Assessment of left atrial function in patients with type 2 diabetes mellitus with a disease duration of six months

Evaluating left atrial function changes by speckle tracking echocardiography in type 2 diabetes patients in Central Vietnam: a cross-sectional comparative study

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that detrimentally affects multiple systems in the body, with a particular emphasis on the vascular and nervous systems. Despite its significant impact, limited studies have explored the influence of this condition on the left atrial (LA) function. To address this gap, our study utilized speckle tracking echocardiography (STE) to assess LA function in patients with T2DM in Central Vietnam.

RESULTS

The cross-sectional comparative study enrolled 134 subjects involving 66 patients with T2DM and 68 healthy individuals meeting the selection and exclusion criteria of the study. In our study, healthy individuals demonstrated higher values for LA reservoir strain (LASr), LA conduit strain (LAScd), and LA contractile strain (LASct), measuring 38.75% ± 5.43%, 19.58% ± 5.91%, and 19.16% ± 4.98%, respectively. In contrast, the T2DM group exhibited lower values for LASr, LAScd, and LASct, which measured 31.2% ± 4.56%, 14.77% ± 6.3%, and 16.36% ± 4.82%, respectively (p < 0.05). T2DM patients with normal LA volume index (LAVI) and normal left ventricular mass index (LVMI), LASr, LAScd, and LASct results were 32.07% ± 5.28%, 16.28% ± 6.95%, and 15.64% ± 5.32%. respectively.

CONCLUSIONS

STE of the LA reveals a noteworthy reduction in reservoir, conduit, and contractile functions within the T2DM group when compared to the control group (p < 0.05). Furthermore, these impaired functions persist in T2DM patients even in the absence of increased LAVI and LVMI.

Impact of Cardiac Magnetic Resonance Left Atrial Ejection Fraction in Advanced Ischemic Cardiomyopathy

BACKGROUND

The prognostic significance of cardiac magnetic resonance (CMR)-based left atrial ejection fraction (LAEF) is not well defined in the ischemic cardiomyopathy (ICM) cohort.

OBJECTIVES

The authors sought to assess the prognostic impact of LAEF, when adjusted for left ventricular remodeling, myocardial infarct size (MIS), left atrial volume index, and functional mitral regurgitation (FMR), on outcomes in patients with advanced ICM.

METHODS

ICM patients who underwent CMR were retrospectively evaluated (April 2001-December 2019). LAEF, left atrial volume index, MIS, left ventricular remodeling, and FMR were derived from CMR. The primary clinical endpoint was a composite of all-cause mortality and cardiac transplant. A baseline multivariable Cox proportional hazards regression model was constructed to assess prognostic power of LAEF.

RESULTS

There were 718 patients (416 primary events) evaluated, with a median duration of follow-up of 1,763 days (4.8 years) and a mean LAEF of 36% ± 15%. On multivariable analysis, higher LAEF was independently associated with reduced risk (HR: 0.24, 95% CI: 0.12-0.48, P < 0.001), even after adjusting for FMR and MIS. The highest adjusted risk was observed in patients with an LAEF <20% and an MIS of >30% (HR: 3.20, 95% CI: 1.73-5.93). The lowest risk was in patients within the comparator group with an LAEF of >50% and a MIS of <15% (HR: 1.07, 95% CI: 0.81-1.42).

CONCLUSIONS

Reduced LAEF is independently associated with increased mortality in ICM. Risk associated with declining LAEF is continuous and incremental to other risk factors for adverse outcomes in patients with ICM even after adjusting for MIS and FMR severity.

Interaction effect of type 2 diabetes mellitus and hypertension on left atrial function: a three-dimensional echocardiography study

Background

Type 2 diabetes mellitus (T2DM) and hypertension (HT) often coexist and contribute to left atrial (LA) functional abnormalities. The aim of the present study was to explore whether there is a potential interaction effect between T2DM and HT on LA function.

Methods

A total of 135 patients (45 with T2DM only, 45 with HT only, and 45 with both T2DM and HT) were enrolled and compared to 45 age- and sex-matched controls. LA volume fraction, including LA ejection fraction (LAEF), LA expansion index (LAEI), LA passive emptying fraction (LAPEF), and LA active emptying fraction (LAAEF), and strain parameters, including LA reservoir longitudinal strain (LASr), LA conduit longitudinal strain (LAScd), and LA contraction longitudinal strain (LASct), were obtained using three-dimensional echocardiography (3DE).

Results

Patients with T2DM had significantly more impaired LA reservoir and conduit functions compared to those without T2DM (P<0.05), and patients with HT had a significantly more impaired LA reservoir function, conduit function, and booster pump function compared to those without HT (P<0.05). Two-way analysis of variance showed that there were significant additive interaction effects between T2DM and HT with respect to LASr (PT2DM + HT =0.002) and LAScd (PT2DM + HT =0.001). Generalized linear model demonstrated that T2DM + HT had a greater relative contribution than either T2DM or HT alone to the LA strain indexes, even after adjustment for other confounders (LASr, βT2DM + HT =-3.931, 95% CI: -6.237 to -1.624, P=0.001; LAScd, βT2DM + HT=-3.781, 95% CI: -5.653 to -1.908, P<0.001).

