Assessment of Interventricular Dyssynchrony by Real Time Three‐Dimensional Echocardiography: An In Vitro Study in a Porcine Model

Background: Loss of synchronous contraction between or within the right and left ventricle (RV, LV) leads to adverse ventricular function. We used real time three‐dimensional echocardiography (RT3DE) for evaluation of severity of interventricular dyssynchrony and function in a porcine heart model. Methods: Six fresh in vitro porcine hearts were used to create a controlled model of LV and RV dyssynchrony using two sets of pulsatile pumps. Synchronized and dyssynchronized pump settings were used with two different dyssynchronized settings: LV filled first and RV filled first. Results: There was good correlation between actual measurement and RT3DE for interventricular time difference (r = 0.95, P < 0.0001) and stroke volume (SV) for LV and RV (0.89, 0.85; P < 0.0001, respectively). RT3DE data showed a small but significant underestimation for actual volume (P < 0.05). The intra‐ and interobserver variabilities are 2.9 ± 1.5% and 3.1 ± 5.4% for LV and RV SVs, and 1.7 ± 2.4% and 2.2 ± 3.2% for time differences by RT3DE. There was significant difference in RV SV between synchrony and dyssynchrony when the RV filled first (P < 0.05), but not in other groups. The same pattern was found in RT3DE derived SVs (synchrony versus dyssynchrony with RV filled first, P < 0.05). Conclusions: There is no compromise in LV SV during interventricular dyssynchrony; but RV SV was significantly diminished when the RV filled first. RT3DE is a feasible, robust and reproducible method to identify interventricular dyssynchrony and to evaluate ventricular SVs. (Echocardiography 2010;27:709‐715)     

In vitro validation of right ventricular volume and mass measurement by real-time three-dimensional echocardiography

OBJECTIVE: To evaluate initially the feasibility and accuracy of real-time three-dimensional echocardiography (RT-3DE) for quantifying right ventricular (RV) volume and wall mass in an in vitro experimental study. METHODS: In ten excised porcine hearts, measurements of RV volume and free wall mass with RT-3DE were outlined and calculated by 2-, 4-, 8- and 16-plane methods with Tom Tec 4D Cardio-View RT 1.0. The results were compared with those of 2D length method and 2D biplane Simpson method. The values of RV silicone latex cast and free wall mass measured by water displacement were served as reference values. RESULTS: RV shapes of excised porcine hearts with RT-3DE were similar to those of the actual anatomic RVs and RV silicone latex casts. From the findings of analysis of variance and Student-Newman-Keuls test, there was no significant difference between measurements of RV volume with RT-3DE 16-plane (mean 64.05 ml), 8-plane (61.83 ml) and the reference values of RV silicone latex casts (62.94 ml). No significant difference was found between measurements of RV free wall mass with 16-plane (72.81 g), 8-plane (71.05 g) and the reference values of RV free wall masses (76.21 g). However, there was significant difference between measurements of RV volume and free wall mass with 2-plane, 2D biplane Simpson method and the reference values. Furthermore, the measurements of RV volume and free wall mass with 16-plane and 8-plane were better correlated with the reference values than those with 4-plane and 2D length method. CONCLUSIONS: RT-3DE will be a valuable technique for quantifying irregular crescentic RV volume and wall mass.     

Prognostic value of right ventricular mass, volume, and function in idiopathic pulmonary arterial hypertension.

AIMS: This study investigated the relationship between right ventricular (RV) structure and function and survival in idiopathic pulmonary arterial hypertension (IPAH). METHODS AND RESULTS: In 64 patients, cardiac magnetic resonance, right heart catheterization, and the six-minute walk test (6MWT) were performed at baseline and after 1-year follow-up. RV structure and function were analysed as predictors of mortality. During a mean follow-up of 32 months, 19 patients died. A low stroke volume (SV), RV dilatation, and impaired left ventricular (LV) filling independently predicted mortality. In addition, a further decrease in SV, progressive RV dilatation, and further decrease in LV end-diastolic volume (LVEDV) at 1-year follow-up were the strongest predictors of mortality. According to Kaplan-Meier survival curves, survival was lower in patients with an inframedian SV index or= 84 mL/m(2), and an inframedian LVEDV相似文献   

