Prognostic significance of Tp-e interval and Tp-e/QTc ratio in patients with COVID-19.

OBJECTIVE: Ventricular arrhythmias were the most frequent manifestations in patients with COVID-19. Both the natural course of the disease and the treatment drugs used have effects on ventricular repolarization. The objective of this study was to evaluate the effects of repolarization parameters obtained from surface electrocardiography (ECG) on prognosis. PATIENTS AND METHODS: Participants were 205 consecutive patients hospitalized with COVID-19 diagnosis. The 12-lead surface ECG was obtained from each patient on admission. The ECG results were evaluated against the patients' clinical characteristics and outcomes by experienced cardiology specialists. RESULTS: The mean age was higher in the non-survivor group compared to the survivor group (57.4 ± 15.7 vs. 65.6 ± 16.6; p = 0.001). The demographical characteristics were similar between the survivor and non-survivor groups. Multivariate analyses demonstrated that age (OR: 1.041; p = 0.009), D-dimer (OR: 1.002; p = 0.031), high-sensitivity troponin I (hs-TnI) (OR: 1.010; p = 0.041), pneumonia on computed tomography (CT) (OR: 4.985; p < 0.001), the peak-to-end interval of the T wave (Tp-e) (OR: 3.421; p < 0.001), and Tp-e/QTc ratio (OR: 1.978; p = 0.013) were statistically significant independent predictors in terms of determining mortality. CONCLUSIONS: Prolonged Tp-e interval and increased Tp-e/QTc ratio on admission are decent predictors and linked with mortality. ECG is a practical study to evaluate prognosis and potential arrhythmias, as well as initiating suitable treatment.

Dean-flow-coupled elasto-inertial three-dimensional particle focusing under viscoelastic flow in a straight channel with asymmetrical expansion-contraction cavity arrays.

In this paper, 3D particle focusing in a straight channel with asymmetrical expansion-contraction cavity arrays (ECCA channel) is achieved by exploiting the dean-flow-coupled elasto-inertial effects. First, the mechanism of particle focusing in both Newtonian and non-Newtonian fluids was introduced. Then particle focusing was demonstrated experimentally in this channel with Newtonian and non-Newtonian fluids using three different sized particles (3.2 µm, 4.8 µm, and 13 µm), respectively. Also, the effects of dean flow (or secondary flow) induced by expansion-contraction cavity arrays were highlighted by comparing the particle distributions in a single straight rectangular channel with that in the ECCA channel. Finally, the influences of flow rates and distances from the inlet on focusing performance in the ECCA channel were studied. The results show that in the ECCA channel particles are focused on the cavity side in Newtonian fluid due to the synthesis effects of inertial and dean-drag force, whereas the particles are focused on the opposite cavity side in non-Newtonian fluid due to the addition of viscoelastic force. Compared with the focusing performance in Newtonian fluid, the particles are more easily and better focused in non-Newtonian fluid. Besides, the Dean flow in visco-elastic fluid in the ECCA channel improves the particle focusing performance compared with that in a straight channel. A further advantage is three-dimensional (3D) particle focusing that in non-Newtonian fluid is realized according to the lateral side view of the channel while only two-dimensional (2D) particle focusing can be achieved in Newtonian fluid. Conclusively, this novel Dean-flow-coupled elasto-inertial microfluidic device could offer a continuous, sheathless, and high throughput (>10 000 s(-1)) 3D focusing performance, which may be valuable in various applications from high speed flow cytometry to cell counting, sorting, and analysis.

Retrieval of a malpositioned left subclavian artery stent from the ascending aorta: combined percutaneous and surgical management.

Chronic upper limb ischemia is an uncommon clinical condition and is most often caused by subclavian artery stenosis. Surgical and percutaneous treatment modalities have been shown to be effective for the management of subclavian artery occlusion. Because of lower mortality and morbidity rates, percutaneous interventions for subclavian arterial occlusions are more acceptable than surgery. Chronic total occlusions of the subclavian artery are challenging to treat percutaneously because of the structure and complexity of the lesion. The complexity of the lesion causes its own complications. In this paper, we report a case of a completely occluded left subclavian artery that was complicated by a malpositioned stent hanging into the aortic arch and the ascending aorta during percutaneous intervention, which was successfully managed by our heart team.

Effect of cardiac rehabilitation on left atrial functions in patients with acute myocardial infarction.

