Left atrioventricular coupling index in hypertrophic cardiomyopathy and risk of new-onset atrial fibrillation

Cardiac magnetic resonance left atrioventricular coupling index as a prognostic tool in hypertrophic cardiomyopathy

AIMS

A novel marker left atrioventricular coupling index (LACI) has been proved to be associated with cardiovascular events in patients without history of cardiovascular disease. However, the studies on cardiac magnetic resonance-derived LACI in hypertrophic cardiomyopathy (HCM) patients are limited, and the prognostic value of LACI has still not been studied thoroughly, so we aimed to explore the association between LACI and adverse clinical outcomes in HCM patients.

METHODS

A total of 206 HCM patients underwent cardiac magnetic resonance examination were retrospectively enrolled. LACI is defined by the ratio between the left atrial (LA) volume and the left ventricular (LV) volume in LV end-diastolic phase. The composite endpoint was categorized into death-related, heart failure-related, and arrhythmia-related events, reflecting mortality risk, heart failure progression, and arrhythmia burden, respectively. Receiver operating characteristics curve analysis was used to determine the optimal cut-off value for LACI to distinguish HCM patients at high risk of adverse clinical outcome. Multivariable Cox regression models were built including significant clinical variables, LA ejection fraction (LAEF), LA volume index (LAVI), late gadolinium enhancement (LGE) extent and LACI. The improvement of discrimination by adding LACI to a clinical model was assessed using C-statistic, net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

RESULTS

Thirty-four HCM patients reached the endpoint during a median follow-up time of 60 [interquartile range (50-68)] months. In the multivariate Cox regression analysis, LACI [hazard ratio 1.054, 95% confidence interval (CI): 1.037, 1.071; P < 0.001] was an independent predictor of the composite events after adjustment for age and atrial fibrillation. Then 40.09% was identified as an optimal cut-off for LACI in the risk stratification. Integrating LACI to the clinical model yielded higher C-statistic 0.892 with 95% CI (0.861, 0.922) compared with LA diameter, LAEF, LAVI and LGE extent, providing an improvement in prediction of high-risk patients (NRI = 0.627, 95% CI: 0.112-0.934; IDI = 0.295, 95% CI: 0.016-0.709).

CONCLUSIONS

LACI is an independent risk factor for clinical adverse outcome and is superior to conventional LA parameters and LGE extent for the identification of high-risk HCM patients.

Clinical Utility of Atrioventricular Coupling Index in Cardiovascular Disease

Atrioventricular coupling refers to the synchronized interaction between the atrial and ventricular phases of contraction and relaxation within the cardiac cycle. Atrioventricular coupling can be assessed by the left atrioventricular coupling index and right atrioventricular coupling index. These indices provide a comprehensive assessment of the functional interdependence between the atrial and ventricular chambers, and offer insights into cardiac performance beyond traditional markers. Atrioventricular coupling indices are critical for aiding in risk stratification and clinical decision-making, ultimately improving patient outcomes. This review focuses on the clinical utility of atrioventricular coupling in various cardiac pathologies.

Atrial Cardiomyopathy in Atrial Fibrillation: A Multimodal Diagnostic Framework

Atrial fibrillation (AF) is increasingly recognized as the clinical manifestation of an underlying atrial disease process rather than a purely electrical disorder. This evolving paradigm has given rise to the concept of atrial cardiomyopathy (AtCM), encompassing structural, electrical, contractile, and molecular remodeling of the atrial myocardium that contributes to AF initiation, maintenance, and progression. Although consensus definitions of AtCM now exist, its integration into clinical practice remains limited, with AF management still largely guided by arrhythmic patterns rather than substrate characterization. This review synthesizes current diagnostic strategies for AtCM within the context of AF, emphasizing a multimodal approach. We outline advances in cardiac imaging-including echocardiography, cardiac magnetic resonance, and computed tomography-for detailed assessment of atrial morphology, function, and fibrosis. Electroanatomic mapping is discussed as a key invasive tool for substrate localization, while electrocardiographic indices such as P-wave morphology and dispersion serve as accessible surrogates of electrical remodeling. In parallel, we examine the role of circulating biomarkers and emerging genomic, transcriptomic, and epigenomic markers in refining disease phenotyping. Despite promising progress, significant challenges remain. Standardization of imaging protocols, validation of biomarker thresholds, and integration of artificial intelligence tools are needed to enhance clinical utility. A diagnostic framework informed by atrial substrate assessment may support more tailored therapeutic decision-making in AF. Future research should prioritize the harmonization of diagnostic criteria and explore how substrate profiling in AF may refine risk stratification and improve clinical outcomes.

Left atrial remodelling and function in various left ventricular hypertrophic phenotypes

AIMS

How the underlying aetiology and pathophysiology of left ventricular (LV) hypertrophy affects left atrial (LA) remodelling and function remains unexplored. The present study aims to investigate the influence of various hypertrophic phenotypes on LA remodelling and function.

