Atrial dilation and altered function are mediated by age and diastolic function but not before the eighth decade

Assessment and Management of Atrial Fibrillation in Older Adults with Frailty

Atrial fibrillation (AF) is a major driver of morbidity and mortality among older adults with frailty. Moreover, frailty is highly prevalent in older adults with AF. Understanding and addressing the needs of frail older adults with AF is imperative to guide clinicians caring for older adults. In this review, we summarize current evidence to support the assessment and management of older adults with AF and frailty, incorporating numerous recent landmark trials and studies in the context of the 2023 US AF guideline.

Left atrial cardiomyopathy: Pathophysiological insights, assessment methods and clinical implications

Atrial cardiomyopathy is defined as any complex of structural, architectural, contractile or electrophysiological changes affecting atria, with the potential to produce clinically relevant manifestations. Most of our knowledge about the mechanistic aspects of atrial cardiomyopathy is derived from studies investigating animal models of atrial fibrillation and atrial tissue samples obtained from individuals who have a history of atrial fibrillation. Several noninvasive tools have been reported to characterize atrial cardiomyopathy in patients, which may be relevant for predicting the risk of incident atrial fibrillation and its related outcomes, such as stroke. Here, we provide an overview of the pathophysiological mechanisms involved in atrial cardiomyopathy, and discuss the complex interplay of these mechanisms, including aging, left atrial pressure overload, metabolic disorders and genetic factors. We discuss clinical tools currently available to characterize atrial cardiomyopathy, including electrocardiograms, cardiac imaging and serum biomarkers. Finally, we discuss the clinical impact of atrial cardiomyopathy, and its potential role for predicting atrial fibrillation, stroke, heart failure and dementia. Overall, this review aims to highlight the critical need for a clinically relevant definition of atrial cardiomyopathy to improve treatment strategies.

Obesity-hyperlipidemia, Hypertension, and Left Atrial Enlargement During Stroke in Young Adults

BACKGROUND

This study investigated the association between left atrial enlargement and stroke severity in young adults. We also studied the differences between the normal and left atrial enlargement groups in clinical data.

METHODS

A total of 135 young stroke patients admitted to the Department of Neurology of the Taizhou People's Hospital were recruited from January 2018 to December 2021. The patients were divided into normal and enlarged groups by left atrial size. The relationship between the left atrial diameter and the National Institutes of Health Stroke Scale score was analyzed apart from the differences in clinical variables.

RESULTS

No relationship was observed between the left atrial diameter and the National Institutes of Health Stroke Scale score ( r =-0.045 P =0.603). The univariate analysis of both groups revealed that hypertension ( P =0.004), hyperlipidemia ( P =0.001), body mass index ( P =0.000), obesity ( P =0.015), and not stroke etiologic subtypes were associated with left atrial enlargement. In binary logistic regression analysis models, hyperlipidemia 3.384 (95% CI, 1.536 to 7.452), hypertension 2.661 (95% CI, 1.066 to 6.639), and obesity 2.858 (95% CI, 1.158 to 7.052) were significantly associated with the young stroke of left atrial enlargement.

CONCLUSIONS

In young adults, obesity-hyperlipidemia and hypertension were significantly associated with left atrial enlargement in stroke.

The value of left atrial longitudinal strain in evaluating left atrial appendage spontaneous echo contrast in non-valvular atrial fibrillation

Background

Spontaneous echo contrast (SEC) observed in transesophageal echocardiography (TEE) is a reliable predictor of the risk of future ischemic stroke in patients with non-valvular atrial fibrillation (NVAF). Left atrial strain globally reflects atrial function, remodeling and distensibility. The left atrial appendage (LAA) is a myogenic remnant of the left atrium, which can actively relax and contract. The left atrial appendage (LAA) is an important part of releasing the pressure of the left atrium. The key role of the left atrium is to regulate the left ventricular filling pressure, act as a reservoir for pulmonary venous return during ventricular contraction, and act as a conduit, transferring blood to the Left ventricle during early ventricular diastole. The purpose of this study was to explore the relationship between left atrial function and left atrial appendage spontaneous echo contrast (LAASEC).

Methods

A retrospective study of 338 patients with non-valvular AF was conducted. Two-dimensional speckle-tracking echocardiography provided the following metrics of LA strain: LA strain during the reservoir phase (LASr), LA strain during the conduit phase (LAScd). LA or LAA has the dense SEC of more than grade 3, which is defined as mud like change or pre thrombosis.

Results

Patients with level 3 SEC (n = 81) has lower LASr than those with lower grades of SEC (n = 257) (7.20 ± 3.70 vs. 17.48 ± 8.67, P < 0.001). Multivariate logistic regression model showed that the type of atrial fibrillation (persistent∼), increased heart rate, decreased LASr were independently associated with the dense LAASEC (OR (CI 95%), 5.558 (1.618-19.09), 1.016 (1.006-1.026) 0.002, 1.224 (1.085-1.381), both P < 0.01). Venn Diagram showed that lower CHADVASC2 score groups had dense SEC cases. Receiver operating characteristic (ROC) curve was used for analyzing results and selecting cut off values. The cut off point for LASr < 8.85% and CHADVASC2 score was >2 scores with sensitivity and specificity were 79% and 85%.

Conclusion

Lower LASr is independently associated with the dense LAASEC in NVAF and has incremental values superior to clinical scores. The decrease of LASr may be a potential non-invasive parameter for evaluating the higher risk of LAA thrombosis.

A masked, placebo-controlled, randomized clinical trial evaluating safety and the effect on cardiac function of low-dose rapamycin in 17 healthy client-owned dogs

Introduction

Geroscience studies of low-dose rapamycin in laboratory species have identified numerous benefits, including reversing age-related cardiac dysfunction. Cardiovascular benefits have been observed in dogs with 10 weeks of treatment, raising questions about possible benefits and adverse effects of long-term use of low-dose rapamycin. The objectives of this study were to assess the impact of 6 months of low-dose rapamycin on echocardiographic indices of cardiac function in healthy dogs and to document the occurrence of adverse events.

Methods

Seventeen client-owned dogs aged 6-10 years, weighing 18-36 kg, and without significant systemic disease were included in a prospective, randomized, placebo-controlled, masked clinical trial. Low-dose rapamycin (0.025 mg/kg) or placebo was administered three times per week for 6 months. Baseline, 6-month, and 12-month evaluation included physical examination, cardiology examination, and clinicopathology. Three-month evaluation included physical examination and clinicopathology. Owners completed online questionnaires every 2 weeks.

Results

There were no statistically significant differences in echocardiographic parameters between rapamycin and placebo groups at 6 or 12 months. No clinically significant adverse events occurred. In 26.8% of the bi-weekly surveys owners whose dogs received rapamycin reported perceived positive changes in behavior or health, compared to 8.1% in the placebo group (p = 0.04).

Discussion

While no clinically significant change in cardiac function was observed in dogs treated with low-dose rapamycin, the drug was well-tolerated with no significant adverse events.

