/kg group, and JuA 75 mg/kg group. Echocardiography was used to detect the cardiac function parameters of rats in each group, and then, hematoxylin and eosin staining was used to assess the histopathological injury in myocardial tissues. Levels of blood lipids, myocardial injury indexes, and inflammatory factors of rats in each group were measured by biochemical tests and enzyme linked immunosorbent assay, and the levels of Bax, Bcl-2, c-caspase-3, PPAR-α, p65, p-p65, IκBα, and p-IκBα protein expression in myocardial tissues were detected by western blot.

Results

Compared with the CHD group, JuA therapy significantly improved injury in myocardial tissue and endothelial tissue. It also strengthened cardiac function, while decreasing total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol levels in the serum and increasing high-density lipoprotein cholesterol levels. In addition, JuA also restrained cardiomyocytes apoptosis and inhibited the inflammatory reaction by reducing TNF-α, IL-1β, and IL-6 expression in myocardial tissues. Furthermore, administration of JuA inhibited the activation of PPAR-α pathway by preventing the phosphorylation of p65 and IκBα in myocardial tissues of CHD rats.

Conclusion

JuA may improve cardiac function, alleviate myocardial and endothelial injury, and also ameliorate dyslipidemia and inflammatory reaction in rats with CHD, where JuA probably plays a protective role by inhibiting the activation of PPAR-α pathway.

The Effect of TAVR on Left Ventricular and Left Atrial Mechanics in Patients with Aortic Stenosis

Background. Measures of adverse cardiac remodeling, left ventricular global longitudinal strain (LVGLS) and left atrial (LA) phasic function, are predictive of cardiac events in patients with severe aortic stenosis (AS). How these parameters of cardiac function change following TAVR requires further investigation. Methods. A number of 109 consecutive patients with symptomatic severe AS who were seen in the heart valve clinic between 2014 and 2019 for TAVR were included. All patients underwent echocardiographic assessment prior to and 30 days following TAVR, with LVGLS and LA phasic function evaluation using 2D speckle-tracking echocardiography. Heart failure hospitalization, and death were assessed at 12 months. Results. The mean age of the study cohort was 81 ± 7.3 years. Following TAVR, there was a significant reduction in NYHA class III/IV symptoms [89 (82%) vs. 12 (11%), p < 0.01], and median mean aortic valve gradient [44 mmHg (16) vs. 9 mmHg (7), p < 0.01]. There was no significant change in the median LVEF [62% (13) vs. 62% (6.0), p = 0.2]; however, the LVGLS significantly increased following TAVR [15 ± 3.5% vs. 18 ± 3.3%, p < 0.01]. The median LA reservoir, conduit and contractile function significantly improved following TAVR [22.0% (14.0) vs. 18.0% (14.0) p < 0.01, 8.9% (5.4) vs. 7.8% (4.8) p < 0.01, 12% (11.0) vs. 9.6% (11.0) p < 0.01, respectively]. The incidence of death or heart failure hospitalization at 12 months was low, and occurred in eight patients (7.3%). Conclusions. TAVR results in significant short-term reverse LV and LA remodeling, as shown by improvement in LV GLS and all three components of LA phasic function, despite no change in the LVEF. The findings indicate the possible utility of strain imaging for the assessment of global LV and LA function following TAVR.

The Central Role of Left Atrium in Heart Failure

In past cardiovascular medicine, the attention to the left ventricle-identified as the only indicator and determinant of healthy or unhealthy cardiac conditions- has systematically hidden the role of the left atrium (LA). The recent advances in cardiovascular imaging have provided a better understanding of LA anatomy, physiology, and pathology, making us realize that this functional structure is far from being an innocent spectator. We now know that the LA's mechanical and neuro-hormonal properties play a relevant part in several cardiovascular diseases, including atrial fibrillation, ischemic heart disease, valvular heart disease, and heart failure. The present review aims to describe the role of LA in the specific setting of heart failure. We provide currently available information on LA structure and function and summarize its role as a determinant of symptoms, prognosis, and potential therapeutic target in heart failure patients.

The Prognostic Value of Left Atrial Global Longitudinal Strain and Left Atrial Phasic Volumes in Patients Undergoing Transcatheter Valve Implantation for Severe Aortic Stenosis

INTRODUCTION

The changes and the prognostic implications of left atrial (LA) volumes (LAV), LA function, and vascular load in patients undergoing transcatheter aortic valve implantation (TAVI) for severe aortic stenosis (AS) are less known.