In Vitro Feasibility and Accuracy of Three-Dimensional Echocardiography for Ventricular Volume Assessment in Very Small Hearts

To evaluate the in vitro accuracy of three-dimensional echocardiography (3-DE) for estimation of ventricular volume in very small hearts, left ventricular (LV) volume was determined by 3-DE in the excised hearts of 10 guinea pigs and 10 rabbits, and right ventricular (RV) volume was determined in 20 rabbits. The effect of edge enhancement, Sigma filter, and slice distance (1 mm versus 0.5 mm) was assessed in each heart. True volumes were obtained from ventricular casts. Mean cast volume was 1.38 ± 0.83 mL for LVs and 1.63 ± 1.01 mL for RVs. Correlations between 3-DE and true volumes were r > 0.99 (P < 0.0001) for both ventricles. Accuracy was not affected by ventricular type, slice distance, or Sigma filter. Mean percent difference from true volume was significantly less (P = 0.03) with edge enhancement. Ventricular volume can be assessed reliably by 3-DE in very small hearts. The edge enhancement feature improved the accuracy of the measurements.     

How the left and right sides of the heart, as well as pulmonary venous drainage, adapt to an increasing degree of head-up tilting in hypertrophic cardiomyopathy: differences from the normal heart

OBJECTIVES: We aimed to assess the differences in the adaptive response of patients with hypertrophic cardiomyopathy (HCM) compared with normal subjects, as well as any association with increased susceptibility to the test. BACKGROUND: Diastolic function contributes importantly in the adaptation of the normal heart to head-up tilting. This mechanism may be disturbed by an impaired relaxation in HCM. METHODS: Twenty-one male patients with HCM (46 +/- 6 years old) and 22 healthy men (44 +/- 8 years) were studied using Doppler echocardiography after 1 and 10 min of head-up tilting at 20 degrees, 40 degrees and 60 degrees. RESULTS: In control subjects, tilting was associated with 1) a predominance of diastolic pulmonary venous flow and early left ventricular (LV) filling (atrium functioning as an open conduit); 2) right ventricular (RV) shrinkage; and 3) no LV dimensional variations. In patients with HCM, tilting was associated with 1) a prevalence of systolic pulmonary venous flow (atrium functioning as a reservoir in which filling depends on atrial relaxation and compliance) and late diastolic transmitral flow (atrium working as a booster pump); 2) LV shrinkage; and 3) no RV dimension variations. These mechanisms did not prevent stroke volume (SV) from decreasing at 40 degrees and 60 degrees in both groups. Because of a lower increase in heart rate (HR), a reduction in cardiac output (CO) was greater in patients with HCM. The responses were similar after 1 and 10 min of tilting in control subjects, whereas in patients, blood pressure (BP), SV and LV dimension fell more after 10 min. CONCLUSIONS: Adaptation of the normal heart to tilting is based on a ventricular interaction and LV diastolic properties; HCM relies on left atrial diastolic and systolic functions. An inadequate HR reaction to a fall in BP and SV in HCM (depressed reflexogenic activity) contributes to making CO more vulnerable by greater and more prolonged displacements.     

四维自动左室定量分析技术评价正常人左室容积及功能的初步研究

目的:探讨四维自动左室定量分析技术(4D AUTO LVQ)评价正常人左心室容积及功能的可行性及重复性.方法:在单心动周期(SB,single heart beat)及多心动周期(MB,multi-heartbeat)成像模式下分别采集20例正常志愿者左室三维图像(3-dimensional echocardiography),并分别使用4DAUTO LVQ技术测量左室舒张末容积(LVEDV)、左室收缩末容积(LVESV)及射血分数(EF),同时使用二维双平面Simpson's法及M型Teichholtz法检测同一组志愿者LVEDV、LVESV和EF.将4种方法所得的测值分别进行比较.结果:①M型测量的LVEDV测值与其他3种方法测值间差异有统计学意义(P<0.05),SB模式及MB模式下4D ATUO LVQ测量的LVEDV相关系数r为0.769;②SB、MB模式下4D ATUO LVQ方法测量的LVESV、双平面Simpson's法测量的LVESV测值与M型测值间差异均有统计学意义(P<0.05),SB与MB模式下测量的LVESV相关系数r为0.86;③SB、MB模式下测量的EF值与双平面Simpson's法及M型测值间差异均有统计学意义(P<0.05),SB与MB模式下测量的EF值相关系数r为0.428;Bland-Altman一致性分析表明4D AUTO LVQ在SB与MB模式下所测容积及EF值具有较高一致性.④SB模式下的3DE图像存储时间短于MB模式图像存储时间,差异有统计学意义(P<0.05);4D AUTO LVQ及Simpson's法后处理时间差异均无统计学意义(P>0.05).⑤SB与MB模式下4D AUTO LVQ测量LVEF观察者内变异系数分别为8.50%、6.50%,观察者间变异系数分别为7.75%、6.50%.结论:4D AUTO LVQ技术定量分析左室容积及EF有效、可行、快捷,具有临床应用价值.     

