Assessment of Myocardial Perfusion during Adenosine Stress Using Real Time Three‐Dimensional and Two‐Dimensional Myocardial Contrast Echocardiography: Comparison with Single‐Photon Emission Computed Tomography

Objectives: To evaluate diagnostic accuracy of adenosine two‐dimensional and three‐dimensional myocardial contrast echocardiography (2D‐ and 3D‐MCE) compared with single‐photon emission computed tomography (SPECT) for assessing myocardial perfusion. Methods: From January through August 2007, patients with known or suspected CAD who were referred for SPECT underwent simultaneous adenosine 2D‐MCE and 3D‐MCE (live and full volume [FV]). Perfusion and wall motion in 17 segments in the left anterior descending, left circumflex, and right coronary artery territories were analyzed. Results: We studied 30 patients: mean (SD) age, 72.6 (8.2) years; 19 (63%) men. Perfusion by SPECT was abnormal in 13 patients (43%). When comparing MCE with SPECT, sensitivity was comparable for 2D‐MCE, 92%; live 3D‐MCE, 91%; and FV 3D‐MCE, 90%. Specificity was comparable for 2D‐MCE, 75%; live 3D‐MCE, 69%; and FV 3D‐MCE, 79%. Agreement between live 3D‐MCE and 2D‐MCE was 92% (κ[SE], 0.83 [0.17]) and between FV 3D‐MCE and 2D‐MCE, 88% (κ[SE], 0.76 [0.13]). For eight patients in whom SPECT showed reversible defects, live 3D‐MCE correctly identified defects in seven (88%), whereas FV 3D‐MCE correctly identified them in five (63%) (P = 0.57). Conclusion: Myocardial perfusion assessment is feasible by 3D‐MCE with the advantage of rapid, facile acquisition and offline image manipulation. (Echocardiography 2010;27:421‐429)     

Two‐ and Three‐Dimensional Speckle Tracking Echocardiography: Clinical Applications and Future Directions

Two‐dimensional speckle tracking echocardiography (2D STE) is a novel technique of cardiac imaging for quantifying complex cardiac motion based on frame‐to‐frame tracking of ultrasonic speckles in gray scale 2D images. Two‐dimensional STE is a relatively angle independent technology that can measure global and regional strain, strain rate, displacement, and velocity in longitudinal, radial, and circumferential directions. It can also quantify rotational movements such as rotation, twist, and torsion of the myocardium. Two‐dimensional STE has been validated against hemodynamics, tissue Doppler, tagged magnetic resonance imaging, and sonomicrometry studies. Two‐dimensional STE has been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies, and identifying early subclinical changes in various pathologies. A large number of studies have evaluated the role of 2D STE in predicting response to cardiac resynchronization therapy in patients with severe heart failure. However, the clinical utility of 2D STE in the above mentioned conditions remains controversial because of conflicting reports from different studies. Emerging areas of application include prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and effect of intracoronary injection of bone marrow stem cells on left ventricular function in patients with acute myocardial infarction. The emerging technique of three‐dimensional STE may further extend its clinical usefulness.     

New Approach for Rotational Dyssynchrony Using Three‐Dimensional Speckle Tracking Echocardiography

Left ventricular (LV) twist can be evaluated using two‐dimensional speckle tracking echocardiography (2DSTE) by analyzing difference between apical and basal rotation. However, it is unable to evaluate global rotational dyssynchrony because it cannot assess mid‐wall rotation. Recently developed three‐dimensional STE (3DSTE) can investigate LV global rotational dyssynchrony. In this study, we investigated the role of torsion on the long‐term effects of cardiac resynchronization therapy (CRT) using 3DSTE. We evaluated 43 patients by 3DSTE: 12 CRT responders, 14 CRT nonresponders, and 17 healthy normal controls. Regional torsion and rotation were assessed using 3DSTE across 16 segments during CRT‐off (native conduction) and CRT‐on. The following parameters were calculated: global peak twist, Δ global peak twist (difference between CRT‐on and CRT‐off), and torsion delay index. The torsion delay index was considered to be the rotational energy lost by rotational dyssynchrony. Global peak twist did not show significant differences between the responders and nonresponders during CRT‐off (4.0 ± 3.4° vs. 2.8 ± 2.3°, P = 0.295), but it significantly improved in responders compared to nonresponders after CRT‐on (5.4 ± 3.5° vs. 2.6 ± 2.6°, P = 0.029). The torsion delay index during CRT‐off was significantly higher in responders compared to nonresponders and normal controls (18.5 ± 11.3 vs. 8.6 ± 3.8 and 7.8 ± 5.5, P = 0.010 and P = 0.004, respectively). The torsion delay index during CRT‐off significantly correlated with the Δ global peak twist (r = 0.503, P = 0.009). Improvement in LV global peak twist, which is one of the mechanisms for the long‐term effects of CRT correlated with the torsion delay index during native conduction that can only be calculated by 3DSTE.     