Quantification of Left Atrial Size and Function in Cardiac MR in Correlation to Non-Gated MR and Cardiovascular Risk Factors in Subjects without Cardiovascular Disease: A Population-Based Cohort Study

Background: In magnetic resonance imaging (MRI), the comparability of gated and non-gated measurements of the left atrial (LA) area and function and their association with cardiovascular risk factors have not been firmly established. Methods: 3-Tesla MRIs were performed on 400 subjects enrolled in the KORA (Cooperative Health Research in the Augsburg Region) MRI study. The LA maximum and minimum sizes were segmented in gated CINE four-chamber sequences (LAmax and LAmin) and non-gated T1 VIBE-Dixon (NGLA). The area-based LA function was defined as LAaf = (LAmax − LAmin)/LAmax. Inter-and intra-reader reliability tests were performed (n = 31). Linear regression analyses were conducted to link LA size and function with cardiovascular risk factors. Results: Data from 378 subjects were included in the analysis (mean age: 56.3 years, 57.7 % male). The measurements were highly reproducible (all intraclass correlation coefficients ≥ 0.98). The average LAmax was 19.6 ± 4.5 cm2, LAmin 11.9 ± 3.5 cm2, NGLA 16.8 ± 4 cm2 and LAaf 40 ± 9%. In regression analysis, hypertension was significantly associated with larger gated LAmax (β = 1.30), LAmin (β = 1.07), and non-gated NGLA (β = 0.94, all p ≤ 0.037). Increasing age was inversely associated with LAaf (β = −1.93, p < 0.001). Conclusion: LA enlargement, as measured in gated and non-gated CMR is associated with hypertension, while the area-based LA function decreases with age.

Multi-parametric analyses to investigate dependencies of normal left atrial strain by cardiovascular magnetic resonance feature tracking

Left-atrial (LA) strain is the result of complex hemodynamics, which may be better characterized using a multiparametric approach. Cardiovascular magnetic resonance (CMR) feature tracking was used to perform a comprehensive LA strain assessment of 183 enrolled healthy volunteers (11–70 years, 97 females, median 32.9 ± 28.3 years). Novel strain dependencies were assessed using multi-parametric regression (MPR) analyses. LA volumetric data, left ventricular strain, transmitral and pulmonary venous blood flow parameters were utilized to create clusters for MPR of all subjects and a heart rate controlled subgroup (pulse: 60–75/min, N = 106). The LA reservoir(r) and conduit(c) strains of the total cohort were significantly elevated (p ≤ 0.001) in women (r: 49.7 ± 12.9%, c: 32.0 ± 11.0%) compared to men (r: 42.9 ± 11.4%, c: 26.1 IQ 10.5%). In contrast, there were no gender-specific differences (p > 0.05) for subgroup LA reservoir, conduit and booster(b) strains (all, r: 47.3 ± 12.7%; c: 29.0 IQ 15.5%; b: 17.6 ± 5.4%) and strain rates (all, 2.1 IQ 1.0 s⁻¹; − 2.9 IQ 1.5 s⁻¹; − 2.3 IQ 1.0 s⁻¹). MPR found large effect sizes (|R²|≥ 0.26) for correlations between strain and various cardiac functional parameters. Largest effect size was found for the association between LA conduit strain and LA indexed booster volume, LA total ejection fraction, left ventricular global radial strain and E-wave (|R²|= 0.437). In addition to providing normal values for sex-dependent LA strain and strain rate, no gender differences were found with modified heart rate. MPR analyses of LA strain/strain rate and various cardiac functional parameters revealed that heart rate control improved goodness-of-fit for the overall model.

Cardiovascular magnetic resonance assessment of left atrial size and function in endurance athletes

Background: Left atrial (LA) dilatation is linked to cardiovascular disease and atrial fibrillation but its associations in athletes are unknown. The authors investigated whether aerobic fitness and clinical parameters are associated with LA dilatation and emptying fraction (EF) in endurance athletes. Materials & methods: 65 endurance athletes underwent cardiovascular magnetic resonance to assess LA size and function along with fitness assessment. 25 sedentary controls underwent an identical cardiovascular magnetic resonance protocol. Results: In athletes, LA volume index was elevated, while total and passive LAEFs were decreased versus sedentary controls. Increasing age and maximal oxygen uptake were associated with LA volume index. Only older age was associated with decreased total LAEF. Conclusion: LA dilatation in athletes is associated with increasing age and aerobic fitness rather than conventional cardiovascular risk factors.

Assessment of age, gender, and anxiety on ECG waveform morphology in a large population of domestic dogs

Cardiovascular diseases are major causes of death in the western world and this incidence increases in the elderly population. With aging, there are physiologic changes to the cardiac structure secondary to adipose tissue deposition, calcification of valve leaflets and changes in the structure of the heart including atrial remodeling. Such changes can make the myocardium more susceptible to stress leading to a higher prevalence of cardiovascular diseases in the aging population. Studies in healthy humans have shown that these structural and molecular changes in the heart are manifested as changes on an electrocardiogram (ECG). Using animal models, similar ECG changes have been found in guinea pigs, rabbits, and mice. No veterinary study has specifically evaluated if comparable aging changes occur in canine species. In this cross-sectional retrospective study, 12,026 ECGs from apparently healthy dogs were obtained and evaluated. Age was observed to have both linear and non-linear associations with multiple ECG variables, including P wave amplitude and duration, R amplitude and QRS duration. This study confirmed that, like humans, there may be ECG changes secondary to normal physiological cardiac aging. Further studies are warranted to confirm and elaborate on these findings as canines may be a useful model for cardiac aging in humans.

Left Atrial Phasic Function in Older Adults Is Associated with Fibrotic and Low-Grade Inflammatory Pathways

INTRODUCTION

Concomitant risk factors challenge the mechanistic understanding of cardiac aging. We determined the degree to which the left atrial function could be distinguished by advanced cardiac magnetic resonance (CMR) imaging in older adults and assessed associations between the left atrial function and the plasma biomarkers related to biological aging and cardiovascular disease [serum monocyte chemoattractant protein-1 (MCP1), matrix metallopeptidase 9 (MMP-9), B-type natriuretic peptides (BNPs), galectin-3 (Gal-3), high-sensitivity cardiac troponin I (hsTn1), high-sensitivity C-reactive protein (hs-CRP), and soluble urokinase plasminogen activator receptor (sUPAR)].

METHODS

Among a cross-sectional population-based cohort of older adults, longitudinal LA strain including reservoir strain (εs), conduit strain (εe), and booster strain (εa) as well as peak strain rates (SRs, SRe, SRa) were determined using CMR and studied in association with blood biomarkers.

RESULTS

We studied 243 community adults (42.8% female, mean age 70.3 ± 9.5 years). In bivariate analysis, εe and SRe were reduced in gradation with increasing risk factors (all p values <0.0001). Corresponding levels of sUPAR (ng/mL) were quantitatively higher in older adults with <2 risk factors (2.5 ± 1.6 vs. 1.7 ± 1.3, p = 0.0005), in those with ≥2 risk factors (3.3 ± 2.4 vs. 1.7 ± 1.3, p < 0.0001), compared to young adults; including between older adults with ≥2 risk factors and older adults with <2 risk factors (3.3 ± 2.4 vs. 2.5 ± 1.6, p = 0.017). Based on multivariate analysis, sUPAR was significantly associated with both εe (OR 1.52, p = 0.006) and SRe decline (OR 1.5, p = 0.019). The associations between Gal-3 and εe reduction (OR 1.2, p = 0.022) and between BNP and SRe decline were generally weaker (OR 1.03, p = 0.027). The addition of sUPAR to a model consisting of age, risk factors, Gal-3, and BNPs increased the area under the curve of εe from 0.72 to 0.77 (p = 0.015).

