Left Atrial Size and Function in a Canine Model of Chronic Atrial Fibrillation and Heart Failure

Atrial fibrillation is an independent risk factor for heart failure hospitalization in heart failure with preserved ejection fraction

AIMS

Atrial fibrillation (AF) is a common comorbid condition in heart failure with preserved ejection fraction (HFpEF). The effect of AF on heart failure (HF) exacerbation in HFpEF has not been well described. This study investigated how AF modifies the clinical trajectory of HFpEF patients after hospitalization for decompensated HF.

METHODS AND RESULTS

We stratified HFpEF subjects by AF diagnosis and performed longitudinal analysis to compare risk for HF hospitalization after index hospitalization for decompensated HF. All-cause mortality, 30 day all-cause readmissions, and response to inpatient diuresis were also evaluated. Of 90 subjects enrolled, 35.6% (n = 32) had AF. Subjects with AF were older (72.5 vs. 60.5 years; P < 0.01), more often male (46.9% vs. 24.1%; P = 0.03), and had greater left atrial diameter (4.9 vs. 3.8 cm; P < 0.01) compared with those without AF. Subjects with AF had a higher risk for HF hospitalization than their counterparts without AF (P = 0.02); this relationship remained significant following multivariable competing risk regression with propensity score weighting (hazard ratio 2.53, P = 0.04 and hazard ratio 2.91, P = 0.04, with overlap and inverse probability weighting, respectively). Although having AF appeared to increase the risk of all-cause hospital readmission within 30 days of discharge (37.5% vs. 17.5%; P = 0.036), this relationship failed to remain significant following propensity score adjustment for clinical covariates.

CONCLUSIONS

Atrial fibrillation is an independent risk factor for HF rehospitalization in HFpEF. Further understanding of the interplay between AF and HFpEF will be critical to guide the selection of appropriate rhythm management strategies in this population.

A Review on Atrial Fibrillation (Computer Simulation and Clinical Perspectives)

Atrial fibrillation (AF), a heart condition, has been a well-researched topic for the past few decades. This multidisciplinary field of study deals with signal processing, finite element analysis, mathematical modeling, optimization, and clinical procedure. This article is focused on a comprehensive review of journal articles published in the field of AF. Topics from the age-old fundamental concepts to specialized modern techniques involved in today’s AF research are discussed. It was found that a lot of research articles have already been published in modeling and simulation of AF. In comparison to that, the diagnosis and post-operative procedures for AF patients have not yet been totally understood or explored by the researchers. The simulation and modeling of AF have been investigated by many researchers in this field. Cellular model, tissue model, and geometric model among others have been used to simulate AF. Due to a very complex nature, the causes of AF have not been fully perceived to date, but the simulated results are validated with real-life patient data. Many algorithms have been proposed to detect the source of AF in human atria. There are many ablation strategies for AF patients, but the search for more efficient ablation strategies is still going on. AF management for patients with different stages of AF has been discussed in the literature as well but is somehow limited mostly to the patients with persistent AF. The authors hope that this study helps to find existing research gaps in the analysis and the diagnosis of AF.

Prognostic power of left atrial strain in patients with acute heart failure

AIMS

Left atrial (LA) dysfunction can be associated with left ventricular (LV) disorders; however, its clinical significance has not been well-studied in patients with acute heart failure (AHF). We evaluated prognostic power of peak atrial longitudinal strain (PALS) of the left atrium according to heart failure (HF) phenotypes and atrial fibrillation (AF).

METHODS AND RESULTS

From an AHF registry with 4312 patients, we analysed PALS in 3818 patients. Patients were categorized into PALS tertiles. We also divided the patients according to HF phenotypes [HF with reduced ejection fraction (HFrEF), HF with mid-range ejection fraction (HFmrEF), or HF with preserved ejection fraction (HFpEF)] and presence of AF. The primary outcomes were all-cause mortality and HF hospitalization. PALS was weakly but significantly correlated with LA volume index (r = -0.310, P < 0.001), E/e' (r = -0.245, P < 0.001), and LV ejection fraction (r = 0.371, P < 0.001). A total of 2016 patients (52.8%) experienced adverse clinical events during median follow-up duration of 30.6 months (interquartile ranges 11.6-54.4 months). In the multivariate analysis, PALS was a significant predictor of events [hazard ratio (HR) 0.984, 95% confidence interval (CI) 0.971-0.996; P = 0.012]. Patients with the lowest tertile (HR 1.576, 95% CI 1.219-2.038; P < 0.001) had a higher number of events than those with the highest tertile in the multivariate analysis. In the subgroup analysis, however, PALS was not a prognosticator (HR 0.987, 95% CI 0.974-1.000; P = 0.056) in AF patients. The prognostic power of PALS was not different between HFrEF (HR 0.977, 95% CI 0.969-0.974; P < 0.001), HFmrEF (HR 0.984, 95% CI 0.972-0.996; P = 0.008), and HFpEF (HR 0.980, 95% CI 0.973-0.987; P < 0.001, P for interaction = 0.433).