METHODS

We enrolled 150 symptomatic patients (mean age 82 ± 8 years, 58% female, and pre-TAVI aortic valve area 0.40 ± 0.19 cm/m2) with severe AS who underwent 2D transthoracic echocardiography and 2D speckle tracking echocardiography at average 21 ± 35 days before and 171 ± 217 days after TAVI. The end point was a composite of new onset of atrial fibrillation, hospitalization for heart failure and all-cause death (major adverse cardiac events [MACE]).

RESULTS

After TAVI, indexed maximal LA volume and minimum volume of the LA decreased by 2.1 ± 10 mL/m2 and 1.6 ± 7 mL/m2 (p = 0.032 and p = 0.011, respectively), LA function index increased by 6.8 ± 11 units (p < 0.001), and LA stiffness decreased by 0.38 ± 2.0 (p = 0.05). No other changes in the LA phasic volumes, emptying fractions, and vascular load were noted. Post-TAVI, both left atrial and ventricular global peak longitudinal strain improved by about 6% (p = 0.01 and 0.02, respectively). MACE was reached by 37 (25%) patients after a median follow-up period of 172 days (interquartile range, 20-727). In multivariable models, MACE was associated with both pre- and post-TAVI LA global peak longitudinal strain (hazard ratio [HR] 0.75, CI 0.59-0.97; and HR 0.77, CI 0.60-1.00, per 5 percentage point units, respectively), pre-TAVI LV global endocardial longitudinal strain (HR 1.37, CI 1.02-1.83 per 5 percentage point units), and with most of the LA phasic volumes.

CONCLUSION

Within 6 months after TAVI, there is reverse LA remodeling and an improvement in LA reservoir function. Pre- and post-TAVI indices of LA function and volume remain independently associated with MACE. Larger studies enrolling a greater diversity of patients may provide sufficient evidence for the utilization of these imaging biomarkers in clinical practice.

Prognostic value of left atrial volume index in patients with rheumatic mitral stenosis

Background

The significance of left atrial volume index (LAVI) for predicting outcomes in patients with mitral stenosis (MS) has been unclear, even though rheumatic MS is known to be associated with left atrium enlargement and functional deterioration.

Hypothesis

The current study aimed to investigate the prognostic value of LAVI, based on the severity in patients with rheumatic MS.

Methods

We retrospectively reviewed 611 patients with pure rheumatic MS. The prognostic value of LAVI and the effect of MS severity on the prognostic value of LAVI for events were evaluated. The events were defined as a composite end‐point that included all‐cause death, heart failure admission, mitral valve replacement, percutaneous mitral valvuloplasty, and stroke.

Results

There were 236 (38.6%) overall events during a median follow‐up of 8 months. The optimal LAVI cutoff for the prognostic threshold was 57 ml/m². The MS severity had a significant effect on the prognostic value of LAVI. A LAVI >57 ml/m² was a prognostic value for events in progressive MS (hazard ratio [HR]: 2.40, 95% confidence interval [CI]: 1.41–5.40, p = .004) and in patients with severe MS (HR: 1.70, 95% CI: 1.06–2.74, p = .029), but it was not prognostic in patients with very severe MS (HR: 1.02, 95% CI: 0.56–1.84, p = .955).

Conclusions

The prognostic value of LAVI varies and is dependent on the MS severity. A LAVI >57 mL/m² was independently associated with poor outcomes in patients with progressive MS, while this association was minimized in patients with severe MS.

The left atrium and the right ventricle: two supporting chambers to the failing left ventricle

Heart failure (HF) is mainly caused by left ventricular (LV) impairment of function, hence detailed assessment of its structure and function is a clinical priority. The frequent involvement of the left atrium (LA) and the right ventricle (RV) in the overall cardiac performance has recently gained significant interest with specific markers predicting exercise intolerance and prognosis being proposed. The LA and RV are not anatomically separated from the LV, while the LA controls the inlet the RV shares the interventricular septum with the LV. Likewise, the function of the two chambers is not entirely independent from that of the LV, with the LA enlarging to accommodate any rise in filling pressures, which could get transferred to the RV via the pulmonary circulation. In the absence of pulmonary disease, LA and RV function may become impaired in patients with moderate-severe LV disease and raised filling pressures. These changes can often occur irrespective of the severity of systolic dysfunction, thus highlighting the important need for critical assessment of the function of the two chambers. This review evaluates the pivotal role of the left atrium and right ventricle in the management of HF patients based on the available evidence.