CONCLUSION

By advanced CMR imaging, a panel of circulating biomarkers comprising galectin, MMP-9 and sUPAR were associated with left atrial dysfunction in older adults. Higher levels of Gal-3 and MMP-9 may be suggestive of fibrotic mechanisms in left atrial aging while impairments in left atrial strain seen in association with circulating sUPAR may be related to immune activation in the left atrium in response to left atrial remodeling and fibrotic processes.

The Role of Oxidative Stress in the Aging Heart

Medical advances and the availability of diagnostic tools have considerably increased life expectancy and, consequently, the elderly segment of the world population. As age is a major risk factor in cardiovascular disease (CVD), it is critical to understand the changes in cardiac structure and function during the aging process. The phenotypes and molecular mechanisms of cardiac aging include several factors. An increase in oxidative stress is a major player in cardiac aging. Reactive oxygen species (ROS) production is an important mechanism for maintaining physiological processes; its generation is regulated by a system of antioxidant enzymes. Oxidative stress occurs from an imbalance between ROS production and antioxidant defenses resulting in the accumulation of free radicals. In the heart, ROS activate signaling pathways involved in myocyte hypertrophy, interstitial fibrosis, contractile dysfunction, and inflammation thereby affecting cell structure and function, and contributing to cardiac damage and remodeling. In this manuscript, we review recent published research on cardiac aging. We summarize the aging heart biology, highlighting key molecular pathways and cellular processes that underlie the redox signaling changes during aging. Main ROS sources, antioxidant defenses, and the role of dysfunctional mitochondria in the aging heart are addressed. As metabolism changes contribute to cardiac aging, we also comment on the most prevalent metabolic alterations. This review will help us to understand the mechanisms involved in the heart aging process and will provide a background for attractive molecular targets to prevent age-driven pathology of the heart. A greater understanding of the processes involved in cardiac aging may facilitate our ability to mitigate the escalating burden of CVD in older individuals and promote healthy cardiac aging.

Changes in left atrial structure and function over a decade in the general population

AIMS

Assessing left atrial (LA) size and function is an important part of the echocardiographic examination. We sought to assess how LA size and function develop over time, and which clinical characteristics promote atrial remodelling.

METHODS AND RESULTS

We examined longitudinal changes of the LA between two visits in the Copenhagen City Heart Study (n = 1065). The median time between the examinations was 10.4 years. LA measurements included: maximal LA volume (LAVmax), minimal LA volume (LAVmin), and LA emptying fraction (LAEF). Clinical and echocardiographic accelerators were determined from linear regression. The value of LA remodelling for predicting incident atrial fibrillation (AF) and heart failure (HF) was examined by Cox proportional hazards regressions. During follow-up, LAVmax and LAVmin significantly increased by 8.3 and 3.5 mL/m2, respectively. LAEF did not change. Age and AF were the most impactful clinical accelerators of LA remodelling with standardized beta-coefficients of 0.17 and 0.28 for changes in LAVmax, and 0.18 and 0.38 for changes in LAVmin, respectively. Left ventricular (LV) systolic function, diameter, and mass were also significant accelerators of LA remodelling. Changes in both LAVmax and LAVmin were significantly associated with incident AF [n = 46, ΔLAVmax: HR = 1.06 (1.03-1.09), P < 0.001 and ΔLAVmin: HR = 1.14 (1.10-1.18), P < 0.001, per 1 mL/m2 increase] and HF [n = 27, ΔLAVmax: HR = 1.08 (1.04-1.12), P < 0.001 and ΔLAVmin: HR = 1.13 (1.09-1.18), P < 0.001, per 1 mL/m2 increase].

CONCLUSION

Both maximal and minimal LA volume increase over time. Clinical accelerators included age and AF. LV structure and systolic function also accelerate LA remodelling. LA remodelling poses an increased risk of clinical outcomes.

Melatonin to Rescue the Aged Heart: Antiarrhythmic and Antioxidant Benefits

Aging comes with gradual loss of functions that increase the vulnerability to disease, senescence, and death. The mechanisms underlying these processes are linked to a prolonged imbalance between damage and repair. Damaging mechanisms include oxidative stress, mitochondrial dysfunction, chronodisruption, inflammation, and telomere attrition, as well as genetic and epigenetic alterations. Several endogenous tissue repairing mechanisms also decrease. These alterations associated with aging affect the entire organism. The most devastating manifestations involve the cardiovascular system and may lead to lethal cardiac arrhythmias. Together with structural remodeling, electrophysiological and intercellular communication alterations during aging predispose to arrhythmic events. Despite the knowledge on repairing mechanisms in the cardiovascular system, effective antiaging strategies able to reduce the risk of arrhythmias are still missing. Melatonin is a promising therapeutic candidate due to its pleiotropic actions. This indoleamine regulates chronobiology and endocrine physiology. Of relevance, melatonin is an antiaging, antioxidant, antiapoptotic, antiarrhythmic, immunomodulatory, and antiproliferative molecule. This review focuses on the protective effects of melatonin on age-induced cardiac functional and structural alterations, potentially becoming a new fountain of youth for the heart.

Changes in left atrial phasic strain and mechanical dispersion: Effects of age and gender

PURPOSE

Left atrial (LA) function by two-dimensional (2D) strain is an emerging tool with increasing clinical utility. Age and gender are key modulators of strain parameters; however, the specific time course for LA structural and functional changes is not clearly defined.

METHODS

A total of 147 healthy individuals (20-69 years) underwent transthoracic echocardiography; subjects were evaluated by age (decade) and gender. LA and left ventricular (LV) volumetric and strain measurements were performed.

RESULTS

Left atrial reservoir (ƐR) and conduit strain (ƐCD) with negatively correlated with age (r =-.36; r = -.56; P < .001, respectively) being significantly lower by the 6th and 5th decades, respectively. Contractile strain (ƐCT) positively correlated with age (r = .36; P < .001), being significantly higher by the 6th decade. ƐR and ƐCD were higher in young females (20-34 years) compared to young males (P = .033 and P < .001, respectively). ƐCT was significantly higher in middle-aged adult males (35-50yrs; P = .010), though seen later in females (≥51 years; P = .005). Standard deviation of time to positive strain (SD-TPS) significantly higher by the 5th decade and correlated with age in both males (r = .44; P <.001) and females (r = .40; P = .001).

CONCLUSION

We demonstrate that ƐR and ƐCD are lower with age, with differing rates between males and females. As a compensatory mechanism for decline in ƐCD, ƐCT is higher, more notably in males; comparatively, females display a more prominent decline in ƐR and ƐCD with age. Alteration in electromechanical properties occurred in both genders with SD-TPS becoming higher with age.

