Left atrial mechanical functions in elite male athletes

Cardiac Resynchronization Therapy and Left Atrial Remodeling: A Novel Insight?

Cardiac resynchronization therapy (CRT) restores ventricular dyssynchrony, improving left ventricle (LV) systolic function, symptoms, and outcome in patients with heart failure, systolic dysfunction, and prolonged QRS interval. The left atrium (LA) plays tremendous roles in maintaining cardiac function, being often inflicted in various cardiovascular diseases. LA remodeling implies structural-dilation, functional-altered phasic functions, and strain and electrical-atrial fibrillation remodeling. Until now, several important studies have approached the relationship between LA and CRT. LA volumes can predict responsiveness to CRT, being also associated with improved outcome in these patients. LA function and strain parameters have been shown to improve after CRT, especially in those who were positive responders to it. Further studies still need to be conducted to comprehensively characterize the impact of CRT on LA phasic function and strain, and, also, in conjunction with its impact on functional mitral regurgitation and LV diastolic dysfunction. The aim of this review was to provide an overview of current available data regarding the relation between CRT and LA remodeling.

Effect of coronavirus disease-2019 infection on left atrial functions

Objective:

Left atrial (LA) dysfunction is a crucial risk factor for cardiovascular events, and various pathologies may affect LA function. Coronavirus disease-2019 (COVID-19) is an ongoing global pandemic causing morbidity and mortality. In the present study, we aimed to evaluate LA functions in patients who recovered from COVID-19.

Methods:

Sixty consecutive patients recovered from COVID-19 and 60 healthy individuals as a control group were included in the study. Blood samples and echocardiography measurements were obtained from each subject. The two groups were compared in terms of demographic and echocardiographic characteristics.

Results:

In the COVİD-19 group, LA maximum volume (LAV_max) (P = 0.040), LA pre-A volume (LAVpre-A) (P = 0.014), and LA active emptying fraction (P = 0.027) were higher, while LA passive emptying fraction (P = 0.035) was lower. In addition, left ventricular ejection fraction (P = 0.006) and isovolumetric relaxation time (P = 0.008) were decreased in this group. Although LA volume index was higher in the COVID-19 group, it does not reach statistical significance.

Conclusion:

LA functions may be impaired in patients recovered from COVID-19 infection.

Tissue Doppler imaging of the atrial lateral wall: Correlation with atrial strain rate and parameters of diastolic function

OBJECTIVE

To evaluate the velocity profile of the lateral wall of the left atrium (LA) using pulsed-wave color tissue Doppler imaging (TDI) on line and its correlation with two-dimensional strain rate imaging (SRI) by speckle tracking, of equal segments and phases, and other parameters of diastolic function in a population of individuals without known cardiovascular disease.

MATERIALS AND METHODS

A total of 91 adults aged 18-74 years, without cardiovascular history, hypertension, diabetes, dyslipidemia or obesity, were evaluated. A Doppler echocardiogram was performed. The lateral wall of the LA was divided subjectively into three portions, the atrial roof was excluded; the peak velocities of the basal and midportions, and their average, were measured with pulsed-wave TDI on line and SRI. Using both techniques, a first positive wave (S'la and SRS-reservoir phase) and two negative waves (E'la and SRE-conduit phase-and A'la and SRA-atrial systole-respectively) were obtained. E'la/A'la ratio and SRE/SRA ratio were analyzed.

RESULTS

The median age was 42 years, and 54.9% of the subjects were female. S'la presented moderate correlation with S' lateral mitral annulus. Both E'la and the E'la/A'la relationships showed moderate to good correlation with various diastolic dysfunction parameters evaluated and SRI. A'la did not present a statistically significant correlation with any of the variables evaluated.

CONCLUSION

Evaluation of the lateral wall of the LA by pulsed-wave color TDI on line is feasible in the vast majority of patients. In the conduit phase, E'la and the E'la/A'la relationship showed correlation with the parameters that evaluate diastolic function and SRI.

Left atrial strain after maximal exercise in competitive waterpolo players

Left atrial (LA) function is a determinant of left ventricular (LV) filling. It carries out three main functions: reservoir, conduit, contractile. Aim of this study was to evaluate the role of LA and its deformation properties on LV filling at rest (R) and immediately after a maximal exercise (ME) through the speckle tracking echocardiography. Population enrolled was composed by 23 water polo athletes who performed a ME of six repeats of 100 m freestyle swim sets. At ME peak atrial longitudinal strain was reduced but all strain rate (SR) parameters increased, respectively positive peak SR at reservoir phase, SR negative peak at rapid ventricular filling (SRep) and SR negative peak at late ventricular filling (SRlp), that corresponds to atrial contraction phase. We showed a parallel increase in E and A pulsed Doppler wave and SRep and SRlp; particularly at ME, A wave and SRlp increased more respectively than E wave and SRep. SRlp was related to ejection fraction (EF) (r = -0.47; p < 0.01). At multivariate analysis SRlp was an independent predictor of EF (β: -0.47; p = 0.016). The increased sympathetic tone results into increased late diastolic LV filling with augmented atrial contractility and a decrease in diastolic filling time. During exercise LV filling was probably optimized by an enhanced and rapid LA conduit phase and by a vigorous atrial contraction during late LV filling.