METHODS AND RESULTS

Patients with LV hypertrophy who underwent cardiac magnetic resonance (CMR) were compared to a control group. CMR data were analysed retrospectively to assess LA strain, volume, sphericity, and left atrioventricular coupling index (LACI). Independent clinical associates of LA strain were assessed using multivariable linear regression analysis. A total of 375 individuals were included: 148 with hypertrophic cardiomyopathy (HCM), 35 with cardiac amyloidosis (CA), 41 with hypertensive (HTN) heart disease, 97 with severe asymptomatic aortic stenosis (AS), and 54 with normal CMR. Indexed LA end-systolic (iLVmax), diastolic volumes, and LA sphericity were the largest in patients with CA (59.1 ± 16.9 mL/m2, 46.8 ± 16.4 mL/m2, and 83.2 ± 2.1%, respectively). Patients with CA presented a higher LACI when compared with other groups (58 ± 2% vs. 42 ± 2% in HCM, 39 ± 2% in HTN heart disease, 37 ± 2% in AS, and 22 ± 1% in normal), while no differences were observed across others. Patients with CA showed the lowest LA reservoir [9.6% (0.6-18.6%)] and booster strain (9.1 ± 5.4%), whereas no differences were observed across other groups. LACI and iLAVmax were independently correlated with LA reservoir (β = 0.15 and β = -39.33, respectively), LA conduit (β = 0.08 and β = -17.08, respectively), and LA booster strains (β = 0.1 and β = -28.69, respectively). LA sphericity was independently correlated with LA reservoir strain (β = -0.51). Finally, LV global longitudinal strain was independently correlated with LA reservoir (β = -0.43), conduit (β = -0.20), and booster strain (β = -0.24).

CONCLUSION

LA characteristics differ among LV hypertrophic phenotypes. LACI and iLAVmax are independently correlated with LA function, while LA sphericity correlates independently with LA reservoir strain.

The power of the left atrioventricular coupling index in cardiovascular disease

The left atrioventricular coupling index (LACI) has emerged as a novel and transformative biomarker in cardiovascular research, addressing long-standing limitations in traditional cardiac function assessments. By quantifying the ratio of left atrial to left ventricular end-diastolic volumes, LACI offers unprecedented prognostic insights into a wide range of cardiovascular diseases, including atrial fibrillation, heart failure, and myocardial infarction, as well as other conditions such as hypertension and cardiomyopathies. Recent evidence highlights its unique ability to integrate atrial and ventricular dynamics, offering a more comprehensive perspective on cardiac health and disease progression. This review synthesizes the latest advancements in LACI research, elucidates its underlying pathophysiological mechanisms, and explores its expanding clinical applications as a pivotal tool for risk stratification, precision diagnostics, and personalized therapy in cardiovascular medicine.

The role of left atrio-ventricular coupling index and left atrial ejection fraction in predicting onset of atrial fibrillation and adverse cardiac events in hypertrophic cardiomyopathy

BACKGROUND

Several predictors of atrial fibrillation (AF) onset in patients with hypertrophic cardiomyopathy (HCM) have been proposed, however, all of them showed limited accuracy. This study aims to assess the role of new echographic parameters in predicting AF onset and major adverse cardiovascular outcomes (cardiovascular death or heart transplantation).

METHODS

Clinical and imaging data from 141 patients with HCM and without a history of AF were retrospectively analyzed over a 5-year period. Patients who developed AF during the study were compared to those who did not. The analysis focused on key atrial parameters, including the Left Atrial Contraction Index (LACI) and Left Atrial Ejection Fraction (LAEF). LACI was defined as the ratio of left atrial end-diastolic volume to left ventricular end-diastolic volume. Echocardiographic measurements were standardized using cardiac magnetic resonance (CMR) as the reference. Regarding statistical analysis, each significant continuous variable was categorized by identifying a cut-off value using the Youden index. Independent associations with outcomes and cumulative survival were assessed using Cox regression analysis.

RESULTS

Thirty-five patients developed AF, at a mean time of 4 years. The HCM-AF group had significantly higher values of LACI, left atrial diameter (LAD), and left atrial minimum volume (LAVmin). A LACI > 43% on echocardiography and LACI > 44% on CMR showed the best performance in identifying patients at risk for AF. In multivariate analysis, an echocardiographic LAEF < 43% was independently associated with the occurrence of AF (HR 2.9, 95% CI: 1.2-6.9). Additionally, a LAD > 40.5 mm was independently associated with AF onset, with a hazard ratio of 2.5 (95% CI 1.1-5.5). Eleven patients experienced the composite outcome of cardiovascular death or heart transplant, and a LACI > 60% was associated with this outcome.

CONCLUSION

In patients with HCM, both LACI and LAEF were significantly associated with the occurrence of AF over a 4-year period, demonstrating higher sensitivity and specificity compared to other parameters. A LACI > 60% was also found to be associated with cardiovascular death or heart transplant in this population.

