Regional Ejection Fraction Research Articles

A novel method for sensitive determination of subclinical right ventricular systolic dysfunction in patients with obstructive sleep apnea.

The aim of this study was to evaluate right ventricular (RV) regional systolic function and dyssynchrony in patients with newly diagnosed obstructive sleep apnea using real-time three-dimensional (3D) echocardiography. Eighty-two subjects without hypertension, diabetes mellitus or any cardiac or pulmonary disease referred for evaluation of obstructive sleep apnea (OSA) had overnight polysomnography and complete echocardiographic assessment. According to the apnea hypopnea index (AHI), subjects were divided into four groups: group 1: control subjects (AHI < 5, n = 19), group 2: patients with mild OSA (AHI: 5-14, n = 21), group 3: moderate OSA (AHI: 15-30, n = 18), group 4: severe OSA (AHI > 30, n = 24). Real-time three-dimensional echocardiographic images were acquired to obtain RV regional (inflow, body and outflow) ejection fraction (EF) and time to minimum systolic volume in all subjects. Body weight and body mass index were greater in the severe and moderate OSA group than those of mild and controls group (P < 0.05). There was a significant decrease in mean SaO2 and the lowest SaO2 in severe OSA when compared to other groups (P < 0.001). Inflow EF and global EF were significantly lower in moderate and severe OSA patients than in controls (P < 0.05). Inflow EF and global EF were negatively correlated with AHI (r = -0.534 and r = -0.479, respectively, P < 0.001). In patients with OSA, RV inflow and global systolic function were impaired and were in inverse relationship with AHI. Evaluation of RV regional systolic function using real-time three-dimensional echocardiography may play a potential role in the noninvasive assessment of the severity of OSA.

Three-Dimensional Echocardiography in the Evaluation of Right Ventricular Global and Regional Systolic Function in Patients with Atrial Septal Defect before and after Percutaneous Closure.

To evaluate right ventricular (RV) global and regional systolic function in patients with atrial septal defect (ASD) before and after percutaneous closure using real time three-dimensional echocardiography (RT3DE). RT3DE was performed in 81 patients with ASD within 24 hours before and after percutaneous closure to obtain RV global and regional ejection fraction (EF) in three compartments (inflow, body, and outflow). RV fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), peak tricuspid systolic velocity (S), and pulmonary vascular resistance (PVR) were recorded. Forty matched normal adults were included as controls. When compared with controls, RV global and regional EF were decreased in preclosure patients (P < 0.001). FAC was lower while TAPSE and S were higher in preclosure patients than in controls (P < 0.05). After closure, RV systolic function parameters were all reduced (P < 0.001). Regional EF in the body compartment was the lowest among the three compartments in ASD patients (P < 0.05). Procedural percentage changes of RV global EF and regional EF in the inflow compartment were lower than those of two-dimensional systolic function parameters (P < 0.05). RV global and regional EF in the inflow compartment were negatively correlated with PVR in patients after closure (r = -0.601, -0.543, P < 0.001). RV global and regional systolic functions are impaired in open and closed ASD. RT3DE-derived systolic function parameters are negatively correlated with RV after load. RT3DE has potential value in the evaluation of RV systolic function in patients with ASD.

Regional ejection fraction and regional area strain for left ventricular function assessment in male patients after first-time myocardial infarction.

In this work, we present a method to assess left ventricle (LV) regional function from cardiac magnetic resonance (CMR) imaging based on the regional ejection fraction (REF) and regional area strain (RAS). CMR scans were performed for 30 patients after first-time myocardial infarction (MI) and nine age- and sex-matched healthy volunteers. The CMR images were processed to reconstruct three-dimensional LV geometry, and the REF and RAS in a 16-segment model were computed using our proposed methodology. The method of computing the REF was tested and shown to be robust against variation in user input. Furthermore, analysis of data was feasible in all patients and healthy volunteers without any exclusions. The REF correlated well with the RAS in a nonlinear manner (quadratic fit-R(2) = 0.88). In patients after first-time MI, the REF and RAS were significantly reduced across all 16 segments (REF: p < 0.05; RAS: p < 0.01). Moreover, the REF and RAS significantly decreased with the extent of transmural scar obtained from late gadolinium-enhanced CMR images. In addition, we show that the REF and RAS can be used to identify regions with compromised function in the patients with preserved global ejection fraction with reasonable accuracy (more than 78%). These preliminary results confirmed the validity of our approach for accurate analysis of LV regional function. Our approach potentially offers physicians new insights into the local characteristics of the myocardial mechanics after a MI.