Initial clinical experience of real-time three-dimensional echocardiography in patients with ischemic and idiopathic dilated cardiomyopathy

The geometry of the left ventricle in patients with cardiomyopathy is often sub-optimal for 2-dimensional ultrasound when assessing left ventricular (LV) function and localized abnormalities such as a ventricular aneurysm. The aim of this study was to report the initial experience of real-time 3-D echocardiography for evaluating patients with cardiomyopathy. A total of 34 patients were evaluated with the real-time 3D method in the operating room (n = 15) and in the echocardiographic laboratory (n = 19). Thirteen of 28 patients with cardiomyopathy and 6 other subjects with normal LV function were evaluated by both real-time 3-D echocardiography and magnetic resonance imaging (MRI) for obtaining LV volumes and ejection fractions for comparison. There were close relations and agreements for LV volumes (r = 0.98, p <0.0001, mean difference = -15 +/- 81 ml) and ejection fractions (r = 0.97, p <0.0001, mean difference = 0.001 +/- 0.04) between the real-time 3D method and MRI when 3 cardiomyopathy cases with marked LV dilatation (LV end-diastolic volume >450 ml by MRI) were excluded. In these 3 patients, 3D echocardiography significantly underestimated the LV volumes due to difficulties with imaging the entire LV in a 60 degrees x 60 degrees pyramidal volume. The new real-time 3D echocardiography is feasible in patients with cardiomyopathy and may provide a faster and lower cost alternative to MRI for evaluating cardiac function in patients.     

Reduced intrathoracic blood volume and left and right ventricular dimensions in patients with severe emphysema: an MRI study

BACKGROUND: Left ventricular (LV) filling is impaired in patients with severe emphysema manifesting in small end-diastolic dimensions. We hypothesized that the hyperinflated lungs of these patients with high intrinsic positive end-expiratory pressure will decrease intrathoracic blood volume (ITBV) and ventricular preload. We therefore measured ITBV, and LV and right ventricular (RV) dimensions and function using MRI techniques in patients with severe emphysema. METHODS: Patients with severe emphysema (n = 13) and matched healthy volunteers (n = 11) were included. The magnetic resonance (MR) examination consisted of three parts: (1) evaluation of RV and LV dimensions and function and interventricular septum curvature using cine MRI; (2) quantification of aortic flow using MR phase velocity mapping; and (3) calculation of the cardiopulmonary peak transit time (PTT) from the pulmonary artery to the ascending aorta using contrast-enhanced, time-resolved, two-dimensional MR angiography. RESULTS: There were no differences between the groups regarding age, height, or weight. In the emphysema patients, ITBV index (- 35%), LV end-diastolic volume index (LVEDVI) [- 21%], RV end-diastolic volume index (- 20%), cardiac index (- 22%), and stroke volume index (SVI) [- 40%] were lower compared to control subjects. LV and RV end-systolic volumes, LV wall mass, septal curvature, and PTT did not differ between the groups. LVEDVI (r = 0.83) as well as SVI (r = 0.82) correlated closely to ITBV index. SVI correlated closely to LVEDVI (r = 0.84). CONCLUSIONS: LV and RV performance is impaired in patients with severe emphysema because of small end-diastolic dimensions. One possible explanation for the decreased biventricular preload in these patients is intrathoracic hypovolemia caused by hyperinflated lungs.     

