Impact of the number of image planes of real-time three-dimensional echocardiography on the accuracy of left atrial and ventricular volume measurements

The clinical benefits of adding a third dimension to assess the left ventricle with echocardiography

Three-dimensional echocardiography is a novel imaging technique based on acquisition and display of volumetric data sets in the beating heart. This permits a comprehensive evaluation of left ventricular (LV) anatomy and function from a single acquisition and expands the diagnostic possibilities of noninvasive cardiology. It provides the possibility of quantitating geometry and function of LV without preestablished assumptions regarding cardiac chamber shape and allows an echocardiographic assessment of the LV that is less operator-dependent and therefore more reproducible. Further developments and improvements for widespread routine applications include higher spatial and temporal resolution to improve image quality, faster acquisition, processing and reconstruction, and fully automated quantitative analysis. At present, three-dimensional echocardiography complements routine 2DE in clinical practice, overcoming some of its limitations and offering additional valuable information that has led to recommending its use for routine assessment of the LV of patients in whom information about LV size and function is critical for their clinical management.

Cardiac MRI of acute coronary syndrome

Acute coronary syndrome (ACS) is a major cause of morbidity and mortality worldwide. New serological biomarkers, such as troponins, have improved the diagnosis of ACS; however, the diagnosis of ACS can still be difficult as there is marked heterogeneity in its presentation and significant overlap with other disorders presenting with chest pain. Evidence is accumulating that cardiac MRI provides information that can aid the detection and differential diagnosis of ACS, guide clinical decision-making and improve risk-stratification after an event. In this review, we present the relevant cardiac MRI techniques that can be used to detect ACS accurately, provide differential diagnosis, identify the sequelae of ACS, and determine prognostication after ACS.

Left atrial volume by real-time three-dimensional echocardiography: validation by 64-slice multidetector computed tomography

BACKGROUND

Left atrial (LA) enlargement has been acknowledged as a significant predictor of cardiovascular morbidity and mortality.

METHODS

To evaluate the accuracy of two-dimensional and three-dimensional echocardiography for determining LA volume, LA volume measurements by echocardiography were compared with those measured by 64-slice multidetector computed tomography (MDCT) as a reference standard.

RESULTS

Fifty-seven consecutive patients (mean age, 66 ± 11 years; 59% men) referred to echocardiography and MDCT on the same day were prospectively evaluated. LA volume by three-dimensional echocardiography was correlated closely with that by MDCT (r = 0.95, P < .0001), with 8% underestimation. LA volume by two-dimensional echocardiography was correlated less well with that measured by MDCT (r = 0.86, P < .0001) and consistently underestimated LA volume by 19%, particularly as the left atrium enlarged.

CONCLUSIONS

LA volume assessment by three-dimensional echocardiography was correlated closely with that measured by MDCT, albeit with an 8% underestimation. Three-dimensional echocardiography is a feasible noninvasive method to evaluate LA volume.

End-systolic and end-diastolic left atrial volume assessment by two-dimensional echocardiography: a comparison study with magnetic resonance imaging

BACKGROUND

The left atrial volume (LAV) is an important indicator of the severity of certain diseases, and measuring LAV through the cardiac cycle may enable the evaluation of various left atrium (LA) functional parameters. The results of two-dimensional (2D) echocardiographic LAV measurement methods vary, and no technique is accepted as being optimal.

OBJECTIVE

This study compared the accuracy of end-systolic and end-diastolic LAV measurements by 2D echocardiography with those obtained by magnetic resonance imaging (MRI).

METHODS

Fifty consecutive patients who underwent both echocardiography and MRI due to clinical reasons with nonselective cardiac disease were studied. LAVs by 2D echocardiography were obtained with the prolate ellipsoid (PE), biplane area-length (AL), and modified Simpson's (MS) methods.

RESULTS

End-systolic and end-diastolic LAVs calculated by each method correlated significantly with MRI results (P < 0.0001). The prolate ellipsoid method provided LAVs that most correlated with MRI results, and the biplane area-length and modified Simpson's methods provided LAVs with small mean differences (<5 ml) compared to MRI results.

CONCLUSION

All three methods of 2D echocardiographic LAV measurement provide valuable LAV data, suggesting the possibility of evaluating various LA functional parameters.

Measurement of left ventricular ejection fraction by real time 3D echocardiography in patients with severe systolic dysfunction: comparison with radionuclide angiography

AIM

Measurement of left ventricular ejection fraction (LVEF) using real time 3D echocardiography (3DE) has been performed in subjects with preserved or modestly reduced systolic function. Our aim was to evaluate this technique in the subset of patients with severe systolic dysfunction.