CARDIAC REGIONAL FUNCTION OF YOUNG SPORTSMEN WITH FALSE TENDONS IN THE LEFT VENTRICLE

The aim of the study is to evaluate cardiac regional function of young athletes with false tendons (FT) in the left ventricle (LV). The focus was on mechanical asynchrony in LV wall. Forty-seven young athletes (mean age 20.2 ± 2.9 years) with connective tissue dysplasia syndrome underwent transthoracic echocardiography. To formalize FT topology, the 3D-model of LV geometry was reconstructed based on three short-axis sections and one long-axis section of LV. On average, 4.0 ± 1.0 FT with different localization and orientation in LV were determined. Cardiac function was estimated in 12 regions at LV long-axis section in the course of complete heart cycle. RMS variations of the regional systolic function duration (dT) and the variation coefficient of regional ejection fraction (Cv r-EF) for 12 regions served as measures of the mechanical asynchrony. Wide variety of asynchrony parameters was obtained. The value of dT varied from 24.2 to 84.1 ms (40.4 ± 27.8 ms); Cv r-EF — from 8.0% to 42.0% (20.83 ± 8.35%). Significant correlations between total number of FT per heart and dT (r = 0.396; P &lt; 0.01) and between median transverse FT (connect interventricular septum and lateral LV wall) and Cv r-EF (r = 0.301; P &lt; 0.05) were found. Detailed analyses of FT morphology with respect of LV regional function peculiarities showed that higher extent of asynchrony associates with the transverse and oblique FT mainly located at basal and/or medial portions of LV chamber.

Three-dimensional changes in regional right ventricular curvature and function in tetralogy of fallot

Background Many patients with Tetralogy of Fallot (TOF) have residual pulmonic stenosis and/or regurgitation after surgical repair, leading to maladaptive right ventricular (RV) remodeling. Cardiovascular magnetic resonance (CMR) is currently the gold standard for evaluating RV size and function. Analysis of regional volume and three-dimensional (3D) curvature of the RV from CMR images may provide new insights into the remodeling process. The aim of this study is to describe RV remodeling by characterizing regional endocardial surface curvature and function in patients with TOF. Methods CMR (1.5T Philips Achieva) was performed in subjects with repaired TOF (N=17, age range 9-53 years) and healthy volunteers (N=10, age range 23-43 years). The RV end-diastolic and end-systolic endocardial surfaces were manually segmented from a contiguous stack of short axis cine slices to construct a 3D model using custom software (figure). This model was used to measure regional volume and ejection fraction for the RV inflow, outflow, and trabecular regions. Local endocardial surface curvature was displayed on a color map of the 3D volume surface and regional curvature was calculated for the RV inflow, outflow, trabecular, free wall, and septal segments. The values for curvature were indexed to volume to remove the influence of volume between regions. The parameters from individuals with TOF were compared to those acquired from the healthy volunteers. Results As shown in the table, individuals with TOF had larger global RV volume and reduced ejection fraction when compared to controls. The trabecular region had relatively preserved ejection fraction, despite exhibiting the most enlargement. Conversely, the outflow and inflow regions had greater reductions in ejection fraction but only mild enlargement. The Trabecular region enlargement coincided with increased regional curvature, which was not as striking in the inflow and outflow regions. Those with TOF had higher overall free wall curvature. Septal curvature in TOF patients was higher (slightly convex) compared to controls (slightly concave). Global curvature, combining all septal and free wall regions, was higher in TOF patients. Conclusions Using analysis of RV 3D regional curvature and volumes from CMR images, we show that individuals with repaired TOF have regional variation in RV remodeling and function. Further evaluation is required to understand the clinical implications of this variable remodeling.