Prognosis and Risk Stratification of Patients With Advanced Heart Failure (from PROBE)

In recent years, many prognostic scores have been developed for advanced chronic heart failure (CHF), but none of them is comprised of first- and second level echocardiographic indexes. The aim was to create a new prognostic echocardiographic score for patients with advanced CHF. Patients with advanced CHF were analyzed by standard, 3D, and speckle tracking echocardiography and followed prospectively for 2 ± 0.7 years recording major adverse cardiac events (MACE): cardiovascular death, hospitalization for HF, emergency heart transplantation, and left ventricular assist device or intra-aortic balloon pump implantation. A total of 110 patients were enrolled. The best predictors of MACE were selected on the basis of area under the curve by receiver operating characteristic analysis >0.70: left atrial volume index (no MACE vs MACE groups, 51.3 ± 20 ml/m² vs 67 ± 20 ml/m², p = 0.0003), right ventricular sphericity index (0.53 ± 0.09 vs 0.61 ± 0.10, p = 0.0002), right ventricular fractional area change (41 ± 9% vs 33 ± 9.5, p <0.0001), free-wall right ventricular longitudinal strain (-20 ± 4.5% vs -16 ± 6%, p = 0.0013). A prognostic score formula was calculated as: PROBE score = 1(if left atrial volume index >65 ml/m²) + 1(if right ventricular sphericity index >0.53) + 0.5(if right ventricular fractional area change <36.5%) + 1(if free-wall right ventricular longitudinal strain >-14%). It presented an area under the curve by receiver operating characteristic analysis of 0.90 and classified patients at low (PROBE ≤1), intermediate (PROBE = 1 to 2), or high (PROBE >2) risk of MACE. The Kaplan-Meier analysis revealed a strong correlation between the event-free survival rate and the 3 groups. In conclusion, the PROBE score, with first- and second level echocardiographic parameters, demonstrated a good predictive value for MACE. It represents a useful tool for a noninvasive, individualized, and accurate evaluation and stratification of prognosis in patients with advanced CHF.

Left atrial remodeling postseptal myectomy for severe obstructive hypertrophic cardiomyopathy: Analysis by two-dimensional speckle-tracking echocardiography

BACKGROUND

Septal myectomy relieves left ventricular outflow obstruction (LVOTO) and is associated with excellent long-term outcomes. LVOTO is associated with diastolic dysfunction and increased left atrial (LA) size. We sought to investigate the changes in LA volumes and function postmyectomy and the association between these changes with clinical outcomes postmyectomy.

METHODS

Sixty-six hypertrophic cardiomyopathy patients undergoing myectomy were retrospectively studied. Preprocedural and 6- to 18-month postmyectomy follow-up transthoracic echocardiographic images were obtained. LA volumes and strain were assessed by two-dimensional speckle-tracking echocardiography.

RESULTS

Left atrial volumes, that is, indexed maximal, minimal, and pre-A volumes reduced postmyectomy, yet remained increased compared to controls (105.6 ± 34.5 mL vs 84.9 ± 26.7 mL, 45.2 ± 25.7 mL vs 35.4 ± 22.6 mL, 70.1 ± 31.4 mL vs 35.4 ± 22.6 mL, respectively, P < 0.05). The total emptying index did not improve postmyectomy and remained lower than controls (58.6 ± 12.4 vs 59.9 ± 12.8, P = NS) whereas atrial contraction improved, yet did not normalize (active emptying index 36.1 ± 14.9 vs 41.1 ± 16.2, P < 0.05). The conduit volume remained reduced postmyectomy (18.6 ± 13.3 mL vs 16.6 ± 15.1 mL, P = NS). LA strain also did not improve postmyectomy (26.8 ± 7.3 vs 28.5 ± 8.8, P = NS). A multivariable logistic regression identified preprocedural E/e' ratio and indexed maximal LA volume, as independent predictors for LA volume reduction ≥20% postmyectomy. During a mean follow-up of 4.9 ± 2.3 years postmyectomy, 24.2% of the patients developed atrial fibrillation and <5% of patients were severely symptomatic. We found no associations between LA volumes/function and atrial fibrillation or symptoms postmyectomy.