Effects of heart rate changes on left ventricular volume and ejection fraction: a 2-dimensional echocardiographic study

The influence of heart rate on left ventricular (LV) volumes and ejection fraction (EF) using 2-dimensional (2-D) echocardiography during atrial pacing was analyzed. The study was performed in 13 normal control subjects, 23 patients with coronary heart disease and 8 patients with dilated cardiomyopathy. An electronic sector scanner (2.25 MHz, 84 degrees) was used. Under constant scanning of the left ventricle, heart rate was increased, in steps of 20 beats/min, from 80 to 140 beats/min. The 2-D echocardiograms were stored on videotape and analyzed off-line. The end-diastolic and end-systolic volumes (EDV and ESV) were determined using a disc method. Stroke volume (SV) and EF were calculated. Constant LV scanning was possible during atrial stimulation, as shown by the analysis of simultaneously recorded 2-D echocardiograms and cineventriculograms at different heart rates, revealing a constant position of the echocardiographic transducer. Simultaneous recordings of cineventriculography and 2-D echocardiography at 80 and 120 beats/min showed that despite differences in absolute values, percent changes of LV volumes and EF determined with both methods were similar. Thus, changes of LV function can be analyzed by 2-D echocardiography. In normal control subjects, an increase in heart rate of 10 beats/min reduced EDV by 4 ml, ESV by 2 ml, SV by 2 ml and EF by 1%, corresponding to percent reductions of 4, 2, 5 and -2%, respectively. In contrast, the absolute decreases in the patients were 6 ml, 1 ml, 5 ml and 2% and the percent changes 2%, 1%, 8% and 5%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ventricular interdependence in patients with dual-chamber pacing: a Doppler tissue imaging study

PURPOSE: To analyze pulsed-Doppler tissue imaging (DTI) of the right ventricular (RV) tricuspid annulus and left ventricular (LV) mitral annulus in patients paced in the DDD mode at three different pacing modes as compared with healthy subjects, and to investigate possible physiologic interaction between the RV and LV in this subgroup of patients. METHODS: We selected a population of 22 subjects with pacemakers (PM) for atrioventricular (AV) block and/or sick sinus syndrome and compared them to 20 healthy subjects. Standard echo Doppler and DTI parameters were measured at baseline (heart rate [HR] 70 beats/min; AV delay 125 msec) and after at least 5 minutes of constant stimulation at two different pacing modes: (1) HR 70 beats/min, AV delay 188 msec, and (2) HR 89 beats/min, AV delay 125 msec. LV stroke volume was obtained by LV outflow Doppler method. RESULTS: In the PM group, RV and LV annulus exhibited significantly higher peak systolic (S(m)) and early (E(m)) diastolic wall velocities than controls. In the PM population, LV stroke volume was strongly associated to RV E(m) peak velocity (r = 0.83; P < 0.00001) and RV S(m) peak velocity (r = 0.81; P < 0.0001). These associations between LV stroke volume and RV DTI parameters remained significant even after increase of HR and AV delay in the pacing modalities. Moreover, univariate relations were found in the PM group between DTI indexes of RV tricuspid annulus and the homologous indexes of LV mitral annulus. In a multiple linear regression analysis, both RV E(m) (P < 0.001) and RV S(m) (P < 0.001) were related independently to LV stroke volume (cumulative R(2) = 0.85, P < 0.00001). CONCLUSIONS: Our findings suggest the usefulness of pulsed-DTI to display physiologic ventricular interaction in patients with PM. Therefore, DTI may be taken into account as a valuable supporting tool to predict LV systolic performance and to select the most appropriate pacing mode in individual PM patients.     

Determination of left ventricular volume, ejection fraction, and myocardial mass by real-time three-dimensional echocardiography

Reconstructed three-dimensional (3-D) echocardiography is an accurate and reproducible method of assessing left ventricular (LV) functions. However, it has limitations for clinical study due to the requirement of complex computer and echocardiographic analysis systems, electrocardiographic/respiratory gating, and prolonged imaging times. Real-time 3-D echocardiography has a major advantage of conveniently visualizing the entire cardiac anatomy in three dimensions and of potentially accurately quantifying LV volumes, ejection fractions, and myocardial mass in patients even in the presence of an LV aneurysm. Although the image quality of the current real-time 3-D echocardiographic methods is not optimal, its widespread clinical application is possible because of the convenient and fast image acquisition. We review real-time 3-D echocardiographic image acquisition and quantitative analysis for the evaluation of LV function and LV mass.     