Quantitative description of the 3D regional mechanics of the left atrium using cardiac magnetic resonance imaging

The left atrium (LA) plays an important role in the maintenance of hemodynamic and electrical stability of the heart. One of the conditions altering the atrial mechanical function is atrial fibrillation (AF), leading to an increased thromboembolic risk due to impaired mechanical function. Preserving the regions of the LA that contribute the greatest to atrial mechanical function during curative strategies for AF is important. The purpose of this study is to introduce a novel method of regional assessment of mechanical function of the LA. We used cardiac MRI to reconstruct the 3D geometry of the LA in nine control and nine patients with paroxysmal atrial fibrillation (PAF). Regional mechanical function of the LA in pre-defined segments of the atrium was calculated using regional ejection fraction and wall velocity. We found significantly greater mechanical function in anterior, septal and lateral segments as opposed to roof and posterior segments, as well as a significant decrease of mechanical function in the PAF group. We suggest that in order to minimize the impact of the AF treatment on global atrial mechanical function, damage related to therapeutic intervention, such as catheter ablation, in those areas should be minimized.

Abstract 9912: Global Intracoronary Infusion of Allogeneic Atrial Cardiosphere-Derived Cells (CDCs) Stimulates Myocyte Regeneration and Reverses LV Remodeling in Miniature Swine With Chronic Myocardial Infarction

Background: Intracoronary infusion of autologous CDCs (icCDCs) into the infarct-related artery using the “stop flow” technique improves regional function in patients but global function remains unchanged. We tested the hypothesis that this reflects the inability to regress cellular hypertrophy and replace myocytes lost in remote remodeled regions that can be overcome by global intracoronary infusion of CDCs. Methods: Miniswine (n=10) were studied 8 weeks after chronic infarction was produced by LAD microembolization (1x10 6 microspheres, 45μm diameter). Ejection fraction decreased from 63 ± 2% at baseline to 31 ± 2% four weeks after infarction (p&lt;0.05 vs. baseline) and remained unchanged at 8 weeks (32 ± 2%, p-ns vs. 4 weeks). Allogeneic CDCs (20 x 10 6 CDCs, cyclosporine 100 mg/day) isolated from donor atrial biopsies were infused into the 3 major coronary distributions without interrupting flow. We assessed myocardial function (echo), myocyte proliferation (Ki67) and infarct size (TTC) in comparison to untreated controls. Regional myocyte regeneration was quantified by assessing myocyte nuclear density and size. Results: Infusing icCDCs into infarcted and remodeled remote myocardium increased regional function and ejection fraction (Table). icCDCs stimulated myocyte proliferation (Ki67) in LAD and remote regions by three-fold. As a result, myocyte number (nuclear density) increased by 35% and myocyte cell diameter decreased by 33% in both LAD and remote myocardium. The reduction in infarct volume after icCDCs was not significant. Conclusion: We conclude that global infusion of allogeneic icCDCs without “stop flow” 1.) stimulates myocyte proliferation throughout the LV and 2.) in a model of infarction, improves regional function with a substantial increase in left ventricular ejection fraction. Thus, allogeneic icCDCs may afford a widely available platform to reverse LV dysfunction in patients with chronic post infarction LV remodeling.

Comparison of 4D-MicroSPECT and MicroCT for Murine Cardiac Function

The objective of this study was to compare a new generation of four-dimensional micro-single photon emission computed tomography (microSPECT) with microCT for the quantitative in vivo assessment of murine cardiac function. Four-dimensional isotropic cardiac images were acquired from anesthetized normal C57BL/6 mice with either microSPECT (n = 6) or microCT (n = 6). One additional mouse with myocardial infarction (MI) was scanned with both modalities. Prior to imaging, mice were injected with either technetium tetrofosmin for microSPECT or a liposomal blood pool contrast agent for microCT. Segmentation of the left ventricle (LV) was performed using Vitrea (Vital Images) software, to derive global and regional function. Measures of global LV function between microSPECT and microCT groups were comparable (e.g., ejection fraction = 71 ± 6 % microSPECT and 68 ± 4 % microCT). Regional functional indices (wall motion, wall thickening, regional ejection fraction) were also similar for the two modalities. In the mouse with MI, microSPECT identified a large perfusion defect that was not evident with microCT. Despite lower spatial resolution, microSPECT was comparable to microCT in the quantitative evaluation of cardiac function. MicroSPECT offers an advantage over microCT in the ability to evaluate simultaneously myocardial radiotracer distribution and function, simultaneously. MicroSPECT should be considered as an alternative to microCT and magnetic resonance for preclinical cardiac imaging in the mouse.