CONCLUSION

Postmyectomy LA volumes decreased, and the contractile function improved. There was no association between LA volumes/function and clinical outcomes postmyectomy. Notably, the LA remained enlarged (though to a lesser degree) with reduced strain and emptying fraction, suggesting possible atrial myopathy.

Left atrial phasic function in hypertensive patients with significant aortic stenosis and preserved ejection fraction

The purpose of this investigation was to evaluate the influence of hypertension on left atrial (LA) function in patients with moderate and severe AS. This cross-sectional study included 121 patients with moderate and severe AS and preserved left ventricular (LV) ejection fraction ( > 50%) and 79 age-matched controls who underwent a comprehensive echocardiographic examination. LA phasic function was determined by both volumetric and strain methods. Our findings showed that the LV ejection fraction was similar between hypertensive and normotensive AS patients. Maximal, minimal, and pre-A LA volume indexes gradually increased from controls to moderate-to-severe AS patients. The total, passive and active LA emptying fraction (EF) gradually decreased in the same direction. LA phasic function estimated with strain analysis showed that reservoir, conduit, and pump LA phasic functions were lower in all AS patients than in normotensive controls. However, there was no significant difference between moderate and severe AS except in LA pump function, which was lower in severe AS. Differences in LA phasic function were more prominent in volumetric than in strain analyses. Blood pressure, LV mass index, and AS severity were independent of other clinical and echocardiographic parameters associated with LA phasic function in patients with AS. In conclusion, hypertension has an additive impact on LA phasic function in patients with moderate and severe AS. Blood pressure and AS severity were independently associated with LA phasic function parameters in AS patients. Volumetric assessment of LA phasic function should not be completely replaced with strain analysis.

Left atrial strain and distensibility in relation to left ventricular dysfunction and prognosis in aortic stenosis

OBJECTIVE

To test the relationship between left atrial (LA) distensibility (LAD), LA strain (LAS), and left ventricular (LV) dysfunction and prognosis in aortic stenosis (AS).

METHODS

Transthoracic Doppler echocardiography was performed prospectively in 102 consecutive patients with AS (77 with severe, 25 with moderate, mean age 77 years). LA volume was calculated by the area-length method in apical four- and two-chamber views, immediately before mitral valve opening (Vol_max ) and at mitral valve closure (Vol_min ). LAD was defined as (Vol_max   - Vol_min ) × 100%/Vol_min . LAS (mean of maximal strain from the 4-2 chamber views) was conducted using a dedicated software package. The endpoint was hospitalization for heart failure and death from any cause.

RESULTS

Left atrial strain, LAD, and LA vol/m² were significantly correlated with LV diastolic parameters, and PASP (all, P < 0.05). However, LAD and LAS but not LA vol/m² were significantly correlated with Charlson score, LV global longitudinal strain, and to transaortic mean gradient (all, P < 0.05). At a median follow-up of 25 months, 53 patients had an event. LAS, LAD, LA vol/m², and Charlson index were associated with events (all, P < 0.05). In multivariate analysis, LAD, LAS, and Charlson index (all, P < 0.01) remained independently associated with events. Using a ROC curve analysis, LAD ≤ 69% and LAS ≤ 17% were the best cutoffs associated with an event.

CONCLUSION

In patients with moderate to severe AS, LAD and LAS are associated with LV dysfunction, AS severity, and are independently linked to events.

Left Atrial Size and Function in Patients With Congenital Aortic Valve Stenosis

Little information exists on left atrial (LA) function in healthy children and in patients with congenital aortic valve stenosis (AS). We sought to determine whether patients with significant congenital AS have detectable abnormalities in LA size and function compared with matched normal controls. Retrospective chart review and analysis of 2-dimensional echocardiographic images for phasic left atrial volumes (LAVs) and longitudinal LA strain by speckle tracking in children ≥1 years of age with ≥ moderate isolated congenital AS. LAVs and LA strain in AS cases were compared with age, gender, and body surface area-matched controls (healthy children with a normal echocardiogram). Between June 2004 and October 2012, there were 36 eligible AS cases [age 13 (range 3 to 27) years; 30 males] with a median maximal Doppler gradient of 63 (range 43 to 94) mm Hg. No significant interobserver and intraobserver differences were noted in the analyses of normal subjects. Significantly higher phasic body surface area-adjusted LAVs [preatrial contraction: p = 0.01; minimal: p = 0.04] and higher LA contractile function parameters [indexed active LA stroke volume: p = 0.03; peak negative strain p = 0.04] were noted in AS cases compared with matched controls. In conclusion, compared with normal, children with congenital AS have higher preatrial contraction and minimal phasic LA volumes and higher LA contractile function.