Prognostic value of left atrioventricular coupling index in heart failure

AIMS

To investigate the distribution of left atrioventricular coupling index (LACI) among patients with heart failure and left ventricular ejection fraction (LVEF) < 50% and to explore its association with the combined endpoint of all-cause death or HF hospitalization at long-term follow-up.

METHODS AND RESULTS

Patients with HF and LVEF < 50% undergoing cardiac magnetic resonance were evaluated. Patients with atrial fibrillation or flutter were excluded. Left atrioventricular coupling index was measured as the ratio between the left atrial (LA) and the LV end-diastolic volumes. Patient population was divided according to LACI tertiles and followed up. Total of 478 patients (mean age 62 ± 12 years, 78% male) were included. The median value of LACI was 27.1% (interquartile range 19.9-34.5). Patients within the worst LACI tertile (≥30.9%) showed smaller LV volumes and larger LA volumes as compared with patients in the first or second tertile (LACI 6.2-22.2 and LACI 22.3-30.9, respectively). Left atrioventricular coupling index was significantly associated with the combined endpoint [hazard ratio (HR) 1.87, P = 0.01]. After adjusting for sex, age, ischaemic HF aetiology, LVEF, LA reservoir strain, diabetes mellitus, LV scar, mitral regurgitation, and LVEDVi, LACI remained significantly associated with the combined endpoint (HR 1.77, P = 0.02). Patients with the highest LACI values had worse outcomes compared with patients in first and second tertiles (HR 1.69, P = 0.02 and HR 1.77, P = 0.02, respectively).

CONCLUSION

In patients with HF and LVEF <50%, LACI is independently associated with adverse events. Patients with most impaired left atrioventricular coupling have the worst clinical outcomes.

The Possibilities and Importance of Assessing the Left Atrioventricular Coupling Index Using Various Diagnostic Imaging Methods in an Adult Population: A Comprehensive Review

Cardiovascular diseases are a leading cause of death worldwide, and they are becoming even more frequent due to the aging of society. Due to this fact, new parameters that are useful in diagnosing, as well as in assessing, the risk of cardiovascular events, and in future prognosis estimation, should be developed. The left atrioventricular coupling index (LACI) has been recently introduced as the one parameter meeting these criteria. The current review aims to collect all available data and assess whether the LACI may be a valuable tool in daily clinical practice, and, simultaneously, to direct future research on the subject. The LACI is a parameter that can be calculated based on echocardiographic, cardiac CT and CMR examinations. It appears to be of use in several cardiovascular diseases, especially heart failure and atrial fibrillation, both in diagnostics and as a prognostic marker. Moreover, the LACI is a useful marker in cardiomyopathies, myocardial infarction, beta-thalassemia major and light-chain amyloidosis. However, the number of studies on the subject of LACI is limited, and some of these studies are based on the same cohort of patients. Future studies should take up the subject of the LACI, especially when it comes to the value of calculating the LACI based on various imaging techniques, including echocardiography.

Impact of transapical beating-heart septal myectomy on left atrial remodeling and atrioventricular coupling in hypertrophic obstructive cardiomyopathy

BACKGROUND

Assessment of left atrial (LA) functional strain and atrioventricular coupling is increasingly recognized as critical in patients with hypertrophic obstructive cardiomyopathy (HOCM), associated with adverse atrial remodeling and malignant arrhythmia. The effect of transapical beating-heart septal myectomy (TA-BSM) on the improvement of LA function and atrioventricular coupling remains uncertain.

METHODS

The patients with HOCM who underwent TA-BSM in Tongji Hospital between April 2022 and October 2023 were prospectively investigated. The LA structure parameters (diameters and volumes), functional parameters (total LA emptying fraction [LAEF], total strain [εs], peak positive strain rate [SRs], passive LAEF, passive strain [εe], peak early negative strain rate [SRe], active LAEF, active strain [εa], and late peak negative strain rate [SRa]), and the left atrioventricular coupling index (LACI) obtained using CMR before and after TA-BSM were compared. The Pearson or Spearman correlation analysis was used to investigate the relationships between LA parameters and LACI. The univariate and multivariate linear regression analyses were used to identify variables associated with the rate of change in strains.

RESULTS

A total of 133 patients [median (Q1, Q3), 48 (35.0, 57.5) years; 92 males] were evaluated. Further, 133 healthy participants matched for age and sex were included as controls. The LA size, reservoir function (total LAEF, εs, and SRs), conduit function (passive LAEF, εe, and SRe), and booster function (active LAEF, εa, and SRa) were worse than control group but improved to various degrees after TA-BSM (all P < 0.05). The subgroup with poor atrioventricular coupling had greater rate of change of εs, εa, and SRa postoperatively (all P < 0.001). LACI was highly correlated with strain and strain rate before TA-BSM, which decreased slightly postoperatively. In multivariable regression analysis, preoperative LACI was highly correlated with the rate of change of εs (adjusted β = -0.449, P < 0.001), εe (adjusted β = -0.285, P < 0.001), and εa (adjusted β = -0.286, P = 0.001).

