Comparison of left atrial function in healthy individuals versus patients with non-ST-segment elevation myocardial infarction using two-dimensional speckle tracking echocardiography

Effect of Metabolic Syndrome on Left Atrial and Left Ventricular Deformation and Atrioventricular Interactions in Patients With Myocardial Infarction

BACKGROUND

Metabolic syndrome (MetS) is associated with worse prognosis in patients with myocardial infarction (MI). However, it is unclear how MetS in MI patients is associated with left atrial (LA) and left ventricular (LV) deformation.

PURPOSE

To determine the effect of MetS on LA and LV deformation and atrioventricular interactions in MI patients.

STUDY TYPE

Retrospective.

POPULATION

One hundred eighty-one MI patients (73 MetS+ and 108 MetS-), 107 age- and sex-matched controls (49 MetS+ and 58 MetS-).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession (SSFP)/segmented phase-sensitive inversion recovery SSFP sequence.

ASSESSMENT

LA strain and strain rates (reservoir, conduit, and active), left atrioventricular coupling index (LACI), and LV geometry and radial, circumferential and longitudinal global peak strains (PS) were compared among groups.

STATISTICAL TESTS

Two-way analysis of variance, Spearman and Pearson's correlation coefficients, and multivariable linear regression analysis. P value <0.05 indicated statistical significance.

RESULTS

Compared with controls, the MI patients with or without MetS showed impaired LA function (reservoir, conduit, and active) and LV deformation (radial, circumferential, and longitudinal PS) and higher LACI. The MetS+ group had lower LA reservoir and conduit function and LV deformation than MetS- group. The MetS-MI interaction was not statistically significant. Furthermore, multivariable linear regression showed that MetS was independently associated with LA and LV deformation (β = -0.181 to -0.209) in MI patients; LA function was independently associated with LV circumferential PS (β = 0.230 to 0.394) and longitudinal PS (β = 0.189 to 0.420), and LA passive strain and strain rate were negatively associated with LV mass (β = -0.178 and -0.298).

DATA CONCLUSION

MetS may be associated with the LA and LV dysfunction in MI patients. Impaired LV deformation and LV hypertrophy are independently associated with LA dysfunction in MI patients, and the MI patients have higher LACI than controls, suggesting atrioventricular interaction alterations.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: 3.

The Impact of Sonothrombolysis on Left Ventricular Diastolic Function and Left Atrial Mechanics Preventing Left Atrial Remodeling in Patients With ST Elevation Acute Myocardial Infarction

BACKGROUND

The diagnostic ultrasound-guided high mechanical index impulses during an intravenous microbubble infusion (sonothrombolysis) improve myocardial perfusion in acute ST segment elevation myocardial infarction, but its effect on left ventricular diastolic dysfunction (DD), left atrial (LA) mechanics and remodeling is unknown. We assessed the effect of sonothrombolysis on DD grade and LA mechanics.

METHODS

One hundred patients (59 ± 10 years; 34% women) were randomized to receive either high mechanical index impulses plus percutaneous coronary intervention (PCI) (therapy group) or PCI only (control group) (n = 50 in each group). Diastolic dysfunction grade and LA mechanics were assessed immediately before and after PCI and at 48 to 72 hours, 1 month, and 6 months of follow-up. Diastolic dysfunction grades were classified as grades I, II, and III. The LA mechanics was obtained by two-dimensional speckle-tracking echocardiography-derived global longitudinal strain (GLS).

RESULTS

As follow-up time progressed, increased DD grade was observed more frequently in the control group than in the therapy group at 1 month and 6 months of follow-up (all P < .05). The LA-GLS values were incrementally higher in the therapy group when compared with the control group at 48 to 72 hours, 24.0% ± 7.3% in the therapy group versus 19.6% ± 7.2% in the control group, P = .005; at 1 month, 25.3% ± 6.3% in the therapy group versus 21.5% ± 8.3% in the control group, P = .020; and at 6 months, 26.2% ± 8.7% in the therapy group versus 21.6% ± 8.5% in the control group, P = .015. The therapy group was less likely to experience LA remodeling (odds ratio, 2.91 [1.10-7.73]; P = .03). LA-GLS was the sole predictor of LA remodeling (odds ratio, 0.79 [0.67-0.94]; P = .006).

CONCLUSION

Sonothrombolysis is associated with better DD grade and LA mechanics, reducing LA remodeling.