CONCLUSION

PALS was a significant prognostic marker in AHF patients. The prognostic power was similar regardless of HF phenotypes, but PALS was not associated with clinical events in AF patients.

Predictive value of left atrial function for latent paroxysmal atrial fibrillation as the cause of embolic stroke of undetermined source

BACKGROUND

In patients with embolic stroke of undetermined source (ESUS), paroxysmal atrial fibrillation (AF) is often diagnosed, however, the risk of paroxysmal AF in ESUS has not been well described. Several studies have suggested a linkage between left atrial (LA) functional parameters and risk of AF in stroke patients. The aim of this study was to assess the role of LA functional parameters as predictors of latent paroxysmal AF in ESUS on admission.

METHODS

Between January 2015 and December 2019, consecutive stroke patients with suspected ESUS at admission were prospectively included in this study. They were under hospital electrocardiographic monitoring for detection of new-onset AF. Various echocardiographic parameters including left atrial strain were assessed for association with new-onset AF.

RESULTS

We gathered 1082 consecutive patients with ischemic stroke. After exclusions, 121 patients with suspected ESUS at admission formed the study cohort. New-onset AF was detected in 46 (38%) patients during hospital electrocardiographic monitoring (median follow-up: 18 days). LA pump and reservoir strains were significantly and independently associated with new-onset AF. Receiver operating characteristic analysis for the association with new-onset AF showed that the areas under the curve (AUCs) of clinical parameters plus one of each strain (LA pump strain: AUC: 0.86±0.04 and LA reservoir strain: AUC: 0.76±0.05) models were significantly better than plus LA volume index (AUC: 0.68±0.04, compared p-values <0.05).

CONCLUSIONS

LA strain was significantly associated with new development of AF. Patients with impaired LA function at admission should be carefully monitored to find AF.

Comprehensive assessment of left atrial and ventricular remodeling in paroxysmal atrial fibrillation by the cardiovascular magnetic resonance myocardial extracellular volume fraction and feature tracking strain

Atrial fibrillation (AF) is a progressive disease that starts with structural or functional changes in the left atrium and left ventricle, and evolves from paroxysmal toward sustained forms. Early detection of structural or functional changes in the left atrium and left ventricle in the paroxysmal stage could be useful for identifying a higher risk of progression to persistent AF and future cardio-cerebrovascular events. The aim of this study was to test the hypothesis that the feature tracking (FT) left atrial (LA) strain and left ventricular (LV) extracellular volume fraction (ECV) derived from cardiovascular magnetic resonance (CMR) could detect early changes in remodeling of the left atrium and ventricle in the paroxysmal AF (PAF) stage. The participants were comprised of 106 PAF patients (age, 66.1 ± 10.7 years; 66% male) who underwent clinical CMR before pulmonary vein isolation and 20 control subjects (age, 68.3 ± 8.6 years; 55% male). The CMR-FT LA strain/phasic function and LV-ECV were compared between the PAF and control groups. The total and passive LA empty fraction (LAEF) and LA strain (corresponding to LA reservoir and conduit function) were decreased in the PAF group as compared to the control group. However, active LAEF (corresponding to the LA booster pump function) did not differ significantly between the PAF group (33.9 ± 10.9%) and control group (37.9 ± 13.3%, p = 0.15), while the active LA strain (corresponding to the LA booster pump function) was significantly decreased in the PAF group (11.4 ± 4.3 vs. 15.2 ± 5.6%, p = 0.002). The LV-ECV was significantly greater in the PAF group (28.7 ± 2.8%) than control group (26.6 ± 2.0%, p = 0.002). In the PAF group, the LV-ECV correlated significantly with the E/e′ and LA volume index. Regarding the LA strain, correlations were seen between the LV-ECV and both the reservoir function and conduit function. CMR-FT LA strain in combination with the LV-ECV in a single clinical study offers a potential imaging marker that identifies LA/LV remodeling including subtle LA booster pump dysfunction undetectable by the conventional booster pump LAEF in the PAF stage.

