A new 2D-based method for myocardial velocity strain and strain rate quantification in a normal adult and paediatric population: assessment of reference values.

BACKGROUND: Recent advances in technology have provided the opportunity for off-line analysis of digital video-clips of two-dimensional (2-D) echocardiographic images. Commercially available software that follows the motion of cardiac structures during cardiac cycle computes both regional and global velocity, strain, and strain rate (SR). The present study aims to evaluate the clinical applicability of the software based on the tracking algorithm feature (studied for cardiology purposes) and to derive the reference values for longitudinal and circumferential strain and SR of the left ventricle in a normal population of children and young adults. METHODS: 45 healthy volunteers (30 adults: 19 male, 11 female, mean age 37 +/- 6 years; 15 children: 8 male, 7 female, mean age 8 +/- 2 years) underwent transthoracic echocardiographic examination; 2D cine-loops recordings of apical 4-four 4-chamber (4C) and 2-chamber (2C) views and short axis views were stored for off-line analysis. Computer analyses were performed using specific software relying on the algorithm of optical flow analysis, specifically designed to track the endocardial border, installed on a Windows based computer workstation. Inter and intra-observer variability was assessed. RESULTS: The feasibility of measurements obtained with tissue tracking system was higher in apical view (100% for systolic events; 64% for diastolic events) than in short axis view (70% for systolic events; 52% for diastolic events). Longitudinal systolic velocity decreased from base to apex in all subjects (5.22 +/- 1.01 vs. 1.20 +/- 0.88; p < 0.0001). Longitudinal strain and SR significantly increased from base to apex in all subjects (-12.95 +/- 6.79 vs. -14.87 +/- 6.78; p = 0.002; -0.72 +/- 0.39 vs. -0.94 +/- 0.48, p = 0.0001, respectively). Similarly, circumferential strain and SR increased from base to apex (-21.32 +/- 5.15 vs. -27.02 +/- 5.88, p = 0.002; -1.51 +/- 0.37 vs. -1.95 +/- 0.57, p = 0.003, respectively). Values of global systolic SR, both longitudinal and circumferential, were significantly higher in children than in adults (-1.3 +/- 0.2, vs. -1.11 +/- 0.2, p = 0.006; -1.9 +/- 0.6 vs. -1.6 +/- 0.5, p = 0.0265, respectively). No significant differences in longitudinal and circumferential systolic velocities were identified for any segment when comparing adults with children. CONCLUSION: This 2D based tissue tracking system used for computation is reliable and applicable in adults and children particularly for systolic events. Measured with this technology, we have established reference values for myocardial velocity, Strain and SR for both young adults and children.

The limitations of echocardiography in the overall diagnosis of the morphological lesions associated with infective endocarditis: comparison of echocardiographic and surgical findings.

Echocardiography is commonly accepted as the method of choice for the non-invasive diagnosis of vegetations and other lesions associated with infective endocarditis. To assess the accuracy of echocardiography in the overall diagnosis of the morphological cardiac lesions we retrospectively analyzed and compared the preoperative echocardiographic data with the surgical findings of 120 consecutive cases operated for infective endocarditis. Transthoracic echocardiography (TTE) was used in 60 cases (51 with native and 9 with prosthetic valves), both TTE and transesophageal echocardiography (TEE) in 50 (26 with native and 24 with prosthetic valves) and only TEE in 10 patients who underwent emergency surgery. The echocardiographic diagnosis was correct in all the cases, but incomplete in 26 (16 with native and 10 with prosthetic valves). Most of the incomplete diagnoses occurred regarding vegetations, perforations of the valvular leaflets and perivalvular abscesses. There were no differences between aortic or mitral valves (14/66 vs 11/60; p = ns), native or prosthetic (16/79 vs 10/37; p = ns), TTE or TEE (13/60 vs 13/60; p = ns); however, TEE was performed in more complex cases and in severely ill patients. In six of the incomplete diagnoses, echocardiography preceded surgery by one week or more, and in six the mistakes were not confirmed by the reviewer. In conclusion, our study suggests that an echocardiographic diagnosis of endocarditis may be correct but sometimes incomplete. In patients without prosthetic valves who have a technically-adequate transthoracic echocardiogram, transesophageal echocardiography is not indispensable but should be chosen from time to time. However, the patients with endocarditis and no contraindication to the transesophageal procedure should undergo both transesophageal and transthoracic echocardiography before surgery in order to obtain as much and the most definite information possible. An echocardiographic study should be repeated just before any surgical procedures in patients with active endocarditis. Finally, it needs to be emphasized that the training and clinical judgement of the operator performing the study are important elements determining the results of echocardiographic study.