Change in Left Atrioventricular Coupling Index to Predict Incident Atrial Fibrillation: The Multi-Ethnic Study of Atherosclerosis (MESA)

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.

Incremental Prognostic Value of Left Atrial Strain in Patients With Suspected Myocarditis and Preserved Left Ventricular Ejection Fraction

BACKGROUND

Analysis of left atrial (LA) strain and left atrioventricular coupling index (LACI) have prognostic value in cardiovascular diseases. However, the prognostic value of LA strain and LACI in patients with suspected myocarditis and preserved left ventricular ejection fraction (LVEF) is unclear.

PURPOSE

To investigate the prognostic value of LA strain and LACI in patients with suspected myocarditis and preserved LVEF in comparison with conventional MRI outcome predictors.

STUDY TYPE

Retrospective.

POPULATION

One hundred sixty-five patients with clinically suspected myocarditis and preserved LVEF with available follow-up data.

FIELD STRENGTH/SEQUENCE

Steady-state free precession cine and phase-sensitive inversion recovery segmented gradient echo late gadolinium enhancement sequences at 3.0 T.

ASSESSMENT

Left ventricular (LV) and LA strain were evaluated using feature tracking. LACI was calculated as the ratio of LA and LV volumes at LV end-diastole. Patients were followed-up with the primary endpoint being major adverse cardiovascular events (MACE).

STATISTICAL TESTS

Independent-samples t-test and Mann-Whitney U test to compare patients with and without MACE, receiver operating characteristic (ROC) curve analysis to define high/low risk groups, Kaplan-Meier survival analysis and Cox proportional hazards regression to assess prognosis. A P value of <0.05 was considered statistically significant.

RESULTS

The associations of LV strain parameters (including global radial, circumferential, and longitudinal strain) and LACI with MACE were not significant (P = 0.511, 0.108, 0.148, and 0.847, respectively). An optimal LA conduit strain (Ԑe) cutoff value of 10.4% was identified to best classify patients into low- and high-risk groups. Only Ԑe was significantly associated with MACE in both univariable (hazards ratio [HR] 0.936, 95% confidence interval [CI] 0.884-0.991) and multivariable Cox survival analyses (HR 0.937, 95% CI 0.884-0.994).

DATA CONCLUSION

LA conduit strain has prognostic value in patients with suspected myocarditis and preserved LVEF, incremental to conventional MRI outcome predictors, whereas LACI was not associated with MACE occurrence.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Left atrioventricular coupling index assessed with three-dimensional echocardiography: a prognostic marker of short-term outcomes in light-chain cardiac amyloidosis

BACKGROUND

Light-chain cardiac amyloidosis (AL-CA) is associated with structural and functional changes in the left atrium and left ventricle. This study aims to assess the value of the left atrioventricular coupling index (LACI) assessed by three-dimensional echocardiography (3DE) for predicting primary outcome in AL-CA.

METHODS

Participants with biopsy-confirmed AL-CA from April 2022 to February 2024 were prospectively analysed. LACI, the ratio of left atrial volume min to left ventricular end-diastolic volumes, was calculated offline using EchoPAC 204. The primary outcome was defined as all-cause death.

RESULTS

Sixty-seven biopsy-proven AL-CA patients were studied (age: 62.98 ± 10.20 years; 67% male). The median follow-up was 121 days (range: 7 ∼ 732 days). All-cause mortality occurred in 26 (39%) patients. Multivariate Cox regression revealed a significant association of LACI after adjusting for NT-pro BNP, troponin T, moderate tricuspid regurgitation, pericardial and pleural effusion (adjusted HR: 10.58, p = 0.008). Kaplan-Meier curves displayed prognostic differences based on median LACI (cut-off : 0.57, p = 0.002). The likelihood ratio χ2 test showed that LACI added predictive value to Mayo 2004, European 2015 modification of Mayo 2004, and Mayo 2012 models (All p < 0.001).

CONCLUSIONS

3DE-based LACI is independently associated with all-cause mortality in AL-CA patients and augments prognostic value to traditional staging models.

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.

Cardiovascular magnetic resonance-derived left atrioventricular coupling index as a novel prognostic marker for light-chain amyloidosis

BACKGROUND

Left atrioventricular coupling index (LACI) is a novel biomarker, and the prognostic value of LACI to predict cardiovascular events has been validated. The present study aimed to explore the prognostic value of LACI in patients with light-chain (AL) amyloidosis.

