Application of tissue Doppler to interpretation of dobutamine echocardiography and comparison with quantitative coronary angiography

The main limitation of dobutamine echocardiography (DE) is its subjective interpretation. We sought to reduce the need for expert interpretation by developing a quantitative approach to DE using myocardial Doppler velocity (MDV) in 242 patients undergoing DE. In 128 patients with a normal dobutamine echocardiogram, the normal range was designed to give a specificity of 80%. The accuracy of this range was investigated in 114 consecutive patients who underwent coronary angiography within 2 months of DE. A standard dobutamine echocardiographic protocol was used, with MDV gathered from color tissue Doppler at rest and peak stress. Wall motion at these stages was scored by experienced observers using a 16-segment model and MDV was measured off-line. Sensitivity and specificity of wall motion scoring and MDV were obtained by comparison with angiographic evidence of disease, defined as stenosis > 50% of the coronary artery diameter. The normal range in tethered segments (septum, anteroseptum, and inferior) was > or = 7 cm/s in the basal segments and > or = 5 cm/s in the midsegments. In the free wall (anterior, lateral, and posterior), the cutoff was > or = 6 cm/s in the base and > or = 4 cm/s in the midventricle. Of 114 patients undergoing angiography, 84 (75%) had significant stenoses, and the sensitivity of wall motion scoring and MDV were 88% and 83%, respectively, with specificities of 81% and 72% (p = NS). The accuracy was similar overall (86% vs 80%), as well as in each vascular territory. These data suggest that a fully quantitative interpretation of DE using site-specific normal ranges of tissue Doppler, which account for regional variations of base-apex function, is feasible and equivalent in accuracy to expert wall motion scoring.     

Contrast echocardiography is superior to tissue harmonics for assessment of left ventricular function in mechanically ventilated patients

BACKGROUND: Assessment of left ventricular function by echocardiography is frequently challenging in mechanically ventilated patients. We evaluated the potential value of contrast-enhanced imaging and tissue harmonic imaging over standard fundamental imaging for endocardial border detection (EBD) in these patients. METHODS AND RESULTS: Fifty patients underwent standard transthoracic 2D echocardiography and were imaged in fundamental and tissue harmonic modes and subsequently with intravenous contrast (Optison). Two echocardiographers reviewed all studies for ease of visualization of endocardial border segments and scoring of wall motion. EBD for each wall segment was graded from 1 to 4 (1 = excellent EBD). Wall motion was scored by a standard 16-segment model and 1 to 5 scale. Studies were categorized as nondiagnostic if 4 of 6 segments in the apical 4-chamber view were either poorly seen or not seen (EBD score 3 or 4). Quantification of ejection fraction was independently performed offline. Visualization of 68% of all segments improved with contrast echocardiography versus 17% improvement with tissue harmonics compared with fundamental mode. Significant improvement (poor/not seen to good/excellent) occurred in 60% of segments with contrast echocardiography versus 18% with tissue harmonics. A total of 850 segments were deemed poor/not seen, 78% of which improved to good/excellent with contrast echocardiography versus 23% with tissue harmonics. Interobserver agreement on EBD was 64% to 70%. Conversion of nondiagnostic to diagnostic studies occurred in 85% of patients with contrast echocardiography versus 15% of patients with tissue harmonics. Scoring of wall motion with fundamental mode, tissue harmonics, and contrast echocardiography was possible in 61%, 74%, and 95% of individual segments, respectively (P <.001). Wall motion scoring was altered in 17% of segments with contrast echocardiography and in 8% with tissue harmonics. Interobserver agreement on wall motion scoring was 84% to 88%. Contrast echocardiography permitted measurement of ejection fraction 45% (P =.003) more often over fundamental mode versus a 27% (P =.09) increase with tissue harmonics. CONCLUSIONS: Contrast echocardiography is superior to tissue harmonic imaging for EBD, wall motion scoring, and quantification of ejection fraction in mechanically ventilated patients.     

