Determinants of left ventricular systolic function after acute myocardial infarction: the role of residual myocardial ischaemia.
BACKGROUND
Left ventricular systolic function (LVSF) is one of the major determinants of survival after acute myocardial infarction (AMI). Some factors such as the infarct size and localization, and the patency of the infarct-related artery are known determinants of LVSF. However, the long-term effect of myocardial ischaemia on LVSF has been poorly studied in clinical settings.


OBJECTIVE
To assess the acute and long-term effects of myocardial ischaemia on LVSF in patients recovering from an AMI.


METHODS
A cohort of 74 patients recovering from AMI was studied. Myocardial ischaemia was detected by means of ambulatory electrocardiogram (ECG) monitoring at recruitment (4+/-2 days after AMI), exercise ECG test and stress echocardiography at discharge (7+/-4 days after AMI). LVSF was studied by means of two-dimensional echocardiography at recruitment, at discharge, and at 1, 3, 6 and 12 months after AMI.


RESULTS
Patients with myocardial ischaemia on ambulatory ECG monitoring and stress echocardiography had worse LVSF at recruitment than those without ischaemia. The presence of myocardial ischaemia on ambulatory ECG monitoring was an independent determinant of LVSF at recruitment together with infarct localization and size (assessed by creatine kinase MB isoenzyme (CK-MB) levels). Patients with signs of myocardial ischaemia on ambulatory ECG monitoring and stress echocardiography had a progressive left ventricular dysfunction compared with those without ischaemia.


CONCLUSIONS
Residual ischaemia is an independent determinant of LVSF after AMI and its presence implied a progressive worsening of the LVSF. Because left ventricular systolic dysfunction is a major determinant of survival after AMI, its precursors, among them residual myocardial ischaemia, should be identified. Treatment of ischaemia is known to be associated with improved prognosis and improved LVSF.
Quintana
M
M
Karolinska Institute at the Department of Cardiology Huddinge University Hospital, Stockholm, Sweden. miguel.quintana@labtek.ki.se
Lindvall
K
K
D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D025401:Echocardiography, Stress; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000503:physiopathology; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D016277:Ventricular Function, Left / Q000502:physiology*