METHODS

We prospectively enrolled 179 patients with AL amyloidosis who underwent cardiovascular magnetic resonance imaging between December 2011 and January 2020. LACI was defined as the ratio between the left atrial volume and the left ventricular volume at end-diastole. The primary endpoint was all-cause mortality. Receiver operating characteristic curve was used to identify the optimal cut-off of LACI in predicting all-cause mortality. Univariable and multivariable Cox proportional hazard models were used to assess the association of LACI and primary endpoint.

RESULTS

During a median follow-up of 30 months, 118 (65.9 %) patients with all-cause mortality were documented. LACI was significantly higher in patients with primary endpoint compared to those without primary endpoint (55.4 %, interquartile range: 31.6 %-71.5 % vs. 39.4 %, interquartile range: 24.1 %-54.7 %, p = 0.001). The optimal cut-off for LACI to predict mortality was 49.3 %. In multivariate Cox regression analysis, LACI≥49.3 % (HR 1.907, 95 % CI 1.273-2.857, p = 0.002) was an independent predictor of all-cause mortality. On Kaplan-Meier analysis, patients at advanced Mayo stage (IIIa and IIIb) can be further risk stratified using LACI≥49.3 % (log-rank p = 0.035, p = 0.025).

CONCLUSION

The LACI provides powerful independent prognostic value in AL amyloidosis. The LACI has incremental prognostic value to predict all-cause mortality over the Mayo stage in patients at the advanced Mayo stage.

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.

Assessment of left atrial function and left atrioventricular coupling via cardiac magnetic resonance in individuals with prediabetes and diabetes

AIMS

Assessment of left atrial (LA) function and the left atrioventricular coupling index (LACI) have recently been increasingly recognized as important indices for cardiovascular diseases associated with the presence of prediabetes and diabetes. We aimed to evaluate LA function and the LACI in patients with prediabetes and diabetes via cardiac magnetic resonance (CMR).

METHODS

In this retrospective study, we included 35 patients with prediabetes, 32 patients with diabetes, and 84 healthy control participants. The LACI and LA total, passive, and active emptying fractions (LATEmF, LAPEmF, and LAAEmF, respectively) were calculated. The LA reservoir, conduit, and booster pump strains (εs, εe, and εa), and peak positive, peak early negative, and peak late negative strain rates (SRs, SRe, and SRa) were obtained via CMR-feature tracking (CMR-FT). For the statistical analyses, one-way analysis of variance, the Kruskal-Wallis test, and linear regression were conducted, and Pearson's and interclass correlation coefficients were calculated.

RESULTS

Compared with healthy control participants, patients with prediabetes or diabetes presented lower εs and εe values and a relatively preserved LACI. Patients with diabetes presented considerably reduced SRs, SRe, and LAPEmF. Elevated glycated haemoglobin (HbA1c) levels were independently associated with decreased magnitudes of εs, SRs, εe, and SRe. No significant associations were found between the LACI and the HbA1c or LA deformation parameters. We observed significant correlations between LATEmF and εs, LAPEmF and εe and between LAAEmF and εa.

CONCLUSIONS

CMR-FT provides a potential noninvasive approach for the early detection of alterations in the LA reservoir and conduit function in individuals with prediabetes and diabetes.

Predictive value of the left atrioventricular coupling index for recurrence after radiofrequency ablation of paroxysmal atrial fibrillation

BACKGROUND

Although patients with paroxysmal atrial fibrillation (PAF) are preferred to undergo catheter ablation (CA), the high possibility of recurrence following surgery is still concerning. We aimed to evaluate the ability of the left atrioventricular coupling index (LACI), which is the ratio of the left atrium end-diastolic volume to the left ventricle end-diastolic volume, to predict PAF recurrence after CA.

METHODS

Patients with PAF undergoing CA for the first time between January 2018 and June 2021 were admitted and grouped by recurrence within a year. LACI was measured before CA using ultrasonography. Risk factors identified by multivariable logistic regression analysis, and the area under the receiver operating characteristic (ROC) curve was used to assess the ability of LACI to predict PAF recurrence after CAP.

RESULTS

Among the 204 patients treated at our hospital, 164 patients were included in the research after eliminating those who were lost to follow-up. Among them, 56 individuals had recurrence following a 90-day blanking period. Recurrence is more likely in elderly patients with high blood pressure. Patients who suffered recurrence exhibited lower left atrial ejection fraction and increased LACI, left atrial volume minimum, and left atrium volume index maximum. LACI was an independent risk factor for postoperative recurrence (OR: 1.526, 95% CI: 1.325-1.757, P < 0.001), and ROC displayed remarkable predictive value [area under the curve (AUC) = 0.868].