Effect of left ventricular volume on right ventricular end-systolic pressure-volume relation. Resetting of regional preload in right ventricular free wall

Effect of left ventricular (LV) volume on right ventricular (RV) end-systolic pressure-volume relation (ESPVR) was investigated, and the mechanism was examined from a standpoint of the alteration of RV free wall mean fiber length. Twelve cross-circulated isovolumically contracting canine hearts in which both ventricular volumes were controlled independently were used, and RV-ESPVR was determined at three different LV volume levels. At small (10.2 +/- 0.6 ml), middle (15.3 +/- 1.0 ml), and large (20.5 +/- 1.4 ml) LV volume, the slope of the RV-ESPVR was 2.63 +/- 0.13, 2.74 +/- 0.13, and 2.89 +/- 0.12 mm Hg/ml, respectively, and each value was significantly different from the others (p less than 0.01). The volume intercept (V0) of the relation (RV-V0) was significantly decreased with the increment of LV volume (RV-V0 in small, middle, and large LV volume; 3.92 +/- 0.68, 3.39 +/- 0.67, and 2.87 +/- 0.71 ml, respectively; p less than 0.01). In nine hearts, RV free wall lengths in latitudinal and meridional direction were measured at three LV volume levels when RV volume was held constant (16.1 +/- 1.1 ml). RV latitudinal end-diastolic length was significantly augmented with increasing LV volume (latitudinal length in small, middle, and large LV volume; 9.68 +/- 0.55, 9.81 +/- 0.56, and 9.92 +/- 0.55 mm, respectively). RV meridional end-diastolic length also increased significantly with increasing LV volume.(ABSTRACT TRUNCATED AT 250 WORDS)     

Systolic direction of right ventricular contrast trajectories in the detection of ventricular septal defect with left-to-right shunt

Abnormal systolic direction of contrast flow toward the transducer within the right ventricle was demonstrated on M-mode echocardiograms in patients with ventricular septal defect (VSD) and left-to-right shunt. The usefulness of this new technique was tested in 30 patients with VSD proved at catheterization and in 300 control subjects. In all subjects, 2-dimensional (2-D) visualization of the defect, 2-D negative contrast effect and M-mode demonstration of positive contrast within the left ventricular (LV) cavity were also performed. Sensitivity and specificity for each technique and each hemodynamic subgroup of patients were determined and compared. A sensitivity of 100% for the diagnosis of VSD by anterior right ventricular (RV) systolic direction of contrast trajectories was achieved in 20 patients with relatively small VSDs and mild to moderate elevation of RV pressure (RV-LV pressure ratio 60%) and mean pulmonary to systemic blood flow ratio of 1.7. Sensitivities of 2-D echocardiography, 2-D negative contrast technique and positive LV contrast appearance on M-mode echocardiography were 63%, 71% and 53%, respectively. Sensitivity of 100% for systolic anterior direction of contrast trajectories was also calculated in 6 patients with RV-LV pressure ratios from 61 to 80% and mean pulmonary to systemic blood flow ratio of 2.7. Sensitivities of 2-D echocardiography, 2-D negative contrast technique and positive contrast appearance in the LV cavity by M-mode echocardiography were 75%, 60% and 86%, respectively. In 4 patients with systemic or nearly systemic RV pressure, sensitivity of systolic anterior direction of RV contrast trajectories decreased drastically, to only 67%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Newer Imaging Modalities in the Assessment of Heart Function in Single Ventricle Hearts

The limitations of geometry assumptions in 2-dimensional echocardiographic assessment of the single ventricle (SV) have been overcome by recent advances in 3-D echocardiography. Improved reproducibility for measuring ventricular volumes and ejection fraction using 3-D echocardiography makes it ideally suited for serial monitoring of SV systolic function and should be considered in routine echocardiography imaging protocols for SV. The moderate correlation of Doppler derived E/e' ratio with invasive ventricular end diastolic pressure in SV, suggests it might be useful in the assessment of SV diastolic function. Speckle tracking imaging is intensely studied and promises to be a simple and repeatable imaging tool for quantifying SV function. In contrast, the advances in cardiac magnetic resonance imaging techniques promise to offer insights into the pathogenesis of myocardial dysfunction in SV. Late gadolinium enhancement imaging is a robust tool in assessing macroscopic myocardial scarring and T₁ mapping and stress perfusion imaging are newer modalities that might improve understanding of the mechanisms in progressive myocardial dysfunction in SV hearts.     

