Speckle Tracking Imaging in Normal Stress Echocardiography.

OBJECTIVES: Exercise stress echocardiography is a widely used modality for the diagnosis and follow-up of patients with coronary artery disease. During the last decade, speckle tracking imaging has been used increasingly for accurate evaluation of cardiac function. This work aimed to assess speckle-tracking imaging parameters during nonischemic exercise stress echocardiography. METHODS: During 2011 to 2014 we studied 46 patients without history of coronary artery disease, who completed exercise stress echocardiography protocol, had normal left ventricular function, a nonischemic response, and satisfactory image quality. These exams were analyzed with speckle-tracking imaging software at rest and at peak exercise. Peak strain and time-to-peak strain were measured at rest and after exercise. Clinical follow-up included a telephone contact 1 to 3 years after stress echo exam, confirming freedom from coronary events during this time. RESULTS: Global and regional peak strain increased following exercise. Time-to-peak global and regional strain and time-to-peak strain adjusted to the heart rate were significantly shorter in all segments after exercise. Rest-to-stress ratio of time-to-peak strain adjusted to the heart rate was 2.0 to 2.8. CONCLUSIONS: Global and regional peak strain rise during normal exercise echocardiography. Peak global and regional strain occur before or shortly after aortic valve closure at rest and after exercise, and the delay is more apparent at the basal segments. Time-to-peak strain normally shortens significantly during exercise; after adjustment to heart rate it shortens by a ratio of 2.0 to 2.8. These data may be useful for interpretation of future exercise stress speckle-tracking echocardiography studies.

Real-time quantitative automatic assessment of left ventricular ejection fraction and regional wall motion by speckle imaging.

BACKGROUND: Echocardiographic assessment of left ventricular function includes calculation of ejection fraction and regional wall motion analysis. Recently, speckle imaging was introduced for quantification of left ventricular function. OBJECTIVES: To assess LVEF by speckle imaging and compare it with Simpson's method, and to assess the regional LV strain obtained by speckle imaging in relation to conventional echocardiographic scores. METHODS: Thirty consecutive patients, 28 with regional LV dysfunction, underwent standard echocardiographic evaluation. LV end-diastolic volume, LV end-systolic volume and EF were calculated independently by speckle imaging and Simpson's rule. The regional peak systolic strain presented by speckle imaging as a bull's-eye map was compared with the conventional visual estimate of echo score. RESULTS: Average EDV obtained by speckle imaging and by Simpson's method was 85.1 vs. 92.7 ml (P = 0.38), average ESV was 49.4 vs. 48.8 ml (P = 0.94), calculated EF was 43.9 vs. 50.5% (P = 0.08). The correlation rate with Simpson's rule was high: 0.92 for EDV, 0.96 for ESV, and 0.89 for EF. The peak systolic strain in two patients without wall motion abnormality was 17.3 +/- 4.7; in normal segments of patients with regional dysfunction, peak systolic strain (13.4 +/- 4.9) was significantly higher than in hypokinetic segments (10.5 +/- 4.5) (P < 0.000001). The strain in hypokinetic segments was significantly higher than in akinetic segments (6.2 +/- 3.6) (P < 0.000001). CONCLUSIONS: Speckle imaging can be successfully used for the assessment of LV volumes and EF. Bull's-eye strain map, created by speckle imaging, can achieve an accurate real-time segmental wall motion analysis.

Non-invasive measurement of cardiac output by whole-body bio-impedance during dobutamine stress echocardiography: clinical implications in patients with left ventricular dysfunction and ischaemia.

OBJECTIVES: To compare non-invasive determination of cardiac index (CI) by whole body electrical bioimpedance using the NICaS apparatus and Doppler echocardiography, and the role of cardiac power index (Cpi) and total peripheral resistance index (TPRi) calculation during dobutamine stress echocardiography (DSE). SUBJECTS AND METHODS: We enrolled 60 consecutive patients undergoing DSE. Patients were prospectively divided into 3 groups: Group 1 (n = 20): normal DSE (control). Group 2 (n = 20): EF<40% without significant ischaemia. Group 3 (n = 20): patients with significant ischaemia on DSE. Measurements of CI were performed at the end of each stage of DSE by both echocardiographic left ventricular outflow track flow and the NICaS apparatus, using whole-body bio-impedance. MAP was measured simultaneously and TPRi and Cpi were calculated. RESULTS: The correlation between non-invasive CI as determined by NICaS and echocardiography was 0.81, although Echocardiographic readings of CI were higher during administration of higher doses of dobutamine. Lower EF correlated with lower Cpi, especially stress induced Cpi. Hence, patients with reduced EF (group 2) had a blunted increase in Cpi during stress. Patients with ischaemia (group 3) had a blunted increase in Cpi as well as a decrease in Cpi and increase in TPRi during the last stages of DSE. CONCLUSION: Measurement of CI by NICaS correlated well with Doppler derived CI. The calculation of Cpi and TPRi changes during dobutamine stress may provide important clinical information.