CONCLUSIONS

High LACI is significantly associated with postoperative recurrence in PAF patients, and LACI has incremental prognostic value to predict recurrence.

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.

Left and right atrioventricular coupling index in patients with beta-thalassemia major

The aim of this cross-sectional study was to investigate the relationship of left atrioventricular coupling index (LACI) and right atrioventricular coupling index (RACI) with demographics, clinical data, cardiovascular magnetic resonance findings, and cardiac complications (heart failure, arrhythmias, and pulmonary hypertension) in a cohort of patients with beta-thalassemia major (β-TM). We evaluated 292 β-TM patients (151 females, 36.72 ± 11.76 years) consecutively enrolled in the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project. Moreover, we assessed 32 sex- and age-matched healthy controls (12 females, mean age 40.78 ± 14.35 years). LACI was determined by calculating the ratio of the left atrium end-diastolic volume to the left ventricle end-diastolic volume, while RACI was defined by calculating the ratio of the right atrium end-diastolic volume to the right ventricle end-diastolic volume. Compared to healthy control, β-TM demonstrated increased LACI (22.99 ± 13.58% vs. 16.05 ± 5.28%; p < 0.0001) and RACI (27.84 ± 10.30% vs. 17.06 ± 5.03%; p < 0.0001). Aging, diabetes, splenectomy, and the presence of late gadolinium enhancement (LGE) showed a significant positive association with both LACI and RACI. In stepwise regression analysis, the presence of LGE was found to be an independent predictor of both impaired LACI and RACI (β coefficient = 0.244, p < 0.0001 and β coefficient = 0.218, p = 0.003; respectively). LACI and RACI were not correlated with myocardial iron overload. Patients with cardiac complications had significantly higher LACI and RACI than patients without cardiac complications. In patients with β-TM, LACI and RACI were significantly associated with the presence of LV LGE. In addition, patients with cardiac complications had impaired LACI and RACI.

Left Atrial Coupling Index Predicts Heart Failure in Patients with End Stage Renal Disease

Background and Objectives: We aimed to ascertain the predictive power of the left atrial coupling index (LACI) in patients with end stage renal disease (ESRD) for heart failure with preserved ejection fraction (HFpEF). Materials and Methods: This is a retrospective study including 100 subjects between 18 and 65 years of age with ESRD and not on dialysis treatment. Patients were divided into groups with and without HFpEF. The LACI was defined as the ratio of the left atrial volume index (LAVI) to the a' wave in tissue Doppler imaging (TDI). Statistical analyses were performed, including univariate and multivariate regression analyses. Results: The mean age of the participants was 47 ± 13.3 years. Individuals with HFpEF exhibited a higher LACI. Univariate and multivariate regression analyses demonstrated that the predictive capacity of the LACI for HFpEF was considerably higher than that of the LAVI and other echocardiographic parameters. Conclusions: Higher LACI levels were consistently related to the presence of HFpEF in ESRD patients. The LACI can be easily obtained in daily practice using conventional Doppler echocardiographic measurements during left atrial functional assessments.

Differential Stroke Volume between Left and Right Ventricles as a Predictor of Clinical Outcomes: The MESA Study

Background Valvular heart disease and intracardiac shunts can disrupt the balance between left ventricular (LV) and right ventricular (RV) stroke volumes. However, the prognostic value of such imbalances has not been established among asymptomatic individuals. Purpose To assess the association between differential ventricular stroke volumes quantified using cardiac MRI and clinical outcomes in individuals without cardiovascular disease. Materials and Methods This secondary analysis of a prospective study included participants without cardiovascular disease at enrollment (July 2000 to July 2002) who underwent cardiac MRI. Differences in stroke volume were calculated as LV stroke volume minus RV stroke volume, and participants were categorized as having balanced (greater than or equal to -30 mL to ≤30 mL), negative (less than -30 mL), or positive (>30 mL) differential stroke volumes. Multivariable Cox proportional hazard regression models were used to test the association between differences in stroke volume and adverse outcomes. Results A cohort of 4058 participants (mean age, 61.4 years ± 10 [SD]; 2120 female) were included and followed up for a median of 18.4 years (IQR, 18.3-18.5 years). During follow-up, 1006 participants died, 235 participants developed heart failure, and 764 participants developed atrial fibrillation. Compared with participants who had a balanced differential stroke volume, those with an increased differential stroke volume showed a higher risk of mortality (hazard ratio [HR], 1.73 [95% CI: 1.12, 2.67]; P = .01), heart failure (HR, 2.40 [95% CI: 1.11, 5.20]; P = .03), and atrial fibrillation (HR, 1.89 [95% CI: 1.16, 3.08]; P = .01) in adjusted models. Participants in the negative group, with a decreased differential stroke volume, showed an increased risk of heart failure compared with those in the balanced group (HR, 2.09 [95% CI: 1.09, 3.99]; P = .03); however, this was no longer observed after adjusting for baseline LV function (P = .34). Conclusion Participants without cardiovascular disease at the time of study enrollment who had an LV stroke volume exceeding the RV stroke volume by greater than 30 mL had an increased risk of mortality, heart failure, and atrial fibrillation compared with those with balanced stroke volumes. ClinicalTrials.gov Identifier: NCT00005487 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Almeida in this issue.