BACKGROUND: The objective of this study was to analyze the effects of cardiac rehabilitation (CR) on the atrial function of patients with acute myocardial infarction (AMI) who had been successfully revascularized through percutaneous coronary intervention (PCI). METHODS: Forty-two AMI patients having undergone CR were enrolled in this observational study. Assessments were performed before and after 6 weeks of CR. Left atrial strain analysis was carried out by two-dimensional speckle tracking echocardiography. Left ventricular ejection fraction (LVEF) was measured by the biplane Simpson's method. Pulsed-wave Doppler at the tip of mitral valve leaflets enabled us to measure early (E) and late (A) diastolic filling velocities, deceleration time (DT) of early filling velocity and isovolumic relaxation time (IVRT). Left ventricle tissue velocity was measured by tissue Doppler imaging of the lateral mitral annulus (e') and E/e' was subsequently calculated. Ratio of E/e' to left atrium (LA) peak strain was used to estimate LA stiffness. RESULTS: Following CR, LVEF (P=0.010), LA strain (P<0.001) and LA stiffness (P=0.013) all showed improvement, while other parameters remained unchanged. CONCLUSION: Post-AMI cardiac rehabilitation and revascularization by PCI might have favourable effects on LA function.

Coronary vessel diameters during and after primary percutaneous coronary artery intervention.

BACKGROUND: Primary percutaneous coronary intervention (P-PCI) is the gold standard treatment for acute coronary syndromes. Plasma levels of catecholamines and other vasopressors are elevated during acute myocardial infarction (AMI) and coronary vasoconstriction is frequent. We aimed to compare the reference vessel diameter (RVD) of the infarct-related artery (IRA) during primary PCI and after an average of 3 days. METHODS: Coronary angiography (CAG) was performed on 58 patients with acute ST-segment elevation myocardial infarction (STEMI) and TIMI 3 flow after P-PCI (43 men, 15 women; mean age, 55.5 ± 10 years). TIMI 3 flow was achieved either by simple balloon dilatation and/or thrombus aspiration. Lesion length, RVD, minimal lumen diameter (MLD), mean vessel diameter (meanD), and area of stenosis were compared during P-PCI and follow-up CAG. RESULTS: RVD, MLD, and meanD values were significantly higher during the follow-up CAG than after P-PCI (RVD 2.7 ± 0.7 mm vs. 2.9 ± 0.7 mm, p = 0.001; MLD 1.5 ± 0.5 mm vs. 1.7 ± 0.4 mm, p = 0.002; meanD 2.2 ± 0.5 mm vs. 2.4 ± 0.5 mm, p = 0.001). Area of stenosis values were significantly lower during the follow-up CAG than after primary PCI (69.5 ± 16.5 % vs. 62.1 ± 15 %, p = 0.001). Lesion lengths were not statistically significant during the follow-up CAG and primary PCI (lesion length 24.0 ± 10.8 mm vs. 22.1 ± 8.8 mm, p > 0.05). CONCLUSION: This study showed that RVD was higher at the follow-up CAG a few days after AMI in patients who had TIMI 3 flow after P-PCI with simple balloon dilatation and/or thrombus aspiration. A delay of a few days for stent implantation in P-PCI allows for larger-diameter stent use and may help to reduce stent thrombosis and restenosis rates.

Echocardiographic evaluation of right ventricular functions after successful percutaneous recanalization of right coronary artery chronic total occlusions.

BACKGROUND: No data exist on regarding possible improvement will occur in right ventricular (RV) functions after successful recanalization of right coronary artery chronic total occlusions (RCA CTOs). AIM: Our aim was to evaluate the revascularization induced changes in RV functions by novel echocardiographic techniques like tissue Doppler imaging (TDI) and two dimensional speckle tracking echocardiography (2DSTE). PATIENTS AND METHODS: Forty-one consecutive successfully recanalized patients with RCA CTOs were included in our study. All included patients underwent standard echocardiography with TDI and 2DSTE to assess RV function before procedure and repeated after 24 hours and 1 month. RESULTS: There were no significant changes in tricuspid annular plane systolic excursion, systolic myocardial velocities, and fractional area change values. However, RV global longitudinal strain and systolic strain rate values showed a significant increase at 24 hours after percutaneous coronary intervention compared to baseline (-23.6±4.1% vs. -19.7±3.9%, p < 0.001 and -1.55±0.18s-1 vs. -1.18±0.17s-1, p < 0.001, respectively). Moreover, improvement of the RV functions in patients with RCA CTOs was further suggested by the higher RV isovolumic acceleration values at 1-month compared with baseline (2.29±0.62 vs. 2.05±0.5 m/s2, p = 0.014). CONCLUSIONS: TDI derived isovolumic acceleration and 2DSTE derived global longitudinal strain and systolic strain rate values showed improvement in RV functions after successful percutaneous recanalization of RCACTOs suggesting viability of RV in chronic ischemia.