Improved detection of inferobasal ischemia during dobutamine echocardiography with doppler tissue imaging.

OBJECTIVES: The purpose of this study was quantitative evaluation of the inferobasal segment during dobutamine stress echocardiography using Doppler tissue imaging (DTI). BACKGROUND: Overdiagnosis of myocardial ischemia during dobutamine echocardiography is a common problem. DTI may permit more accurate quantitative diagnosis of ischemia. METHODS: A total of 50 patients with normal contraction of the inferobasal segment at rest were referred for dobutamine stress echocardiography. All underwent coronary angiography. Systolic and diastolic myocardial velocities were measured from apical 2-chamber view at rest and at the peak of dobutamine infusion. RESULTS: Stenosis of the right coronary artery >or= 70% was detected in 11 patients. Conventional stress echocardiography was falsely positive in 10.3% and falsely negative in 27.3%. When DTI was combined with conventional stress echocardiography, sensitivity and specificity was 81.8% and 97.4%, respectively. CONCLUSION: DTI may enhance the diagnosis of inferior ischemia during dobutamine echocardiography and can be added to conventional imaging in the treatment of these patients.

Diverse presentations of cardiac rupture following acute myocardial infarction.

BACKGROUND: Cardiac rupture is a rare but ominous complication of myocardial infarction. OBJECTIVES: To study the clinical presentation, medical course, outcome and echocardiographic predictors of patients with myocardial rupture. METHODS: We evaluated 15 consecutive patients with cardiac rupture during a 4 year period in our department. The current report explores the presence of potential risk factors, timing, relation to the thrombolysis, coronary interventions and outcome. RESULTS: The index event in all patients was first ST elevation myocardial infarction. In seven patients rupture occurred in the first 24 hours. Pericardial effusion on admission with a clot was present in three patients. Five patients received thrombolytic therapy. Only three patients underwent coronary angioplasty, but in one case it was performed late and in two patients the culprit artery could not be opened. Six patients reached the operating room, of whom three survived. CONCLUSIONS: The lack of early mechanical reperfusion in acute myocardial infarction and thrombolytic therapy are risk factors for cardiac rupture. Pericardial effusion on admission and evidence of a clot are echocardiographic indicators of cardiac rupture and should alert the medical team to further assess the possibility of cardiac rupture.

Improved detection of spontaneous echo contrast in the aorta with tissue Doppler imaging.

AIMS: Spontaneous echo contrast (SEC) within the cardiac chambers has been associated with increased risk of thromboembolism. We investigated the presence and severity of SEC in the aorta with tissue Doppler imaging (TDI) and compared these to the aortic flow velocity and to the clinical profile of the patients. METHODS AND RESULTS: Seventy patients (35 males, 35 females, mean age 64, 22-86 years) underwent TEE for standard indications. Spontaneous echo contrast was studied with conventional and TDI imaging. Aortic flow velocity was measured in the center and lateral part of the descending aorta. SEC of any grade was detected in 24 patients with conventional imaging and in 53 using TDI (P < 0.0001). The presence of swirling was associated with aortic atherosclerosis, older age, history of hypertension and coronary artery disease, atrial fibrillation, and previous embolic events. There was correlation between intraaortic swirling, larger descending aortic diameter (23.6 vs 17 mm, P < 0.00001) and lower peak aortic flow velocity (55 vs 68 cm/s, P = 0.038). CONCLUSION: Spontaneous echo contrast in the aorta is common in high-risk patients and is associated with increased clinical profile, larger aortic diameter, and lower peak aortic flow velocity. Tissue Doppler imaging is more sensitive in the detection of SEC than conventional imaging.