Segmental myocardial viability by echocardiography at rest.

BACKGROUND: Myocardial viability assessment adds value to the therapeutic decision-making of patients with ischemic heart disease. In this feasibility study, we investigated whether established echocardiographic measurements of post-systolic shortening (PSS), strain, strain rate and wall motion score (WMS) can discover viable myocardial segments. Our hypothesis is that non-viable myocardial segments are both akinetic and without PSS. METHODS: The study population consisted of 26 examinations strictly selected by visible dysfunction. We assessed WMS, strain by speckle tracking and strain rate by tissue Doppler. The segments (16*26 = 416) were categorized into either normokinetic/hypokinetic or akinetic/dyskinetic and whether there was PSS. The reference method was the presence of scar with segmental percentage volume scar fraction >50%, detected by late gadolinium-enhanced cardiovascular magnetic resonance. Agreement with echocardiography was evaluated by Kappa coefficient. RESULTS: WMS had Kappa coefficient 0.43 (sensitivity 99%, specificity 35%). Kappa coefficient of strain was 0.28 (sensitivity 98%, specificity 23%). By combining PSS in akinetic segments with WMS and strain, the Kappa coefficient was 0.06 and 0.08 respectively. CONCLUSION: Segmental viability was best shown by the presence of systolic function. Post-systolic shortening adds no value to the assessment of segmental myocardial viability.

Retrospective Ultrasound Doppler Quantification Using a Single Acquisition in Healthy Adults.

OBJECTIVE: Using an experimental tool for retrospective ultrasound Doppler quantification-with high temporal resolution and large spatial coverage-simultaneous flow and tissue measurements were obtained. We compared and validated these experimental values against conventional measurements to determine if the experimental acquisition produced trustworthy tissue and flow velocities. METHODS: We included 21 healthy volunteers. The only exclusion criterion was the presence of an irregular heartbeat. Two ultrasound examinations were performed for each participant, one using conventional and one using experimental acquisition. The experimental acquisition used multiple plane wave emissions combined with electrocardiography stitching to obtain continuous data with over 3500 frames per second. With two recordings covering a biplane apical view of the left ventricle, we retrospectively extracted selected flow and tissue velocities. RESULTS: Flow and tissue velocities were compared between the two acquisitions. Statistical testing showed a small but significant difference. We also exemplified the possibility of extracting spectral tissue Doppler from different sample volumes in the myocardium within the imaging sector, showing a decrease in the velocities from the base to the apex. CONCLUSION: This study demonstrates the feasibility of simultaneous, retrospective spectral and color Doppler of both tissue and flow from an experimental acquisition covering a full sector width. The measurements were significantly different between the two acquisitions but were still comparable, as the biases were small compared to clinical practice, and the two acquisitions were not done simultaneously. The experimental acquisition also enabled the study of deformation by simultaneous spectral velocity traces from all regions of the image sector.

Automated tissue Doppler imaging for identification of occluded coronary artery in patients with suspected non-ST-elevation myocardial infarction.

PURPOSE: Identification of regional dysfunction is important for early risk stratification in patients with suspected non-ST-elevation myocardial infarction (NSTEMI). Strain echocardiography enables quantification of segmental myocardial deformation. However, the clinical use is hampered by time-consuming manual measurements. We aimed to evaluate whether an in-house developed software for automated analysis of segmental myocardial deformation based on tissue Doppler imaging (TDI) could predict coronary occlusion in patients with suspected NSTEMI. METHODS: Eighty-four patients with suspected NSTEMI were included in the analysis. Echocardiography was performed at admission. Strain, strain rate and post-systolic shortening index (PSI) were analyzed by the automated TDI-based tool and the ability to predict coronary occlusion was assessed. For comparison, strain measurements were performed both by manual TDI-based analyses and by semi-automatic speckle tracking echocardiography (STE). All patients underwent coronary angiography. RESULTS: Seventeen patients had an acute coronary occlusion. Global strain and PSI by STE were able to differentiate occluded from non-occluded culprit lesions (respectively - 15.0% vs. -17.1%, and 8.1% vs. 5.1%, both p-values < 0.05) and identify patients with an acute coronary occlusion (AUC 0.66 for both strain and PSI). Measurements of strain, strain rate and PSI based on TDI were not significantly different between occluded and non-occluded territories. CONCLUSION: Automated measurements of myocardial deformation based on TDI were not able to identify acute coronary occlusion in patients with suspected NSTEMI. However, this study confirms the potential of strain by STE for early risk stratification in patients with chest pain.