Intra- and inter-observer reproducibility of transthoracic pulmonary venous Doppler flow indices after acute myocardial infarction.

AIMS: To examine the intra- and inter-observer reproducibility of pulmonary venous flow indices in patients with acute myocardial infarction. METHODS: Two investigators, blinded to the results of the other examination, each examined 28 clinically stable post infarction patients in sinus rhythm. The two stored digital Doppler recordings from each patient were analysed in a blinded manner by both investigators to obtain the intra- and inter-observer reproducibility including both a new recording and new measurements. RESULTS: The intra- and inter-observer coefficients of variation for the different variables ranged between 5-15% and 8-23% respectively. For some of the indices there was a difference in means between the observers, and the indices were influenced in different degree by a new measurement and new recording. The degree of variability found in this study indicates wide relative limits of agreement, ranging from +/-10% to +/-45%. CONCLUSION: The reproducibility of pulmonary venous flow indices was only moderate with relatively wide limits of agreement. The reproducibility was, however, comparable to other echocardiographic measurements of left ventricular dimensions and function.

Regional myocardial systolic function during acute myocardial ischemia assessed by strain Doppler echocardiography.

OBJECTIVES: We sought to evaluate if echocardiographic strain measurements could detect acute myocardial ischemia, and to compare this new method with myocardial velocity measurements and wall motion score index. BACKGROUND: Tissue Doppler echocardiography (TDE) is a promising method for assessing regional myocardial function. However, myocardial velocities measured by tissue Doppler echocardiography (TDE) vary throughout the left ventricle (LV) because of tethering effects from adjacent tissue. Strain Doppler echocardiography (SDE) is a new tool for measuring regional myocardial deformation excluding the effect of adjacent myocardial tissue. METHODS: Seventeen patients undergoing angioplasty of the left anterior descending coronary artery (LAD) were studied. Left ventricular longitudinal wall motion was assessed by TDE and SDE from the apical four-chamber view before, during and after angioplasty from multiple myocardial segments simultaneously. RESULTS: Systolic strain values were uniformly distributed in the different nonischemic LV segments, whereas systolic velocities decreased from basis to apex. During LAD occlusion, strain measurement showed expansion in the apical septal segment in 16 of 17 patients (7.5 +/- 6.5% vs. -17.7 +/- 7.2%, p < 0.001) and reduced compression in the mid-septal segment (p < 0.05) compared with baseline. Segments not supplied by LAD remained unchanged. Tissue Doppler echocardiography showed reduced velocities in all septal segments (p < 0.05) during angioplasty even though LAD does not supply the basal septal segment. Negative systolic velocities were present in 11 of 17 patients. Wall motion score index increased during ischemia (1.3 +/- 0.4, p < 0.05). CONCLUSIONS: The new SDE approach might be a more accurate marker than TDE for detecting systolic regional myocardial dysfunction induced by LAD occlusion.

Myocardial strain by Doppler echocardiography. Validation of a new method to quantify regional myocardial function.

BACKGROUND: Myocardial strain is a measure of regional deformation, and by definition, negative strain means shortening and positive strain, elongation. This study investigates whether myocardial strain can be measured by Doppler echocardiography as the time integral of regional velocity gradients, using sonomicrometry as reference method. METHODS AND RESULTS: In 13 anesthetized dogs, myocardial longitudinal strain was measured on apical images as the time integral of regional Doppler velocity gradients. Ultrasonic segment-length crystals were placed near the left ventricular (LV) apex and near the base. Apical ischemia was induced by occluding the left anterior descending coronary artery (LAD), and preload was increased by saline. Percentage systolic strain by Doppler correlated well with strain by sonomicrometry (y=0.82x-1.79, r=0.92, P<0.01). During LAD occlusion, apical myocardium became dyskinetic, as indicated by positive strain values and negative Doppler velocities. At the LV base, myocardial strain by Doppler, strain by sonomicrometry, and velocity of shortening by sonomicrometry (dL/dt) were unchanged during apical ischemia. However, myocardial Doppler velocities at the base decreased from 4.2+/-0.7 (+/-SEM) to 2.7+/-0. 4 cm/s (P<0.05), probably reflecting loss of motion caused by tethering to apical segments. Volume loading increased myocardial Doppler velocities from 2.2+/-0.3 to 4.1+/-0.8 cm/s (P<0.05) and Doppler-derived strain from -12+/-1% to -22+/-2% (P<0.05), whereas peak LV elastance remained unchanged. CONCLUSIONS: Myocardial strain by Doppler echocardiography may represent a new, powerful method for quantifying regional myocardial function and is less influenced by tethering effects than Doppler tissue imaging. Like myocardial Doppler velocities, strain is markedly load-dependent.