GW24-e0649 Assessment of left ventricular regional systolic function in patients with hypertrophic cardiomyopathy by real-time three-dimensional echocardiography

ObjectivesThe aim of our study is to assess left ventricular regional systolic function in patients with hypertrophic cardiomyopathy (HCM) using real-time three-dimensional echocardiography (RT-3DE).MethodsRT-3DE was performed in 25 HCM patients...

Assessment of regional left ventricular systolic function in patients with hypertrophic cardiomyopathy by real-time three-dimensional echocardiography

Objective To assess regional left ventricular systolic function in patients with hypertrophic cardiomyopathy (HCM) using real-time three-dimensional echocardiography (RT-3DE).Methods Twenty-five patients with HCM which was asymmetric septal hypertrophy,and twenty healthy subjects were enrolled in the study.The apical four-chamber view of left ventricular was acquired by RT-3DE.The left ventricular volume-time curves were analyzed quantitatively with Tomtec 4D LV-Analysis 3.0,and regional end-diastolic volume and end-systolic volume of left ventricular (rEDV,rESV),the time to minimum systolic volume (rESVT),regional stroke volume (rSV),regional ejection fraction (rEF),regional-global ejection fraction (rgEF) and the parameters of left ventricular dyssynchrony were measured.Results In the HCM group,the values of Tmsv16-Dif,Tmsv16-SD,Tmsv16-Dif％,Tmsv16-SD％ were significantly lower compared with the control group (P ＜ 0.01),and rEDV,rSV,rEF and rgEF in hypertrophic segments were lower than those in non-thickening and mild-thickening segments (P ＜0.05).In the control group,there were no significant difference of those parameters among all segments (P ＞0.05).The values of rEDV,rSV and rgEF in hypertrophic segments decreased in the HCM group (P ＜0.05),at the basal level,rEF in hypertrophic segments decreased,at the apical level,it increased,but the differences at the mid-ventricular level between the two groups were not significant;the values of rEF and rgEF in non-thickening and mild-thickening segments increased (P ＜0.05).Conclusions RT-3DE could sensitively detect left ventricular dyssynchrony and accurately assess regional left ventricular volume and function of different segments in patients with HCM. Key words: Echocardiography, real-time three-dimensional; Cardiomyopathy, hypertrophic; Ventricular function, left

Right Ventricular Regional Systolic Function and Dyssynchrony in Patients with Pulmonary Hypertension Evaluated by Three-Dimensional Echocardiography

The aim of this study was to evaluate right ventricular (RV) regional systolic function and dyssynchrony in patients with pulmonary hypertension (PH) using real-time three-dimensional echocardiography. Real-time three-dimensional echocardiographic images were acquired to obtain RV regional (inflow, body, and outflow) ejection fraction (EF) and time to minimum systolic volume in 70 patients with PH and 26 normal controls. Pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance measured by echocardiography in all subjects and by right heart catheterization in 17 patients were recorded. Inflow EF and global EF were significantly lower in patients with PH than in controls (P < .05). Body EF was significantly decreased in patients with moderate (PASP, 50-69 mm Hg) and severe (PASP ≥ 70 mm Hg) PH (P < .05). Outflow EF was significantly lowered in patients with severe PH (P < .001). The standard deviation of regional time to minimum systolic volume corrected by heart rate was significantly prolonged in patients with severe PH (P < .05). Inflow EF and global EF were negatively correlated with PASP (r = -0.731 and r = -0.769, respectively, P < .001) and with pulmonary vascular resistance (r = -0.789 and r = -0.801, P < .001). In patients with PH, RV inflow and global systolic function was impaired in inverse relationship with PASP and pulmonary vascular resistance. RV systolic synchronicity was impaired in patients with severe PH. Evaluation of RV regional systolic function using real-time three-dimensional echocardiography may play a potential role in the noninvasive assessment of the severity of PH.