Impaired Left Atrial Performance Resulting From Age-Related Arial Fibrillation Is Associated With Increased Fibrosis Burden: Insights From a Clinical Study Combining With an in vivo Experiment

Background: Atrial fibrillation (AF) is increasingly considered an age-related degenerative disease, whose process is associated with the development of impaired left atrial (LA) performance. However, the subtle dynamic changes of LA performance in AF during aging have yet to be fully elucidated. Atrial fibrosis is a key substrate for the development of AF, but the progression of fibrosis during aging and its relationship with LA dysfunction need to be further explored. Methods: A total of 132 control individuals and 117 persistent AF patients were prospectively studied. Subjects were further stratified into three age groups (age group 1: younger than 65 years, age group 2: between 65 and 79 years old, and age group 3: older than 80 years). The two-dimensional speckle tracking imaging was carried out for analyzing the alterations in LA function underlying LA remodeling, whereas electroanatomic mapping was performed to investigate LA fibrosis burden. In animal study, aged mice and young mice served as research subjects. Echocardiography and histological staining were used to assess LA performance and fibrosis burden, respectively. Results: Echocardiography showed progressive increases in LA dimension and LA stiffness index, and progressive decreases in LA global longitudinal strain and LA strain rates with advancing age in both AF and control cohorts, which was more prominent in AF cohort. Electroanatomic mapping showed progressive decrease in mean LA voltage and progressive increases in LA surface area, low-voltage area %, and LA volume with advancing age, whereas more significant alterations were observed in AF patients. Moreover, left atrial global longitudinal strain was positively correlated with mean LA voltage, whereas LA stiffness index was negatively related to mean LA voltage. In animal experiment, increased LA size and pulmonary artery dimension as well as longer P-wave duration and more prominent LA fibrosis were found in aged mice. Conclusions: This study provides new evidence of subtle changes in structure and performance of left atrium and their association with atrial fibrosis in both AF and non-AF subjects during physiological aging. In addition, our study also provides normal values for LA structure and performance in both AF and non-AF conditions during aging. These measurements may provide an early marker for onset of AF and LA adverse remodeling.

Longitudinal evaluation of cardiovascular function in six healthy cats aged 1-8 years

OBJECTIVES

The purpose of this study was to determine the impact of ageing on the cardiovascular system of healthy adult cats.

METHODS

Six experimental cats were used. Echocardiography and measurements of systolic blood pressure (SBP) were performed every year for 8 years (from 1 year of age to 8 years of age) in all cats. Age-related changes to left ventricular (LV) structures, LV systolic and diastolic function, and SBP were assessed.

RESULTS

There were no significant changes in LV structures and SBP. Peak longitudinal strain rate during systole was decreased at 8 years of age, and peak longitudinal strain rate during diastole was decreased from 6 years of age.

CONCLUSIONS AND RELEVANCE

This study revealed that some measures of cardiac function recorded in six healthy cats from 1 to 8 years of age were affected as the cats got older; however, there were no structural changes or changes in measurements that are routinely assessed in clinical practice.

Usefulness of left atrial strain for predicting incident atrial fibrillation and ischaemic stroke in the general population

AIMS

Left atrial enlargement predicts incident atrial fibrillation (AF). However, the prognostic value of peak atrial longitudinal strain (PALS) for predicting incident AF in participants from the general population is currently unknown. Our aim was to investigate if PALS can be used to predict AF and ischaemic stroke in the general population.

METHODS AND RESULTS

A total of 400 participants from the general population underwent a health examination, including two-dimensional speckle tracking echocardiography of the left atrium. The primary endpoint was incident AF at follow-up. All participants with known AF and prior stroke at baseline were excluded (n = 54). The secondary endpoint consisted of the composite of AF and ischaemic stroke. During a median follow-up of 16 years, 36 participants (9%) were diagnosed with incident AF and 30 (7%) experienced an ischaemic stroke, resulting in 66 (16%) experiencing the composite outcome. PALS was a univariable predictor of AF [per 5% decrease: hazard ratio (HR) 1.42; 95% confidence interval (CI) (1.19-1.69), P < 0.001]. However, the prognostic value of PALS was modified by age (P = 0.002 for interaction). After multivariable adjustment PALS predicted AF in participants aged <65 years [per 5% decrease: HR 1.46; 95% CI (1.06-2.02), P = 0.021]. In contrast, PALS did not predict AF in participants aged ≥65 years after multivariable adjustment [per 5% decrease: HR 1.05; 95% CI (0.81-1.35), P = 0.72]. PALS also predicted the secondary endpoint in participants aged <65 years and the association remained significant after multivariable adjustment.

CONCLUSION

In a low-risk general population, PALS provides novel prognostic information on the long-term risk of AF and ischaemic stroke in participants aged <65 years.

Tissue Doppler Imaging and strain rate of the left atrial lateral wall: age related variations and comparison with parameters of diastolic function

Background

Strain Rate Imaging (SRI) is one of the most used techniques to study left atrial (LA) and diastolic function. Its availability in low-income countries is diminished since it requires additional expensive software, among other limitations. In contrast, Tissue Doppler Imaging (TDI) is widely available and easy to use. We hypothesize TDI could detect changes in LA and diastolic function associated with age similarly to SRI. The aim of this study is to evaluate the effects of age on LA and diastolic function assessed by LA lateral wall TDI online by spectral pulse, and to compare them with age-related variations of LA SRI and other parameters of diastolic function in a population of healthy adults.

Materials and methods

Ninety-one healthy adults were prospectively evaluated. In apical four - chamber view the LA lateral wall was divided in three portions. Peak velocities of basal and mid portions were measured with TDI online by spectral pulse and with SRI by speckle tracking. A first positive wave (S’la and SRS) and two negative waves (E’la and SRE, and A’la and SRA respectively) were obtained. E’la/A’la ratio and SRE/SRA ratio were analyzed. The distribution of the variables by age subgroups was described and analyzed. Correlation analyses were performed.

Results

The median age was 42 years old and 54.9% were female. E’la/A’la showed a negative good correlation with age. E’la/A’la and SRE/SRA ratios changed from > 1 to < 1 in the age group of 41–50 years old, while this occurred in the group of 51–60 years old for the E/A ratio. Lateral and septal mitral annulus E´ showed decrease with age and prolongation of E-wave deceleration time was observed in the age group over 61 years old.

Conclusion

Normal values​​ according to age group of TDI of the LA lateral wall were obtained. Age-related changes in LA and diastolic function could be detected as early with TDI as with SRI. Future studies are required to explore if this method could be used to address in part LA or diastolic function in other populations with established cardiovascular disease or at risk of presenting it, which could be useful in low-income settings, where SRI is not available.

Comparative assessment of left atrial volume in healthy cats by two-dimensional and three-dimensional echocardiography

Background

The left atrium (LA) is an important prognostic parameter in cardiac pathologies of cats. Its size is currently measured in one-dimensional methods, while human medicine considers two- and three-dimensional echocardiography as standard. The objectives of this study were to compare monoplane, biplane, triplane and real-time three dimensional echocardiography for volumetric measurement of the left atrium in healthy cats and establish a reference interval for further studies on cats with heart disease. Additionally, the influence of age, sex and weight on left atrial volume (LAV) was tested.

