Assessment of mitral valve geometry in nonvalvular atrial fibrillation patients with or without ventricular dysfunction: insights from high volume rate three-dimensional transesophageal echocardiography.

Meticulous understanding of the mechanisms underpinning mitral regurgitation in atrial fibrillation (AF) patients is crucial to optimize therapeutic strategies. The morphologic characteristics of mitral valves in atrial functional mitral regurgitation (FMR) patients with and without left ventricular (LV) dysfunction were evaluated by high volume rate (HVR) three-dimensional transesophageal echocardiography (3D-TEE). In our study, 68 of 265 AF patients who underwent 3D-TEE were selected, including 36 patients with AF, FMR, and preserved LV function (AFMR group) and 32 patients with AF, FMR, and LV dysfunction (VFMR group). In addition, 36 fever patients without heart disease were included in the control group. Group comparisons were performed by one-way analysis of variance for continuous variables. The left atrium (LA) was enlarged in the AFMR and VFMR groups compared with the control group. The mitral annulus (MA) in the AFMR group was enlarged and flattened compared with the control group and was smaller than in the VFMR group. The annulus area fraction was significantly diminished in the AFMR and VFMR groups, indicative of reduced MA contractility. The posterior mitral leaflet (PML) angle was smallest in the AFMR group and largest in the control group, whereas the distal anterior mitral leaflet angle did not significantly differ among the three groups. LA remodeling causes expansion of the MA and reduced MA contractility, disruption of the annular saddle shape, and atriogenic PML tethering. Comparison of atrial FMR patients with and without LV dysfunction indicates that atriogenic PML tethering is an important factor that aggravates FMR. HVR 3D-TEE improves the 3D temporal resolution greatly.

[Assessment of Left Atrial Appendage Size and Morphology by Enhanced Cardiac Computed Tomography in Patients with Non-valvular Atrial Fibrillation].

OBJECTIVE: This study was designed to investigate left atrial appendage (LAA) size and morphology characteristics in patients with non-valvular atrial fibrillation (NVAF) by enhanced cardiac computed tomography (CT) scanning,and to evaluate the predictive value of these parameters for thromboembolic risk. METHODS: A total of 189 NVAF patients were prospectively enrolled during December 2012 to January 2014 in West China Hospital of Sichuan University. Fifty-two atrial tachycardia patients without organ dysfunction were also recruited as controls. All subjects were scheduled for radiofrequency ablation and underwent enhanced cardiac CT scan. The clinical characteristics,comorbid diseases,anticoagulant therapy,and AF chronicity were collected and CHA2DS2-VASc score was calculated for the assessment of thromboembolic risk. The NVAF cohort was also divided further into LAA thrombus present (n=13) and absent (n=176) subgroup according to LAA with thrombus or not. Differencesin size and morphology characteristics of the LAA were compared among controls and different CHA2DS2-VASc thromboembolic risk subgroups,and between LAA thrombus and non-thrombus group. In addition,logistic regression analysis was used to identify whether these parameters predict thrombus formation independent of the CHA2DS2-VASc score in NVAF patients. RESULTS: Compared with controls,NVAF patients had significantly bigger orifice size. Windsock and cactus-type LAA were main morphology in controls,while the distribution of the four kinds of LAA types were similar in NVAF patients. The orifice and volume of the LAA were increased with increasing CHA2DS2-VASc riskscore,and chicken wing-type LAA was the predominant prevalence in low-intermediate thromboembolic risk subgroup while cauliflower in high thromboembolic risk subgroup. Compared with non-thrombus patients,LAA-thrombussubgroup exhibited a significantly increased orifice and volume,and higher prevalenceof the cauliflower shaped LAA. Logistic regression showed that the LAA orifice and cauliflower shape were independent predictors for thrombus formation in patients with NVAF following adjustment for the CHA2DS2-VASc score. CONCLUSION: Cardiac images obtained with CTis feasible for the analysis of LAA size and morphology,and these parameters provide incremental value in assessing the LAA thrombus risk in patients with NVAF.

Assessment of the left atrial appendage structure and morphology: comparison of real-time three-dimensional transesophageal echocardiography and computed tomography.