High resolution real-time CMR of function and flow: initial clinical results

Background A new MRI technology for real-time MRI at high temporal and high spatial resolution was applied to CMR. First clinical applications cover dynamic imaging of wall motion and volume changes during cardiac arrhythmias as well as quantitative flow measurements under physiologic stress maneuvers. Methods A recently introduced real-time MRI method based on undersampled radial FLASH sequences with image reconstruction by regularized nonlinear inversion was applied to CMR. Anatomical imaging in real time was performed at 34 ms temporal resolution (30 fps) using 1.5 mm in-plane resolution and 6 mm slice thickness. Real-time quantitative flow measurements employed two acquisitions at 20 ms resolution, yielding a temporal resolution of 40 ms (25 fps) at 1.3 mm in-plane resolution and 6 mm slice thickness. Healthy volunteers as well as patients with arrhythmia were examined in a clinical 3T MR scanner. The image series were analyzed using a modified standard software capable of dealing with 100 to 900 images per slice position. The ECG signal was co-registered for documentation and ease of image analysis. Results The new high-resolution real-time MRI technique was used to analyze the beat-to-beat variability of patients with arrhythmia and to define ejection fractions in normal and arrhythmic episodes. Quantitative flow measurements were obtained in all major intrathoracic vessels during free breathing. Specific measurements during increased (Valsalva maneouver) and reduced intrathoracic pressure (Mueller maneouver) were obtained in healthy volunteers to document cardiovascular response to physiologic stressors. Regional wall motion, ventricular volumes, myocardial mass and ejection fraction were derived including standard deviations based on temporal variability of the heart cycle. Suitable software strategies for the analysis of the large datasets are indispensible to bring real-time CMR into clinical routine.

Computerized left ventricular regional ejection fraction analysis for detection of ischemic coronary artery disease with multidetector CT angiography

Regional ejection fraction (REF) provides important functional information of the left ventricular regional myocardium. We aimed to test the diagnostic accuracy of computerized REF analysis for detecting the ischemia and significant stenosis with multidetector CT angiography (MDCT). This is a retrospective study including 155 patients who underwent MDCT scans for evaluation of coronary artery disease. Among them, 83 patients also underwent SPECT imaging and invasive coronary angiography (ICA). Two groups of patients were defined: Control group with 0 coronary artery calcium and normal global and regional ventricular function, and comparison group. REF measurement was performed on all patients using computerized software. Control group REF measurements will be used as reference standard (mean-2SD REF/mean global ejection fraction) to define abnormal REF. The sensitivity, specificity, positive and negative predictive value of REF in detecting perfusion defects (fixed and reversible) was 73, 80, 75 and 79 % respectively, in a patient based analysis of comparison group. The diagnostic accuracy of REF in predicting significant stenosis (>50 %) on ICA compared with SPECT was 72 versus 61 % and 85 versus 79 % in patient and vessel based analysis of comparison group, respectively. ROC curve analysis showed REF to be a better predictor of perfusion defects on SPECT compared with significant stenosis (>50 %) alone or stenosis combined with REF (P < 0.05). The computerized assessment of REF analysis is comparable to SPECT in predicting ischemia and a better predictor of significant stenosis than SPECT. This study also provides reference standard to define abnormal values.