Diagnosis of myocardial viability by exercise echocardiography]

This study determined whether the diagnosis of myocardial viability could be established on the basis of the contractile reserve during low level exercise with an ergometer using echocardiography. The study involved 22 patients with transmural old myocardial infarction who underwent exercise echocardiography, followed by coronary intervention after a mean 4 days. Exercise echocardiography was started from 50 W and stepped up by 25 W every 3 min up to a maximum of 150 W. Low level exercise was administered for 1 to 2 min at 50 W. A 16-segment model was used for the left ventricular wall motion, which was evaluated by five-grade scoring, ranging from normokinesis to dyskinesis. If patients showed improvement by one point or more in the score for segments of dyskinesis, akinesis, or severe hypokinesis on the exercise echocardiography, they were considered to have positive viability. The golden standard for the diagnosis of myocardial viability was that wall motion abnormalities before exercise echocardiography should be improved by one point or more after coronary intervention. Before exercise echocardiography, there were 152 segments showing wall motion abnormalities assessed as severe hypokinesis or more. After coronary intervention, improvement of the wall motion by one grade or more was found in 2 of the 18 segments (11%) for dyskinesis, in 38 of the 96 segments (40%) for akinesis, and in 22 of the 38 segments (58%) for severe hypokinesis; improvement for the segments of severe hypokinesis was significantly better than those for dyskinesis and akinesis. Out of 19 segments with akinesis before exercise echocardiography in which wall motion was improved during low level exercise, 16 segments (84%) showed improvement in wall motion after coronary intervention. Out of 77 segments with akinesis before exercise echocardiography in which no change or worsening was seen during low level exercise, 22 segments (29%) showed improved wall motion after coronary intervention. There were 38 segments with severe hypokinesis before exercise echocardiography; out of 12 segments in which wall motion was improved during low level exercise, 7 segments (58%) showed improved wall motion after coronary intervention. Out of 26 segments with severe hypokinesis before exercise echocardiography in which no change or worsening was seen during low level exercise, 11 segments (42%) showed improved wall motion after coronary intervention. Wall motion was improved after coronary intervention in 20 of 25 segments (80%) that showed the biphasic response, in 4 of 7 segments (57%) that showed improvement, in 14 of 43 segments (33%) that showed worsening, in 24 of 77 segments (31%) for no change; the biphasic response showed a significantly higher improvement compared to worsening or no change. If segments in which wall motion was improved during low level exercise are regarded as positive viability segments, occurrences of the sensitivity, specificity and diagnostic accuracy of myocardial viability were 50%, 84%, and 71%, respectively.     

Two-dimensional echocardiographic demonstration of restoration of normal wall motion after acute myocardial infarction

Left ventricular wall motion was assessed by 2-dimensional (2-D) echocardiography in 17 patients admitted with a first transmural acute myocardial infarction (AMI). The left ventricular myocardium was divided into 17 segments and wall motion was scored from 1 (dyskinesia) to 6 (hyperkinesia) in each segment. Reproducibility of the wall motion scoring system when assessed separately by 2 observers was 89% and when assessed by the same observer at different times, 91%. Seven patients had anterior and 10 inferior wall AMI on the electrocardiogram. Abnormal wall motion was present in 7.3 +/- 2.8 segments (mean +/- standard deviation) on the initial 2-D echocardiogram. On follow-up echocardiograms wall motion was unchanged in 7 patients. In 5 wall motion improved by at least 2 in 2 or more contiguous segments. In 5 other patients wall motion returned to normal in all segments that had shown an abnormality on the initial echocardiogram. These 5 patients (group A), compared with the 12 patients in whom wall motion did not return to normal in all segments (group B), showed fewer involved segments (5.4 +/- 1.7 vs 8 +/- 2.8) and a higher total wall motion score (76 +/- 4 vs 63 +/- 7) (p less than 0.05) on the initial echocardiogram. Duration from the time of the AMI to return of normal wall motion in group A varied from 2 to 8 weeks. Thus, wall motion abnormalities seen on 2-D echocardiography after transmural AMI often improve and wall motion returns to normal in some patients.     

Novel stress echocardiographic model incorporating the extent and severity of wall motion abnormality for risk stratification and prognosis