Simplified Single Plane Echocardiography Is Comparable to Conventional Biplane Two‐Dimensional Echocardiography in the Evaluation of Left Atrial Volume: A Study Validated by Three‐Dimensional Echocardiography in 143 Individuals

The left atrial volume index (LAVI) is a biomarker of diastolic dysfunction and a predictor of cardiovascular events. Three‐dimensional echocardiography (3DE) is highly accurate for LAVI measurements but is not widely available. Furthermore, biplane two‐dimensional echocardiography (B2DE) may occasionally not be feasible due to a suboptimal two‐chamber apical view. Simplified single plane two‐dimensional echocardiography (S2DE) could overcome these limitations. We aimed to compare the reliability of S2DE with other validated echocardiographic methods in the measurement of the LAVI. We examined 143 individuals (54 ± 13 years old; 112 with heart disease and 31 healthy volunteers; all with sinus rhythm, with a wide range of LAVI). The results for all the individuals were compared with B2DE‐derived LAVIs and validated using 3DE. The LAVIs, as determined using S2DE (32.7 ± 13.1 mL/m²), B2DE (31.9 ± 12.7 mL/m²), and 3DE (33.1 ± 13.4 mL/m²), were not significantly different from each other (P = 0.85). The S2DE‐derived LAVIs correlated significantly with those obtained using both B2DE (r = 0.98; P < 0.001) and 3DE (r = 0.93; P < 0.001). The mean difference between the S2DE and B2DE measurements was <1.0 mL/m². Using the American Society of Echocardiography criteria for grading LAVI enlargement (normal, mild, moderate, severe), we observed an excellent agreement between the S2DE‐ and B2DE‐derived classifications (κ = 0.89; P < 0.001). S2DE is a simple, rapid, and reliable method for LAVI measurement that may expand the use of this important biomarker in routine echocardiographic practice.     

Comparison of Left Ventricular Stroke Volume Assessment by Two‐ and Three‐Dimensional Echocardiography in a Swine Model of Acute Myocardial Infarction Validated by Thermodilution Method

Background: Accurate left ventricular stroke volume (LVSV) measurement is clinically important in patients presenting with acute myocardial infarction. Three‐dimensional echocardiography (3DE) is expected to overcome limitations of two‐dimensional echocardiography (2DE). However, inaccuracy in volumetry by 3DE has often been reported hindering further clinical application. This study aimed at comparing agreement and correlation with the thermodilution method (TDM) between 2DE and 3DE measurement of LVSV. Methods: Swine model of myocardial infarction was created and LVSV was measured by 3DE by subtracting end‐systolic from end‐diastolic volume (3DE‐method). Pulsed Doppler ultrasound and left ventricular outlet tract area were used to measure LVSV by 2DE (2DE‐method). TDM was performed by the Swan‐Ganz catheter. Bland–Altman analysis followed by assessment of intraclass correlation coefficient (ICC) were performed between 2DE‐method and TDM as well as 3DE‐method and TDM. Results: A total of 25 comparisons revealed a significant overestimation of LVSV by the 2DE‐method (bias = 6.5 mL; 95% confidence interval [CI], 3.9–9.0 mL; P < 0.0001), whereas there was no significant bias by the 3DE‐method (bias =–1.6; 95% CI, –4.3 to 1.1 mL; P = 0.22). The ICC between 2DE and TDM was 0.49 (95% CI, 0.14–0.74) whereas ICC between 3DE and TDM was 0.75 (95% CI, 0.51–0.88). Conclusions: This study elucidated that LVSV is better estimated by 3DE‐method compared to the conventional 2DE‐method. This investigation will provide a more accurate, quick and noninvasive way of LVSV and cardiac output assessment at bedside by further application of 3DE.     