Improved Interpretation of Pulmonary Artery Wedge Pressures through Left Atrial Volumetry-A Cardiac Magnetic Resonance Imaging Study

BACKGROUND

The pulmonary artery wedge pressure (PAWP) is regarded as a reliable indicator of left ventricular end-diastolic pressure (LVEDP), but this association is weaker in patients with left-sided heart disease (LHD). We compared morphological differences in cardiac magnetic resonance imaging (CMR) in patients with heart failure (HF) and a reduced left ventricular ejection fraction (LVEF), with or without elevation of PAWP or LVEDP.

METHODS

We retrospectively identified 121 patients with LVEF < 50% who had undergone right heart catheterization (RHC) and CMR. LVEDP data were available for 75 patients.

RESULTS

The mean age of the study sample was 63 ± 14 years, the mean LVEF was 32 ± 10%, and 72% were men. About 53% of the patients had an elevated PAWP (>15 mmHg). In multivariable logistic regression analysis, NT-proBNP, left atrial ejection fraction (LAEF), and LV end-systolic volume index independently predicted an elevated PAWP. Of the 75 patients with available LVEDP data, 79% had an elevated LVEDP, and 70% had concomitant PAWP elevation. By contrast, all but one patient with elevated PAWP and half of the patients with normal PAWP had concomitant LVEDP elevation. The Bland-Altman plot revealed a systematic bias of +5.0 mmHg between LVEDP and PAWP. Notably, LAEF was the only CMR variable that differed significantly between patients with elevated LVEDP and a PAWP ≤ or >15 mmHg.

CONCLUSIONS

In patients with LVEF < 50%, a normal PAWP did not reliably exclude LHD, and an elevated LVEDP was more frequent than an elevated PAWP. LAEF was the most relevant determinant of an increased PAWP, suggesting that a preserved LAEF in LHD may protect against backward failure into the lungs and the subsequent increase in pulmonary pressure.

Left ventricular hypertrophy phenotype to predict incident atrial fibrillation: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIM

Left ventricular hypertrophy (LVH) has been shown to be associated with the occurrence of atrial fibrillation (AF). However, the predictive value of the LVH phenotype for incident AF remains uncertain. This study aimed to investigate the predictive value of LVH phenotype for incident AF.

METHODS AND RESULTS

This study utilized the Multi-Ethnic Study of Atherosclerosis (MESA) data. LVH was defined by cardiac magnetic resonance measured LV mass index. Isolated LVH was determined as LVH without elevated cardiac biomarker and malignant LVH was determined as LVH with at least 1 elevated biomarker. Receiver-operating characteristic (ROC) analysis was performed to calculate areas under the curves (AUC) for predicting AF. A total of 4983 community-dwelling participants were included, with a mean age of 61.5 years. 279 (5.6 %) had isolated LVH, and 222 (4.5 %) had malignant LVH. During a median follow-up of 8.5 years, 272 incident AF was observed. Compared to participants without LVH and elevated cardiac biomarkers, those with isolated LVH (HR, 1.82; 95 % CI, 1.03-3.20) and malignant LVH (HR, 4.13; 95 % CI, 2.77-6.16) had a higher risk of incident AF. Malignant LVH carried a 1.5-fold increased risk of AF compared to isolated LVH (HR: 2.48, 95 % CI: 1.30-4.73). Including the LVH phenotype in the CHARGE-AF model improved model discrimination (AUC increase: 0.03, p < 0.001).

CONCLUSIONS

The risks of AF incidence varied across LVH phenotypes. Malignant LVH carried the highest risk among LVH phenotypes. LVH phenotype provides incremental predictive value over the variables included in the CHARGE-AF model.