The prognostic value of stress echocardiography to predict future cardiac events using the extent and severity of wall motion abnormalities is not well defined. The objective of this study was to develop and validate a prognostic model for interpretation of stress echocardiographic studies by using the extent and severity of wall motion abnormalities. We evaluated 1,500 patients (59 +/- 13 years old; 51% men) who underwent stress echocardiography (34% on the treadmill exercise and 66% on dobutamine). Left ventricular regional wall motion was assessed by consensus of 2 experienced echocardiographers. Follow-up periods (mean 2.7 +/- 1.0 years) for confirmed myocardial infarction (n = 31) and cardiac death (n = 44) were identified. Multivariate regression analysis identified 2 independent predictors of cardiac events: the number of left ventricular wall segments with new wall motion abnormalities (an index of the extent of ischemia) and the maximal magnitude of new wall motion abnormalities (an index of the severity of ischemia). The ischemic extent (chi-square 48.7, p <0.0001) and maximal severity (chi-square 52.0, p <0.0001) were exponentially correlated with an increase in event rate. On the basis of these data, a prognostic model was defined that uses ischemic extent and maximal severity as stress-dependent orthogonal variables. With this 3-dimensional model, the predicted event rate ranged over sevenfold, from a low of 0.9%/year in patients without any wall motion abnormalities to a high of 6.7%/year in patients with extensive and severe wall motion abnormalities. The extent and severity of wall motion abnormalities by stress echocardiography are independent and cumulative predictors of prognosis in patients who have suspected or known ischemic heart disease.     

Contrast and harmonic imaging improves accuracy and efficiency of novice readers for dobutamine stress echocardiography

BACKGROUND: Newer contrast agents as well as tissue harmonic imaging enhance left ventricular (LV) endocardial border delineation, and therefore, improve LV wall-motion analysis. Interpretation of dobutamine stress echocardiography is observer-dependent and requires experience. This study was performed to evaluate whether these new imaging modalities would improve endocardial visualization and enhance accuracy and efficiency of the inexperienced reader interpreting dobutamine stress echocardiography. METHODS AND RESULTS: Twenty-nine consecutive patients with known or suspected coronary artery disease underwent dobutamine stress echocardiography. Both fundamental (2.5 MHZ) and harmonic (1.7 and 3.5 MHZ) mode images were obtained in four standard views at rest and at peak stress during a standard dobutamine infusion stress protocol. Following the noncontrast images, Optison was administered intravenously in bolus (0.5-3.0 ml), and fundamental and harmonic images were obtained. The dobutamine echocardiography studies were reviewed by one experienced and one inexperienced echocardiographer. LV segments were graded for image quality and function. Time for interpretation also was recorded. Contrast with harmonic imaging improved the diagnostic concordance of the novice reader to the expert reader by 7.1%, 7.5%, and 12.6% (P < 0.001) as compared with harmonic imaging, fundamental imaging, and fundamental imaging with contrast, respectively. For the novice reader, reading time was reduced by 47%, 55%, and 58% (P < 0.005) as compared with the time needed for fundamental, fundamental contrast, and harmonic modes, respectively. With harmonic imaging, the image quality score was 4.6% higher (P < 0.001) than for fundamental imaging. Image quality scores were not significantly different for noncontrast and contrast images. CONCLUSION: Harmonic imaging with contrast significantly improves the accuracy and efficiency of the novice dobutamine stress echocardiography reader. The use of harmonic imaging reduces the frequency of nondiagnostic wall segments.     

Improvement in regional wall motion after percutaneous transluminal coronary angioplasty during acute myocardial infarction: utility of two-dimensional echocardiography

In the setting of acute myocardial infarction, 16 patients undergoing successful coronary angioplasty (PTCA) within 6 hours of presentation (group I) and eight patients receiving conventional medical therapy (group II) were studied by serial two-dimensional (2D) echocardiography to assess the functional recovery of myocardium. All patients underwent 2D echocardiograms within 24 hours of presentation and at a minimum of 6 days after admission. Wall motion analysis was quantified with a wall motion score index based on 16 left ventricular wall segments. Wall motion score index improved significantly from early to late echocardiographic study in the patients undergoing PTCA (1.65 +/- 0.29 to 1.40 +/- 0.30; p less than 0.001), whereas the index did not improve in the conventionally treated group (1.54 +/- 0.26 to 1.58 +/- 0.25; p = NS). One patient in group II had a greater than or equal to 10% improvement in wall motion score index compared to 11 of 16 in group I (p less than 0.01). In all cases improvement in wall motion score index was due to improvement in regional wall motion in the area of infarction. In group I, 40 of 77 (52%) infarct zone segments showed improvement of at least one grade, versus 4 of 28 (14%) segments in group II (p less than 0.001). These data indicate that regional myocardial function improves in the majority of patients undergoing successful PTCA as emergency therapy for acute myocardial infarction and that serial 2D echocardiography is an excellent means to quantify this improvement.     

Differentiation of subendocardial and transmural infarction using two-dimensional strain rate imaging to assess short-axis and long-axis myocardial function.