Effect of lifetime endurance training on left atrial mechanical function and on the risk of atrial fibrillation

BACKGROUND

Left atrium (LA) dilation and P-wave duration are linked to the amount of endurance training and are risk factors for atrial fibrillation (AF). The aim of this study was to evaluate the impact of LA anatomical and electrical remodeling on its conduit and pump function measured by two-dimensional speckle tracking echocardiography (STE).

METHOD

Amateur male runners >30 years were recruited. Study participants (n=95) were stratified in 3 groups according to lifetime training hours: low (<1500 h, n=33), intermediate (1500 to 4500 h, n=32) and high training group (>4500 h, n=30).

RESULTS

No differences were found, between the groups, in terms of age, blood pressure, and diastolic function. LA maximal volume (30±5, 33±5 vs. 37±6 ml/m(2), p<0.001), and conduit volume index (9±3, 11±3 vs. 12±3 ml/m(2), p<0.001) increased significantly from the low to the high training group, unlike the STE parameters: pump strain -15.0±2.8, -14.7±2.7 vs. -14.9±2.6%, p=0.927; conduit strain 23.3±3.9, 22.1±5.3 vs. 23.7±5.7%, p=0.455. Independent predictors of LA strain conduit function were age, maximal early diastolic velocity of the mitral annulus, heart rate and peak early diastolic filling velocity. The signal-averaged P-wave (135±11, 139±10 vs. 148±14 ms, p<0.001) increased from the low to the high training group. Four episodes of non-sustained AF were recorded in one runner of the high training group.

CONCLUSION

The LA anatomical and electrical remodeling does not have a negative impact on atrial mechanical function. Hence, a possible link between these risk factors for AF and its actual, rare occurrence in this athlete population, could not be uncovered in the present study.

Left atrium systolic and diastolic function assessment in hypertensive patients with preserved ejection fraction

Left atrium remodeling is a physiological response to pressure overload in hypertensive patients. The aim of this study is to determine the relationship between left atrium remodeling and left ventricle diastolic dysfunction in hypertensive patients with preserved systolic function.

MATERIALS AND METHODS

We conducted a prospective study on 96 hypertensive patients (48.75 ± 5.01 years, 50 men) and 96 healthy control subjects (48.17 ± 8.52 years, 56 men), whose data were all evaluated by echocardiography measuring left atrium volumes during the reservoir,conduit and pump phases. Standard indices reflecting left ventricular filling were also assessed.

RESULTS

Medium left atrium volume indexed for body surface was significantly higher in hypertensive patients – 30.87 (6.38) mL/m² vs.21.72 (2.52) mL/m². Indexed left atrium volume was strongly associated with left ventricle diastolic function (p <0.0001). When compared to normal subjects, patients with mild diastolic dysfunction had lower corrected passive emptying volumes ( p < 0.0001) and higher corrected active emptying volumes (p = 0.001), thus leading to similar corrected total emptying volumes ( p < 0.001). However, patients with moderate diastolic dysfunction had smaller active emptying volumes, but higher passive and total emptying volumes when compared to normal controls and patients with mild diastolic dysfunction.

CONCLUSIONS

Left atrium indexed volumes evaluation during the reservoir,conduit and pump phases proved to be essential for early diastolic dysfunction assessment in hypertensive patients.

Left atrial function: physiology, assessment, and clinical implications

The interest in the left atrium (LA) has resurged over the recent years. In the early 1980s, multiple studies were conducted to determine the normal values of LA size. Over the past decade, LA size as an imaging biomarker has been consistently shown to be a powerful predictor of outcomes, including major public health problems such as atrial fibrillation, heart failure, stroke, and death. More recently, functional assessment of the LA has been shown to be, at least as, if not more robust, a marker of cardiovascular outcomes. Current available data suggest that the combined evaluation of LA size and LA function will augment prognostication. The aim of this review is to provide a critical appraisal of current echocardiographic techniques for the assessment of LA function and the implications of such assessment for prediction and disease prevention.

Influence of regression of left ventricular hypertrophy on left atrial size and function in patients with moderate hypertension

OBJECTIVES

The aim of the study was to evaluate the effect of regression of left ventricular (LV) hypertrophy on left atrial (LA) size and function in patients treated with telmisartan, an angiotensin II receptor blocker.