[Using CT to Evaluate Cardiac Function]

A comprehensive evaluation of cardiac function includes information in relation to cardiac output and systemic venous return. The heart is composed of four chambers: two atria and two ventricles, each with its own unique mechanical function. These four cardiac chambers, their valves, and the pulmonary circulation system are inter-related as they preload or afterload on each other. Cardiac dysfunction is a failure of global cardiac function, resulting in typical clinical manifestations. To investigate the underlying cause of cardiac dysfunction, a step-by-step evaluation of cardiac blood flow tracks is necessary. In this context, imaging markers showing details of the cardiac structures have an important role in assessing cardiac function. An image-based evaluation allows for investigation of function in terms of individual cardiac components. Evaluation of cardiac function using cardiac CT has recently been validated. This review aimed to discuss cardiac CT-based imaging markers for comprehensive and detailed cardiac function assessment.

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.

Association of Lipoprotein(a) Levels With Myocardial Fibrosis in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Lipoprotein(a) (Lp[a]) has been identified as an emerging risk factor for adverse cardiovascular (CV) outcomes, including heart failure. However, the connections among Lp(a), myocardial fibrosis (interstitial and replacement), and cardiac remodeling as pathways to CV diseases remains unclear.

OBJECTIVES

This study investigated the relationship between Lp(a) levels and myocardial fibrosis by cardiac magnetic resonance (CMR) T1 mapping and late gadolinium enhancement, as well as cardiac remodeling by cine CMR, in the MESA (Multi-Ethnic Study of Atherosclerosis) cohort.

METHODS

The study included 2,040 participants with baseline Lp(a) measurements and T1 mapping for interstitial myocardial fibrosis (IMF) evaluation in 2010. Lp(a) was analyzed as a continuous variable (per log unit) and using clinical cutoff values of 30 and 50 mg/dL. Multivariate linear and logistic regression were used to assess the associations of Lp(a) with CMR measures of extracellular volume (ECV fraction [ECV%]), native T1 time, and myocardial scar, as well as parameters of cardiac remodeling, in 2,826 participants.

RESULTS

Higher Lp(a) levels were associated with increased ECV% (per log-unit Lp[a]; β = 0.2%; P = 0.007) and native T1 time (per log-unit Lp[a]; β = 4%; P < 0.001). Similar relationships were observed between elevated Lp(a) levels and a higher risk of clinically significant IMF defined by prognostic thresholds per log-unit Lp(a) of ECV% (OR: 1.20; 95% CI: 1.04-1.43) and native T1 (OR: 1.2; 95% CI: 1.1-1.4) equal to 30% and 955 ms, respectively. Clinically used Lp(a) cutoffs (30 and 50 mg/dL) were associated with greater prevalence of myocardial scar (OR: 1.85; 95% CI: 1.1-3.2 and OR: 1.9; 95% CI: 1.1-3.4, respectively). Finally, higher Lp(a) levels were associated with left atrial enlargement and dysfunction.

CONCLUSIONS

Elevated Lp(a) levels are linked to greater subclinical IMF, increased myocardial scar prevalence, and left atrial remodeling.

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.

Effect of Metabolic Dysfunction-Associated Fatty Liver Disease on Left Ventricular Deformation and Atrioventricular Coupling in Patients With Metabolic Syndrome Assessed by MRI

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) was recently recognized as an important risk factor for cardiovascular diseases.

PURPOSE

To examine the effect of MAFLD on cardiac function in metabolic syndrome by MRI.

STUDY TYPE

Retrospective.

POPULATION

One hundred seventy-nine patients with metabolic syndrome (MetS), 101 with MAFLD (MAFLD [+]) and 78 without (MAFLD [-]). Eighty-one adults without any of the components of MetS or cardiac abnormalities were included as control group.

FIELD STRENGTH/SEQUENCE

3.0 T; balanced steady-state free precession sequence.

ASSESSMENT

Left atrial (LA) strain was assessed during three phases: reservoir strain (LA-RS), conduit strain (LA-CS), and booster strain (LA-BS). Left ventricular (LV) global longitudinal (LV-GLS) strain was also derived. The left atrioventricular coupling index (LACI) was calculated as the ratio of LA end-diastolic volume (LA-EDV) and LV-EDV.

STATISTICAL TESTS

Student's t test or Mann-Whitney U test; One-way analysis of variance. A P value <0.05 was considered statistically significant.

