Left atrial anatomy and physiology: echo/Doppler assessment

Global left ventricular strains and left atrial volumes are not associated in healthy adults - Detailed analysis from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

Introduction

During the heart cycle, left ventricular (LV) contractility is characterized by complex deformation and rotational mechanics, resulting in LV ejection. The present study seeks to expand our knowledge by examining dependence of LV strains representing LV deformation on left atrial (LA) volumes in healthy circumstances. Therefore, the aim of this study was to evaluate the associations between LA volumes and LV strains as assessed simultaneously by three-dimensional speckle-tracking echocardiography (3DSTE) in normal healthy adults.

Methods

The present study consisted of 302 healthy adults, but according to exclusion criteria, 137 subjects were excluded due to inferior image quality. The final population comprised 165 individuals (mean age: 33.1 ± 12.3 years, 75 males) who were voluntarily recruited for screening. Two-dimensional echocardiography extended with 3DSTE was performed in all subjects for detailed LV/LA analysis.

Results

Overall feasibility for simultaneous assessment of LV strains and LA volumes proved to be 55 % with excellent intra- and interobserver correlations. All global LV strains were similar, regardless of the LA volumes examined. All LA volumes and volume-based functional properties respecting the cardiac cycle were similar, regardless the global LV strains examined.

Conclusions

LV strains and LA volumes can be simultaneously assessed by 3DSTE. Global LV strains and LA volumes are not associated in healthy adults.

Correlations between vegetative autonomic function and specific left atrial functions in healthy adults: Insights from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

INTRODUCTION

The functioning of the left atrium (LA) is partly controlled by the neural system. It was purposed to evaluate correlations between the result of Ewing's 5 standard cardiovascular reflex tests (SCRTs) characterizing autonomic function and LA volumetric and functional features as assessed by three-dimensional speckle-tracking echocardiography (3DSTE) in healthy individuals.

MATERIALS AND METHODS

The current study comprised 18 healthy volunteers being in sinus rhythm (mean age: 35 ± 12 years, 10 men). Measurement of blood pressure, ECG, 5 SCRTs, two-dimensional Doppler echocardiography and 3DSTE were performed. These parameters were in normal ranges in all cases.

RESULTS

From LA volumetric parameters, only systolic total atrial emptying fraction (r = 0.559, p = 0.037) and early diastolic passive atrial emptying fraction (r = 0.539, p = 0.047) correlated with systolic blood pressure response to standing representing sympathetic autonomic function. From LA strains, peak mean segmental LA radial strain (RS) (r = -0.532, p = 0.050), global and mean segmental LA circumferential strain (CS) (r = 0.662, p = 0.010 and r = 0.635, p = 0.015, respectively) representing systolic LA function correlated with Valsalva ratio representing parasympathetic autonomic function. Global LA-RS (r = -0.713, p = 0.040) and LA-CS (r = 0.657, p = 0.011) and mean segmental LA-CS (r = 0.723, p = 0.003) at atrial contraction representing end-diastolic atrial contraction showed correlations with Valsalva ratio, as well. Peak global and mean segmental LA-CS (r = 0.532, p = 0.050 and r = 0.530, p = 0.050) and the same strains at atrial contraction (r = 0.704, p = 0.005 and r = 0.690, p = 0.006) representing systolic function and end-diastolic atrial contraction correlated with systolic blood pressure response to standing representing both parasympathetic and sympathetic autonomic functions.

CONCLUSIONS

Significant correlations between features of vegetative autonomic function represented by Ewing's 5 SCRTs and specific LA functions represented by 3DSTE-derived LA volume-based functional properties and strains could be demonstrated in healthy adults.

The Role of the Left Atrium: From Multimodality Imaging to Clinical Practice: A Review

In recent years, new interest is growing in the left atrium (LA). LA functional analysis and measurement have an essential role in cardiac function evaluation. Left atrial size and function are key elements during the noninvasive analysis of diastolic function in several heart diseases. The LA represents a “neuroendocrine organ” with high sensitivity to the nervous, endocrine, and immune systems. New insights highlight the importance of left atrial structural, contractile, and/or electrophysiological changes, introducing the concept of “atrial cardiomyopathy”, which is closely linked to underlying heart disease, arrhythmias, and conditions such as aging. The diagnostic algorithm for atrial cardiomyopathy should follow a stepwise approach, combining risk factors, clinical characteristics, and imaging. Constant advances in imaging techniques offer superb opportunities for a comprehensive evaluation of LA function, underlying specific mechanisms, and patterns of progression. In this literature review, we aim to suggest a practical, stepwise algorithm with integrative multimodality imaging and a clinical approach for LA geometry and functional analysis. This integrates diastolic flow analysis with LA remodelling by the application of traditional and new diagnostic imaging techniques in several clinical settings such as heart failure (HF), atrial fibrillation (AF), coronary artery disease (CAD), and mitral regurgitation (MR).