METHODS

Patients population included 80 patients with mild-moderate LV hypertrophy treated with telmisartan. Patients were followed over a period of 12 months from the start of telmisartan treatment. LA size was measured during systole from the parasternal long-axis view from M-mode. Atrial function was assessed by Doppler-echocardiography and the following parameters were measured: transmitral peak A velocity, atrial filling fraction, atrial ejection force (AEF), peak E velocity, deceleration time and isovolumic relaxation time, LA maximal and minimal volume, and LV cardiac mass index (LVMI).

RESULTS

All patients had an increased LVMI and decrease during follow-up. LA dimensions were greater at baseline and reduced after 1 year of treatment. LA volume indexes maximal volume, minimal volume and P volume were reduced compared with baseline value (maximal volume from 35+/-5 to 32+/-5, p<0.05; minimal volumes from 14+/-2 to 10+/-4, p<0.05). AEF, a parameter of atrial systolic function, increased from 12+/-3 to 15+/-2.4 (p<0.01). The reduction of LA volumes correlate with reduction of LVMI (LA maximal volume and LVMI r = 0.45; p<0.01; LA minimal volume and LVMI r = 0.34; p<0.05). A positive correlation was also found between LV mass index and P volume (r = 0.41; p<0.01), LV mass index and LA active emptying volume (r = 0.39; p<0.01), and LV mass index and LA total emptying volume (r = 0.38; p<0.05).

CONCLUSIONS

The present study suggests that regression of LV hypertrophy due to telmisartan is associated with reduction of LA volumes that expresses variation of LV end-diastolic pressure. The reduction of LV end-diastolic pressure is associated with an increase in diastolic filling and with a significant reduction of active and passive emptying contribution of left atrium to LV stroke volume.

Assessment of Atrial Function

This article discusses the traditional and more recent echocardiographic measures that have been employed to evaluate atrial function. Conventional parameters commonly used and reported in the literature include the study of the various phases of atrial activity using atrial volume measurements, the peak A wave velocity, its velocity time integral (VTI) and the fraction of atrial contribution (all obtained from transmitral flow), as also the atrial ejection force. Newer parameters for atrial function assessment include Doppler tissue imaging (DTI) including segmental atrial contractility using colour Doppler tissue imaging (CDTI) and estimates of atrial strain and strain rate.

Early Effects of Percutaneous Mitral Valvuloplasty on Left Atrial Mechanical Functions

It has been suggested that successful percutaneous balloon mitral valvuloplasty (PMV) decreases the intensity of spontaneous left atrial contrast, reduces the size of the left atrium, and improves left atrial function in patient with mitral stenosis. However, left atrial mechanical functions immediately after PMV have not been extensively evaluated yet. The aim of this study was to evaluate the effects of PMV on left atrial mechanical functions. Twenty patients with critical mitral stenosis who have normal sinus rhythm (male/female: 4 to 16; mean age: 33 +/- 8 years) were included in the study. Left atrial mechanical functions were evaluated before and after PMV, including left atrial passive emptying volume, LA passive emptying fraction, conduit volume, left ventricular stroke volume, LA active emptying volume, LA active emptying fraction, LA total emptying volume and LA total emptying fraction. PMV resulted in a significant increase in the mitral valve area (p < 0.001) and a substantial reduction in the mean transmitral pressure gradient (p < 0.001) as well as LA diameter (p < 0.002). LA maximal volume, minimal volume and atrial presystolic volumes were significantly decreased after PMV (p: 0.001; p: 0.002; p: 0.001, respectively). The conduit volume was increased and LA total emptying volume was decreased after PMV (p: 0.014; p: 0.035). The other left atrial volumes were not altered after PMV. The early increase in conduit volume and the decrease in left atrial presystolic volume indicate that PMV has favorable effects on atrial reservoir and conduit functions. PMV therefore improves atrial mechanic functions.

The effect of pulmonary hypertension on left atrial mechanical functions in chronic obstructive lung disease

BACKGROUND

Left atrial (LA) function is an important determinant of left ventricular (LV) filling. However, the effect of pulmonary hypertension (PH) on LA mechanical function in chronic obstructive lung disease (COLD) has not been studied, yet.

METHODS

49 patients with COLD and 25 controls were included in this study. Patients were divided into two subgroups: patients without PH (group 1, n=21) and with PH (group 2, n=28). LA volumes were determined at mitral valve opening (Vmax), at onset of atrial systole (Vp) and at mitral valve closure (Vmin) according to biplane area-length method. The following LA parameters were calculated: passive emptying volume (PEV=Vmax-Vp), conduit volume [CV=LV stroke volume-(Vmax-Vmin)], passive emptying fraction (PEF=PEV/Vmax), active emptying volume (AEV=Vp-Vmin), active emptying fraction (AEF=AEV/Vp), total emptying volume (TEV=Vmax-Vmin), percent contribution of PEV, CV and AEV to LV stroke volume.