Conclusions

Both T2DM and HT had an adverse effect on LA function. The coexistence of both conditions further impaired LA performance in an additive interaction fashion.

Diabetic microvascular complications are associated with left atrial structural alterations in asymptomatic type 2 diabetes patients: A cross-sectional study

AIMS

We used 4D-Auto LAQ to quantitatively evaluate the morphological and functional changes of left atrium in patients with asymptomatic type 2 diabetes mellitus (T2DM), and explored its correlations with diabetic microvascular complications (MICRO).

METHODS

This study included 319 patients with asymptomatic T2DM. According to the occurrence of MICRO, these patients were divided into 3 groups: patients with no complication, 1 complication, and 2-3 complications. 4D-Auto LAQ was used to evaluate left atrial volume (LAVImin, LAVImax, LAVIpre) and calculate the left atrial function (DEI, PEI, AEI) in different phases. Multiple linear regression was used to analyze the correlation between changes in left atrial volume and function and the number of MICROs in DM patients.

RESULTS

A total of 279 patients with asymptomatic T2DM were included in this study. (1) The ultrasound data of the three T2DM groups showed that there was no significant difference in left ventricular size and function among the three groups; (2) with the increase of MICRO number, the left atrial volume (LAVImin, LAVImax, LAVIpre) progressively increased, the left atrial storage function index (DEI) gradually decreased, and the differences were significant (P < 0.05). (3) Multiple linear regression analysis showed that: with the increase of MICRO number (no complication→1 complication→2-3 complications), the left atrial volume (LAVImin, LAVIpre) showed an increasing trend (both P < 0.05).

CONCLUSION

In asymptomatic T2DM patients, MICRO number showed a significant positive correlation with LAVImin and LAVIpre (P < 0.05). Therefore, the increase in left atrial volume can dynamically reflect the severity of microvascular lesions in patients with asymptomatic T2DM.

Atrioventricular coupling and left atrial abnormality in type 2 diabetes mellitus with functional mitral regurgitation patients verified by cardiac magnetic resonance imaging

BACKGROUND

Functional mitral regurgitation (FMR) in type 2 diabetes mellitus (T2DM) patients induced by left ventricular (LV) enlargement and mitral valve abnormality may aggravated the impairment in left atrial (LA) compliance. Thus, this study aimed to depict how FMR and LV dysfunction affect LA compliance in T2DM patients with FMR.

MATERIALS AND METHODS

A total of 148 patients with T2DM and 49 age- and sex-matched normal controls underwent cardiac magnetic resonance examination. LA longitudinal strain and LA and LV functional indices were compared among controls and different T2DM patients. The multivariate analysis was used to identify the independent indicators of LA longitudinal strain.

RESULTS

T2DM Patients without FMR had a lower total LA empty fraction (LAEF) compared with the controls (all P < 0.05). T2DM patients with mild and moderate FMR showed increased LA volume (LAV) and LV volume while decreased LAEF, LA strain, and LV ejection fraction (P < 0.05). T2DM patients with severe FMR showed markedly increased LAV and LV volume while decreased LAEF, LA strain, and LVEF (P < 0.05). In T2DM patients with FMR, reservoir strain (εs) was independently correlated with LV end-diastolic volume (LVEDV) (β = - 0.334) and regurgitation degree (β = - 0.256). The passive strain (εe) was independently correlated with regurgitation degree (β = - 0.297), whereas the active strain (εa) was independently correlated with LVESV (β = - 0.352) and glycated haemoglobin (β = - 0.279).

CONCLUSION

FMR may aggravate LA and LV dysfunction in T2DM patients. Regurgitation degree was an independent determinant of the εs and the εe, LVEDV was an independent determinant of the εs, and LVESV was an independent determinant of the εa in T2DM patients with FMR.

Determinants of the Volumetric Markers of Left Atrial Contraction Function in Coronary Artery Disease: A Cross-sectional Study

BACKGROUND

A body of research advocates the prognostic role and usefulness of the volumetric markers of left atrial (LA) phasic functions in the diagnosis of LA dysfunction. We aimed to determine the independent determinants of the volumetric markers of LA contraction function in candidates for coronary artery bypass graft (CABG) surgery.

METHODS

This cross-sectional study enrolled 516 candidates for CABG. The biplane maximal, minimal, and pre-P volumes of the LA were measured with two-dimensional echocardiography, and LA active emptying fraction was calculated. The standardized correlation coefficient for the correlation between each factor and LA active emptying fraction was calculated by using univariate and backward multivariable regression analyses.