Impaired left ventricular filling due to right ventricular pressure overload in primary pulmonary hypertension: noninvasive monitoring using MRI

OBJECTIVE: To analyze the effect of primary pulmonary hypertension (PPH) on cardiac function using MRI. METHODS: In 12 patients (9 women; age range, 30 to 56 years), the diagnosis of PPH had been established by catheterization (mean +/- SD pulmonary artery pressure [PAP] was 56 +/- 8 mm Hg). With breath-hold cine MRI, a series of short-axis images was acquired covering the whole left ventricle (LV) and right ventricle (RV). The curvature, defined as 1 divided by the radius of curvature in centimeters, was calculated for the septum and the LV free wall in early diastole. Leftward ventricular septal bowing (LVSB) is denoted by a negative curvature. For the LV and the RV, the end-diastolic volume (EDV), stroke volume (SV), and volumetric filling rate were calculated. The control subjects were all healthy (n = 14; 11 women; age range, 20 to 57 years). RESULTS: In the patients, LVSB was quantified in early diastole by the septal curvature of - 0.14 +/- 0.07 cm(-1), and the septal to free-wall curvature ratio of - 0.42 +/- 0.21. LV EDV and LV SV correlated negatively with diastolic PAP (p = 0.004 and p = 0.04, respectively). In patients vs control subjects, RV SV was reduced (52 +/- 12 mL vs 82 +/- 11 mL, p < 0.0001); LV peak filling rate was smaller (2.2 +/- 0.7 EDV/s vs 3.3 +/- 0.5 EDV/s, p < 0.001); LV EDV was smaller (81 +/- 23 mL vs 117 +/- 19 mL, p = 0.001); and LV SV was smaller (49 +/- 18 mL vs 83 +/- 13 mL, p < 0.0001). CONCLUSION: In PPH, RV pressure overload leads to LVSB and reduced RV output. By decreased blood delivery, LV filling is reduced, which results in decreased LV SV by the Frank-Starling mechanism.     

Echocardiographic ventricular shape analysis in congenital heart disease with right ventricular volume or pressure overload

In this 2-dimensional (2-D) echocardiographic study, a computerized Fourier analysis technique refined from one that allows quantification of changes in septal shapes in normal fetuses, newborns and infants allowed analysis of left ventricular (LV) shapes in 14 patients with right ventricular (RV) volume overload (atrial septal defects), 5 with volume and pressure overload (total anomalous pulmonary venous connection), and 10 with pressure overload (complete transposition of the great arteries [TGA] with intact ventricular septum). Diastolic shape factors in the 3 groups were significantly different from those of normal subjects (p less than 0.01). Highest diastolic values were found in patients with TGA (mean 4.59 +/- 1.28). Systolic shape factors were similar in patients with atrial septal defect and normal subjects. Significant differences existed between normal subjects and patients with total anomalous pulmonary venous connection, with the greatest differences in systolic shape factor being 5.61 for TGA vs 1.87 (p less than 0.005) for normal subjects. Shape factor correlated well with hemodynamic data for RV/LV systolic pressure ratios (r = 0.93, p less than 0.001) for normalized interventricular pressure differences (r = -0.95, p less than 0.001). The lower the normalized systolic pressure difference or the higher the RV/LV ratio, the more the septum encroached into the LV cavity. Significant but weaker correlations were noted for values during diastole. Quantitative application of Fourier shape factor analysis to LV shapes allows numerical expression of visually interpreted distortions over a wide range of geometric alterations.     

Dynamic aspects of acute mitral regurgitation: effects of ventricular volume, pressure and contractility on the effective regurgitant orifice area.