Safety of balloon pre-dilatation in the treatment of severe carotid artery stenosis.

AIM: To assess early outcome of predilatation prior stenting of severe carotid artery stenosis and to evaluate early major adverse cardiovascular and cerebral events (MACCE). PATIENTS AND METHODS: The study group consisted of 265 consecutive patients (200 males, 65 female, mean age 66.7 ± 8.6 years) in whom 275 percutaneous transluminal angioplasty (PTA) procedures of carotid arteries were performed. Staged carotid stenting was performed in patients with bilateral carotid stenosis. Neuroprotection with a distal protection device was used in all cases. The patients were divided into two groups: direct carotid stent implantation without previous pre-dilation was performed in 233 patients (direct stenting group) and predilatation was performed in 42 patients (predilatation group). Early events were recorded and analyzed subsequently. RESULTS: We treated 275 carotid stenoses and the stent was implanted in all patients. Ten patients (3.7%) were treated by staged carotid artery stenting (CAS) due to bilateral carotid artery disease. The technical success rate was 97.1%. During 1-month follow-up, the prevalence of primary endpoint was 2.18%. The prevalence of MACCE at 30 days was higher in the predilatation group (2.4% vs. 2.1%; p = 0.924). Also periprocedural rate of hypotension was higher in predilatation group (7.1% vs. 1.7%; p = 0.04). CONCLUSIONS: Balloon predilatation prior to stenting can be performed to treat severe carotid artery stenosis with acceptable periprocedural complication rate.

Elevated uric acid and functional mitral regurgitation in dilated cardiomyopathy.

BACKGROUND: Recent findings suggest that there is a close relationship between chronic heart failure and uric acid. AIMS: The aim of the study was to assess whether increased uric acid levels in patients with dilated cardiomyopathy might correlate with the degree of functional mitral regurgitation (MR). MATERIALS AND METHODS: Sixty two consecutive patients diagnosed with dilated cardiomyopathy were included in the study. The patients were classified according to severity of functional MR into two groups: mild-moderate functional MR (ERO < 0.2 cm2) and severe functional MR. RESULTS: The patients with severe functional MR had significantly higher serum uric acid levels compared to patients without severe functional MR (6.34 ± 1.61 mg/dL vs 5.43 ± 1.17 mg/dL respectively, p = 0.012). Furthermore, tenting area, an important predictor of functional MR severity, was moderately correlated with the serum uric acid levels (r = 0.351, p = 0.005). It was also shown that the serum uric acid concentrations were inversely correlated with left ventricular (LV) ejection fraction, and positively correlated with LV volumes. There was also a significant relation between the serum uric acid and left atrial volumes and also brain natriuretic peptide (BNP) levels. CONCLUSIONS: In conclusion, this study demonstrates that elevated serum uric acid levels in patients with dilated cardiomyopathy are correlated with the severity of functional MR and echocardiographic volume indices.

Three-dimensional nanofabrication of polystyrene by focused ion beam.

Focused ion beam micromachining provides a maskless and resistless technique for prototyping of structures from thermoplastic polymers, an example being the production of polystyrene microcantilevers with potential applications as micro/nanoelectromechanical systems sensors and actuators. The applicability of FIB technology is, however, often restricted by the damage created by high energy gallium ion bombardment and local beam heating, which can affect the desired properties and limit the minimum achievable size of the fabricated structure. To investigate the ion-induced damage and determine the limitations of the technique for polymer nanofabrication, we have exposed thin polystyrene film to the ion beam at varying ion doses, ion energies and specimen temperatures. Ion doses ranging from 10(16) to 10(18) ions cm(-2) show significant gallium implantation, redeposition of sputtered material and chemical degradation in the polymer. Raman results show that the local heating in polymer during milling is severe at room temperature, damaging the aromatic carbon bonding (C = C) in particular. These observations are supported by the results of a beam heating model and Monte Carlo simulations. The chemical degradation caused by local beam heating is found to be significantly reduced by cooling the specimen to -25°C during milling. This is consistent with observations that reversible and repeatable thermal actuation of a fabricated polystyrene-platinum microcantilever is only observed when the cantilever is prepared at low temperature milling. Using this cooling approach, polymer structures can be fabricated with dimensions as low as 200 nm and still retain a sufficient volume of material unaffected by the ion beam.