Results

One dimensional monoplane Simpson method of discs (SMOD) in the right parasternal four chamber view (r4) and the left apical 2 chamber view (l2) as well as biplane SMOD had no significant difference for left atrial maximum volume (LAMax). They can be used as equivalent in future studies and one common reference range was set up (1.96 ± 0.54 ml). Those three methods produced significantly higher volumes than triplane echocardiography (RTTPE) and real time three dimensional echocardiography (RT3DE) using TomTec® software. LA volumetry with RTTPE and RT3DE-TomTec™ was more feasible than expected, but low RT3DE image quality was the main reason for excluding patients. Neither age nor weight had an influence on LA volume in healthy cats. Male LAV results were only slightly, but in 2D and RTTPE significantly higher than those of female cats with a range of + 10.46% to + 19.58%.

Conclusions

Monoplane, biplane, triplane and real-time three dimensional echocardiography were feasible for LA volumetry in healthy cats and showed acceptable intra- and interobserver variability. One common LAMax reference range for monoplane r4, l2 and biplane SMOD was set up. Raw data can be used for LA volumes and does not need to be correlated with the cat’s weight or age. Male cats have only slightly but significantly larger atria than females in 2D and RTTPE. Therefore, under reservation, also sex related limit values were defined.

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.

Incidence and Predictors of Atrial Fibrillation Progression

Background The incidence and predictors of atrial fibrillation (AF) progression are currently not well defined, and clinical AF progression partly overlaps with rhythm control interventions (RCIs). Methods and Results We assessed AF type and intercurrent RCIs during yearly follow-ups in 2869 prospectively followed patients with paroxysmal or persistent AF. Clinical AF progression was defined as progression from paroxysmal to nonparoxysmal or from persistent to permanent AF. An RCI was defined as pulmonary vein isolation, electrical cardioversion, or new treatment with amiodarone. During a median follow-up of 3 years, the incidence of clinical AF progression was 5.2 per 100 patient-years, and 10.9 per 100 patient-years for any RCI. Significant predictors for AF progression were body mass index (hazard ratio [HR], 1.03; 95% CI, 1.01-1.05), heart rate (HR per 5 beats/min increase, 1.05; 95% CI, 1.02-1.08), age (HR per 5-year increase 1.19; 95% CI, 1.13-1.27), systolic blood pressure (HR per 5 mm Hg increase, 1.03; 95% CI, 1.00-1.05), history of hyperthyroidism (HR, 1.71; 95% CI, 1.16-2.52), stroke (HR, 1.50; 95% CI, 1.19-1.88), and heart failure (HR, 1.69; 95% CI, 1.34-2.13). Regular physical activity (HR, 0.80; 95% CI, 0.66-0.98) and previous pulmonary vein isolation (HR, 0.69; 95% CI, 0.53-0.90) showed an inverse association. Significant predictive factors for RCIs were physical activity (HR, 1.42; 95% CI, 1.20-1.68), AF-related symptoms (HR, 1.84; 95% CI, 1.47-2.30), age (HR per 5-year increase, 0.88; 95% CI, 0.85-0.92), and paroxysmal AF (HR, 0.61; 95% CI, 0.51-0.73). Conclusions Cardiovascular risk factors and comorbidities were key predictors of clinical AF progression. A healthy lifestyle may therefore reduce the risk of AF progression.

Importance of the Left Atrium: More Than a Bystander?

Left atrial size and function parameters are associated with adverse outcomes in multiple disease states, including heart failure with reduced and preserved ejection fraction. Recent data suggest that phasic left atrial function and left atrial stain measurements also hold prognostic information. Three-dimensional echocardiography provides more accurate and reproducible quantification of left atrial volumes than 2-dimensional echocardiography when compared with cardiac magnetic resonance reference standards. Greater accessibility to these advanced imaging techniques allows for the integration of these parameters into routine clinical practice.

In-depth echocardiographic analysis of left atrial function in healthy adults using speckle tracking echocardiography and volumetric analysis

Purpose

Left atrial (LA) dilatation is predictive for complications in a multitude of cardiac diseases; therefore, adequate assessment is essential. Technological advances have made it possible to quantify LA function with Speckle Tracking Echocardiography (STE); however, there are currently no recommendations for normal values with regard to LA function. We aimed to assess LA myocardial and volumetric function in a healthy cohort and investigate correlations with baseline characteristics.

Methods

This prospective cohort study included 147 (aged 20–72) healthy individuals and assessed LA volumetric function using maximum, minimum and pre‐a‐wave volumes and myocardial function using reservoir function using peak strain in LA relaxation (LA‐strain), conduit function using peak strain rate in early LA contraction (LA‐SRe) and pump function using peak strain rate in late LA contraction (LA‐SRa).

Results

Mean LA‐strain was 39.7 ± 6.2%, LA‐SRe −2.78 ± 0.62 s⁻¹ and LA‐SRa −2.56 ± 0.62 s⁻¹. Subjects were divided into 5 age decades (each 50% female). LA‐strain and LA‐SRe were lower in the oldest groups, whereas LA‐SRa was higher. LA‐SRa was higher in males(−2.69 ± 0.68 s⁻¹ vs −2.42 ± 0.52 s⁻¹). Age‐specific values are provided. Age proved to be an independent predictor for LA‐SRa after correction for blood pressure and heart rate. LA expansion index and passive emptying fraction decreased with age, while active emptying fraction increased with age. LA maximum volume did not increase with age.

Conclusion

This study provides normal values for the three phasic functions of the LA, assessed with STE and volumetric function. Our results suggest the need for age‐specific reference ranges, and normal values for this cohort have been calculated.

The aging heart

As the elderly segment of the world population increases, it is critical to understand the changes in cardiac structure and function during the normal aging process. In this review, we outline the key molecular pathways and cellular processes that underlie the phenotypic changes in the heart and vasculature that accompany aging. Reduced autophagy, increased mitochondrial oxidative stress, telomere attrition, altered signaling in insulin-like growth factor, growth differentiation factor 11, and 5'- AMP-activated protein kinase pathways are among the key molecular mechanisms underlying cardiac aging. Aging promotes structural and functional changes in the atria, ventricles, valves, myocardium, pericardium, the cardiac conduction system, and the vasculature. We highlight the factors known to accelerate and attenuate the intrinsic aging of the heart and vessels in addition to potential preventive and therapeutic avenues. A greater understanding of the processes involved in cardiac aging may facilitate our ability to mitigate the escalating burden of CVD in older individuals and promote healthy cardiac aging.

Determinants of Normal Left Atrial Volume in Heart Failure with Moderate-to-Severely Reduced Ejection Fraction

Background

Indexed left atrial volume (LAVi) is a robust predictor of adverse cardiovascular events. A minority of patients with moderate-to-severe left ventricular (LV) systolic dysfunction maintain normal LAVi. We followed clinical and echocardiographic parameters for at least 6 months to understand how this population is different from patients with similar systolic dysfunction and dilated left atria.