Incremental Value of Live/Real Time Three‐Dimensional over Two‐Dimensional Transesophageal Echocardiography in the Assessment of Atrial Septal Pouch

An atrial septal pouch (ASP) results from partial fusion of the septum primum and the septum secundum, and depending on the site of fusion, the pouch can be left‐sided (LASP) or right‐sided (RASP). LASPs have been described in association with thrombi found in patients admitted with acute strokes, raising awareness of its potential cardioembolic role, especially in those with no other clearly identifiable embolic source. We retrospectively studied 39 patients in whom the presence of an ASP had been identified by three‐dimensional transesophageal echocardiography (3DTEE) and who had a two‐dimensional transesophageal echocardiogram (2DTEE) performed during the same clinical encounter. The incremental value provided by 3DTEE over 2DTEE included the detection of six ASPs not found by 2DTEE; the detection of two ASPs in the same subject (in four patients) not identified by 2DTEE; larger ASP measurements of length and height in over 80% of the cases; and measurement of the ASP width (elevational axis) for the calculation of the area of the ASP opening, because of its unique capability to view the pouch en face. In addition, the volume of ASP and of the echogenic masses contained in the ASP (four of 39 patients) could be calculated by 3DTEE, which is a superior parameter of size characterization when compared to individual dimensions. One of these patients who presented with ischemic stroke diagnosed by magnetic resonance imaging had a large (>2 cm) mass in a LASP, with echolucencies similar to those seen in thrombi and associated with clot lysis and resolution. This mass completely disappeared on anticoagulant therapy lending credence that it was most likely a thrombus. There was no history of stroke or any other type of embolic event in the other three patients with masses in ASP. In conclusion, this retrospective study highlights the incremental value of 3DTEE over 2DTEE in the comprehensive assessment and characterization of ASPs, which can aid in the clarification of their role in cryptogenic stroke patients.     

Three‐Dimensional Speckle Tracking Echocardiography–Derived Left Atrial Strain Parameters Are Reduced in Patients with Atrial Fibrillation (Results from the MAGYAR‐Path Study)

Objective: Three‐dimensional (3D) speckle tracking echocardiography (3DSTE) is a novel imaging modality for assessing cardiac function. We aimed to analyze left atrial (LA) function using 3DSTE in patients with atrial fibrillation (AF). Methods: 3DSTE was performed in 20 patients prior to their pulmonary vein isolation for AF. Every patient underwent a complete two‐dimensional echocardiographic study at the same time. 3DSTE‐derived circumferential (CS), longitudinal (LS), radial (RS), 3D (3DS), and area strain (AS) values were measured in the basal (b), mid (m), and superior (s) regions of the LA. 3DSTE‐defined maximal (LA_max) and minimal LA volumes (LA_min) and LA total emptying fraction were calculated automatically. Eleven randomly selected age‐ and gender‐matched healthy volunteers served as controls. Results: Patients with AF had significantly larger LA_max and LA_min and reduced LS, RS and CS.3DS and AS were significantly lower throughout the LA in cases with AF (3DS?b, ?m, ?s [AF patients vs. controls]: ?18 ± 8% vs. ?29 ± 8%, P = 0.001; ?14 ± 6% vs. ?22 ± 7%, P = 0.002; ?10 ± 7% vs. ?20 ± 9%, P = 0.002; AS?b, ?m, ?s [AF patients vs. controls]: 35 ± 15% vs. 52 ± 13%, P = 0.004; 50 ± 21% vs. 72 ± 19%, P = 0.009; 31 ± 21% vs. 65 ± 27%, P < 0.0001, respectively). Conclusions: 3DSTE‐derived “uni‐dimensional” LS, RS, CS, as well as novel strain parameters (3DS, AS) are significantly reduced in patients with AF compared to matched controls. 3DS and AS might be new strain parameters providing further insights into the alterations of LA function in patients developing AF.     

Incremental Value of Live/Real Time Three‐Dimensional Transesophageal Echocardiography over the Two‐Dimensional Modality in the Assessment of Cardiac Lymphoma

We describe a case of cardiac lymphoma where live/real time three‐dimensional transesophageal echocardiography provided additional information compared to two‐dimensional transesophageal echocardiography regarding the extent of tumor infiltration. In addition, it gave a quantitative assessment of the tumor burden by providing its volume.