Left Atrial Function Predicts Atrial Arrhythmia Recurrence Following Ablation of Long-Standing Persistent Atrial Fibrillation

From Atrial Fibrillation Management to Atrial Myopathy Assessment: The Evolving Concept of Left Atrium Disease in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most prevalent genetically inherited cardiovascular disorder in adults and a significant cause of heart failure and sudden cardiac death. Historically, atrial fibrillation (AF) has been considered as a critical aspect in HCM patients as it is considered to be a marker of disease progression, escalates the frequency of heart failure hospitalisations, increases the risk of thromboembolic events, and worsens quality of life and outcome. Increasing evidence suggests that AF is the result of a subtle long-standing process that starts early in the history of HCM. The process of left atrial dilation accompanied by morphologic and functional remodelling is the quintessential prerequisite for the onset of AF. This review aims to describe the current understanding of AF pathophysiology in HCM, emphasising the role of left atrial myopathy in its development. In addition, we discuss risk factors and management strategies specific to AF in the context of HCM, providing insights into the complexities and challenges of treating this specific patient population.

The Clinical Applications of Left Atrial Strain: A Comprehensive Review

Left atrial (LA) strain imaging, which measures the deformation of the LA using speckle-tracing echocardiography (STE), has emerged recently as an exciting tool to help provide diagnostic and prognostic information for patients with a broad range of cardiovascular (CV) pathologies. Perhaps due to the LA's relatively thin-walled architecture compared with the more muscular structure of the left ventricle (LV), functional changes in the left atrium often precede changes in the LV, making LA strain (LAS) an earlier marker for underlying pathology than many conventional echocardiographic parameters. LAS imaging is typically divided into three phases according to the stage of the cardiac cycle: reservoir strain, which is characterized by LA filling during systole; conduit strain, which describes LA deformation during passive LV filling; and booster strain, which provides information on the LA atrium during LA systole in late ventricular diastole. While additional large-population studies are still needed to further solidify the role of LAS in routine clinical practice, this review will discuss the current evidence of its use in different pathologies and explore the possibilities of its applications in the future.

Left atrial appendage closure in conjunction with radiofrequency ablation: Effects on left atrial functioning in patients with paroxysmal atrial fibrillation

Objective

In the present study, we investigated the impact of left atrial appendage closure (LAAC) following catheter ablation (CA) on the left atrial structure and functioning of patients with paroxysmal atrial fibrillation (AF).

Methods

Patients with paroxysmal AF were enrolled in this single-center prospective cohort study between April 2015 and July 2021; 353 patients received CA alone, while 93 patients received CA in combination with Watchman LAAC. We used age, gender, CHA2DS2-VASc, and HAS-BLED scores as well as other demographic variables to perform propensity score matching. Patients with paroxysmal AF were randomly assigned to the CA combined with Watchman LAAC group (combined treatment group) and the simple CA group, with 89 patients in each group. The left atrial structure, reserve, ventricular diastole, and pump functions and their changes in patients were assessed using routine Doppler echocardiography and 2D speckle tracking echocardiography over the course of a 1-year follow-up.

Results

At 1-week follow-up, the reserve, ventricular diastole, and pump functions of the left atrium (LA) increased in both groups; these functions were gradually restored at the 1- to 3-month follow-up; they were close to or returned to their pre-operative levels at the 3-month follow-up; and no significant differences were found compared with the pre-operative levels at the 12-month follow-up. In the first 3 months, the reserve (Ƹ, SRs) and pump functions (SRa) in the combined treatment group decreased significantly when compared with the simple CA group, and the differences were statistically significant.

Conclusion

Patients with paroxysmal AF may experience a short term, partial effect of LAAC on LA reserve and pump functions, which are gradually restored and the effect disappears by 12 months.

Left atrial strain predicts the rhythm outcome in patients with persistent atrial fibrillation undergoing left atrial cryoablation during minimally invasive mitral valve repair

Objectives

Patients with atrial fibrillation (AF) have lower left atrial (LA) strain, which is a predictor for LA function. Here, we evaluated the prognostic value of LA strain to predict the rhythm outcome in patients with persistent AF undergoing LA cryoablation concomitant to minimally invasive mitral valve repair.