CONCLUSION

LA reverse remodeling was confirmed by CMR in HOCM after TA-BSM and LACI may be a potential factor affecting LA strain improvement and expected to be an effective indicator for long-term monitoring of postoperative left heart function.

A novel index evaluating left atrioventricular coupling function in chronic kidney disease with diabetes patients

The left atrioventricular coupling index (LACI) evaluates the coupling function between the left atrial (LA) and left ventricular (LV) chambers. However, little is known about LACI in chronic kidney disease (CKD) patients. This study aimed to assess the impact of concurrent CKD and type 2 diabetes mellitus (T2DM) on left atrioventricular coupling function compared to CKD patients without T2DM. A retrospective analysis included 173 CKD 4-5 stage patients who underwent echocardiographic examinations. The study comprised 75 CKD patients with T2DM (CKD + DM) and 98 CKD patients without T2DM (CKD-DM). During the follow-up, major adverse cardiac events (MACE) were tracked until June 30, 2024, or death, with a median duration of 21 (18, 27) months, 20.8% of patients experienced MACE, and 10.4% passed away. This study employed speckle tracking echocardiography to evaluate LA and LV strain, alongside the LACI, analyzing its role in predicting MACE. CKD + DM patients showed a notable rise in LACI compared to CKD-DM patients, hinting at a link between diabetes and impaired left atrioventricular coupling in CKD. Patients with lower LACI had superior clinical outcomes during follow-up (P < 0.001). Univariate and multivariate Cox regression analyses underscored LACI as an independent predictor for heightened MACE risk in CKD 4-5 stage patients. This study highlights a potential association between diabetes and impaired left atrioventricular coupling function in CKD 4-5 stage patients, with LACI independently linked to an increased risk of MACE.

Predicting mortality after transcatheter aortic valve replacement using AI-based fully automated left atrioventricular coupling index

BACKGROUND

This study aimed to determine whether artificial intelligence (AI)-based automated assessment of left atrioventricular coupling index (LACI) can provide incremental value above other traditional risk factors for predicting mortality among patients with severe aortic stenosis (AS) undergoing coronary CT angiography (CCTA) before transcatheter aortic valve replacement (TAVR).

METHODS

This retrospective study evaluated patients with severe AS who underwent CCTA examination before TAVR between September 2014 and December 2020. An AI-prototype software fully automatically calculated left atrial and left ventricular end-diastolic volumes and LACI was defined by the ratio between them. Uni- and multivariate Cox proportional hazard methods were used to identify the predictors of mortality in models adjusting for relevant significant parameters and Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score.

RESULTS

A total of 656 patients (77 years [IQR, 71-84 years]; 387 [59.0 ​%] male) were included in the final cohort. The all-cause mortality rate was 21.6 ​% over a median follow-up time of 24 (10-40) months. When adjusting for clinical confounders, LACI ≥43.7 ​% independently predicted mortality (adjusted HR, 1.52, [95 ​% CI: 1.03, 2.22]; p ​= ​0.032). After adjusting for the STS-PROM score in a separate model, LACI ≥43.7 ​% remained an independent prognostic parameter (adjusted HR, 1.47, [95 ​% CI: 1.03-2.08]; p ​= ​0.031). In a sub-analysis of patients with preserved left ventricular ejection fraction, LACI remained a significant predictor (adjusted HR, 1.72 [95 ​% CI: 1.02, 2.89]; p ​= ​0.042).

CONCLUSIONS

AI-based fully automated assessment of LACI can be used independently to predict mortality in patients undergoing TAVR, including those with preserved LVEF.

Left Atrial Markers in Diagnosing and Prognosticating Non-Ischemic Cardiomyopathies: Ready for Prime Time?

The left atrium (LA) is pivotal in cardiac hemodynamics, serving as a dynamic indicator of left ventricular (LV) compliance and diastolic function. The LA undergoes structural and functional adaptations in response to hemodynamic stress, infiltrative processes, myocardial injury, and arrhythmic triggers. Remodeling of the LA in response to these stressors directly impacts pulmonary circulation, eventually leading to pulmonary capillary involvement, pulmonary artery hypertension, and eventually right ventricular failure. LA dysfunction and fibrosis also contribute to the future risk of atrial arrhythmias and mitral regurgitation. The parameters of LA size and function are being recognized as robust markers for the progression of several cardiac pathologies as well as important tools for prognostication. In this article, we briefly describe the different modalities and markers used to evaluate LA pathology in patients with nonischemic cardiomyopathies (NICM). We then provide an overview of the studies that compared the association of the different LA parameters with disease severity and future prognosis. We also identify the gaps in knowledge before these LA parameters make a case for clinical adoption.

Alterations in left atrial and left ventricular coupling in mixed aortic valve disease

AIMS

To characterize left atrial (LA) and left ventricular (LV) function and atrioventricular (AV) coupling in patients with moderate mixed aortic valve disease (MMAVD) against those with isolated moderate or severe aortic valve disease and controls.