The dynamics of acute mitral regurgitation were studied in six open-chest dogs in whom a portion of the anterior leaflet was excised. Phasic mitral and aortic flows were measured electromagnetically and left ventricular filling volume, regurgitant volume (RV) and forward stroke volume (SV) were calculated. The systolic pressure gradient (SPG) between the left ventricle (LV) and left atrium (LA) was obtained from high-fidelity pressure transducers. The effective mitral regurgitant orifice area (MRA) was calculated from the hydraulic equation of Gorlin. Volume infusion resulted in significant increases in both left atrial and left ventricular pressures; thus, the SPG was unchanged and the increase in RV was due primarily to the increase in MRA. Angiotensin infused to raise arterial pressure resulted in greater increments in left ventricular than left atrial pressure, so that SPG rose significantly. The increase in RV was due to increases in both MRA and SPG. Norepinephrine infusion increased systolic left ventricular pressure and SPG, while left ventricular end-diastolic pressure and left atrial pressure diminished. Despite a significant increase in SPG, RV did not increase, due to a substantial decrease in MRA. Thus, angiotensin and volume infusion induced a substantial increase in regurgitation due to the increase in MRA, while augmentation of contractility after norepinephrine infusion resulted in a decrease in regurgitation through reduction of MRA. These findings support the clinical view that maintaining a small LV with sustained myocardial contractility will reduce mitral regurgitation. Alternatively, left ventricular dilatation can enhance mitral regurgitation by increasing the effective regurgitant orifice independent of SPG.     

Usefulness of triplane tissue Doppler imaging to predict acute response to cardiac resynchronization therapy

This study evaluated the value of triplane tissue Doppler imaging (TDI) to predict acute response after cardiac resynchronization therapy (CRT). Forty-nine patients scheduled for CRT underwent triplane echocardiography with simultaneous TDI acquisition before and 48 hours after implantation. A 3-dimensional left ventricular (LV) volume was generated and LV volumes and ejection fraction were calculated. A parametric imaging technique, tissue synchronization imaging, was applied to portray the area of latest mechanical activation. LV dyssynchrony was quantitatively analyzed by evaluating time from QRS onset to peak myocardial velocity in 12 LV segments from the triplane dataset. Acute response was defined as > or =15% decrease in LV end-systolic volume. Receiver-operating characteristic curves of dyssynchrony parameters were analyzed to identify predictors of response to CRT. Acute response was observed in 47% of patients. Responders had a significantly larger extent of LV dyssynchrony at baseline compared with nonresponders. Optimal prediction of acute response to CRT was obtained with the SD of time delays in all LV segments (sensitivity 91%, specificity 85%). In conclusion, 3-dimensional TDI echocardiography permits parametric and quantitative analyses of LV dyssynchrony and assessment of LV volumes and ejection fraction. LV dyssynchrony parameters, derived from the triplane TDI dataset, were highly predictive for acute volumetric response to CRT.     

Real time triplane echocardiography in the assessment of the functional area of prosthetic aortic valves: reliability and feasibility

Purpose: Our study is aimed at evaluating the feasibility and reliability of a simple method for the measurement of the functional area of prosthetic aortic valves (EOA). Three-dimensional echocardiography has proven accurate for left ventricular volume, stroke volume, and aortic valve area measurement. We studied the feasibility and reliability of real time simultaneous triplane echocardiography (RT3P) for assessing the EOA with a fast formula based on the principle of continuity equation, in which we replaced Doppler-derived stroke volume (SV) with SV directly measured with RT3P. Methods and results: EOA of prosthetic aortic valves were measured in 23 consecutive patients requiring periodical follow up. EOA was calculated using Doppler continuity equation (DCE) and the RT3P method by replacing Doppler-derived SV with SV measured with real time triplane echocardiography. We compared functional areas obtained with the two methods with the prosthetic area indicated in the manufacturer's specifications and with the mean transprosthetic gradient. Both methods had a good correlation with the area indicated by the manufacturer. RT3P revealed an inverse correlation between functional area and mean gradient that was better than DCE (P = 0.0359). Inter- and intraobserver variability was not different between the two methods. Execution time was significantly shorter for RT3P. Conclusions: RT3P is a simple method that can be performed quite rapidly, and can complement the overall assessment of prosthetic valve function. Further studies can confirm our technique. (Echocardiography 2012;29:34-41).