Left Atrial Dysfunction, Fibrosis and the Risk of Thromboembolism in Patients With Paroxysmal and Persistent Atrial Fibrillation

Mavacamten-Associated Temporal Changes in Left Atrial Function in Obstructive HCM: Insights From the VALOR-HCM Trial

BACKGROUND

In severely symptomatic patients with obstructive hypertrophic cardiomyopathy (HCM), the VALOR-HCM (A Study to Evaluate Mavacamten in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy Who Are Eligible for Septal Reduction Therapy) trial showed that mavacamten reduced the eligibility for septal reduction therapy with sustained improvement in left ventricular outflow tract gradients. Mavacamten also resulted in favorable cardiac remodeling, including improvement in biomarkers (eg, N-terminal pro-B-type natriuretic peptide and troponin T). However, the impact of mavacamten on left atrial (LA) function is unknown.

OBJECTIVES

The aim of this study was to assess serial changes in LA strain measures in patients enrolled in the VALOR-HCM trial.

METHODS

VALOR-HCM included 112 symptomatic patients with obstructive HCM (mean age 60 years; 51% male). Patients assigned to receive mavacamten at baseline (n = 56) continued therapy for 56 weeks and those assigned to placebo transitioned to mavacamten (n = 52) from week 16 to week 56. Echocardiographic LA strain (reservoir, conduit, and contraction) was measured by using a vendor-neutral postprocessing software.

RESULTS

At baseline, the mean LA volume index (LAVI) and LA strain values (conduit, contraction, and reservoir) were 41.3 ± 16.5 mL/m2, -11.8% ± 6.5%, -8.7% ± 5.0%, and 20.5% ± 8.7%, respectively (all worse than reported normal). LAVI significantly improved by -5.6 ± 9.7 mL/m2 from baseline to week 56 (P < 0.001). There was a significant (P < 0.05) improvement in absolute LA strain values from baseline to week 56 (conduit [-1.7% ± 6%], contraction [-1.2% ± 4.5%], and reservoir [2.8% ± 7.7%]). Patients originally receiving placebo had no differences in LA measurements up to week 16. There was no significant improvement in LA strain values (conduit [-0.9% ± 3.8%], contraction [-0.4% ± 3.4%], and reservoir [1.4% ± 6.1%]; all; P = NS) from baseline to week 56 in patients with history of atrial fibrillation.

CONCLUSIONS

In VALOR-HCM, mavacamten resulted in an improvement in LAVI and LA strain at week 56, suggesting sustained favorable LA remodeling and improved function, except in the atrial fibrillation subgroup. Whether the advantageous LA remodeling associated with long-term treatment with mavacamten results in a favorable impact on the observed high burden of atrial tachyarrhythmias in HCM remains to be proven. (A Study to Evaluate Mavacamten in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy Who Are Eligible for Septal Reduction Therapy [VALOR-HCM]; NCT04349072).

Development and validation of a nomogram superior to CHADS2 and CHA2DS2-VASc models for predicting left atrial appendage dense spontaneous echo contrast/left atrial appendage thrombus

Background

Atrial fibrillation (AF) is one of the most frequently encountered arrhythmias in clinical practice, with stroke triggered by detachment of left atrial appendage thrombus (LAAT) after AF being its most critical complication. The purpose of this study was to construct a nomogram model for forecasting left atrial appendage (LAA) dense spontaneous echo contrast (SEC) and LAAT to accurately identify patients at high risk for stroke.

Methods

A retrospective analysis was conducted on 433 patients with AF receiving transesophageal echocardiography (TEE) in the First Affiliated Hospital of Soochow University from October 2019 to July 2022. These patients were assigned into a non-dense SEC/LAAT group or a dense SEC/LAAT group. We constructed a nomogram model dependent on the odds ratios (ORs) of logistic regression and subsequently compared its performance with two models, CHADS2 and CHA2DS2-VASc.

Results

Female gender, high D-dimer level, low left ventricular ejection fraction, low left atrial ejection fraction, and low left atrial reservoir strain rate were found to be independent factors for predicting LAA SEC/LAAT, with OR values and 95% confidence intervals of 2.811 (1.445-5.469), 2.460 (1.230-4.921), 0.961 (0.927-0.996), 0.950 (0.932-0.967), and 0.173 (0.035-0.848), respectively. The consistency statistic of the nomogram based on these given predictive factors was 0.921, and the calibrated consistency statistic was 0.903. According to receiver operation curve analysis and decision curve analysis, the nomogram was demonstrated to be superior to the CHADS2 and CHA2DS2-VASc models in predicting LAA dense SEC/LAAT. The net reclassification improvement and integrated discrimination improvement of the nomogram were 0.449 (0.324-0.575) and 0.461 (0.408-0.515), when compared with the CHADS2 model, and were 0.521 (0.411-0.632), and 0.432 (0.400-0.504), respectively, when compared with the CHA2DS2-VASc models.

Conclusions

The nomogram model constructed in this study demonstrated excellent performance in predicting LAA dense SEC/LAAT, displaying a superior ability to that of the CHADS2 and CHA2DS2-VASc models.