METHODS AND RESULTS

Retrospective LA and LV peak longitudinal strain (LS) analysis were performed on 260 patients [46 MMAVD, 81 moderate aortic stenosis (AS), 50 severe AS, 48 moderate aortic regurgitation (AR), and 35 severe AR] and 66 controls. Peak LV and LA LS and AV coupling, assessed by combined peak LA and LV strain, was compared between the groups. Analysis of variance and two-sided t-tests were used, and a P-value of <0.01 was considered significant. LV strain was significantly lower in those with MMAVD compared with controls and those with moderate or severe isolated AR but comparable to those with moderate or severe AS (-17.1 ± 1.1% MMAVD vs. -17.7 ± 1.5% moderate AS, P = 0.02, vs. -17.0 ± 1.5% severe AS, P = 0.74). AV coupling was significantly lower in those with MMAVD compared with controls and those with moderate AS or AR but comparable to those with severe AS or AR (47.1 ± 6.8% MMAVD vs. 45.1 ± 5.6% severe AS, P = 0.13, vs. 50.4 ± 9% severe AR, P = 0.07).

CONCLUSION

Impairments in AV coupling are comparable for patients with MMAVD and those with severe isolated AS or AR. Impairments in LV GLS in MMAVD mirror those found in severe AS. These findings suggest that haemodynamic consequences and adverse remodelling are similar for patients with MMAVD and isolated severe disease.

Left Atrioventricular Coupling Index: A Novel Diastolic Parameter to Refine Prognosis in Heart Failure

BACKGROUND

Left atrioventricular coupling index (LACI), an index coupling left atrial to left ventricular (LV) volume at end-diastole, has been shown to be associated with prognosis in different clinical settings. However, the relation between LACI and LV diastolic dysfunction (DD) remains to be established. The aims of the present study were to investigate the association between LACI and LV DD and to assess its prognostic value in patients with heart failure (HF).

METHODS

A total of 1,158 patients with HF in stable condition, on optimal medical therapy, were retrospectively analyzed (derivation cohort). Clinical and echocardiographic features were characterized across LACI tertiles. The independent prognostic value of LACI (end point: all-cause death or HF hospitalization) was assessed using Cox regression. Results were validated in an external cohort of 242 patients with HF.

RESULTS

In the derivation cohort, the median LACI value was 0.29 (interquartile range, 0.19-0.42). Patients in the third tertile (LACI > 0.36) were older and presented with more advanced HF symptoms. Although the prevalence of grade 1 DD (American Society of Echocardiography/European Association of Cardiovascular Imaging classification) progressively decreased across LACI tertiles, the prevalence of grade 3 DD significantly increased (8%, 23%, and 46%, respectively; P < .0001). A cutoff value of ≥0.26 identified moderate to severe DD with an area under the curve of 0.75. During follow-up (median, 28 months; interquartile range, 11-53 months), 407 patients (35%) reached the end point. On multivariable analysis, LACI was independently associated with outcomes (hazard ratio for a 1-SD increase, 1.16; 95% CI, 1.06-1.28; P = .002), showing incremental predictive value over the DD grading system (net reclassification improvement = 0.150, P < .0001). The prognostic value of LACI was consistent in the external validation cohort.

CONCLUSIONS

LACI is associated with DD severity and is an independent predictor of outcomes in patients with HF.

Predicting impaired cardiopulmonary exercise capacity in patients with atrial fibrillation using a simple echocardiographic marker

BACKGROUND

Exercise intolerance is a common symptom associated with atrial fibrillation (AF). However, echocardiographic markers that can predict impaired exercise capacity are lacking.

OBJECTIVE

This study aimed to investigate the association between echocardiographic parameters and exercise capacity assessed by cardiopulmonary exercise testing in patients with AF.

METHODS

This single-center prospective study enrolled patients with AF who underwent echocardiography and cardiopulmonary exercise testing to evaluate exercise capacity at a tertiary center for AF management from 2020 to 2022. Patients with valvular heart disease, reduced left ventricular ejection fraction, or documented cardiomyopathy were excluded.

RESULTS

Of the 188 patients, 134 (71.2%) exhibited impaired exercise capacity (peak oxygen consumption ≤85%), including 4 (2.1%) having poor exercise capacity (peak oxygen consumption <50%). Echocardiographic findings revealed that these patients had an enlarged left atrial end-systolic diameter (LA); smaller left ventricular end-diastolic diameter (LVEDD); and increased relative wall thickness, tricuspid regurgitation velocity, and LA/LVEDD and E/e' ratios. In addition, they exhibited lower peak systolic velocity of the mitral annulus and LA reservoir strain. In the multivariate regression model, LA/LVEDD remained the only significant echocardiographic parameter after adjustment for age, sex, and body mass index (P = .020). This significance persisted even after incorporation of heart rate reserve, N-terminal pro-B-type natriuretic peptide level, and beta-blocker use into the model.

CONCLUSION

In patients with AF, LA/LVEDD is strongly associated with exercise capacity. Further follow-up and validation are necessary to clarify its clinical implications in patient care.