OBJECTIVES: This study sought to differentiate the transmural extent of infarction (TME) by assessment of the short-axis and long-axis function of the left ventricle (LV) using 2-dimensional (2D) strain. BACKGROUND: The differentiation of subendocardial infarction from transmural infarction has significant prognostic and clinical implications. METHODS: Contrast-enhanced magnetic resonance imaging (CE-MRI) and dobutamine stress echocardiography (DBE) were performed in 80 patients (age 63 +/- 10 years) with chronic ischemic LV dysfunction. Myocardial function was assessed in the short axis at the midventricular level using peak strain rate (SR) and strain (S) in circumferential and radial dimensions, and was assessed in the long axis using longitudinal SR and S. Wall motion analysis was performed during DBE to assess for contractile reserve. RESULTS: Transmural infarct segments had lower circumferential S (-10.7 +/- 6.3) and SR (-1.0 +/- 0.4) than subendocardial infarcts (S: -15.4 +/- 7.0, p < 0.0001; SR: -1.4 +/- 0.8, p = 0.02) and normal myocardium (S: p < 0.0001; SR: p < 0.0001). Transmural and subendocardial infarct segments had similar radial S and SR. Subendocardial infarct segments showed significant reduction of longitudinal S (-13.2 +/- 5.6) and SR (-0.91 +/- 0.45) compared with normal myocardium (S: -17.8 +/- 5.4, p < 0.0001; SR: -1.1 +/- 0.41, p < 0.0001), but there were no significant differences between subendocardial and transmural infarct segments (p = 0.09). Wall motion analysis by DBE could not identify subendocardial infarction on CE-MRI (TME 1% to 50%: DBE scar 38%, DBE viable 38%, DBE ischemic 24%, p = NS). CONCLUSIONS: The combined assessment of long-axis and short-axis function using 2D strain may be used to identify TME.     

Factor analysis of the left ventricle by echocardiography (FALVE): a new tool for detecting regional wall motion abnormalities.

BACKGROUND: Factor analysis of the left ventricle in echography was developed to study the regional wall motion. Two factors and associated factor images were estimated using specific constraints: one "constant" factor and another "contraction-relaxation" factor. The constant factor was encoded in green, the positive component of the contraction in red and the negative in blue. METHODS: The evaluation was carried out on 12 patients with LBBB or pacemaker (group A), and on 26 others (group B). The segments were graded separately on the cine-loops by three experienced echocardiographers. Similarly, the three-color combination of the factor images was read at the endocardial border and each segment was scored. RESULTS: An absolute concordance was obtained for 64.8% of the segments and a relative concordance (within one grade) for 97.2%. They were 71% and 99.6% in group B. Most of the discordant cases were explained by the global motion during the cardiac cycle. The standard deviation of the difference between the mean wall motion scores was 0.38 for all the patients; it was reduced to 0.30 in group B. CONCLUSION: Factor analysis is a promising tool to study the regional wall motion. It might become useful for assessing segmental wall motion in 2D and 3D echo.     

The Pocket Echocardiograph: Validation and Feasibility

Background: A new, miniaturized ultrasound device, the pocket echocardiograph (PE), is highly portable and can be carried inside a lab‐coat pocket. Studies of this device are limited and have not examined the use by novice echocardiographers. We hypothesize that a novice echocardiographer can use PE to produce interpretable cardiac images, and that both novice and expert echocardiographers can use PE to accurately quantify ejection fraction. Methods: Unselected subjects (n = 40) in an echocardiography laboratory underwent blinded formal transthoracic echocardiography (TTE) and PE (Acuson P10, Siemens, Mountain View, CA, USA). A cardiology fellow with 2 months of echocardiography training acquired PE images. The fellow and an experienced echocardiographer interpreted the PE studies offline in a blinded fashion. To assess adequacy, studies were graded as technically adequate, limited, or inadequate. A visual estimation of ejection fraction was made. Comparisons were made to the formal reported TTE. Results: Subjects were heterogeneous, 43% male; age 64 ± 17 years, and ejection fraction 52.4%± 12.3%. All PE studies were interpretable, and the vast majority of PE and TTE images were considered technically adequate (77.5% and 85% respectively; P = 0.32). Ejection fraction showed a good correlation, bias, and limits of agreement for the fellow's interpretation (r = 0.78, −5.9%, ±16.6%) with stronger association for the experienced echocardiographer (r = 0.88, −0.8%, ±11.4%). Conclusion: Novice echocardiographers using the PE can produce adequate quality images. Both expert and novice echocardiographers can use PE to quantify ejection fraction over a broad range of patients. The device's low cost and portability may greatly expand the availability of bedside echocardiography for routine or urgent cardiovascular assessment. (Echocardiography 2010;27:759‐764)     

