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.

Left atrial volume index in diabetic hypertensive patients with acute myocardial infarction

Funding Acknowledgements

Type of funding sources: None.

Background

Left atrial (LA) dimension is a marker of LV filling pressure, reflecting the severity and chronicity of diastolic dysfunction. LA is a stable parameter that combines chronic cardiovascular conditions effects and acute increase in filling pressure in acute myocardial infarction. Patients with acute coronary syndrome and increased left atrial volume index (LAVI) have a worse long-term prognosis. In patients with hypertension and diabetes, an increase in the LA dimension predicts cardiovascular events. There are limiting data about the impact of LAVI on the outcome in diabetic hypertensive patients with ST-elevation myocardial infarction (STEMI). Purpose: of the study was to compare LAVI in diabetic and nondiabetic hypertensive patients admitted with STEMI. Methods: ninety-eight hypertensive patients admitted with STEMI were enrolled, sixty-seven with diabetes mellitus and thirty-one without diabetes. The patients with atrial fibrillation and significant valvular disease were not included in the study. The evaluation consisted in clinical examination, echocardiographic measurements, laboratory tests, and 12 leads electrocardiography. 2D Echocardiography area-length technique was used for LA volume measurement. The LA endocardial borders were traced in both the apical four- and two-chamber views, and the results were body surface area indexed. The cut of value was 34ml/m2.  The Devereaux formula determined left ventricle mass index (LVMI), and the ranges were: 125 kg/m2 for males and 95 mg/m2 for females. Left ventricle ejection fraction (LVEF) was < 50% in all cases. Measurements were obtained in the first week after STEMI. The patients were divided into two groups: the first was between 40 and 60 years and the second was above 60 years. According to the age group, mean values (MV) and standard deviation (SD) were calculated, obtaining a comparison between diabetic and nondiabetic patients. Results: LAVI had higher values in diabetic patients: MV: 37.37 (SD: 3.39, CV: 9.07%) compare with nondiabetic patients: MV: 31.07 (SD: 2.67, CV 8.59%), p < 0.0001. Between 40-60 years LAVI MV were 36.43 +/- 3.21 in diabetic patients vs. 29.62+/-1.89 in nondiabetic patients (p = 0.0001); above 60 years of age LAVI MV were: 38.99 +/- 3.04 in diabetic patients and 31.14 +/- 2.8 in nondiabetics patients (p < 0.0001). In both group of age LAVI also correlated with body mass index, LVMI, LV volumes, LV diastolic dysfunction, LVEF, dyslipidemia and smoking. Conclusions: 1. In hypertensive patients admitted with STEMI, diabetes mellitus was an additional factor contributing to increased left atrium dimensions. 2. This study showed a correlation between LAVI and other factors involved in increasing LV filling pressure in hypertensive diabetic patients admitted with STEMI, underlying the importance of LA enlargement evaluation. Further studies with a larger number of patients are need to confirm these results.

Acute cardiotoxicity induced by doxorubicin in right ventricle is associated with increase of oxidative stress and apoptosis in rats

Doxorubicin (DOX) is one of the most effective chemotherapeutic agents, but its efficiency is seriously limited by the risk of developing cardiomyopathy. The most recognized cardiotoxic effect is left ventricular (LF) dysfunction, but MRI and echocardiography data demonstrated significant right ventricle (RV) function impairment. In order to clarify this aspect, the present study investigated the potential of DOX to induce acute RV cardiotoxicity at the same time as LV impairment. Rats were intraperitoneally (i.p.) injected with a single dose of 15 mg/kg DOX. DOX-treated rats were characterized by decreased body and heart weights, elevated levels of creatine kinase (CK-MB) and lactate dehydrogenase (LDH) activities compared to controls. Biochemical analyses on RV tissue revealed that the level of malondialdehyde (MDA) was significant increased (p<0.05) and activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX) antioxidant enzymes were decreased by 13%, 27% and 18%, respectively, compared to control. Histopathogical and electron microscopic studies revealed DOX-induced damage in both ventricles and an increase of interstitial collagen fibers compared to controls (p<0.001), whereas immunohistochemical analysis showed weak and irregular desmin expression. Furthermore, mitochondrion-induced apoptotic pathways were also activated in both ventricles, as reflected by the up-regulation of Bax/Bcl-2 mRNA expression ratio (p<0.001) and increase of Bax and caspase-3 protein expression, as well as by the significant elevation of TUNEL positive nuclei, compared to controls (p<0.001). The results showed that DOX exerted RV toxic effects at the same time as those reported in the LV, which might be mediated through the mitochondrial-dependent apoptosis.

Automation of a series of cutaneous topography measurements from silicon rubber replicas

BACKGROUND/AIMS

Skin relief is a matter of interest for dermatologists and surgeons. One of the methods available for surface topography measurement is based on 3D profilometry using skin surface replicas. and most studies use statistical results obtained from a large number of skin replica samples. The advent of optical profilometers (without contact) made it possible to remove the solid positive replica and to reduce the duration of the profilometric data acquisition. Nevertheless this saving of time, to be really interesting, needs to automate the data acquisition on a series of negative replicas.

METHODS/RESULTS

By adding a video camera to the optical profilometer and then by processing the resulting images, we have conceived a system able to carry out topographic measurements on a series of replicas loosely organized on a sample holder, without any human intervention. The silicon replicas in use have a very light colour: nearly white, sometimes slightly blue or green. The laser spot of the profilometer is so luminous that its red colour looks white through the camera. When choosing a replica holder with a matt dark colour and marking the left upper corner of the study area on the replica in black ink, the colours to be differentiated on the image are then close to the black one and the white one. We accordingly change the colour camera image into a black and white image (with 256 grey levels) and then carry out thresholdings to separate the different objects or information included in this image. With the use of a perfectly circular replica, of an accurately known size, laid on the sample holder at the center of the area filmed by the camera, we adjust the threshold level, which allows separation of the replica from its holder. We then move this calibrated replica in order to find the relationship between the size in pixels and the real size on the sample holder, in various positions of the video image. The software has four main built-in stages: Moving the sample holder beneath the sensor until a part of a replica is detected in the field of view of the camera; Moving the sample holder until this replica lies just in the middle of the image given by the camera; Recognition of the mark of the upper left corner of the surface area to be measured out inside this replica; and Moving the sample holder until the laser spot of the profilometer coincides with the origin of the surface area to be measured out, then carrying out this measurement. From the upper left corner of the sample holder, a scanning, line-by-line or column-by-column (according to the selected priority direction), is carried out until the successive replicas are found, and is stopped as soon as the number of replicas entered by the operator is reached.

CONCLUSION

The simplicity of the algorithms used makes it possible to distinguish the next measurement area from the preceding one in a few seconds.