Structural and functional abnormalities of left-sided cardiac chambers in Barlow's disease without significant mitral regurgitation

AIMS

This study aims to explore the presence of left ventricular (LV) and left atrial (LA) morphological and functional abnormalities in patients with Barlow's disease (BD) without significant mitral regurgitation (MR) and to investigate whether these abnormalities may predict MR progression.

METHODS AND RESULTS

Consecutive patients with BD were retrospectively identified from two tertiary centres; those with MR graded from trivial to mild-to-moderate were selected and matched with healthy controls in a 1:1 ratio. Conventional and speckle-tracking echocardiographic data were collected. The development of moderate-to-severe or greater MR was evaluated on follow-up echocardiograms. Patients with BD (n = 231) showed increased LV dimensions and indexed LV mass (LVMi) in comparison with controls (P < 0.001); LV remodelling worsened with higher MR severity and was accompanied by an increased prevalence of eccentric LV hypertrophy (eLVH). Moreover, BD patients had larger LA volumes and more impaired LA reservoir strain vs. controls (P < 0.001), while LV strain was similar between the two groups. Multivariable linear regression analyses in the overall population identified BD and MR grade as independent predictors of remodelling markers (LV dimensions, LVMi, and LA volume) and BD as independent correlate of LA strain. MR progression was observed in 51 BD subjects (out of 170 patients with available follow-up). On Cox regression analysis, age, eLVH, mild-to-moderate MR, and mitral annular disjunction (MAD) emerged as independent predictors of MR progression.

CONCLUSION

BD patients without significant MR show early LV and LA remodelling, together with reduced LA strain. MR progression was associated with eccentric LV remodelling, MAD, and MR severity.

Insulin resistance may accelerate typical changes in heart function among type 1 diabetes patients, particularly in overweight patients: a preliminary study

Introduction

Type 1 diabetes (T1D) is a metabolic disease characterized by insulin deficiency and subsequent hyperglycemia. Cardiovascular diseases are the prime cause of mortality and morbidity among patients with T1D. Accumulating metabolic disturbances and accelerated cardiac fibrosis fuel the development of heart dysfunction. As insulin resistance (IR) is a risk factor for the development and worsened course of heart failure, this study aimed to assess its impact on heart function in patients with T1D.

Methods

Adult participants were recruited prospectively. The inclusion criteria included a diagnosis of T1D. The exclusion criteria were other types of diabetes, symptoms/treatment of heart failure, AST and/or ALT exceeding the upper reference limit by ≥2x, hepatitis, alcoholism, metformin treatment, and pregnancy. The participants underwent a medical interview, physical examination, biochemical test, and echocardiography.

Results

The mean age in the study group was 38 ± 9.6 years, and the mean diabetes duration was 21.8 ± 11.3 years. The median BMI in the study cohort was 23.39 kg/m2. Patients with IR had significantly lower mitral E/A ratio and left ventricular and left atrial volume ratio (LVLAVR), higher LV mass index, and presented with altered mitral annular velocities.

Conclusions

IR seems to accelerate the pattern of typical changes in heart function among patients with T1D, especially in the overweight subgroup.

Left atrial structural and functional remodelling in Fabry disease and cardiac amyloidosis: A comparative analysis

BACKGROUND

Fabry disease (FD) and transthyretin cardiac amyloidosis (TTR CA) are cardiomyopathies with hypertrophic phenotype that share several features, including left atrial (LA) enlargement and dysfunction, but direct comparative data are lacking. Aim of the present study was to perform a comparative analysis of LA remodelling between the two diseases.

METHODS AND RESULTS

In this prospective study, a total of 114 patients (31 FD and 83 TTR CA) were included; all of them had left ventricular hypertrophy (LVH), defined as left ventricular (LV) wall thickness ≥ 12 mm. Despite similar degree of LVH, patients with TTR CA showed worse LV systolic and diastolic function. LA maximal volume index was not significantly different between the two groups (p = 0.084), while patients with TTR CA showed larger LA minimal volume index (p = 0.001). Moreover, all phases of LA mechanics were more impaired in the TTR CA group vs FD (reservoir: 6.9[4.2-15.5] vs 19.0[15.5-29.5], p < 0.001). After excluding patients with atrial fibrillation (AF), these differences remained clearly significant. In multivariable regression analyses, LA reservoir strain showed an independent correlation with TTR CA, controlling for demographic characteristics, AF and LV systolic and diastolic performance (p ≤ 0.001), whereas LV global longitudinal strain did not. Finally, among echocardiographic parameters, LA function demonstrated the highest accuracy in discriminating the two diseases.

CONCLUSIONS

TTR CA is characterized by a more advanced LA structural and functional remodelling in comparison to patients with FD and similar degree of LVH. The association between TTR CA and LA dysfunction remains consistent after adjustment for potential confounders.

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.