RESULTS

The multivariable regression analysis demonstrated that the heart rate (β = 0.15; p = 0.001), S (β = 0.09; p = 0.036), E/e′ ratio (β = −0.11; p = 0.014), left ventricle (LV) ejection fraction (β = 0.15; p = 0.001), and LA enlargement (β = −0.19; p < 0.001) were the independent determinants of LA active emptying fraction.

CONCLUSIONS

The independent determinants of LA contraction function were the heart rate, S, LV ejection fraction, LA enlargement, and E/e′ ratio in candidates for CABG surgery.

Impaired Relaxation and Reduced Lusitropic Reserve in Atrial Myocardium in the Obese Patients

Background: Obesity can influence the structure and function of the atrium, but most studies focused on the relationship of body mass index (BMI) and overt left atrium (LA) dysfunction as assessed by clinical imaging. We combined the assessment of right atrium (RA) function in vivo and in vitro in obese and non-obese patients scheduled for elective cardiac surgery.

Methods: Atrial structure and function were quantified pre-operatively by echocardiography. RA tissue removed for the establishment of extracorporeal support was collected and RA trabeculae function was quantified in vitro at baseline and with adrenergic stimulation (isoproterenol). Fatty acid-binding protein 3 (FABP3) was quantified in RA tissue. Results were stratified according to the BMI of the patients.

Results: About 76 patients were included pre-operatively for the echocardiographic analysis. RA trabeculae function at baseline was finally quantified from 46 patients and RA function in 28 patients was also assessed with isoproterenol. There was no significant correlation between BMI and the parameters of atrial function measured by the clinical echocardiography. However, in vitro measurements revealed a significant correlation between BMI and a prolonged relaxation of the atrial myocardium at baseline, which persisted after controlling for the atrial fibrillation and diabetes by the partial correlation analysis. Acceleration of relaxation with isoproterenol was significantly lower in the obese group (BMI ≥ 30 kg/m²). As a result, relaxation with adrenergic stimulation in the obese group remained significantly higher compared to the overweight group (25 kg/m² ≤ BMI < 30 kg/m², p = 0.027) and normal group (18.5 kg/m² ≤ BMI < 25 kg/m², p = 0.036). There were no differences on impacts of the isoproterenol on (systolic) developed force between groups. The expression of FABP3 in the obese group was significantly higher compared to the normal group (p = 0.049) and the correlation analysis showed the significant correlations between the level of FABP3 in the RA trabeculae function.

Conclusion: A higher BMI is associated with the early subclinical changes of RA myocardial function with the slowed relaxation and reduced adrenergic lusitropy.

Label-free and noninvasive method for assessing the metabolic status in type 2 diabetic rats with myocardium diastolic dysfunction

This study assesses the metabolic status of rat diabetic cardiomyopathy (DCM) models. Echocardiography is used to detect the diastolic dysfunction in type 2 diabetic rats, and a lower threshold for inducible atrial fibrillation is found in type 2 diabetic rats with diastolic dysfunction compared to the control. Metabolic abnormalities are detected by status changes of reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H), which is an essential coenzyme in cells or tissues. Fluorescence lifetime imaging microscopy (FLIM) is used to monitor changes in NAD(P)H in both myocardial tissues and blood. FLIM reveals that the protein-bound proportion of NAD(P)H in rat myocardium in the DCM group is smaller than the control group, which indicates the oxidative phosphorylation rate of the DCM group decreased. Similar results are found for blood plasma of DCM rats by the FLIM study. FLIM exhibits high potential for screening DCM as a label-free, sensitive, and noninvasive method.

Chronic consumption of a high-fat diet rich in corn oil activates intrinsic cell death pathway and induces several ultrastructural changes in the atria of healthy and type 1 diabetic rat

This study investigates the effect of chronic consumption of a high-fat diet rich in corn oil (CO-HFD) on atrial cells ultrastructure, antioxidant levels and markers of intrinsic cell death of both control and type 1 diabetes mellitus (T1DM)-induced rats. Adult male rats (10 rats/group) were divided into four groups: control fed standard diet (STD) (3.82 kcal/g, 9.4% fat), CO-HFD (5.4 kcal/g, 40% fat), T1DM fed STD, and T1DM + CO-HFD. CO-HFD and T1DM alone or in combination impaired systolic and diastolic functions of rats and significantly reduced levels of GSH and the activity of SOD, enhanced lipid peroxidation, increased protein levels of P53, Bax, cleaved caspase-3, and ANF and decreased levels of Bcl-2 in their atria. Concomitantly, atrial cells exhibited fragmentation of the myofibrils, disorganized mitochondria, decreased number of atrionatriuretic factor (ANF) granules, and loss of gap junctions accompanied by changes in capillary walls. Among all treatments, the severity of all these findings was more severe in T1DM and most profound in the atria of T1DM + CO-HFD. In conclusion, chronic consumption of CO-HFD by T1DM-induced rats elicits significant biochemical and ultrastructural damage to rat atrial cells accompanied by elevated oxidative stress and mitochondria-mediated cell death.