Quantification of left atrial contractile function using two-dimensional speckle tracking echocardiography in horses after conversion of atrial fibrillation to sinus rhythm

INTRODUCTION/OBJECTIVES

In horses, persistent atrial dysfunction is a prognostic indicator of recurrence of atrial fibrillation (AF). The objective of this study was to quantify left atrial (LA) contractile function in Warmblood horses after successful cardioversion of AF to sinus rhythm, using standard two-dimensional echocardiography (2DE) and two-dimensional speckle tracking (2DST) analyses, and to provide proof-of-concept for use of 2DST to detect LA contractile dysfunction in horses.

ANIMALS, MATERIALS, AND METHODS

Nineteen Warmblood horses with AF and successful transvenous electrical cardioversion (TVEC) or medical cardioversion using quinidine sulfate (QS) were included. Echocardiography was performed at 24 hr, 72 hr, and 1-6 months after cardioversion. Conventional 2DE-derived indices of LA size and function and global longitudinal strain (S_L) and longitudinal strain rate (SR_L) during LA contractile function were measured to detect differences in LA size and function over time and between treatment modalities. The association between 2DE-derived indices and global S_L and SR_L, respectively, and the agreement of the variables to detect LA dysfunction were assessed.

RESULTS

Global S_L and SR_L, as well as active LA fractional area change (FAC) identified cases with LA dysfunction after TVEC and QS cardioversion and proved useful to demonstrate LA functional recovery over time. Agreement between active LA FAC and S_L and SR_L, respectively, to diagnose atrial dysfunction was substantial to fair at 24 hr after cardioversion and decreased with time.

CONCLUSION

This study shows that 2DST is useful to quantify LA contractile dysfunction in horses after cardioversion of AF.

Multimodality Imaging for Best Dealing With Patients in Atrial Arrhythmias

The management of atrial fibrillation (AF) is not only a clinical challenge but also an imaging challenge. The role of different imaging modalities to estimate the thromboembolic risk in AF is a key clinical question. The present review summarizes the advances of myocardial imaging in the stratification of thromboembolic risk, diagnosis, and management of left atrial thrombosis in patients with AF. These imaging techniques are also important for understanding arrhythmias and their consequences. It is becoming fundamental for guiding therapy. Still, large studies are required, but be sure that left atrial imaging will become more and more clinically fundamental.

Prognostic value of echocardiographic indices of left atrial morphology and function in dogs with myxomatous mitral valve disease

Background

The prognostic relevance of left atrial (LA) morphological and functional variables, including those derived from speckle tracking echocardiography (STE), has been little investigated in veterinary medicine.

Objectives

To assess the prognostic value of several echocardiographic variables, with a focus on LA morphological and functional variables in dogs with myxomatous mitral valve disease (MMVD).

Animals

One‐hundred and fifteen dogs of different breeds with MMVD.

Methods

Prospective cohort study. Conventional morphologic and echo‐Doppler variables, LA areas and volumes, and STE‐based LA strain analysis were performed in all dogs. A survival analysis was performed to test for the best echocardiographic predictors of cardiac‐related death.

Results

Most of the tested variables, including all LA STE‐derived variables were univariate predictors of cardiac death in Cox proportional hazard analysis. Because of strong correlation between many variables, only left atrium to aorta ratio (LA/Ao > 1.7), mitral valve E wave velocity (MV E vel > 1.3 m/s), LA maximal volume (LAVmax > 3.53 mL/kg), peak atrial longitudinal strain (PALS < 30%), and contraction strain index (CSI per 1% increase) were entered in the univariate analysis, and all were predictors of cardiac death. However, only the MV E vel (hazard ratio [HR], 4.45; confidence interval [CI], 1.76‐11.24; P < .001) and LAVmax (HR, 2.32; CI, 1.10‐4.89; P = .024) remained statistically significant in the multivariable analysis.

Conclusions and Clinical Importance

The assessment of LA dimension and function provides useful prognostic information in dogs with MMVD. Considering all the LA variables, LAVmax appears the strongest predictor of cardiac death, being superior to LA/Ao and STE‐derived variables.