Myocardial strain assessment using velocity vector imaging in normally grown fetuses at term

OBJECTIVES

To assess prospectively fetal myocardial deformation at term in normally grown fetuses using the velocity vector imaging (VVI) two-dimensional speckle-tracking technique, and to explore myocardial deformation changes over the last 4 weeks of pregnancy.

METHODS

This was a prospective, observational cohort study of 276 women with an uncomplicated singleton pregnancy who underwent fortnightly ultrasound from 36 weeks' gestation until delivery at the Mater Mother's Hospital, Brisbane, Australia. Fetal myocardial deformation (assessed by global and segmental longitudinal systolic myocardial strain and strain rate of both right and left ventricles) was measured using VVI software.

RESULTS

Mean global longitudinal left and right ventricular strain and strain rate values decreased between each time point. At 36, 38 and 40 weeks' gestation, left ventricular global strain (%) and strain rate (/s) decreased, respectively, as follows: -14.6 ± 3.8% and -1.2 ± 0.3/s at 36 weeks; -13.6 ± 3.3% and -1.1 ± 0.3/s at 38 weeks; and -12.3 ± 3.1% and -1.0 ± 0.3/s at 40 weeks. At 36, 38 and 40 weeks, mean right ventricular global strain (%) and mean strain rate (/s) decreased, respectively, as follows: -14.2 ± 3.4% and -1.2 ± 0.2/s at 36 weeks; -13.4 ± 3.0% and -1.1 ± 0.2/s at 38 weeks; and -12.8 ± 2.8% and -1.1 ± 0.2/s at 40 weeks.

CONCLUSIONS

Global ventricular strain values diminish with advancing gestational age. Myocardial deformation imaging is feasible in late gestation and may be useful as an adjunct for the assessment of fetal cardiac function close to birth. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Left atrial function: evaluation by strain analysis

The left atrium has an important role in modulating left ventricular filling and is an important biomarker of cardiovascular disease and adverse cardiovascular outcomes. While previously left atrial (LA) size was utilised, the role of LA function as a biomarker is increasingly being evaluated, both independently and also in combination with LA size. Strain analysis has been utilised for evaluation of LA function and can be measured throughout the cardiac cycle, thereby enabling the evaluation of LA reservoir, conduit and contractile function. Strain evaluates myocardial deformation while strain rate examines the rate of change in strain. This review will focus on the various types of strain analysis for evaluation of LA function, alterations in LA strain in physiological and pathologic states that alter LA function and finally evaluate its utility as a prognostic marker.

Mitral regurgitation severity correlates with symptoms and extent of left atrial dysfunction: Effect of mitral valve repair

PURPOSE

We aimed to assess the relationship between mitral regurgitation (MR) severity, symptoms, and left atrial (LA) structure and function, before and after mitral valve repair (MVR).

METHODS

Global peak atrial longitudinal strain (PALS) was evaluated in 37 patients with severe symptomatic MR and preserved left ventricular (LV) ejection fraction (60.4% ± 4.6%) before and 3 months after MVR and was compared with values from 30 age- and gender-matched controls.

RESULTS

Before surgery, PALS was worse in patients than in controls and indexed LA volume was greater (P < .0001 for both). After MVR, PALS deteriorated further and LA volume decreased (P = .001 and P = .05, respectively) as did LV ejection fraction, longitudinal strain (P = .05 and P < .001, respectively), and LV mass (P < .0001). Before surgery, LA volume correlated modestly with LV end-diastolic volume (R = 0.51; P = .01); effective regurgitant orifice area (EROA) correlated with PALS (R = -0.69, P < .001) and with LV longitudinal strain (R = 0.54, P = .01), and New York Heart Association class correlated with PALS (R = -0.69, P < .001), EROA (R = 0.69, P < .001), and LA volume (R = 0.51, P = .04). LA volume was the strongest predictor of global PALS reduction (P < .001), whereas global PALS was the main predictor of postoperative atrial fibrillation (AF) (P < .001).