In this study, the left atrial appendage (LAA) structure and morphology were assessed using real-time three-dimensional transesophageal echocardiography (RT3D-TEE) and enhanced cardiac computed tomography (CT) scanning, and the two measurements obtained using these different techniques were compared. Two hundred nonvalvular atrial fibrillation (NVAF) patients who were prepared to undergo radiofrequency ablation were enrolled, and 62 controls were enrolled prospectively. RT3D-TEE and CT were performed, and the following parameters were measured: LAA orifice diameter, area, depth, maximum volume, and emptying velocity. The differences between the NVAF patients and controls were compared, and the differences and correlations in the LAA parameters between the two imaging techniques were assessed. The NVAF patients had significantly bigger orifice sizes, orifice areas, and maximum volumes, and lower emptying rates. The AF cohort had roughly equal proportions of the four morphological types, whereas the controls predominantly had the windsock type. A Bland-Altman analysis demonstrated that the LAA measurements obtained using RT3D-TEE were lower than those obtained with the CT. However, linear regression analysis showed the good correlations between the RT3D-TEE and CT measurements of the LAA orifice area, depth and volume (r = 0.86, 0.63, and 0.75, respectively). The use of RT3D-TEE for the visualization and quantitative analysis of LAA parameters is feasible, and the obtained measurements correlate well with those obtained with cardiac CT. This technique may be an ideal tool for guiding LAA occlusion procedures, and combining these two methods may enhance the accuracy of LAA measurements.

Assessment of Left Ventricular Dissipative Energy Loss by Vector Flow Mapping in Patients With End-Stage Renal Disease.

OBJECTIVES: Dissipative energy loss derived from vector flow mapping represents the viscous dissipation of turbulent blood flow. We aimed to determine the left ventricular (LV) energy loss in patients with end-stage renal disease (ESRD). METHODS: Patients with ESRD and a preserved LV ejection fraction, who consisted of a group receiving peritoneal dialysis, a group receiving hemodialysis, and a group receiving preparation for dialysis initiation, were examined by echocardiography; a group of healthy control participants were examined as well. Vector flow mapping analysis was then performed from the apical 4-chamber view to calculate the energy loss during diastole and systole in the left ventricle. RESULTS: Conventional transthoracic echocardiography and LV energy loss calculations were successfully performed in 63 cases and 50 controls. The patients with ESRD had significantly higher diastolic energy loss [median (interquartile range), 71.73 (46.08-106.75) versus 23.32 (17.17-29.26) mW/m; P < .001] and higher systolic energy loss [25.28 (19.03-33.93) versus 12.52 (9.35-16.47) mW/m; P < .001]. A significant difference in diastolic energy loss between the peritoneal dialysis and preparation groups was found [54.92 (39.28-89.94) versus 84.82 (62.58-171.4) mW/m; P = .04]. In patients with ESRD, the log-transformed diastolic energy loss had a significant association with the peak early diastolic transmitral flow velocity (P = .011), peak early diastolic transmitral flow velocity-to-peak early diastolic mitral annular flow velocity ratio (P = .001), LV mass index (P = .017), and heart rate (P = .003). CONCLUSIONS: Impaired blood flow efficiency was detected in patients with ESRD by using dissipative energy loss derived from vector flow mapping. The energy loss value could be a novel parameter for evaluating the ventricular workload of uremic hearts in terms of fluid mechanics.

The hidden opportunity cost of time effect on intertemporal choice.

An interesting phenomenon called "hidden opportunity cost of time effect" was detected in intertemporal choices. The majority of our participants preferred the smaller but sooner (SS) option to the larger but later (LL) option if opportunity cost was explicit. However, a higher proportion of participants preferred the LL to SS option if opportunity cost was hidden. This shift violates the invariance principle and opens a new way to encourage future-oriented behavior. By simply mentioning the "obvious" opportunity cost of alternatives, decision makers can be more informed in prioritizing their long-term goals rather than short-term goals.

[Assessment of left ventricular global systolic function using real-time three-dimensional speckle-tracking echocardiography in patients with hypothyroidism].

