Background: Detection of myocardial viability is crucial for clinical treatment of patients with ischemic cardiomyopathy. Currently, quantitative information for the evaluation of systolic and diastolic function of viable tissue is limited. Our aim was to compare quantitatively systolic and diastolic function in viable and nonviable dysfunctional myocardium in patients with ischemic cardiomyopathy.
Methods: A total of 93 patients (mean age, 62 +/- 10 years) underwent dobutamine stress echocardiography to assess myocardial viability. Pulsed-wave tissue Doppler imaging (TDI) was used to assess systolic ejection velocity (V(S)) and early (V(E)) and late (V(A)) diastolic velocities at rest and at low-dose dobutamine infusion (10 microg/kg per minute) in viable and nonviable dysfunctional regions. Analysis was repeated after dividing study population in patients >or=65 years old (n = 40) and <65 years old (n = 53).
Results: Pulsed-wave TDI demonstrated that V(S) was comparable in dysfunctional viable and nonviable regions at rest (V(S), 6.3 +/- 1.9 cm/s vs 6.3 +/- 2.0 cm/s, respectively, P = .93). However, at low-dose dobutamine challenge, V(S) was significantly higher in viable regions (8.5 +/- 2.7 cm/s vs 7.8 +/- 2.4 cm/s, P = .002). Viable regions had higher V(E) at rest compared with nonviable regions (8.4 +/- 2.5 cm/s vs 7.5 +/- 2.8 cm/s, P = .003). Myocardial velocities were significantly higher in patients >or=65 years old, both in viable and nonviable regions.
Conclusions: Quantification of myocardial motion by pulsed-wave TDI demonstrates that at low-dose dobutamine stress, systolic velocity is markedly improved in viable myocardium, indicating the presence of contractile reserve in viable regions. A superior early diastolic filling at rest can also differentiate viable from nonviable myocardium.