METHODS AND RESULTS

Consecutive patients with LVEF less than 0.35 at two-dimensional echocardiography were included. LVEF obtained by 3DE was compared to the value measured by radionuclide angiography (RNA). Real time full-volume 3DE was performed, with offline semiautomated measurement of LVEF using dedicated software (Cardioview RT, Tomtec) by a single observer blinded to the results of RNA. A total of 50 patients were evaluated, of whom 38 (76%, 27 males, age 69 +/- 13 years) had a 3DE of sufficient quality for analysis. LVEF for this group was 0.21 +/- 0.07 using 3DE and 0.27 +/- 0.08 using RNA. The agreement between the two techniques was rather poor (r = 0.49; P < 0.001; 95% limits of agreements of -0.20 to 0.09). Truncation of the apex was observed in 6 of 38 (16%) patients.

CONCLUSION

In patients with severe systolic dysfunction, 3DE shows poor agreement for measurement of LVEF as compared to RNA. There may be underestimation of up to 20% in absolute terms by 3DE. Accordingly, the two methods are not interchangeable for the follow-up of LV function. A limitation of 3DE may, at least in part, be related to the incomplete incorporation of the apical region into the pyramidal image sector in patients with dilated hearts.

Left atrial function assessed by real-time 3-dimensional echocardiography is related to right ventricular systolic pressure in chronic mitral regurgitation

BACKGROUND

Left atrial (LA) volume is a prognostic index in chronic mitral regurgitation (MR). However, little is known about LA function in this setting. We hypothesized that LA dysfunction is related to pulmonary hypertension in chronic MR.

METHODS

Seventy-one patients with organic chronic MR who underwent real-time 3-dimensional transthoracic echocardiography (RT3DE) were studied. Left atrial volumes and peak passive and active LA emptying rates were obtained. Total LA emptying fraction was calculated as follows: [(maximum - minimum LA volume)/maximum LA volume] x 100. Similarly, active and passive LA emptying fractions were calculated. From transmitral flow, the peak early (E) and late (A) diastolic filling velocities and E/A ratio were obtained. The early (E') and late (A') diastolic myocardial velocities were obtained by tissue Doppler interrogation of mitral annulus.

RESULTS

Effective regurgitant orifice area (EROA) was 0.57 +/- 0.29 cm(2). Right ventricular systolic pressure (RVSP) was measured in 57 patients and averaged 37 +/- 13 mm Hg. Patients with MR and high RVSP displayed higher minimum LA volume, E/A ratio, E/E' ratio, EROA, and MR volume, and lower A' velocity, peak active LA emptying rate, active LA emptying fraction, and total LA emptying fraction than patients with MR and normal RVSP. Multiple regression analysis revealed that EROA (r = 0.51, P = .01) active LA emptying fraction (r = -0.53, P = .02), E/E' ratio (r = 0.50; P = .04), and the lateral A' velocity (r = -0.46; P = .003) were independently correlated with RVSP.

CONCLUSIONS

Left atrial function determined by RT3DE had significant correlation with RVSP in chronic MR, irrespective of MR severity. Thus, pulmonary hypertension in chronic MR may depend not only on MR severity but also on LA function.

Usefulness of left ventricular conic index measured by real-time three-dimensional echocardiography to predict left ventricular remodeling after acute myocardial infarction

Early identification of left ventricular (LV) remodeling after acute myocardial infarction (AMI) is of clinical importance. The predictive value of real-time 3-dimensional echocardiography (RT-3DE) for LV remodeling after AMI is unknown. We prospectively studied 62 patients with AMI who underwent RT-3DE at baseline (72 +/- 5 hours) and 1 month and 6 months after AMI. LV remodeling was defined as a >20% increase from baseline in LV end-diastolic volume (LVEDV) at 6 months. At 6 months, 20 patients (32%) with and 42 (68%) without LV remodeling were identified. Patients with remodeling showed increased LVEDV, from 112.6 +/- 17.2 to 138 +/- 31 ml (p <0.001), and decreased LV ejection fraction (LVEF), from 0.50 +/- 0.07 to 0.44 +/- 0.10 (p <0.01). Changes in LVEDV from baseline to 6-month follow-up were positively correlated with peak creatine kinase-MB, LVEDV, LVEF, wall motion score, deceleration time of E wave, LV sphericity index (LVEDV divided by the volume of a sphere whose diameter is the LV end-diastolic long axis), and LV conic index (LVEDV divided by the volume of a cone whose bottom diameter is the internal diameter of the mitral annulus and height is the LV long axis). LV conic index at baseline was found to be the best predictor of LV remodeling, with a sensitivity and specificity of 100% and 90.9%, respectively, and a cut-off value of >3.87. In conclusion, LV conic index measured by RT-3DE in the early phase after AMI can accurately predict LV remodeling over 6-month follow-up.