Long-term prognostic value of ejection fraction changes during dobutamine-atropine stress echocardiography

OBJECTIVE: Dobutamine stress echocardiography (DSE), using subjective wall motion scoring, provides incremental prognostic information over clinical data. The aim of the study was to test the additional prognostic value of left ventricular ejection fraction (LVEF) changes during DSE at different stages. METHODS: The study population comprised 106 consecutive patients (mean age 60+/-11 years, 73% men) with suspected or known coronary artery disease referred for DSE. Stress-induced ischemia was defined as new or worsening wall motion abnormalities. LVEF was measured at rest, peak stress and recovery. Follow-up was successful in 104 (98%) patients. Four patients who underwent revascularization within 60 days were excluded from the analysis. End-points during follow-up were cardiac death, non-fatal myocardial infarction and late revascularization. RESULTS: During a mean follow-up of 5.3+/-2.1 years, 26% of patients died: 13% due to cardiac death, 6% patients experienced non-fatal myocardial infarction and 38% underwent late revascularization. Rest-to-peak LVEF increase was lower in patients who experienced cardiac death or non-fatal myocardial infarction (4.9+/-8.6 compared with 9.2+/-7.5, P=0.04) and any cardiac events (6.0+/-8.5 compared with 10.5+/-6.7, P=0.004). An inverse correlation was found between left ventricular ejection increase and the number of ischemic segments (P<0.0001). A multivariable Cox proportional hazard model demonstrated that, in addition to clinical data and new wall motion abnormalities, lower LVEF increase had an incremental prognostic value in predicting hard cardiac events (hazard ratio 1.1, 95% confidence interval 1.0-1.2). CONCLUSION: Failure of LVEF to significantly increase during DSE, denoting more extensive ischemia, identifies a higher-risk subgroup for late cardiac events.     

Detection of left ventricular systolic and diastolic abnormalities in patients with coronary artery disease by color kinesis

Background: Color kinesis (CK) is a recently developed echocardiographic technique based on acoustic quantification that automatically tracks and displays endocardial motion in real time and has been used in initial studies to improve the evaluation of global and regional wall motion. Hypothesis: For further validation of the use of CK for analysis of segmental ventricular dysfunction, we assessed its sensitivity and specificity for detection of regional systolic and diastolic wall motion abnormalities in patients with coronary artery disease (CAD). Methods: Two-dimensional (2-D) echocardiography and CK were used to study 15 normal subjects and 63 patients with technically good quality echocardiographic tracings, who underwent coronary arteriography within 1 month of echocardiography. Significant (>70% luminal diameter stenosis) CAD was present in 50 patients (79%). Results: Color kinesis tracked endocardial motion accurately in 93% of left ventricular segments. Wall motion score, systolic segmental endocardial motion (SEM), and the time of systolic SEM (tSEM) and diastolic (tDEM) segmental endocardial motion were calculated. Intra- and interobserver variability were within narrow limits. SEM and tSEM were significantly lower and tDEM was significantly higher in the patient population than in the control group (p< 0.001). Comparison between CK and 2-D echocardiography showed a correlation coefficient of 0.81 between the two techniques. The score was identically graded in 74% of segments, with concordance of 82% in diagnosing segments as abnormal. Interobserver concordance was 86% for CK (r=0.85) and 81% for 2-D echocardiography (r=0.80). The sensitivity and specificity of systolic and diastolic CK parameters for the detection of CAD were 88 and 92% and 77 and 85%, respectively. The positive predictive values were 93 and 96%, respectively, the negative predictive values were 63 and 73%, respectively, and the overall accuracy was 86 and 91%, respectively. Conclusions: Our data suggest that CK is a feasible and sensitive technique for identifying regional systolic as well as diastolic wall motion abnormalities in patients with CAD.     