CONCLUSIONS

In patients with severe MR, EROA correlate with symptoms and LA PALS, which itself predicts the occurrence of postoperative AF. Strain values were superior to 2D data for the prediction of postoperative AF.

Impaired Left Atrial Strain as a Predictor of New-onset Atrial Fibrillation After Aortic Valve Replacement Independently of Left Atrial Size

INTRODUCTION AND OBJECTIVES

Left atrial dysfunction in aortic stenosis may precede atrial enlargement and predict the occurrence of atrial fibrillation (AF). To test this hypothesis, we assessed left atrial function and determined its impact on the incidence of AF after aortic valve replacement.

METHODS

A total of 149 severe aortic stenosis patients (74±8.6 years, 51% men) with no prior AF were assessed using speckle-tracking echocardiography. Left atrial function was evaluated using peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and phasic left atrial volumes. The occurrence of AF was monitored in 114 patients from surgery until hospital discharge.

RESULTS

In multiple linear regression, PALS and PACS were inversely correlated with left atrial dilation, left ventricular hypertrophy, and diastolic function. Atrial fibrillation occurred in 36 patients within a median time of 3 days [interquartile range, 1-4] after aortic valve replacement. In multiple Cox regression, PALS and PACS were independently associated with the incidence of AF (HR, 0.946; 95%CI, 0.910-0.983; P=.005 and HR, 0.932; 95%CI, 0.883-0.984; P=.011, respectively), even after further adjustment for left atrial dimensions. Both reduced PALS and PACS were associated with the incidence of AF in patients with nondilated left atria (P value for the interaction of PALS with left atrial dimensions=.013).

CONCLUSIONS

In severe aortic stenosis, left atrial dysfunction predicted the incidence of postoperative AF independently of left atrial dilation, suggesting that speckle-tracking echocardiography before surgery may help in risk stratification, particularly in patients with nondilated left atria.

Assessment of left atrial function by MRI myocardial feature tracking

BACKGROUND

Left atrium (LA) volumes and function are predictors of cardiovascular events. Because LA function cannot be assessed from cardiovascular magnetic resonance imaging (MRI) using the well-established left ventricular tagging techniques, we hypothesized that adequate feature tracking (FT) applied to conventional cine MRI data could characterize LA function accurately.

METHODS

We studied 10 young (28 ± 7 years) and 10 elderly (64 ± 6 years) healthy subjects, as well as 20 patients with moderate to severe aortic valve stenosis (AVS; 73 ± 15 years, effective aortic valve area: 0.67 ± 0.36 cm(2) ). MRI cine two-, three-, and four-chamber views were analyzed using a newly proposed FT method based on spatial correlation and endocardial detection resulting in: regional and global longitudinal strain and strain rate, radial motion fraction and relative velocity for the three LA motion phases including reservoir, conduit, and LA contraction.

RESULTS

FT reliability was indicated by a good overlap between tracking results and manual LA endocardial borders, the low error for comparison against theoretical strains introduced in a synthetic phantom and the good inter-observer reproducibility (coefficient of variation < 15%). While all LA functional parameters were significantly impaired in AVS patients (p < 0.04), subclinical age-related variations induced a decreasing trend on all LA parameters but were significant only for radial conduit function parameters (p < 0.03). Finally, LA functional parameters characterized LA alteration in AVS with higher sensitivity than conventional LA volumetric parameters.

CONCLUSIONS

Left atrial FT is feasible on MRI cine images and its addition to conventional analysis tools might enhance the diagnosis value of MRI in many heart diseases.

Left atrial mechanics: echocardiographic assessment and clinical implications

The importance of the left atrium in cardiovascular performance has long been acknowledged. Quantitative assessment of left atrial (LA) function is laborious, requiring invasive pressure-volume loops and thus precluding its routine clinical use. In recent years, novel postprocessing imaging methodologies have emerged, providing a complementary approach for the assessment of the left atrium. Atrial strain and strain rate obtained using either Doppler tissue imaging or two-dimensional speckle-tracking echocardiography have proved to be feasible and reproducible techniques to evaluate LA mechanics. It is essential to fully understand the clinical applications, advantages, and limitations of LA strain and strain rate analysis. Furthermore, the technique's prognostic value and utility in therapeutic decisions also need further elucidation. The aim of this review is to provide a critical appraisal of LA mechanics. The authors describe the fundamental concepts and methodology of LA strain and strain rate analysis, the reference values reported with different imaging techniques, and the clinical implications.