Use of SPECT to detect changes in diastolic and coronary reserve in patients with obstructive sleep apnea

To assess diastolic function and coronary artery reserve in patients with obstructive sleep apnea (OSA) using single-photon emission computer tomography (SPECT). Patients with OSA who had normal echocardiograph/electrocardiogram findings were divided into three groups based on OSA severity: mild (n = 15), moderate (n = 13), or severe (n = 18). A control group of participants without OSA (n = 17) was included. SPECT (with technetium-99 m-labeled red blood cells) was performed after the induction of cardiac stress by injection of dobutamine. The following ventricular parameters were determined: left ventricular ejection fraction, peak filling rate (PFR), peak ejection rate, 1/3 filling fraction (1/3FF), and regional ejection fractions (rEF). The median ages of OSA and control participants were 45.0 and 51.0 years, respectively. Median apnea-hypopnea index scores were 3.3, 9.1, 38.5, and 65.2 for the control, mild OSA, moderate OSA, and severe OSA groups, respectively. Post-stress, 1/3FF was significantly lower in the overall OSA group compared with the control group (P < 0.05). PFR was significantly lower in the overall OSA group compared with the control group (P < 0.05) and was significantly lower in the severe OSA group compared with the mild OSA group. Regional ejection fractions rEF3 (cardiac apex and a small part of the inferior wall) and rEF4 (anteroseptal wall) were significantly lower in the overall OSA group compared with the control group, suggesting decreased coronary artery reserve. Our findings suggest that SPECT can be used to detect abnormalities in diastolic function and coronary reserve in patients with OSA who have normal electrocardiogram or echocardiograph findings. SPECT may be useful for the early detection of cardiovascular disease in patients with OSA.

Head-to-Head Comparison of Left Ventricular Function Assessment with 64-Row Computed Tomography, Biplane Left Cineventriculography, and Both 2- and 3-Dimensional Transthoracic Echocardiography: Comparison With Magnetic Resonance Imaging as the Reference Standard

This study was designed to compare the accuracy of 64-row contrast computed tomography (CT), invasive cineventriculography (CVG), 2-dimensional echocardiography (2D Echo), and 3-dimensional echocardiography (3D Echo) for left ventricular (LV) function assessment with magnetic resonance imaging (MRI). Cardiac function is an important determinant of therapy and is a major predictor for long-term survival in patients with coronary artery disease. A number of methods are available for assessment of function, but there are limited data on the comparison between these multiple methods in the same patients. A total of 36 patients prospectively underwent 64-row CT, CVG, 2D Echo, 3D Echo, and MRI (as the reference standard). Global and regional LV wall motion and ejection fraction (EF) were measured. In addition, assessment of interobserver agreement was performed. For the global EF, Bland-Altman analysis showed significantly higher agreement between CT and MRI (p < 0.005, 95% confidence interval: ±14.2%) than for CVG (±20.2%) and 3D Echo (±21.2%). Only CVG (59.5 ± 13.9%, p = 0.03) significantly overestimated EF in comparison with MRI (55.6 ± 16.0%). CT showed significantly better agreement for stroke volume than 2D Echo, 3D Echo, and CVG. In comparison with MRI, CVG-but not CT-significantly overestimated the end-diastolic volume (p < 0.001), whereas 2D Echo and 3D Echo significantly underestimated the EDV (p < 0.05). There was no significant difference in diagnostic accuracy (range: 76% to 88%) for regional LV function assessment between the 4 methods when compared with MRI. Interobserver agreement for EF showed high intraclass correlation for 64-row CT, MRI, 2D Echo, and 3D Echo (intraclass correlation coefficient >0.8), whereas agreement was lower for CVG (intraclass correlation coefficient = 0.58). 64-row CT may be more accurate than CVG, 2D Echo, and 3D Echo in comparison with MRI as the reference standard for assessment of global LV function.

Evaluation of Right Ventricular Regional Volume and Systolic Function in Patients with Pulmonary Arterial Hypertension Using Three‐Dimensional Echocardiography