Methods

Between 01/2016 and 12/2020, 72 patients with persistent AF underwent LA cryoablation during minimally invasive mitral valve surgery. All patients received a complete LA lesion set and left atrial appendage (LAA) closure with a clip. All patients received preoperative transthoracic echocardiography (TTE) with LA and left ventricular strain measurements. Preoperative LA and LV strain analysis was correlated with postoperative rhythm outcome.

Results

The mean age of the patients was 66.9 ± 7.2 years, of whom 42 (58%) were male patients. No major ablation-related complications occurred in any of the patients. Successful LAA closure was confirmed by intraoperative echocardiography in all patients. The 1-year survival rate was 97%. Freedom from AF at 12 months was 72% and 68% off antiarrhythmic drugs. Preoperative LA strain values were statistically significantly higher in patients with freedom from AF at 12 months of follow-up (12.7% ± 6.9% vs. 4.9% ± 4.1%, p = 0.006). Preoperative LV strain value was not associated with postoperative rhythm outcome. In multivariate logistic regression analysis, LA strain (p < 0.001) and AF duration (p = 0.017) were predictors for freedom from AF at 12 months of follow-up.

Conclusions

In our study, LA strain analysis predicted the rhythm outcome in patients with persistent AF undergoing concomitant surgical AF ablation. In the future, LA strain might be a useful tool to guide decision-making on ablation strategies in patients with persistent AF.

Association of Atrial Fibrillation Progression With Left Atrial Functional Reserve and Its Reversibility

BACKGROUND

Atrial fibrillation (AF) progression is closely related to heart failure occurrence, and catheter ablation carries a beneficial effect for heart failure prevention. Recently, particular attention has been given to left atrial (LA) function and functional reserve in the pathogenesis linking AF and heart failure, although its significance and reversibility is not well studied.

METHODS AND RESULTS

We prospectively investigated 164 patients with AF with normal left ventricular systolic function and free from heart failure who underwent first catheter ablation and pre-/postprocedural echocardiography. Conventional and speckle-tracking echocardiography were performed at rest and during passive leg lifting to assess LA size, LA reservoir strain (LARS), and functional reserve calculated as passive leg lifting-LARS - rest-LARS. Patients were categorized into 3 AF subtypes: paroxysmal AF (N=95), persistent AF (PeAF; N=50), and long-standing persistent AF (LS-PeAF; N=19). The PeAF and LS-PeAF groups had larger LA size and reduced LARS compared with the paroxysmal AF group (all P<0.05). LA functional reserve was significantly impaired in the LS-PeAF group (P=0.003). In multivariable analysis, LS-PeAF and advanced age were significantly associated with impaired LA functional reserve. Among 149 patients with sinus rhythm 1 to 2 days after catheter ablation, LARS was significantly improved in both PeAF and LS-PeAF groups but was still lower than that in the paroxysmal AF group. Sinus rhythm restoration also led to amelioration of LA functional reserve in patients with LS-PeAF.

CONCLUSIONS

AF progression was related to impaired LARS and LA functional reserve, and restoration of sinus rhythm might contribute to early LA reverse remodeling.

Multimodality Imaging in Patients with Hypertrophic Cardiomyopathy and Atrial Fibrillation

Ventricular hypertrophy is associated with diastolic dysfunction, resulting in increased left atrial (LA) pressure, enlargement, fibrosis, and decreased LA function. Hypertrophic cardiomyopathy (HCM) is characterized by myocyte disarray, myocardial fibrosis, and hypertrophy. Notably, a thickened and noncompliant LV results in the impairment of diastolic function. These conditions promote LA remodeling and enlargement, which contribute to developing and maintaining atrial fibrillation (AF). AF is an atrial arrhythmia that occurs frequently in HCM, and evaluating the morphology and physiology of the atrium and ventricle is important for treatment and prognosis determination in HCM patients with AF. In addition, it provides a clue that can predict the possibility of new AF, even in patients not previously diagnosed with AF. Cardiac magnetic resonance (CMR), which can overcome the limitations of transthoracic echocardiography (TTE), has been widely used traditionally and even enables tissue characterization; moreover, it has emerged as an essential imaging modality for patients with HCM. Here, we review the role of multimodal imaging in patients with HCM and AF.