Early low-dose dobutamine echocardiography predicts late functional recovery after thrombolyzed acute myocardial infarction

BACKGROUND: This study was undertaken to evaluate the ability of predischarge low-dose dobutamine echocardiography to predict late left ventricular functional recovery after thrombolyzed acute myocardial infarction. METHODS AND RESULTS: Low-dose dobutamine echocardiography was performed in 54 patients 4 +/- 2 days after acute myocardial infarction treated with thrombolysis. Follow-up resting echocardiography was carried out in 49 of these patients at a mean of 18 +/- 6 months later. Viability was defined as recovery of myocardial function at follow-up, expressed as an improvement of wall motion of at least 1 grade or more in at least 2 contiguous infarct zone segments. In 24 of the 49 patients (group I), wall motion at follow-up improved in comparison with the early resting echocardiographic study (1.72 +/- 0.29 vs 1.37 +/- 0.34, P <.001). In the remaining 25 patients (group II), no wall motion enhancement was seen at follow-up (1.57 +/- 0.38 vs 1.58 +/- 0.36, NS). In 22 of the 24 patients in group I, early low-dose dobutamine echocardiography showed improvement in the wall motion score index compared with baseline resting measurements (1.72 +/- 0.29 vs 1.44 +/- 0.24, P <.001). The positive and negative predictive value of early low-dose dobutamine echocardiography to predict functional recovery was 76% and 92%, respectively. CONCLUSION: Predischarge low-dose dobutamine echocardiography is an accurate tool for detecting viable myocardium and predicting late left ventricular recovery after acute myocardial infarction treated with thrombolysis.     

Stress echocardiography and the human factor: the importance of being expert

The aim of this study was to evaluate how the diagnostic accuracy of a stress echocardiographic procedure, such as a dipyridamole echocardiography test, depends on the specific experience of the physician interpreting the test. Recordings of 50 consecutive dipyridamole echocardiographic tests were selected for the first part of the study. They were analyzed by 20 experienced echocardiographers with different backgrounds in stress echocardiography: 10 beginners (less than 20 stress studies interpreted with trained staff) and 10 experienced observers (greater than or equal to 100 stress studies performed). Diagnostic accuracy (true positive + true negative/total number of tests) versus the angiographic reference standard (greater than 70% coronary stenosis of at least one major coronary artery) was 62 +/- 6% for beginners and 85 +/- 3% for experienced observers (p less than 0.0001). In the second part of the study, 10 observers (5 beginners and 5 experienced observers) evaluated 2 different sets of 50 dipyridamole echocardiographic test studies before and after the training of the beginners. Before training, the accuracy of beginners was lower than that of experienced observers (61 +/- 7% versus 85 +/- 3%; p less than 0.001). After training, the accuracy gap was closed (83 +/- 3% versus 86 +/- 2%; p = NS). Therefore, interpretation of stress echocardiographic tests by an echocardiographer without specific training severely underestimates the diagnostic potential of this technique. One hundred stress echocardiographic studies are more than adequate to build the individual learning curve and reach the plateau of diagnostic accuracy that the test can yield.     

The pocket echocardiograph: a pilot study of its validation and feasibility in intubated patients

Background: The clinical use of miniaturized echocardiograph devices is expanding due to the potential to rapidly assess cardiac function in the critically ill patient. Novice echocardiographers have used the pocket echocardiograph (PE) to estimate ejection fraction in ambulatory patients, but have not evaluated intubated patients. We hypothesize that a novice echocardiographer can use PE to acquire interpretable cardiac images, and provide an accurate tool for estimating ejection fraction. Methods: Subjects scheduled for cardiac surgery underwent blinded transesophageal echocardiography (TEE) and PE during a hemodynamically stable period after endotracheal intubation prior to incision. A single cardiology fellow acquired all PE images. The fellow and an experienced echocardiographer interpreted PE studies offline in a blinded fashion, visually estimating ejection fraction and assigning an image quality grade. Comparisons were made to the TEE study. Results: Subjects (n = 22) were 81% male; age 69 ± 9 years, and had a mean ejection fraction of 51%± 10.0%. Parasternal images were adequate in the vast majority of patients (77%), limited in 14%, and unacceptable in 9%, while apical (41%, 45%, and 14%) and subcostal (36%, 32%, and 32%) image quality was inferior. Ejection fraction showed fair correlation, bias, and limits of agreement for the fellow's interpretation (r = 0.50, 4.9%, ± 20.7%), with stronger association for the experienced echocardiographer (r = 0.76, 3.3%, ± 16.6%). Conclusion: A novice echocardiographer using PE can acquire interpretable images in the majority of intubated patients. Novice and expert echocardiographers can reasonably estimate ejection fraction using PE. PE may allow novice echocardiographers to rapidly assess cardiac function in intubated patients. (Echocardiography 2011;28:371‐377)     

Sensitivity, specificity, and predictive accuracies of non-invasive tests, singly and in combination, for diagnosis of hibernating myocardium.