To evaluate right ventricular (RV) regional volume and systolic function in patients with pulmonary arterial hypertension (PAH) using real time three-dimensional echocardiography (RT3DE), and to explore the relationship between parameters measured by RT3DE and right heart catheterization (RHC). RT3DE images were acquired from 24 patients with PAH and 27 normal controls for evaluation and analysis to obtain RV regional end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) in three compartments (inflow, body, and outflow). Conventional echocardiographic parameters were calculated and recorded. RHC was performed in 17 patients to obtain pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR). RV regional EDV and ESV were significantly higher while regional EF was significantly lower in the PAH patients when compared with controls (P < 0.001). In the PAH group, EDV was similar in the inflow and body compartment, both higher than that in the outflow compartment (P < 0.05); EF was the highest in the inflow compartment and the lowest in the body compartment (P < 0.05). RV regional EF in the inflow compartment and global EF were negatively correlated with PASP (r =-0.766, -0.816, P < 0.001) and PVR (r =-0.529, -0.656, P < 0.05). In patients with PAH, RV regional volume was enlarged and systolic function was impaired with distinct characteristics; regional EF in the inflow compartment and global EF were inversely correlated with PASP and PVR. Evaluation of RV regional systolic function using RT3DE may play a potential role in the noninvasive assessment of the severity of PAH.

Evaluation of right ventricular global and regional volume and systolic function in normal children by real-time three-dimensional echocardiography

Objective To evaluate right ventricular(RV) global and regional volume and systolic function by real-time three-dimensional echocardiography (RT-3DE) in normal children with different age.Methods One hundred and ninty-two normal children were divided into five groups by age:group Ⅰ,＜1 years old,32 cases;group Ⅱ,≥1 years old-＜3 years old,46 cases;group Ⅲ,≥3 years old-＜6 years old,36 cases;group Ⅳ,≥6 years old-＜9 years old,41 cases;group Ⅴ,≥9 years old-＜14 years old,37 cases.Full volume imaging of RV was obtained at the parasternal four-chamber view near the apex by RT-3DE.RT-3DE data set were analyzed off-line by TomTec RV-Function.RV were divided into three parts:inflow,body,outflow.The measurements were including RV global and regional end-diastolic volume (EDV),end-systolic volume (ESV),ejection fraction (EF) and the ratio of regional parts EDV to RVEDV. The volume and systolic function were compared in three regional parts.RV global and regional parts EF and the ratio of regional parts EDV to RVEDV were also compared in five age groups.Correlation analysis and curve estimation were studied on RV global and regional EDV with age and physical development indexes.Results In the comparison of three regional parts:inflow EDV and EF were higher than outflow and body parts (P＜0.05).No significant different was found between outflow EDV and body EDV (P＞0.05),however,outflow EF was significant higher than body EF(P＜0.05).The comparison of RV global and regional EF in five age groups were no statistical different (P＞0.12). The ratio of regional parts EDV to RVEDV remained constant in five age groups(P＞0.58).Correlation analysis showed the global and regional RV volume were strongly correlated with age,height,weight and BSA (r＞0.77,P=0.000).The best correlation was found with BSA (r＞0.83,P=0.000).Curve estimation demonstrated that the relationship of RV global and regional EDV with age and physical development indexes could be best expressed by power model,the best matched model were found with BSA.Conclusions Among three regional parts of RV,inflow and outflow parts volume contraction were the two main contribution factors for RV function.In childhood RV volume didn't increase linearly with age and physical development indexes,but in an exponential model. Key words: Echocardiography,real-time three-dimensional; Children; Ventricular function,right

Assessment of left ventricular regional wall motion and ejection fraction with low-radiation dose helical dual-source CT: Comparison to two-dimensional echocardiography

Electrocardiographic (ECG)-based tube current modulation during cardiac CT reduces radiation exposure but significantly increases noise in parts of the cardiac cycle where tube current is minimized. We evaluated the effect of maximal ECG-based tube current reduction on left ventricular (LV) regional wall motion assessment and ejection fraction (EF) by comparing low-radiation helical dual-source CT (DSCT) to 2-dimensional transthoracic echocardiography (2D-TTE). We studied 83 consecutive patients (15 with prior myocardial infarction) who underwent helically acquired DSCT coronary angiography with maximal ECG-based tube current modulation (low-radiation helical DSCT) and 2D-TTE within a 6-month period (median, 1 day), without any change in clinical status between the studies. In all patients, full tube current was applied only at 70% of the R-R interval, with minimal tube current (4% of maximum) in all other parts of the cardiac cycle. Reduced tube voltage (100 kVp) was combined with the maximal dose modulation in 34 patients. DSCT datasets were evaluated by a blinded, experienced cardiologist. Regional wall motion was assessed with the standard 17-segment model, with each segment scored as normal, hypokinetic, akinetic, and dyskinetic. Mean effective radiation dose for the low-radiation helical DSCT was 5.2 ± 1.7 mSv. Regional wall motion was evaluable in all segments on low-radiation helical DSCT. There was excellent agreement of wall motion scoring by low-radiation helical DSCT and 2D-TTE in 1382 of 1411 segments (98%; Cohen's κ value 0.83; 95% confidence interval, 0.76-0.89; P < 0.0001). Mean LVEF was 67.6%± 10.3% on low-radiation helical DSCT and 61.8% ± 10.3% on 2D-TTE (P < 0.0001). Low-radiation dose helical coronary CT angiography with maximal ECG-based tube current modulation is comparable to 2D-TTE for regional wall motion and EF assessment.