Evaluation of right atrial volumes and functions by real-time three-dimensional echocardiography in patients after acute inferior myocardial infarction

BACKGROUND

Right ventricle (RV) involvement causes acute systolic and diastolic functional alterations in the RV in patients after inferior myocardial infarction (IMI), which may result in an increase in left ventricle (LV) end-diastolic and right atrial (RA) pressure. In our study, we sought to evaluate RA volumes and mechanical functions using real-time three-dimensional echocardiography (RT3DE) in IMI patients with or without RV involvement.

METHODS

Ninety-six consecutive patients with IMI (mean age: 59.7 ± 10.2 years, 60 female) were included. RV myocardial involvement (RVMI) was defined as the presence of a culprit lesion at the proximal portion of the first RV marginal branch in coronary angiography. The study population was divided into two groups: IMI (58.3%) and IMI + RVMI (41.7%). Patients were evaluated using conventional two-dimensional echocardiography (2DE) and RT3DE.

RESULTS

In RT3DE measurements, IMI + RVMI patients had significantly higher RA phasic volumes and worse conduit mechanical function. A receiver operating characteristic (ROC) curve analysis revealed that an RT3DE RA maximum volume (Vmax) index > 27.9 mL/m² was an independent predictor of RV involvement in patients after acute IMI, with a sensitivity of 80.0% and a specificity of 89.3%.

CONCLUSIONS

Right ventricle involvement may cause an increase in RA phasic volumes and deterioration of conduit function in patients with acute IMI.

Incremental value of left atrial mechanical dispersion over CHA2 DS2 -VASc score in predicting risk of thrombus formation

PURPOSE

To assess the potential ability of two-dimensional speckle tracking analysis (STE) during atrial fibrillation (AF) to identify patients with LA appendage thrombi (LAAT).

METHODS

This study involved 93 patients with AF (39% female, 67.1 ± 9.5 years) who were referred for a clinical indication for transesophageal echocardiography (TEE). TEE revealed LAAT in 39 (42%) patients. We analyzed standard parameters of the left ventricle (LV) and LA in transthoracic echocardiography. Using STE, we assessed LV global longitudinal strain (LVGLS), peak atrial longitudinal strain (PALS), and intra-atrial asynchrony. The PALS was calculated using the global strain curve (GPALS) and as the mean of peaks derived from segmental strain curves (MPALS).

RESULTS

Patients were comparable with regard to the clinical data. A subgroup with LAAT had lower LV ejection fraction (LVEF) and a lower absolute value of the LVGLS, as well as greater impairment in the LA standard parameters, PALS, and asynchrony. Receiver operating characteristic curve analysis revealed that the LVEF of 30% (P < .001), the LVGLS of -7% (P < .0001), the GPALS of 11% (P < .005), and the LA asynchrony of 22% (P < .01) were the optimal cutoff values for distinguishing both subgroups. LA asynchrony, LVEF, and LVGLS were independently associated with the presence of LAAT in multivariate analyses, and PALS had additional significance over the CHA₂ DS₂ -VASc score.

CONCLUSIONS

Left ventricular systolic dysfunction characterized by both LVEF and LVGLS is an independent factor for LAAT. LA asynchrony provides additional diagnostic value for discriminating between patients with and without LAAT.

Left atrial appendage function assessment and thrombus identification

Background

The diagnosis of thrombus in the left atrium in patients with persistent atrial fibrillation (AF) and may be inconsistent because of variability in thrombus morphology. In some cases it is challenging and requires unusual approach. New Doppler-derived methods might be helpful to identify such thrombi. We evaluated quantitative differences in mechanical function of the left atrial appendage (LAA) basal segments using tissue Doppler imaging (TDI)and speckle tracking echocardiography (STE) in patients with non-valvular AF with and without LAA thrombus and compared them with SR patients.

Methods

A total of 80 patients with normal left ventricular ejection fraction underwent transesophageal echocardiography (40 patients with SR and 40 patients with AF on oral anticoagulants including patients with LAA thrombus). We analyzed the basal segments of LAA including left lateral ridge (LLR) and baso-medial appendage segment (BMAS). Quantitative analysis was used to calculate peak velocity, average velocity, strain, strain rate and deformation.

Results

In patients with AF the lower LLR strain rate was the sole new STE significant parameter differentiating patients with and without LAA thrombi: − 0.9(− 1.2; − 0.1)s^− 1 vs. − 1.6(− 1.9; − 1.3)s^− 1, (p = 0.004). Additionally, patients in SR demonstrated significantly better peak velocity, average velocity, strain, strain rate and deformation than those with AF (p < 0.001).

Conclusions

LLR appeared to be an appropriate site for measuring Doppler derived parameters. It is possible that the strain rate in LLR area may be a novel parameter correlating with the presence of thrombus in patients with AF.