OBJECTIVE: To determine the best test(s) for predicting functional recovery of hibernating myocardium after reperfusion. METHODS: A prospective study to compare echocardiographic left ventricular diastolic wall thickness (> or =5 mm), low-dose dobutamine echocardiography and rest-redistribution thallium-201 scintigraphy, alone and in combination, for predicting recovery of left ventricular akinesis after surgical revascularization. RESULTS: Twenty-eight consecutive patients aged 58+/-9 years were studied. Of the 448 left ventricular segments, 263 were akinetic at rest; 230/263 (87%) had wall thickness > or =5 mm, 135 (51%) had a positive response and 175 (66.5%) were graded viable on thallium. Of akinetic segments 61% improved after surgery. Left ventricular score decreased from 2.3+/-0.4 to 1.8+/-0.4 (P<0.01) and ejection fraction increased from 27+/-10 to 37+/-14% (P<0.01). For predicting results at 1 year, diastolic wall thickness had a sensitivity and a predictive accuracy of a negative test of 100% but a specificity of 28% and predictive accuracy of a positive test of 61%. The addition of dobutamine echocardiography or thallium-201 improved the predictive accuracy of a positive test to 76% and 69%, respectively; the addition of both tests was not of greater benefit than that of a single test. CONCLUSIONS: Diastolic wall thickness <5 mm on echocardiography was the best simple and single predictor of non-recovery of left ventricular dysfunction. The addition of dobutamine echocardiography or thallium-201, but not both, was the best solution for predicting recovery of left ventricular dysfunction. In times of limited resources, these findings are important from a clinical point of view.     

Tissue velocity imaging during dobutamine stimulation for assessment of myocardial viability: segmental analysis in patients after myocardial infarction

BACKGROUND: Dobutamine stress echocardiography (DSE) is an established method for the detection of viable myocardium, but evaluation of this method is subjective. Tissue velocity Imaging (TVI) allows quantitative analysis of regional myocardial wall motion by assessment of systolic myocardial velocities. The aim of this study was to evaluate the diagnostic value of DSE and TVI for detection of viable myocardium. METHODS: In 56 patients (58+/-12 years) with previous myocardial infarction (130+/-42 days, mean ejection fraction 42+/-15%) low-dose DSE was combined with analysis of peak systolic myocardial velocities (Vpeak) by TVI for assessment of myocardial viability. As reference served a follow-up echocardiography after successful revascularization (mean 91+/-3 days). RESULTS: Of a total of 896 segments 200 showed abnormal wall motion (31 mildly hypokinetic, 50 severely hypokinetic, 115 akinetic, 4 dyskinetic). In 125 of these 200 segments regional improvement of regional wall motion was observed (62.5% viable). An increase of Vpeak>1 cm/s during dobutamine stimulation allowed the identification of viable myocardium with a sensitivity of 82% and a specificity 82% (DSE: 77% and 80%). By receiver operating characteristic (ROC) curve analysis, a cut-off value of 1.0 cm/s was the best parameter to differ viable from nonviable myocardium (area under the curve 0.85; p<0.01; 95% CI 0.79 to 0.90). Improvement of global ejection fraction after revascularization (47+/-13%, p=0.11) corresponded with three TVI viable segments with a sensitivity of 92% and a specificity of 89% (p=0.012). CONCLUSIONS: TVI allows the identification of viable myocardium during dobutamine stimulation and enables a quantitative interpretation of DSE.     

Echocardiographic evaluation of segmental wall motion early and late after thrombolytic therapy in acute myocardial infarction: the Western Washington Tissue Plasminogen Activator Emergency Room Trial

