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

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.

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.

[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 &lt; 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].