The present study aimed to investigate the impact of hypothyroidism on left ventricular systolic function using real-time three-dimensional speckle tracking imaging (RT3D-STI). Thirty hypothyroidism patients and forty healthy volunteers were recruited and received RT3DSTI measurement of global longitudinal strain (GLS), global circumferential strain (GCS), global radial strain (GRS), and global area strain (GAS). A comparison of differences between the hypothyroidism patients and those in the healthy group was carried out and we obtained the results as followings. The values of GLS were (-18.93 +/- 3.89) vs. (-21.44 +/- 1.99), with P < 0.01, GRS were (51.13 +/- 11.95) vs. (56.10 +/- 5.76), with P < 0.0; and GAS were (-31.63 +/- 5.38) vs. (-34.40 +/- 2.32), with P < 0.01, i.e. they were lower in hypothyroidism group than those in the health group. While GCS were (-17.75 +/- 1.92) vs. 17.03 +/- 3.45), with P > 0.05, which were not significantly different between the two groups. In linear regres sion, GLS showed significant correlation with both TSH (b = -0.69, P < 0.01) and FT3 (b = 0.71, P < 0.01). Meanwhile, the GRS (b = 2.98, P < 0.05) and GAS (b = 3.11, P < 0.05) linearly correlated with FT3 level. In conclusion, the present study shows that the global longitudinal and radial moves of left ventricular are weaker in patients with hypothyroidism than healthy controls. And the impairment of left ventricular function would aggravate as FSH rises or FT3 declines.

Assessment of aortic and mitral annuli dynamics during the cardiac cycle using speckle tracking echocardiography.

The aims of this study were i) to evaluate mitral and aortic annuli excursion, and aortomitral angle (AMA) during the cardiac cycle in healthy adults using two-dimensional speckle tracking echocardiography, ii) to assess two annuli dynamics and coupling behaviors as an integral, and iii) to detect the relation between two annuli and left ventricular ejection fraction (LVEF). A total of 74 healthy adults underwent transthoracic echocardiography. In the parasternal long-axis view, a number of points were extracted, including right coronary aortic annular, aortomitral fibrous junction, and posterior mitral annular points. The annuli excursion and AMA were measured using a speckle tracking-derived software during the cardiac cycle. During the isovolumic contraction and the isovolumic relaxation phase, annuli excursion and AMA remain stable for a short time. During the systole, annuli excursion increased sharply to the maximum, while AMA narrowed quickly to the minimum value. During the diastole, there are three patterns of decrease in annuli excursion and AMA expansion in different phases. The annuli excursion of three points correlates well with the LVEF (right coronary aortic annulus excursion, r=0.71, P<0.05; non-coronary aortic annulus excursion, r=0.70, P<0.05; posterior mitral annulus excursion, r=0.82, P<0.05). Moreover, there are positive correlations between annuli excursion and the variation of AMA (r=0.60, P<0.05). The annuli excursion and AMA have various regular patterns in healthy adults. The interactions of mitral and aortic annuli correlate with the left ventricular function. Our findings may have relevance to the evaluation of left ventricular function and presurgical planning of patients with valvular diseases.

Assessment right atrial thrombus by real-time three dimensional transthoracic echocardiography in patient with dilated cardiomyopathy.

We report a case of a 52-year-old patient with dilated cardiomyopathy who presented with worsening heart failure. Two-dimensional transthoracic echocardiography and real-time three dimensional transthoracic echocardiography showed severe dilated cardiac chambers, impaired ejection fraction and a mobile right atrial thrombus 2.6 × 1.0 cm in size, traversing the right atrial cavity during the whole cardiac cycle. After one week therapeutic anticoagulation, echocardiography confirmed no evidence of residual thrombus.

[Development of a low-cost single chamber microbial fuel cell type BOD sensor].

