Assessment of residual myocardial viability in regions with chronic electrocardiographic Q-wave infarction.
BACKGROUND
Q waves on the electrocardiogram are often considered to be reflective of irreversibly scarred myocardium due to antecedent transmural myocardial infarction. However, there are some indications that residual viable tissue may be present in Q-wave-infarcted regions. It is clinically relevant to know how many Q-wave regions contain viable tissue because these patients may benefit from revascularization in terms of improvement of function and long-term survival.


METHODS
Patients (n = 150) with chronic electrocardiographic Q-wave infarction, heart failure symptoms, and chronic coronary artery disease underwent dobutamine-atropine stress echocardiography to assess myocardial viability. Residual viability in regions with Q-wave infarction was considered present when the end-diastolic wall thickness (EDWT) was >6 mm and the response during dobutamine infusion indicated viable tissue.


RESULTS
Baseline echocardiography revealed 517 dysfunctional myocardial regions; 202 of the dysfunctional regions were related to Q waves on the electrocardiogram and the other 315 dysfunctional regions were not. EDWT was < or =6 mm in 13 regions with a Q wave on the electrocardiogram, with only 1 region exhibiting viable tissue during dobutamine stress echocardiography. EDWT was >6 mm in 189 regions with a Q wave, with 118 (62%) having viable tissue on dobutamine stress echocardiography. In 6 dysfunctional regions without a Q wave, EDWT was < or =6 mm, with all being nonviable on dobutamine stress echocardiography; of the 309 regions without a Q wave and EDWT >6 mm, 204 (66%) exhibited viability on dobutamine stress echocardiography.


CONCLUSIONS
Fifty-eight percent of dysfunctional regions related to chronic Q waves were viable according to the combined information of EDWT and dobutamine stress echocardiography. EDWT </=6 mm virtually excludes viability; regions with EDWT >6 mm need additional testing to detect or exclude viability.
Schinkel
Arend F l
AF
Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands.
Bax
Jeroen J
JJ
Boersma
Eric
E
Elhendy
Abdou
A
Vourvouri
Eleni C
EC
Roelandt
Jos R T C
JR
Poldermans
Don
D
D002303:Cardiac Output, Low / Q000000981:diagnostic imaging / Q000503:physiopathology; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D025401:Echocardiography, Stress; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013318:Stroke Volume / Q000502:physiology; D014022:Tissue Survival; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology