The link between left atrial longitudinal reservoir strain and mitral apparatus geometry in patients with dilated cardiomyopathy

Background

4-Dimensional Automated Left Atrial Quantification (4D Auto LAQ) is a technique that uses 3D volume data to determine LA strain. 4-Dimensional Automated Mitral Valve Quantification (4D Auto MVQ) evaluates anatomical and functional mitral valve parameters. Our study evaluated patients with dilated cardiomyopathy and tried to find a correlation between LA strain and mitral apparatus geometry.

Methods

We enrolled 61 patients with dilated cardiomyopathy and 25 healthy volunteers. The evaluation consisted of clinical examination, laboratory tests, 12 leads electrocardiography. All participants underwent a complete transthoracic echocardiogram to determine cardiac structure and function according to the current guidelines. Measurement of LA strain and MV was performed using 4D Auto-quantification software. The study evaluated longitudinal strain during reservoir phase (LASr) and the parameters of the MV geometry that could interfere with left atrial function: annulus area, annulus perimeter, anteroposterior (A-P) diameter, posteromedial-anterolateral diameter (PM-AL), (the longest diameter of MV perpendicular to AP diameter); commissural diameter (CD), inter-trigonal distance, tenting height, tenting area, and tenting volume.

Results

1. The patients were divided in two groups: 26 with ischemic dilated cardiomyopathy and 35 with non-ischemic dilated cardiomyopathy. 2. Mean values of MV parameters in patients with dilated cardiomyopathy compare with healthy volunteers were: annulus area: 19.46 cm2 vs 11.85 cm2; annulus perimeter: 16.86 cm vs 12.71cm, A-P diameter 4.53 cm vs 3.45 cm, PM-AL diameter 4.84 cm vs 3.92 cm, CD 4.83 cm, vs 3.94 cm, inter-trigonal distance 3.9 cm vs 2.9 cm, tenting height 1.64 cm vs 1.05 cm, tenting area 4.82 cm2 vs 1.78 cm2, tenting volume 13.49 ml vs 4.27 ml. For LASr, mean values were 10.26 in patients with dilated cardiomyopathy vs 32.14 in healthy volunteers. Mean values of mitral valve parameters and LASr were comparable in ischemic vs non-ischemic cardiomyopathy patients. 3. LASr correlated with anatomical mitral valve parameters: annulus area: r=−0.6, annulus perimeter: r=−0.57, AP diameter: r=−0.58, PM-AL diameter: r=−0.58, commissural diameter: r=−0.66, inter-trigonal distance: r=−0.57, tenting height r=−0.53, tenting area r=−0.55 and tenting volume r=−0.54.

Conclusions

1. In patients with dilated cardiomyopathy phenotype, anatomical parameters of the mitral valve and LASr were altered. Results did not reveal significant differences between ischemic and non-ischemic etiology. 2. A correlation was found between the decrease in LASr and anatomical parameters of the mitral valve, suggesting a link between atrial function deterioration and deformity of mitral apparatus geometry in patients with dilated cardiomyopathy.

Funding Acknowledgement

Type of funding sources: None.

Layer specific strain analysis and QTc interval in patients with STEMI and TIMI 3 early after percutaneous coronary intervention

Background

Heart rate-corrected (QTc) interval may increase in the setting of ST-elevation myocardial infarction (STEMI) even after complete reperfusion of the infarct-related artery. The remaining ischemia affects ventricular repolarization and may be associated with an increased susceptibility for malignant ventricular arrhythmias. Two-dimensional (2D) speckle tracking echocardiography (STE) is an angle-independent technique for evaluating myocardial function. The study aimed to analyze the layers specific strain using STE in patients after percutaneous coronary intervention (PCI) and find a possible correlation with QTc interval.

Methods

74 patients with STEMI and TIMI 3 flow after PCI were enrolled. The study did not include patients with bundle branch block, pacing, or treated with drugs that could increase the QTc interval. The evaluation consisted of clinical examination and laboratory tests. 12 leads electrocardiography evaluated QTc interval. Echocardiographic acquisitions were performed in the first 24–48 hours after PCI, and data were analyzed on the workstation. The global longitudinal strain was measured from apical views, at the level of the endocardium GLSAvgEndo, transmural GLSAvg, epicardium GLSAvgEpi; the difference bewtwen endocardium and epicardium longitudinal strain: GLSAvgEndo-GLSAvgEpi. Layer-specific GLS values were measured as the average of the longitudinal strain of 17 LV segments at each individual layer (Figure 1).

Results

Patients were diveded in two groups: the first included 32 patients with a single vessel disease (43.24%) and the second, 42 patients (56.75%) with multiple vessel damage, but without other indication for revascularization except the culprit lesion. Values for layers strain and QTc interval in the first group were: GLSAvgEndo: −16.2 (SD 2.98, CV 0.18), GLSAvg: −11.46 (SD 6.98, CV 0.6), GLSAvgEndo-GLSAvgEpi: 3.54 (DS 1.06, CV 0.29), QTc: 452.5 (SD 22.65, CV 0.05) and in the second group: GLSAvgEndo: −13.22 (SD 4.01, CV 0.3), GLSAvg: −11.3 (SD 3.39, CV 0.29), GLSAvgEndo-GLSAvgEpi: 3.47 (CV 1.28, CV 0.37), QTc: 490ms (SD 43.07, CV 0.08). QTc interval correlated with and layers strain in the first group: GLSAvgEndo: r=0.56, GLSAvg: r=0.67, GLSendo-GLSepi: r=0.54, and in the second group: GLSAvgEndo: r=0.73, GLSAvg: r=0.75, GLSAvgEndo-GLSAvgEpi: r=0.62.

Conclusions

1. The present study identified decreased longitudinal strain in all myocardial layers in the first days after STEMI, even after a successful PCI. 2. Alterations of QTc dynamicity were more frequent in patients with multivessel lesions 3. The electrical instability related by QTc interval correlated with the myocardial tissue damage related by STE. The correlation was more evident in patients with multivessel disease, even with remaining nonsignificant lesions, suggesting an ongoing process of microcirculatory perfusion damage.

Funding Acknowledgement

Type of funding sources: None.