Perioperative Hypothermia (33°C) Does Not Increase the Occurrence of Cardiovascular Events in Patients Undergoing Cerebral Aneurysm Surgery

Perioperative hypothermia has been reported to increase the occurrence of cardiovascular complications. By increasing the activity of sympathetic nervous system, perioperative hypothermia also has the potential to increase cardiac injury and dysfunction associated with subarachnoid hemorrhage. The Intraoperative Hypothermia for Aneurysm Surgery Trial randomized patients undergoing cerebral aneurysm surgery to intraoperative hypothermia (n = 499, 33.3 degrees +/- 0.8 degrees C) or normothermia (n = 501, 36.7 degrees +/- 0.5 degrees C). Cardiovascular events (hypotension, arrhythmias, vasopressor use, myocardial infarction, and others) were prospectively followed until 3-month follow-up and were compared in hypothermic and normothermic patients. A subset of 62 patients (hypothermia, n = 33; normothermia, n = 29) also had preoperative and postoperative (within 24 h) measurement of cardiac troponin-I and echocardiography to explore the association between perioperative hypothermia and subarachnoid hemorrhage-associated myocardial injury and left ventricular function. There was no difference between hypothermic and normothermic patients in the occurrence of any single cardiovascular event or in composite cardiovascular events. There was no difference in mortality (6%) between groups, and there was only a single primary cardiovascular death (normothermia). There was no difference between hypothermic and normothermic patients in postoperative versus preoperative left ventricular regional wall motion or ejection fraction. Compared with preoperative values, hypothermic patients had no postoperative increase in cardiac troponin-I (median change 0.00 microg/l), whereas normothermic patients had a small postoperative increase (median change + 0.01 microg/l, P = 0.038). In patients undergoing cerebral aneurysm surgery, perioperative hypothermia was not associated with an increased occurrence of cardiovascular events.

Radionuclide Angiographic Determination of Regional Left Ventricular Systolic Function During Rest and Exercise in Patients With Nonischemic Cardiomyopathy Treated With Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) can improve global left ventricular (LV) function. However, limited data are available on regional LV contractility at rest and during exercise. The aim of the present study was to prospectively investigate the effects of CRT on regional LV ejection fraction (EF), global LVEF, and dyssynchrony, during rest and exercise, using radionuclide angiography. A total of 32 consecutive patients with heart failure and nonischemic cardiomyopathy underwent technetium-99m radionuclide angiography with bicycle exercise immediately after CRT implantation (during spontaneous rhythm and after CRT activation) and 3 months later. The regional EF was assessed in the interventricular septum and the lateral wall (LW). Intraventricular dyssynchrony was evaluated using Fourier phase analysis. During spontaneous rhythm, the EF was severely depressed in the septum compared to in the LW. CRT improved septal EF at rest and during exercise both at baseline (p <0.001) and after 3 months (p <0.05). The basal LW EF decreased during CRT (p <0.05, both at rest and during exercise). LV dyssynchrony decreased both at baseline and during follow-up, and the global LVEF showed improvement only at 3 months (p <0.001). In conclusion, in patients with nonischemic cardiomyopathy, CRT affects regional LV function by increasing the septal EF and reducing LW contractility, both at rest and during exercise. This was associated with an improvement in global LVEF and dyssynchrony.