In 92 acute myocardial infarction (AMI) patients treated with tissue plasminogen activator 2.3 +/- 1.2 hours after the onset of chest pain, echocardiography was performed at 11 +/- 14 hours (early) and, in 49 patients, again at 13 +/- 7 weeks (late). Infarct location and the left ventricular wall motion score index--the average score (normal = 1, hypokinetic = 2, akinetic = 3, dyskinetic = 4) for 20 segments--were determined by 2 observers unaware of clinical, angiographic or electrocardiographic data. Concordance between noninvasive infarct location by electrocardiography or echocardiography and infarct-related artery at angiography 4 +/- 2 days later (n = 85) was 76 and 81%, respectively. The early wall motion score index was worse for anterior (1.8 +/- 0.4) versus inferior (1.3 +/- 0.2, p less than 0.0001) or posterior-lateral (1.6 +/- 0.2, p = 0.0003) infarcts. Overall, the wall motion score index improved from early to late echocardiography (n = 49, 1.5 +/- 0.3 to 1.3 +/- 0.3, p = 0.0008). However, improvement was confined to those with time to treatment less than or equal to 2 hours (n = 22, 1.4 +/- 0.3 to 1.2 +/- 0.2, p less than 0.0001), and evidence of reperfusion at angiography (n = 38, 1.5 +/- 0.3 to 1.2 +/- 0.3, p less than 0.0001). The decrease in the wall motion score index was related to a decrease in the number of adjacent involved segments (5.5 +/- 3.0 to 3.7 +/- 3.9/patient, p = 0.0006). Thus, echocardiography early after AMI identifies infarct location. Improvement in regional wall motion is seen after early treatment with intravenous tissue plasminogen activator.     

Quantitative assessment of short axis wall motion using myocardial strain rate imaging

Although left ventricular wall motion has been usually assessed with four-point scale (1 = normal; 2 = hypokinesis; 3 = akinesis; 4 = dyskinesis) based on the visual assessment, this method is only qualitative and subjective. Recently, a new echocardiographic system that enables calculation of myocardial strain rate based on tissue Doppler information has been developed. We investigated whether myocardial strain rate could quantify regional myocardial contraction in 17 patients with and without wall motion abnormalities including 6 patients undergoing dobutamine stress echocardiography. Left ventricular short-axis wall motion was assessed with standard two-dimensional echocardiography at basal, mid-ventricular, and apical levels. The same levels were imaged with tissue Doppler method to determine regional myocardial strain rate. Sixty-four segments were judged normokinesis, 53 segments hypokinesis, and 18 segments akinesis at rest; 16 segments were judged normokinesis and 6 segments hypokinesis at stress. No segments characterized dyskinesis. Strain rates of normokinetic, hypokinetic, and akinetic wall segments at rest were significantly different each other (-2.0 +/- 0.6 for normokinesis,-0.6 +/- 0.5 for hypokinesis,P < 0.0001 vs. normokinesis, and-0.008 +/- 0.3 for akinesis, P < 0.0001 vs. normokinesis and hypokinesis). Further, strain rates well reflected the change in wall motion induced by dobutamine challenge: strain rates in the 15 segments revealing augmented wall motion changed from -2.0 +/- 0.7 to -4.7 +/- 1.7 (1/sec) (P < 0.0001) and those in the 7 segments revealing deteriorated or unchanged wall motion changed from -2.1 +/- 1.0 to -1.7 +/- 0.8 (1/sec) (P < 0.05). In conclusion, strain rate agreed well with assessed wall motion. Strain rate imaging may be a new powerful tool to quantify regional wall contraction.     

Usefulness of a novel ultrasound transducer for continuous monitoring treadmill exercise echocardiography to assess coronary artery disease.

BACKGROUND: The feasibility of a novel ultrasound probe, which can be attached to the left ventricular (LV) apex chest wall and allows free rotation around its long axis direction for the continuous monitoring of LV wall motion, was tested. METHODS AND RESULTS: There were 36 subjects who had coronary artery disease (CAD). By attaching a novel ultrasound probe to the chest wall, the LV apical views were recorded during treadmill exercise stress echocardiography (Echo). The continuous monitoring of LV wall motion was satisfactorily feasible in 30 of 36 patients. The visualization rate of the overall LV segments was higher at rest (90%) compared to that during peak exercise (77%). The segments were better visualized in apical portions (90-100%) than in mid (77-96%) or basal portions (68-87%). The sensitivity, specificity, and accuracy for detecting CAD were 61, 100 and 77%, respectively. The wall motion score index 3 and 6 min after exercise decreased significantly compared to those at peak exercise. The number of segments with dyssynergy was highest at the peak exercise. Ischemic ST-T depression on electrocardiography was observed only at peak stress periods. CONCLUSIONS: Continuous monitoring treadmill exercise Echo using a novel ultrasound probe seems feasible for the non-invasive and physiological assessment of CAD.