Coronary microvascular dysfunction as assessed by multimodal diagnostic imaging in patients with hypertrophic cardiomyopathy is related to the severity of cardiac dysfunction

INTRODUCTION

Coronary microvascular dysfunction (CMD) plays a major role in hypertrophic cardiomyopathy (HCM) physiopathology but its assessment in clinical practice remains a challenge. Nowadays, innovations in invasive and noninvasive coronary evaluation using multimodal imaging provide options for the diagnosis of CMD. The objective of the present study was to investigate if new multimodal imaging diagnosis of CMD could detect HCM patients with more impaired cardiac function by left atrioventricular coupling index (LACI).

METHODS AND RESULTS

A total of 32 consecutive patients with a confirmed diagnosis of HCM (62 ± 13 years, 62% men) were prospectively screened for CMD using a multimodal imaging method. LACI was assessed by cardiovascular magnetic resonance imaging. Fifteen (47%) patients had CMD by multimodal imaging method. Patients with CMD presented a significantly higher LACI (48.5 ± 25.4 vs. 32.5 ± 10.6, p = .03). A multivariate logistic regression analysis demonstrated that CMD was independently associated with LACI (OR = 1.069, 95% CI 1.00-1.135, p = .03).

CONCLUSION

Multimodal imaging diagnosis of CMD is applicable to HCM patients and is associated with more impaired cardiac function.

Left atrioventricular coupling index assessed using cardiac CT as a prognostic marker of cardiovascular death

PURPOSE

The purpose of this study was to investigate the prognostic value of left atrioventricular coupling index (LACI) assessed by cardiac computed tomography (CT), to predict cardiovascular death in consecutive patients referred for cardiac CT with coronary analysis.

MATERIALS AND METHODS

Between 2010 and 2020, we conducted a single-centre study with all consecutive patients without known cardiovascular disease referred for cardiac CT. LACI was defined as the ratio of left atrial to left ventricle end-diastolic volumes. The primary outcome was cardiovascular death. Cox regressions were used to evaluate the association between LACI and primary outcome after adjustment for traditional risk factors and cardiac CT angiography findings.

RESULTS

In 1,444 patients (mean age, 70 ± 12 [standard deviation] years; 43% men), 67 (4.3%) patients experienced cardiovascular death after a median follow-up of 6.8 (Q1, Q3: 5.9, 9.1) years. After adjustment, LACI was positively associated with the occurrence of cardiovascular death (adjusted hazard ratio [HR], 1.07 [95% CI: 1.05-1.09] per 1% increment; P < 0.001), and all-cause death (adjusted HR, 1.05 [95% CI: 1.03-1.07] per 1% increment; P <0.001). After adjustment, a LACI ≥ 25% showed the best improvement in model discrimination and reclassification for predicting cardiovascular death above traditional risk factors and cardiac CT findings (C-statistic improvement: 0.27; Nnet reclassification improvement = 0.826; Integrative discrimination index =0.209, all P < 0.001; likelihood-ratio-test, P < 0.001).

CONCLUSION

LACI measured by cardiac CT is independently associated with cardiovascular death and all-cause death in patients without known cardiovascular disease referred for cardiac CT, with an incremental prognostic value over traditional risk factors and cardiac CT findings.

AI-Based Fully Automated Left Atrioventricular Coupling Index as a Prognostic Marker in Patients Undergoing Stress CMR

BACKGROUND

The left atrioventricular coupling index (LACI) is a strong and independent predictor of heart failure (HF) in individuals without clinical cardiovascular disease. Its prognostic value is not established in patients with cardiovascular disease.

OBJECTIVES

This study sought to determine in patients undergoing stress cardiac magnetic resonance (CMR) whether fully automated artificial intelligence-based LACI can provide incremental prognostic value to predict HF.

METHODS

Between 2016 and 2018, the authors conducted a longitudinal study including all consecutive patients with abnormal (inducible ischemia or late gadolinium enhancement) vasodilator stress CMR. Control subjects with normal stress CMR were selected using propensity score matching. LACI was defined as the ratio of left atrial to left ventricular end-diastolic volumes. The primary outcome included hospitalization for acute HF or cardiovascular death. Cox regression was used to evaluate the association of LACI with the primary outcome after adjustment for traditional risk factors.

RESULTS

In 2,134 patients (65 ± 12 years, 77% men, 1:1 matched patients [1,067 with normal and 1,067 with abnormal CMR]), LACI was positively associated with the primary outcome (median follow-up: 5.2 years [IQR: 4.8-5.5 years]) before and after adjustment for risk factors in the overall propensity-matched population (adjusted HR: 1.18 [95% CI: 1.13-1.24]), in patients with abnormal CMR (adjusted HR per 0.1% increment: 1.22 [95% CI: 1.14-1.30]), and in patients with normal CMR (adjusted HR per 0.1% increment: 1.12 [95% CI: 1.05-1.20]) (all P < 0.001). After adjustment, a higher LACI of ≥25% showed the greatest improvement in model discrimination and reclassification over and above traditional risk factors and stress CMR findings (C-index improvement: 0.16; net reclassification improvement = 0.388; integrative discrimination index = 0.153, all P < 0.001; likelihood ratio test P < 0.001).