Effects of septal myectomy on left atrial and left ventricular function in obstructive hypertrophic cardiomyopathy

AIMS

Mechanical function of the left atrium (LA) and the left ventricle (LV) has been demonstrated to be a prognostic factor in patients with hypertrophic cardiomyopathy (HCM). We explore whether myocardial mechanical function can be improved by septal reduction therapy in symptomatic obstructive HCM.

METHODS AND RESULTS

Among 65 patients who underwent septal myectomy for symptomatic obstructive HCM from 2006 to 2022, 44 were analysed after excluding those who underwent simultaneous valve repair or replacement or maze operation. LA and LV functional variables including LA strain and LV global longitudinal strain were evaluated by two-dimensional and speckle-tracking echocardiography and compared before and 1 year after surgery. After septal myectomy, LA volume index (58.1 ± 18.3 vs. 45.3 ± 14.6 mL/m2 , P = 0.001) decreased significantly. As LV end-systolic dimension increased after surgery, the LV ejection fraction decreased (73.8 ± 6.7 vs. 62.9 ± 8.3%, P < 0.001). LA strain (24.4 ± 9.3 vs. 30.5 ± 13.6%, P = 0.004) improved after septal myectomy, but LV global longitudinal strain deteriorated (-12.6 ± 3.6 vs. -11.6 ± 4.3%, P = 0.033), mainly related to worsening non-septal longitudinal strain (-14.4 ± 4.3 vs. -10.9 ± 8.4%, P = 0.005).

CONCLUSIONS

As haemodynamic loads due to LV outflow tract obstruction was relieved through surgical septal reduction therapy in patients with symptomatic obstructive HCM, there was a significant reduction in LA volume and restoration of LA mechanical dysfunction. However, LV mechanical dysfunction deteriorated even after surgical septal reduction therapy.

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.

Role of cardiac imaging in management of heart failure

The significant advancement in cardiac imaging in recent years led to improved diagnostic accuracy in identifying the specific causes of heart failure and also provided physicians with guidelines for appropriately managing patients with heart failure. Diseases that were once considered rare are now more easily detected with the aid of cardiac imaging. Various cardiac imaging techniques are used to evaluate patients with heart failure, and each technique plays a distinct yet complementary role. This review aimed to discuss the comprehensive role of different types of cardiac imaging in the management of heart failure.

Optimization of guideline-directed medical treatment for heart failure patients with reduced ejection fraction

With the increasing number of medications demonstrating mortality benefits in heart failure with reduced ejection fraction (HFrEF), the pharmacological treatment of HFrEF is entering a new phase. To enhance outcomes in heart failure patients through medical treatment, the choice of appropriate medications and simultaneous and rapid uptitration are critical. However, there are several challenges encountered during this medication uptitration, including issues like hypotension, fatigue, worsening renal function, and hyperkalemia. This paper addresses strategies for effectively managing these challenges to successfully reach the maximum tolerated dose in patients. Additionally, it will discuss the management of comorbidities often associated with heart failure, the importance of exercise and rehabilitation, and the significance of proper nutrition intake, in addition to guideline-directed medical therapy.

ASSOCIATION OF LEFT ATRIAL SPONTANEOUS ECHO CONTRAST WITH CLINICAL AND HEMODYNAMIC CHARACTERISTICS OF PATIENTS WITH LONG-TERM EPISODES OF PERSISTENT ATRIAL FIBRILLATION

OBJECTIVE

The aim: To identify clinical and hemodynamic factors, associated with left atrial spontaneous echo contrast (LASEC) (LASEC in general, and the dense LASEC), in non-valvular persistent atrial fibrillation (AF) patients with the duration of AF episode ≥90 days.

PATIENTS AND METHODS

Materials and methods: The cross-sectional study consecutively enrolled 115 persistent AF patients with the duration of its episode ≥90 days (82 (71,3 %) males; mean age 59 ± 11 years). Transthoracic (TEE) and transesophageal echocardiography (TEE) were performed. LASEC (by TEE) was observed in 79 (68,7 %) patients. The dense (moder¬ate-to-severe) LASEC was detected in 23 (20,0 %) cases.

RESULTS

Results: Heart failure (HF) stage C (OR 2,09 (95 % CI 1,24-3,53); p=0,006), lower TEE-derived left atrial appendage (LAA) flow velocity (FV) (OR 0,94 (95 % CI 0,91-0,98); p=0,003), and the presence of TTE-derived pulmonary hypertension (PH), appeared to be strongly associated with LASEC (AUC for logistic regression model: 0,83 [95 % СI 0,75- 0,89]). The presence of diabetes mellitus type 2 (DM) (OR 2,34 (95 % CI 1,13-4,86); p=0,027), along with lower LAA FV (OR 0,83 (95 % CI 0,76-0,91); p<0,001), were strongly associated with dense LASEC (AUC: 0,89 [95 % CI 0,82-0,94]).

CONCLUSION

Conclusions: The TEE-derived LASEC in patients with long term episodes (≥90 days) of persistent AF was strongly associated with HF stage C and TTE-derived PH, and with lower TEE-derived LAA FV. The presence of DM, in addition to lower LAA FV, was related to dense LASEC.