RESULTS

Among MetS patients, individuals with MAFLD had significantly lower magnitude LV-GLS (-11.6% ± 3.3% vs. -13.8% ± 2.7%) than those without MAFLD. For LA strains, LA-RS (36.9% ± 13.7% vs. 42.9% ± 13.5%) and LA-CS (20.0% ± 10.6% vs. 24.1% ± 9.2%) were also significantly reduced in MAFLD (+) compared to MAFLD (-). The LACIs (17.2% [12.9-21.2] % vs. 15.8% [12.2-19.7] %) were significantly higher in patients with MAFLD compared to those without MAFLD. After adjustment for other clinical factors, MAFLD was found to be independently correlated with LV-GLS (β = -0.270) and LACI (β = 0.260).

DATA CONCLUSION

MAFLD had an unfavorable effect on LV myocardial strain in MetS. Moreover, LA strain and atrioventricular coupling were further impaired in patients with concomitant MAFLD compared to those without MAFLD. Last, MAFLD was independently associated with subclinical LV dysfunction and atrioventricular coupling after adjustment for other clinical factors.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: 3.

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.

The Use of Automated Atrial CMR Measures and a Novel Atrioventricular Coupling Index for Predicting Risk in Repaired Tetralogy of Fallot

Atrial size and function have been recognized as markers of diastolic function, and diastolic dysfunction has been identified as a predictor of adverse outcomes in repaired tetralogy of Fallot (rTOF). This was a retrospective single-center study with the objective of investigating the use of atrial measurements obtained via CMR for predicting outcomes in rTOF patients. Automated contours of the left and right atria (LA and RA) were performed. A novel parameter, termed the Right Atrioventricular Coupling Index (RACI), was defined as the ratio of RA end-diastolic volume to right ventricle (RV) end-diastolic volume. Patients were risk-stratified using a previously validated Importance Factor Score for the prediction of life-threatening arrhythmias in rTOF. Patients with a high-risk Importance Factor Score (>2) had a significantly larger minimum RA volume (p = 0.04) and RACI (p = 0.03) compared to those with scores ≤2. ROC analysis demonstrated RACI to be the best overall predictor of a high-risk Importance Factor Score (AUC 0.73, p = 0.03). Older age at the time of repair and a diagnosis of pulmonary atresia were associated with a larger RACI. Automated atrial CMR measurements are easily obtained from standard CMRs and have the potential to serve as noninvasive predictors of adverse outcomes in rTOF.

Influence of temporal resolution on computed tomography feature-tracking strain measurements

PURPOSE

Temporal resolution significantly affects strain values demonstrated by Magnetic resonance feature-tracking and speckle-tracking echocardiography. We investigated the influence of R-R interval reconstruction increments on left ventricular (LV) and left atrial (LA) strain measurements of Computed tomography feature-tracking (CT-FT).

METHODS

Subjects who underwent retrospective electrocardiogram-gated coronary CT angiography (CCTA) were retrospectively included, and CCTA images were reconstructed in 5% and 10% steps throughout the entire cardiac cycle (0-100% R-R interval). LV global longitudinal strain (GLS), circumferential strain (GCS), radial strain (GRS), LA GLS, ejection fraction (EF), and left atrioventricular coupling indices were computed. We evaluated the consistency and variability of continuous variables between the two reconstruction increment groups, the demarcation between the LA conduit and contraction phases, and observer reproducibility in 20 randomly selected participants.

RESULTS

Eighty-one participants with or without cardiac disease were included. The reconstruction increment of the R-R interval significantly affected the CT-FT-derived strain values. The 5% R-R increment resulted in significantly larger absolute strain values. LV GRS had the greatest difference between the two groups. In the subgroups with heart rates greater than 80 beats per minute or impaired cardiac function, group differences were attenuated, especially for LV GLS, LV GRS, and LA GLS. The prevalence of definite demarcation between the LA conduit and contraction phases was significantly higher in the 5% R-R reconstruction increment group than in the 10% R-R reconstruction increment group. The average heart rate during CCTA scanning was a strong risk factor for indefinite demarcation, which is independent of LVEF. As average heart rate increased, so did the incidence of indefinite demarcation between the LA conduit and contraction phases. The observer reproducibility of LV and LA strain values was independent of the R-R reconstruction increment.

CONCLUSION

Reconstruction increment of the R-R interval is an important source of variation in LV and LA CT-FT strain values, especially with low heart rate and preserved cardiac function. It is essential to control the heart rate and apply a narrow R-R reconstruction increment to quantify phasic LA strain.

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].