Methods and Results

We searched our electronic medical records for "normal" (n=817) and "severely dilated" (n=1094) LA size and LV ejection fraction (EF) ≤ 35% on echocardiogram reports from 2009 to 2015. We analyzed 115 subjects for LAVi, biplane EF, and diastolic parameters over 2 echocardiograms at least 6 months apart. Younger age, white race, being on an angiotensin-converting enzyme inhibitor, smaller end-diastolic LV volume (LVEDV), and longer deceleration time (DT) were associated with having a normal LAVi. The receiver-operating characteristic curve has an area under the curve of 0.95 (p < 0.0001) for this model. An increase in LVESVi and early mitral flow velocity and a decrease in DT explain 32% of the variance seen in LAVi increase over time.

Conclusion

In patients with moderate-to-severely reduced EF, younger age, being on heart failure therapies, and better diastolic dysfunction were independently associated with a normal LAVi. Improvement in systolic and diastolic performances was associated with decreasing LAVi with 6-month to 1-year follow-up.

Advanced Age Attenuates Left Ventricular Filling Efficiency Quantified Using Vortex Formation Time: A Study of Octogenarians With Normal Left Ventricular Systolic Function Undergoing Coronary Artery Surgery

OBJECTIVE

Blood flow across the mitral valve during early left ventricular (LV) filling produces a 3-dimensional rotational fluid body, known as a vortex ring, that enhances LV filling efficiency. Diastolic dysfunction is common in elderly patients, but the influence of advanced age on vortex formation is unknown. The authors tested the hypothesis that advanced age is associated with a reduction in LV filling efficiency quantified using vortex formation time (VFT) in octogenarians undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

Observational study.

SETTING

Veterans Affairs medical center.

PARTICIPANTS

After institutional review board approval, octogenarians (n = 7; 82 ± 2 year [mean ± standard deviation]; ejection fraction 56% ± 7%) without valve disease or atrial arrhythmias undergoing CABG were compared with a younger cohort (n = 7; 55 ± 6 year; ejection fraction 57% ± 7%) who were undergoing coronary revascularization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

All patients were monitored using radial and pulmonary arterial catheters and transesophageal echocardiography. Peak early LV filling (E) and atrial systole (A) blood flow velocities and their corresponding velocity-time integrals were obtained using pulse-wave Doppler echocardiography to determine E/A, atrial filling fraction (β), and E wave deceleration time. Pulse-wave Doppler also was used to measure pulmonary venous blood flow during systole and diastole. Mitral valve diameter (D) was calculated as the average of major and minor axis lengths obtained in the midesophageal LV bicommissural and long-axis transesophageal echocardiography imaging planes, respectively. VFT was calculated as 4 × (1 - β) × SV/(πD³), where SV is the stroke volume measured using thermodilution. Systemic and pulmonary hemodynamics, LV diastolic function, and VFT were determined during steady-state conditions 30 minutes before cardiopulmonary bypass. A delayed relaxation pattern of LV filling (E/A 0.81 ± 0.16 v 1.29 ± 0.19, p = 0.00015; β 0.44 ± 0.05 v 0.35 ± 0.03, p = 0.0008; E wave deceleration time 294 ± 58 v 166 ± 28 ms, p < 0.0001; ratio of peak pulmonary venous systolic and diastolic blood flow velocity 1.42 ± 0.23 v 1.14 ± 0.20, p = 0.0255) was observed in octogenarians compared with younger patients. Mitral valve diameter was similar between groups (2.7 ± 0.2 and 2.6 ± 0.2 cm, respectively, in octogenarians v younger patients, p = 0.299). VFT was reduced in octogenarians compared with younger patients (3.0 ± 0.9 v 4.5 ± 1.2; p = 0.0171). An inverse correlation between age and VFT was shown using linear regression analysis (VFT = -0.0627 × age + 8.24; r² = 0.408; p = 0.0139).

CONCLUSION

The results indicate that LV filling efficiency quantified using VFT is reduced in octogenarians compared with younger patients undergoing coronary artery bypass grafting.

Differences in Cardiovascular Aging in Men and Women

Cardiovascular diseases increase dramatically with age in both men and women. While it is clear that advanced age allows more time for individuals to be exposed to risk factors in general, there is strong evidence that age itself is a major independent risk factor for cardiovascular disease. Indeed, there are distinct age-dependent cellular, structural, and functional changes in both the heart and blood vessels, even in individuals with no clinical evidence of cardiovascular disease. Studies in older humans and in animal models of aging indicate that this age-related remodeling is maladaptive. An emerging view is that the heart and blood vessels accumulate cellular and subcellular deficits with age and these deficits increase susceptibility to disease in older individuals. Aspects of this age-dependent remodeling of the heart and blood vessels differ between the sexes. There is also new evidence that these maladaptive changes are more prominent in older animals and humans with a high degree of frailty. These observations may help explain why men and women are susceptible to different cardiovascular diseases as they age and why frail older adults are most often affected by these diseases.

Shortness of breath in clinical practice: A case for left atrial function and exercise stress testing for a comprehensive diastolic heart failure workup

The symptom cluster of shortness of breath (SOB) contributes significantly to the outpatient workload of cardiology services. The workup of these patients includes blood chemistry and biomarkers, imaging and functional testing of the heart and lungs. A diagnosis of diastolic heart failure is inferred through the exclusion of systolic abnormalities, a normal pulmonary function test and normal hemoglobin, coupled with diastolic abnormalities on echocardiography. Differentiating confounders such as obesity or deconditioning in a patient with diastolic abnormalities is difficult. While the most recent guidelines provide more avenues for diagnosis, such as incorporating the left atrial size, little emphasis is given to understanding left atrial function, which contributes to at least 25% of diastolic left ventricular filling; additionally, exercise stress testing to elicit symptoms and test the dynamics of diastolic parameters, especially when access to the "gold standard" invasive tests is lacking, presents clinical translational gaps. It is thus important in diastolic heart failure work up to understand left atrial mechanics and the role of exercise testing to build a comprehensive argument for the diagnosis of diastolic heart failure in a patient presenting with SOB.

Increased Ca buffering underpins remodelling of Ca2+ handling in old sheep atrial myocytes

KEY POINTS

Ageing is associated with an increased risk of cardiovascular disease and arrhythmias, with the most common arrhythmia being found in the atria of the heart. Little is known about how the normal atria of the heart remodel with age and thus why dysfunction might occur. We report alterations to the atrial systolic Ca2+ transient that have implications for the function of the atrial in the elderly. We describe a novel mechanism by which increased Ca buffering can account for changes to systolic Ca2+ in the old atria. The present study helps us to understand how the processes regulating atrial contraction are remodelled during ageing and provides a basis for future work aiming to understand why dysfunction develops.