Correlations between left atrial volumes and strains in healthy adults: Detailed analysis from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

INTRODUCTION

Little is known about the relationship between left atrium (LA) volumes and contractility features along the cardiac cycle. The present study aimed to assess, by three-dimensional speckle-tracking echocardiography (3DSTE), correlations between LA volumes, volume-based functional properties, and strains during the cardiac cycle in healthy adults.

METHODS

We included 217 healthy adult volunteers (mean age 33.4 ± 12.7 years, 112 males) who underwent complete two-dimensional Doppler echocardiography with 3DSTE.

RESULTS

LA stroke volumes were greater in subjects with the greater maximum LA volume (V_max ) in reservoir, conduit, and booster pump phases of LA function. While LA emptying fraction in LA reservoir phase was not different between subjects depending in their V_max value, a significantly lower LA emptying fraction could be detected in LA conduit phase in subjects whose V_max was >50 mL. In booster pump function, LA emptying fraction was not significantly different whatever the V_max . Only global and mean segmental peak LA radial strain (RS) and 3D strain (3DS) and the same strains at atrial contraction appeared greater in subjects with greater V_max , whereas the other strain parameters were not different.

CONCLUSIONS

In healthy subjects, LA-RS and LA-3DS, objective features of LA contractility, are greater in subjects with greater LA volumes up to a point beyond which this association disappears.

Pathophysiology of Hypertensive Heart Disease: Beyond Left Ventricular Hypertrophy

PURPOSE OF REVIEW

Given that the life expectancy and the burden of hypertension are projected to increase over the next decade, hypertensive heart disease (HHD) may be expected to play an even more central role in the pathophysiology of cardiovascular disease (CVD). A broader understanding of the features and underlying mechanisms that constitute HHD therefore is of paramount importance.

RECENT FINDINGS

HHD is a condition that arises as a result of elevated blood pressure and constitutes a key underlying mechanism for cardiovascular morbidity and mortality. Historically, studies investigating HHD have primarily focused on left ventricular (LV) hypertrophy (LVH), but it is increasingly apparent that HHD encompasses a range of target-organ damage beyond LVH, including other cardiovascular structural and functional adaptations that may occur separately or concomitantly. HHD is characterized by micro- and macroscopic myocardial alterations, structural phenotypic adaptations, and functional changes that include cardiac fibrosis, and the remodeling of the atria and ventricles and the arterial system. In this review, we summarize the structural and functional alterations in the cardiac and vascular system that constitute HHD and underscore their underlying pathophysiology.

Left atrial volume and strain parameters using echocardiography in a black population

Aims

Left atrial (LA) volume is an important predictor of morbidity and mortality in cardiovascular disease. Left atrial strain is a feasible technique for assessing LA function. The EchoNoRMAL study recently highlighted the possibility that ethnic-based differences may exist in LA size. There is a paucity of data regarding LA parameters in an African population. We sought to establish normative values for LA volumetric and strain parameters in a black population.

Methods and results

This cross-sectional study comprised 120 individuals between 18 and 70 years of age. Left atrial volumes were measured by biplane Simpson's method, and strain parameters were measured using Philips QLAB 9 (Amsterdam, The Netherlands) speckle-tracking software. The mean age was 38.7 ± 12.8 years (50% male). Maximum LA volume indexed (LAVi), pre-atrial LAVi, and minimum LAVi were 19.7 ± 5.9, 12.2 ± 4.4, and 7.7 ± 3.2 mL/m2, respectively. Females had a higher LAVi compared with males (20.9 ± 6.3 vs. 18.6 ± 5.3 mL/m2, P = 0.04). Peak global longitudinal strain in the reservoir phase (ɛR) was 39.0 ± 8.3%, and the peak LA strain in the contractile phase (ɛCT) was -2.7 ± 2.5%. No gender differences were noted in ɛR. Body surface area, age, and weight were the main determinants of ɛR on multivariate linear regression analysis.

Conclusion

The data reported in this study establish the normal reference values for phasic LA volumes and strain in a normal black population and serve as a platform for future studies.

[Assessment of left atrial size and function -- from M-mode to 3D speckle-tracking echocardiography]

Left atrium is not a passive heart chamber, because it has a dynamic motion respecting heart cycle and, in accordance with its stretching, it releases atrial natriuretic peptides. Since in the course of certain invasive procedures the size of left atrium may change substantially, its exact measurement and functional characterization are essential. The aim of the present review is to summarize echocardiographic methods for the assessment of left atrial size and functional parameters.