The principle of the detector is based on the effect of microbial toxicity of water sample on the electricity generation in microbial fuel cell (MFC). The performance of the MFC-type biotoxicity detector was evaluated with the synthetic water containing heavy metals of Cd2+ and Cu2+. The experimental results demonstrated that: (1) relative to the conventional methods, the MFC-type detector is easy to operate, and suitable for on-line measurements with high sensitivity; (2) it only requires 4 h to complete measurements, and can get ready for next measurement within 4 h; (3) there is a significant linear correlation between the concentration of toxic metal(s) and inhibition ratios in Coulombic yields of MFC. As the IC20 (concentration causing 20% inhibition) of Cd2+, Cu2+ and mixed metals (Cd2+ and Cu2+) were 0.6, 0.8 and 0.25 mg/L, the regression coefficients were shown to be 0.9960, 0.9744 and 0.9907.

Will simultaneous measurement of E/e' index facilitate the non-invasive assessment of left ventricular filling pressure in patients with non-valvular atrial fibrillation?

AIMS: The ratio of early transmitral flow velocity (E) to early diastolic mitral annular velocity (e') was applied as a non-invasive index to assess left ventricular filling pressure (LVFP). However, the reliability of E/e' was undermined in patients with atrial fibrillation (AF). Recently, a novel method entitled 'dual Doppler' was established, which allows simultaneous recording and display of E and e'. Our study investigates whether the dual-Doppler method improves the reliability of E/e' in AF patients. METHODS AND RESULTS: Forty-nine patients with non-valvular AF underwent conventional echocardiography, dual-Doppler echocardiography, and cardiac catheterization within 4 h. Of 22 patients (45%c) with increased LVFP (>15 mmHg), higher E/e' measured by both conventional tissue Doppler imaging (TDI) and dual-Doppler method was observed. Conventional echocardiographic variables were correlated with LVFP (E/e'(sep), r = 0.404, E/e'(lat), r = 0.487), but E/e' measured synchronously in the dual-Doppler mode yielded a better correlation (E/e'(synchronous sep), r = 0.754, E/e'(synchronous lat), r = 0.765). The intra- and interobserver variability of the dual-Doppler method was significantly lower than the conventional TDI method. CONCLUSION: Good correlations were found between E/e'' and LVFP in patients with AF, particularly in the dual-Doppler mode. E/e' measured by the dual-Doppler method can therefore be applied to assess diastolic dysfunction in AF patients.

Isolated mitral regurgitation: quantitative assessment with 64-section multidetector CT--comparison with MR imaging and echocardiography.

PURPOSE: To evaluate the accuracy of 64-section multidetector computed tomography (CT) for the assessment of the severity of isolated mitral regurgitation by measuring ventricular volumetrics compared with those at magnetic resonance (MR) imaging and echocardiography. MATERIALS AND METHODS: This study was approved by an institutional review board; patient informed consent was obtained. Forty-nine patients (22 men, 27 women; mean age, 39 years +/- 11 [standard deviation]) with isolated mitral regurgitation underwent retrospective electrocardiographically (ECG) gated 64-section CT, echocardiography, and MR imaging for the assessment of the severity of mitral regurgitation. Stroke volumes of the left and right ventricles were measured at 64-section CT and MR imaging. With these measurements, regurgitant volumes (RVs) and regurgitant fractions (RFs) were calculated and compared. The agreement between CT and MR imaging was tested by using linear regression and Bland-Altman analyses. RFs were compared with corresponding echocardiographic grades (grades I-IV) based on the absolute area of the regurgitation jet and in relation to the size of the left atrium by using Spearman rank order correlation and a weighted kappa test. RESULTS: No significant differences were found in calculated RV and RF between 64-section CT and MR imaging (P = .56 and .87, respectively; paired t test). Regression analysis showed that 64-section CT correlated well with MR imaging for the measurement of RV (r = 0.89; 95% confidence interval [CI]: 0.81, 0.94) and for calculating the RF (r = 0.91; 95% CI: 0.84, 0.95). Bland-Altman analysis showed no significant differences in RV (bias, -1.0 mL) and RF (bias, 0.2%) between 64-section CT and MR imaging. The severity of regurgitation estimated by using echocardiography correlated well with that estimated by using 64-section CT (r = 0.95; 95% CI: 0.92, 0.97) and MR imaging (r = 0.94; 95% CI: 0.91, 0.96). CONCLUSION: ECG-gated 64-section CT helps provide quantitative information with high accuracy for determining the severity of isolated mitral regurgitation.