CONCLUSIONS

LACI is independently associated with hospitalization for HF and cardiovascular death in patients undergoing stress CMR, with an incremental prognostic value over traditional risk factors including inducible ischemia and late gadolinium enhancement.

Imaging Early Life Cardiovascular Phenotype

The growing epidemics of obesity, hypertension, and diabetes, in addition to worsening environmental factors such as air pollution, water scarcity, and climate change, have fueled the continuously increasing prevalence of cardiovascular diseases (CVDs). This has caused a markedly increasing burden of CVDs that includes mortality and morbidity worldwide. Identification of subclinical CVD before overt symptoms can lead to earlier deployment of preventative pharmacological and nonpharmacologic strategies. In this regard, noninvasive imaging techniques play a significant role in identifying early CVD phenotypes. An armamentarium of imaging techniques including vascular ultrasound, echocardiography, magnetic resonance imaging, computed tomography, noninvasive computed tomography angiography, positron emission tomography, and nuclear imaging, with intrinsic strengths and limitations can be utilized to delineate incipient CVD for both clinical and research purposes. In this article, we review the various imaging modalities used for the evaluation, characterization, and quantification of early subclinical cardiovascular diseases.

Cardiovascular magnetic resonance-derived left atrioventricular coupling index and major adverse cardiac events in patients following acute myocardial infarction

BACKGROUND

Recently, a novel left atrioventricular coupling index (LACI) has been introduced providing prognostic value to predict cardiovascular events beyond common risk factors in patients without cardiovascular disease. Since data on cardiovascular magnetic resonance (CMR)-derived LACI in patients following acute myocardial infarction (AMI) are scarce, we aimed to assess the diagnostic and prognostic implications of LACI in a large AMI patient cohort.

METHODS

In total, 1046 patients following AMI were included. After primary percutaneous coronary intervention CMR imaging and subsequent functional analyses were performed. LACI was defined by the ratio of the left atrial end-diastolic volume divided by the left ventricular (LV) end-diastolic volume. Major adverse cardiac events (MACE) including death, reinfarction or heart failure within 12 months after the index event were defined as primary clinical endpoint.

RESULTS

LACI was significantly higher in patients with MACE compared to those without MACE (p < 0.001). Youden Index identified an optimal LACI cut-off at 34.7% to classify patients at high-risk (p < 0.001 on log-rank testing). Greater LACI was associated with MACE on univariate regression modeling (HR 8.1, 95% CI 3.4-14.9, p < 0.001) and after adjusting for baseline confounders and LV ejection fraction (LVEF) on multivariate regression analyses (HR 3.1 95% CI 1.0-9, p = 0.049). Furthermore, LACI assessment enabled further risk stratification in high-risk patients with impaired LV systolic function (LVEF ≤ 35%; p < 0.001 on log-rank testing).

CONCLUSION

Atrial-ventricular interaction using CMR-derived LACI is a superior measure of outcome beyond LVEF especially in high-risk patients following AMI. Trial registration ClinicalTrials.gov, NCT00712101 and NCT01612312.

Prognostic value of a left atrioventricular coupling index in pre- and post-menopausal women from the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Sex hormones associated with both the left atrial (LA) and left ventricular (LV) structures in women, but the association of menopause status with left atrioventricular coupling is not established.

AIM

To assess the prognostic value of a left atrioventricular coupling index (LACI) in peri-menopausal women without a history of cardiovascular disease (CVD).

MATERIALS AND METHODS

In all women participating in MESA study with baseline cardiovascular MRI, the LACI was measured as the ratio of the LA end-diastolic volume to the LV end-diastolic volume. Cox models were used to assess the association between the LACI and the outcomes of atrial fibrillation (AF), heart failure (HF), coronary heart disease (CHD) death, and hard CVD.

RESULTS

Among the 2,087 women participants (61 ± 10 years), 485 cardiovascular events occurred (mean follow-up: 13.2 ± 3.3 years). A higher LACI was independently associated with AF (HR 1.70; 95%CI [1.51-1.90]), HF (HR 1.62; [1.33-1.97]), CHD death (HR 1.36; [1.10-1.68]), and hard CVD (HR 1.30; [1.13-1.51], all p < 0.001). Adjusted models with the LACI showed significant improvement in model discrimination and reclassification when compared to traditional models to predict: incident AF (C-statistic: 0.82 vs. 0.79; NRI = 0.325; IDI = 0.036), HF (C-statistic: 0.84 vs. 0.81; NRI = 0.571; IDI = 0.023), CHD death (C-statistic: 0.87 vs. 0.85; NRI = 0.506; IDI = 0.012), hard CVD (C-statistic: 0.78 vs. 0.76; NRI = 0.229; IDI = 0.012). The prognostic value of the LACI had a better discrimination and reclassification than individual LA or LV parameters.

CONCLUSION

In a multi-ethnic population of pre- and post-menopausal women, the LACI is an independent predictor of HF, AF, CHD death, and hard CVD.

CLINICAL TRIAL REGISTRATION

[https://clinicaltrials.gov/], identifier [NCT00005487].