RESULTS

Vmax (p<0.01), PEV (p<0.001) and TEV (p<0.05) were lower in group 2 than in the controls, and the differences between group 1 and control group were insignificant (p>0.05). Vp, Vmin, CV and AEV did not differ among three groups. Percent contribution to LV filling of the PEV was decreased in group 2 when compared to group 1 (p<0.05) and the controls (p<0.01). Percent contribution to LV filling of the AEV was increased in group 2 when compared to the controls (p<0.05). There were inverse correlations between pulmonary artery pressure and the following parameters: LV stroke volume (r=-0.43, p<0.01), mitral E/A (r=-54, p<0.001), Vmax (r=-0.35, p<0.05), PEV (r=-40, p<0.01) and PEF (r=-0.43, p<0.01).

CONCLUSION

This study shows that the alterations of LA mechanical functions in patients with COLD are closely correlated to PH levels. Furthermore, these results underline the importance of maintaining a sinus rhythm in these patients.

Comparison of left atrial volume and function after linear ablation and after cardioversion for chronic atrial fibrillation

Several techniques for treatment of atrial fibrillation (AF) have been developed, including the direct placement of radiofrequency for lesions at open heart surgery. Detailed evaluation of left atrial (LA) function has not been performed after these procedures and has not been compared in patients with chronic AF. We compared the atrial function of patients with sustained sinus rhythm (SR) after linear ablation with a group who underwent direct-current cardioversion and a group of normal controls to investigate the measurable deleterious effects, if any, on atrial function after the surgical procedure. Twenty-one consecutive patients who had maintained SR for >6 months after a linear radiofrequency ablation (LRFA) procedure were studied. As control subjects, we examined 33 patients with chronic AF successfully restored to SR by cardioversion who maintained SR for >6 months and 42 age-matched normal subjects. LA function was decreased in both the LRFA and cardioverted AF groups compared with normal controls. The parameters of LA function, atrial fraction, LA ejection fraction, and the A' velocity were lowest in the LRFA group, intermediate in the cardioverted AF group, and highest in the normal controls (LA function: 15.8 +/- 10%, 26 +/- 10%, 33 +/- 7%; p = 0.0001; LA ejection fraction: 31 +13%, 41 +/- 12%, 51 +/- 9%; p = 0.0001; A' velocity: 4.2 +/- 1.4, 7.6 +/- 2.2, 9.5 +/- 1.9 cm/s; p = 0.0001). LA volumes were increased in the LRFA and cardioverted AF groups compared with normals (62.8 +/- 22 vs 70.6 +/- 17 vs 38.7 +/- 9.8 ml; p = 0.0001). Thus, although LA function is restored and maintained after LRFA has been performed during open heart surgery, LRFA use is associated with a measurable decrease in LA function over and above that found after conventional cardioversion.

Compensatory changes in atrial volumes with normal aging: is atrial enlargement inevitable?

OBJECTIVES

The aim of this study was to evaluate left atrial volume and its changes with the phases (active and passive) of atrial filling, and to examine the effect of normal aging on these parameters and pulmonary vein (PV) flow patterns.

BACKGROUND

Atrial volume change with normal aging has not been adequately described. Pulmonary vein flow patterns have not been volumetrically evaluated in normal aging. Combining atrial volumes and PV flow patterns obtained using transthoracic echocardiography could estimate shifts in left atrial mechanical function with normal aging.

METHODS

A total of 92 healthy subjects, divided into two groups: Group Y (young <50 years) and Group O (old > or =50 years), were prospectively studied. Maximal (Vol(max)) and minimal (Vol(min)) left atrial volumes were measured using the biplane method of discs and by three-dimensional echocardiographic reconstruction using the cubic spline interpolation algorithm. The passive filling, conduit, and active emptying volumes were also estimated. Traditional measures of atrial function, mitral peak A-wave velocity, velocity time integral (VTI), atrial emptying fraction, and atrial ejection force were measured.

RESULTS

As age increased, Vol(max), Vol(min), and total atrial contribution to left ventricle (LV) stroke volume were not significantly altered. However, the passive emptying volume was significantly higher (14.2 +/- 6.4 ml vs. 11.6 +/- 5.7 ml; p = 0.03) whereas the active emptying volume was lower (8.6 +/- 3.7 ml vs. 10.2 +/- 3.8 ml; p = 0.04) in Group Y versus Group O. Pulmonary vein flow demonstrated an increase in peak diastolic velocity (Group Y vs. Group O) with no corresponding change in diastolic VTI or systolic fraction.

CONCLUSIONS

Normal aging does not increase maximum (end-systolic) atrial size. The atrium compensates for changes in LV diastolic properties by augmenting active atrial contraction. Pulmonary vein flow patterns, although diastolic dominant using peak velocity, demonstrated no volumetric change with aging.