Clinical study of right ventricular longitudinal strain for assessing right ventricular dysfunction and hemodynamics in pulmonary hypertension

This study aimed to appraise the application of right ventricular longitudinal strain for assessing right ventricular dysfunction and severe hemodynamic changes in pulmonary hypertension. The study included 53 patients clinically diagnosed with PH. Tissue Doppler-derived tricuspid lateral annular systolic velocity (s'), early diastolic peak velocity (e'), late diastolic peak velocity (a'), tricuspid annular plane systolic excursion (TAPSE), RV index of myocardial performance (RIMP), and right ventricular fractional area change (FAC) were determined. The STI parameter was RV free wall longitudinal peak systolic strain (RV LPSS). The patients were assigned into two groups based on a RV LPSS value of - 19%.RV LPSS, s', TAPSE, RIMP, FAC, a' and e'/a' showed significant differences. PH patients with an RV LPSS≥ -19% exhibited a lower RV function (P < 0.05). RV LPSS was negatively correlated with TAPSE (r = -0.326, P < 0.05) and FAC (r = -0.495, P < 0.001) and positively correlated with RIMP (r = 0.508, P < 0.001). The optimal cut-off value of RV LPSS to reveal an mPAP ≥ 45 mmHg defined based on the receiver operating characteristic curve analysis was - 19.26% with a sensitivity of 83.9% and a specificity of 73.4%.Distinguishing the degree of RV dysfunction by 2D-STI may help physicians to determine the state of cardiac function and degree of PH in patients and offer a basis for subsequent clinical diagnosis and therapy. Our study demonstrates the superiority of RV LPSS for uncovering severe PH over the traditional echocardiographic parameters.

New insights into symptomatic or silent atrial fibrillation complicating acute myocardial infarction

Atrial fibrillation (AF) is the most frequent heart rhythm disorder in the general population and contributes not only to a major deterioration in quality of life but also to an increase in cardiovascular morbimortality. The onset of AF in the acute phase of myocardial infarction (MI) is a major event that can jeopardize the prognosis of patients in the short-, medium- and long-term, and is a powerful predictor of a poor prognosis after MI. The suspected mechanism underlying the excess mortality is the drop in coronary flow linked to the acceleration and arrhythmic nature of the left ventricular contractions, which reduce the left ventricular ejection fraction. The principal causes of AF-associated death after MI are linked to heart failure. Moreover, the excess risk of death in these heart failure patients has also been associated with the onset of sudden death. Whatever its form, AF has a major negative effect on patient prognosis. In recent studies, symptomatic AF was associated with inhospital mortality of 17.8%, to which can be added mortality at 1year of 18.8%. Surprisingly, silent AF also has a negative effect on the prognosis, as it is associated with an inhospital mortality rate of 10.4%, which remains high at 5.7% at 1year. Moreover, both forms of AF are independent predictors of mortality beyond traditional risk factors. The frequency and seriousness of silent AF in the short- and long-term, which were until recently rarely studied, raises the question of systematically screening for it in the acute phase of MI. Consequently, the use of continuous ECG monitoring could be a simple, effective and inexpensive solution to improve screening for AF, even though studies are still necessary to validate this strategy. Finally, complementary studies also effect of oxidative stress and endothelial dysfunction, which seem to play a major role in triggering this rhythm disorder.

Left atrium function in patients with coronary artery disease

PURPOSE OF REVIEW

The left atrial cavity has recently been identified as a potential biomarker for cardiac and cerebrovascular accidents. This review examines the potential of left atrial size and function in predicting cardiovascular disease in the general population and outcomes in coronary artery disease (CAD) patients.

RECENT FINDINGS

The atrium is perfused primarily by branches of the proximal left circumflex coronary artery (LCx), and depression of the cavity mechanical performance has been demonstrated in experimental studies during LCx occlusion. Thus, left atrial volume and function assessment may have prognostic relevance, particularly in CAD patients. Such a line of thinking, however, is challenged by the widespread notion that the contribution by left atrial chamber morphology and functional quantitation to the risk stratification process after a first cardiovascular event is not adequately considered. However, a number of studies have shown that left atrial volume predicts survival and major adverse events after an acute myocardial infarction. Left atrial remodeling also provides an important overall prognostic information and correlates with brain natriuretic peptide after primary percutaneous coronary interventions.

SUMMARY

Evaluation of left atrial size and function is currently of great interest and it will be more so in the very near future, given its potential for insights into the pathophysiology of the ischemic heart, which makes it an important clinical risk identifier in CAD patients.