ABSTRACT

Many cardiovascular diseases, including those affecting the atria, are associated with advancing age. Arrhythmias, including those in the atria, can arise as a result of electrical remodelling or alterations in Ca2+ homeostasis. In the atria, age-associated changes in the action potential have been documented. However, little is known about remodelling of intracellular Ca2+ homeostasis in the healthy aged atria. Using single atrial myocytes from young and old Welsh Mountain sheep, we show the free Ca2+ transient amplitude and rate of decay of systolic Ca2+ decrease with age, whereas sarcoplasmic reticulum (SR) Ca content increases. An increase in intracellular Ca buffering explains both the decrease in Ca2+ transient amplitude and decay kinetics in the absence of any change in sarcoendoplasmic reticulum calcium transport ATPase function. Ageing maintained the integrated Ca2+ influx via ICa-L but decreased peak ICa-L . Decreased peak ICa-L was found to be responsible for the age-associated increase in SR Ca content but not the decrease in Ca2+ transient amplitude. Instead, decreased peak ICa-L offsets increased SR load such that Ca2+ release from the SR was maintained during ageing. The results of the present study highlight a novel mechanism by which increased Ca buffering decreases systolic Ca2+ in old atria. Furthermore, for the first time, we have shown that SR Ca content is increased in old atrial myocytes.

Assessment of left atrium and diastolic dysfunction in patients with hypertensive retinopathy: A real-time three-dimensional echocardiography-based study

The fundoscopic examination of hypertensive patients, which is established hypertension-related target organ damage (TOD), tends to be underutilized in clinical practice. We sought to investigate the relationship between retinal alterations and left atrium (LA) volumes by means of real-time three-dimensional echocardiography (RT3DE). Our population consisted of 88 consecutive essential hypertensive patients (age 59.2 ± 1.2 years, 35 males). All subjects underwent a fundoscopy examination and were distributed into four groups according to the Keith-Wagener-Barker (KWB) classification. The four groups (KWB grades 0-3: including 26, 20, 26, and 16 patients, respectively) did not differ with regard to age, gender, or metabolic profile. There were no significant differences between groups with regard to parameters reflecting LV systolic function and diastolic dysfunction (DD) in two-dimensional echocardiography (2DE). Nevertheless, patients in the higher KWB category had higher values of LA volumes (LA maximal volume index, LA minimal volume index, preatrial contraction volume index, LA total stroke volume index, LA active stroke volume index, p < 0.001) regarding RT3DE. There is also a significant relationship between LA active stroke volume index (ASVI) and duration of hypertension (HT) (r: 0.68, p < 0.001). In the logistic regression analysis, ASVI was independent predictors of LV DD in patients with arterial hypertension (HT). Patients with arterial HT were found to have increased LA volumes and impaired diastolic functions. Assessment of the arterial HT patient by using RT3DE atrial volume analysis may facilitate early recognition of TOD, which is such a crucial determinant of cardiovascular mortality and morbidity.

Effect of Aging on Left Atrial Compliance and Electromechanical Properties in Subjects Without Structural Heart Disease

Aging is associated with changes in left atrial (LA) structure and function. The present study aimed at describing the effect of aging on LA properties in a large cohort of subjects without structural heart disease. We divided 386 subjects (mean age 58 years [range 16 to 91]; 188 men [49%]) clinically referred for echocardiography according to age groups. The P-wave dispersion (PWD), reflecting total atrial conduction time, was measured on a 12-lead surface electrocardiogram as the difference between maximum and minimum P-wave duration. The PA-TDI duration reflecting the total atrial conduction time was measured on tissue Doppler imaging (TDI) as the time between onset of P wave on surface electrocardiogram to peak A'-wave velocity. Two-dimensional speckle-tracking echocardiography was used to assess LA reservoir function, reflecting LA compliance. In the overall population, mean PWD, PA-TDI, and LA reservoir strain were 43 ± 12 ms, 129 ± 27 ms, and 36 ± 13%, respectively. Increasing age was independently associated with prolonged PWD (β = 0.161; p <0.001), PA-TDI (β = 0.476; p <0.001), and reduced LA reservoir strain (β = -0.259; <0.001), suggesting age-related fibrotic changes of the LA myocardium. The association between age and LA reservoir strain was modulated by body mass index (β = -0.582; p <0.001) and LA volume index (β = -0.117; p = 0.014). In conclusion, aging is associated with longer PWD and PA-TDI duration along with a decrease in LA reservoir function. Obesity and larger LA volumes are independently associated with reduced LA compliance.

Effect of ablation pattern on mechanical function in the atrium

BACKGROUND

Atrial fibrillation (AF) is often treated with catheter ablation, which induces scar formation to isolate misfiring electrical signals in the left atrium. Successful ablation restores sinus rhythm at the cost of replacing viable myocardium with scar. The impact of ablation scar on mechanical function of the left atrium is poorly understood.

OBJECTIVE

We used a computational model to simulate various ablation patterns and determine their effect on atrial global and regional mechanical function.

METHODS

A coupled finite-element and hemodynamic circuit model of the left atrium that represents the regional and global mechanics in paroxysmal AF patients was modified to simulate different ablation patterns: step-wise pulmonary vein isolation (PVI), wide area circumferential ablation (WACA), and a posterior ablation developed by nContact, Inc (Morrisville, NC, USA). Atrial pressure-volume relationships and regional wall motion were compared among the models.

RESULTS

Ablation increased passive stiffness and decreased active work performed by the atrium. Active emptying volume decreased with increasing scar by up to 44% (11 mL) at a scar volume of 31%. At matched scar volumes, WACA decreased active emptying more severely than PVI and nContact. Similarly, wall motion was depressed most in the WACA model because WACA involved portions of the lateral wall with higher baseline motion.

CONCLUSION

Simulated ablation depressed atrial mechanical function to an extent that depended on both scar volume and location, primarily through reducing active emptying. Placing ablation scar in regions with high baseline motion resulted in greater depression of active function, while ablation of the posterior wall was less disruptive.

Left Atrial Structure in Relationship to Age, Sex, Ethnicity, and Cardiovascular Risk Factors: MESA (Multi-Ethnic Study of Atherosclerosis)

BACKGROUND

Left atrial (LA) size is a marker of diastolic function and is associated with atrial fibrillation and cardiovascular outcomes. However, there are no large population studies measuring LA structure. The relationship of demographics and cardiovascular risk factors to LA size is largely unknown. This study aimed to determine associations of LA size with demographic factors, cardiac structure and function, and cardiovascular risk factors.

METHODS AND RESULTS

LA volume indexed to body surface area was measured by cardiovascular magnetic resonance steady-state free precession and fast gradient echo cine long- and short-axis images in 2576 asymptomatic participants of MESA ([Multi-Ethnic Study of Atherosclerosis] 68.7 years, 53.0% women, white 42.2%, Chinese American 12.0%, black 24.5%, and Hispanic 21.2%) using biplane and short-axis images. The mean LA volume index was 36.5±11.4 mL/m2 in the entire cohort and 35.5±10.1 mL/m2 in subjects free of cardiovascular risk factors (n=283). Multivariable analysis included adjustment for demographics, ethnicity, cardiovascular risk factors, serological studies, socioeconomic status, left ventricular structure, and medications. In the adjusted analysis, age (β=0.2 mL/m2 per year, P<0.0001), male sex (β=-4.2 mL/m2, P<0.0001), obesity (β=1.3 mL/m2, P<0.01), end-diastolic volume index (β=0.4 mL/m2, P<0.0001), Chinese American (β=-2.6 mL/m2, P<0.0001), and Hispanic (β=1.1 mL/m2, P<0.05) ethnicities were associated with LA volume index. Diabetes mellitus and smoking were not associated with LA volume index. LA volumes measured by steady-state free precession were 3% larger than by fast gradient echo cine cardiovascular magnetic resonance (P<0.001).

