Doppler tissue velocity sampling improves diagnostic accuracy during dobutamine stress echocardiography for the assessment of viable myocardium in patients with severe left ventricular dysfunction.

BACKGROUND: Both nuclear imaging with F18-fluorodeoxyglucose and dobutamine stress echocardiography have been used to identify viable myocardium, although dobutamine-stress echocardiography has been demonstrated to be the less sensitive of the two. AIM: To compare the accuracy of pulsed-wave Doppler tissue sampling with dobutamine-stress echocardiography for the detection of viable myocardium, using F18-fluorodeoxyglucose imaging as a reference. Methods Forty patients with chronic coronary artery disease and left ventricular dysfunction (mean ejection fraction 33+/-11%), underwent F18-fluorodeoxyglucose imaging, dobutamine-stress echocardiography and pulsed-wave Doppler tissue sampling. Evaluation was performed using a six-segment model. RESULTS: Visual assessment by resting echo was feasible in 230 out of 240 segments (96%); 177 (77%) segments showed severe dyssynergy at rest. F18-fluorodeoxyglucose imaging showed viability in 95 (54%) segments while 82 (46%) were non-viable. Ejection phase velocity at rest was not significantly different; ejection velocities during low-dose and peak-dose dobutamine, however, were significantly higher in viable myocardium (8.6+/-2.9 vs 6.0+/-1.8 and 9.3+/-3.1 vs 6.2+/-2.1 cm x s(-1)). Using receiver operating characteristic curves the optimal cut-off value for viability assessment was an increase in the ejection phase velocity low-dose of 1+/-0.5 cm x s(-1), while 0+/-0.5 cm x s(-1)predicted non-viability. The sensitivity and specificity (95%CI) of pulsed-wave Doppler tissue sampling and dobutamine-stress echocardiography for the prediction of viability was respectively 87% (82-92) vs 75% (67-81) (P<0.05) and 52% (44-59) vs 51% (45-59) (P=ns). CONCLUSIONS: The sensitivity of pulsed-wave Doppler tissue sampling is superior to dobutamine-stress echocardiography for the assessment of myocardial viability.

Safety and utility of atropine addition during dobutamine stress echocardiography for the assessment of viable myocardium in patients with severe left ventricular dysfunction.

OBJECTIVE: To assess the feasibility safety and side effects of the addition of atropine to dobutamine stress echocardiography for the detection of viable myocardium in patients with left ventricular dysfunction (ejection fraction < or = 35%) prior to coronary revascularization. BACKGROUND: The assessment of viable and/or ischaemic myocardium has high prognostic value as regards improvement of function and survival after coronary revascularization. The addition of atropine to dobutamine during echocardiographic testing for the presence of viable myocardium is not common practice. Consequently, no data exist on the safety and additional diagnostic value of this practice. METHODS: Two hundred patients with left ventricular ejection fraction < or = 35% were studied. RESULTS: Test end-points were: target heart rate in 164 (82%) of the patients, severe angina in 18 (9%), maximum dobutamine-atropine dose in six (3%), severe ST segment changes in five (2%), cardiac arrhythmias in four (2%), and hypotension in three (1%). Viability could be assessed echocardiogaphically in 105/200 (53%) from a biphasic response (improvement of wall motion with low dose dobutamine and worsening with high dose), in 93 from ischaemia and in 12 from sustained or late improvements. In 36/105 (34%) patients, ischaemic myocardium could only be assessed after the addition of atropine. Cardiac arrhythmias occurred in 11/200 (6%) and hypotension (decrease of systolic blood pressure >30 mmHg) in 21/200 (11%). Neither the use of atropine nor the induction of ischaemia were associated with an increased incidence of cardiac arrhythmias or hypotension. CONCLUSIONS: In a large group of patients with severe left ventricular dysfunction, dobutamine stress echocardiography is feasible and safe in 186/200 (93%); the addition of atropine was necessary in 34% to assess myocardial viability. Hypotension and cardiac arrhythmias were the most frequent side effects, but were not related to the induction of ischaemia or addition of atropine.

FDG SPECT in the assessment of myocardial viability. Comparison with dobutamine echo.

The use of 18F-fluorodeoxyglucose (FDG) imaging with single photon emission computed tomography (SPECT) has been introduced recently to assess myocardial viability. Several centres have now gained experience with cardiac FDG SPECT imaging, and this report is a summary of the currently available FDG SPECT data. Three studies have compared FDG SPECT with FDG positron emission tomography and demonstrated good agreement between them. Initial results in patients undergoing revascularization suggest that FDG SPECT can predict improvement in contractile function after revascularization. Although the initial results are promising, larger studies are needed to determine the precise role of FDG SPECT in the assessment of myocardial viability.