CONCLUSIONS

Age, sex, ethnicity and left ventricular structural parameters were associated with LA size. Importantly, the study provides reference values of normal LA volume index.

Association Between Left Atrial Dilatation and Invasive Hemodynamics at Rest and During Exercise in Asymptomatic Aortic Stenosis

Background—

Transition from an asymptomatic to symptomatic state in severe aortic stenosis is often difficult to assess. Identification of a morphological sign of increased hemodynamic load may be important in asymptomatic aortic stenosis to identify patients at risk.

Methods and Results—

Thirty-nine patients with asymptomatic severe aortic stenosis (aortic valve area <1 cm 2 , peak jet velocity >3.5 m/s) underwent exercise testing with simultaneous invasive hemodynamic monitoring and Doppler echocardiography. Cardiac index, pulmonary artery pressure, and pulmonary capillary wedge pressure (PCWP) were recorded. Patients were followed up for the composite end point of death, unplanned hospitalization, or aortic valve replacement. Patients were stratified into 2 groups according to left atrial (LA) volume index ≥35 mL/m 2 . In 25 patients (64%) LA volume index was ≥35 mL/m 2 . Aortic valve area was similar between groups (0.81±0.15 versus 0.84±0.18 cm 2 ; P =0.58). PCWP was higher at rest and during exercise in patients with LA volume index ≥35 mL/m 2 ( P <0.01), despite similar cardiac index. At rest, PCWP was <12 mm Hg in 11 patients (44%) with LA dilatation, whereas PCWP was <25 mm Hg in 1 patient (4%) with exercise. LA volume index and E/e′ predicted exercise PCWP>30 mm Hg with areas under the receiver operating curve of 0.75 and 0.84, respectively. During follow-up, 14 cardiac events were recorded. LA volume was associated with a hazard ratio of 1.90 (95% confidence interval, 0.92–4.15).

Conclusions—

LA size reflects hemodynamic burden in patients with asymptomatic severe aortic stenosis. Quantitative measurements of LA and diastolic function are associated with left ventricular filling pressures with exercise and could be used to identify asymptomatic patients with increased hemodynamic burden.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT02395107.

Impact of gender and healthy aging on pulmonary capillary wedge pressure estimated by the kinetics-tracking index using two-dimensional speckle tracking echocardiography

Risk stratification in heart failure (HF) among patients and healthy subjects using pulmonary capillary wedge pressure (PCWP) is important for understanding when and why HF develops. The aim of the present study was to evaluate the impact of gender and healthy aging on estimated PCWP using a kinetics-tracking index in patients and in healthy subjects without hypertension. The study population consisted of 198 healthy subjects without cardiovascular or other systemic diseases and who were not taking any medications. Echocardiographic studies were performed using an ACUSON Sequoia 512 ultrasound system. Active left atrial (LA) emptying function (EF) was defined as (pre-atrial contraction LA volume-minimum LA volume)/pre-atrial contraction LA volume × 100%. With an increase in age, the E/A and E/e' ratios (markers of left ventricular (LV) diastolic dysfunction (DD)) showed a similar decrease in males and females. PCWP was maintained at 8.3±1.8 mm Hg in males and 8.2±2.3 mm Hg in females because of compensation by an increase in active LA EF. In contrast, the compensation for LV DD with an increase in active LA EF in females tended to be more gradual (slope=0.11) than in males (slope=0.18, P=0.060 vs. female). The parameters that indicated LV DD deteriorated with advancing age. PCWP might be maintained because of compensation, namely an increase in active LA EF in both males and females. The compensation in female septuagenarians and octogenarians was weaker than in male septuagenarians and octogenarians. This difference in compensation may explain why HF with preserved LV ejection fraction occurs more frequently in females than in males.

Left atrial aging: a cardiac magnetic resonance feature-tracking study

Importance of left atrial (LA) phasic function evaluation is increasingly recognized for its incremental value in terms of prognosis and risk stratification. LA phasic deformation in the pathway of normal aging has been characterized using echocardiographic speckle tracking. However, no data are available regarding age-related variations using feature-racking (FT) techniques from standard cine magnetic resonance imaging (MRI). We studied 94 healthy adults (41 ± 14 yr, 47 women), who underwent MRI and Doppler echocardiography on the same day for left ventricular (LV) diastolic function evaluation. From cine MRI, longitudinal strain and strain rate, radial motion fraction, and radial relative velocity, respectively, corresponding to the reservoir, conduit, and LA contraction phases, were measured using dedicated FT software. Longitudinal strain and radial motion fraction decreased gradually and significantly with aging for both reservoir (r > 0.31, P < 0.003) and conduit (r > 0.54, P < 0.001) phases, whereas they remained unchanged during the LA contraction phase. Subsequently, the LA contraction-to-reservoir ratio increased significantly with age (r > 0.44, P < 0.001). Longitudinal strain rate and radial relative velocity significantly decreased with age (reservoir: r = 0.39, P < 0.001, conduit: r > 0.54, P < 0.001), and these associations tended to be stronger in women than in men. Finally, associations of LA functional indexes with age were stronger in individuals with lower transmitral early-to-atrial maximal velocity ratio and mitral annulus maximal longitudinal velocity, as well as higher transmitral early maximal-to-mitral annulus maximal longitudinal velocity ratio, highlighting the LV-LA interplay. Age-related changes in LA phasic function indexes were quantified by cine MRI images using a FT technique and were significantly related to age and LV diastolic function.

Making better scar: Emerging approaches for modifying mechanical and electrical properties following infarction and ablation

Following myocardial infarction (MI), damaged myocytes are replaced by collagenous scar tissue, which serves an important mechanical function - maintaining integrity of the heart wall against enormous mechanical forces - but also disrupts electrical function as structural and electrical remodeling in the infarct and borderzone predispose to re-entry and ventricular tachycardia. Novel emerging regenerative approaches aim to replace this scar tissue with viable myocytes. Yet an alternative strategy of therapeutically modifying selected scar properties may also prove important, and in some cases may offer similar benefits with lower risk or regulatory complexity. Here, we review potential goals for such modifications as well as recent proof-of-concept studies employing specific modifications, including gene therapy to locally increase conduction velocity or prolong the refractory period in and around the infarct scar, and modification of scar anisotropy to improve regional mechanics and pump function. Another advantage of scar modification techniques is that they have applications well beyond MI. In particular, ablation treats electrical abnormalities of the heart by intentionally generating scar to block aberrant conduction pathways. Yet in diseases such as atrial fibrillation (AF) where ablation can be extensive, treating the electrical disorder can significantly impair mechanical function. Creating smaller, denser scars that more effectively block conduction, and choosing the location of those lesions by balancing their electrical and mechanical impacts, could significantly improve outcomes for AF patients. We review some recent advances in this area, including the use of computational models to predict the mechanical effects of specific lesion sets and gene therapy for functional ablation. Overall, emerging techniques for modifying scar properties represents a potentially important set of tools for improving patient outcomes across a range of heart diseases, whether used in place of or as an adjunct to regenerative approaches.