Cerebral microembolism in acute myocardial infarction.
OBJECTIVE
This study was undertaken to determine the frequency of cerebral microemboli (high-intensity transient signals; HITS) detected by transcranial Doppler (TCD) in patients with acute myocardial infarction (AMI) and to relate them to the various putative risk factors and clinical embolic events.


METHODS
We investigated 112 consecutive patients within 72 hours of admission to an acute coronary care unit using TCD to monitor for cerebral microemboli. Twelve patients were excluded because of failure of ultrasound insonation. All patients had 2-dimensional echocardiograms within the study period.


RESULTS
HITS were detected in 17% of patients, with significantly higher frequency in patients with reduced (<65%) left ventricular (LV) ejection fraction (P=0. 019), akinetic LV segments (P=0.002), and LV thrombus (P=0.015). A marginally significant (P=0.059) increase of HITS was found in patients with anterior AMI. Stroke was significantly more frequent in patients with cerebral microemboli (P=0.01).


CONCLUSIONS
HITS were detected in 17% of patients in spite of adequate antithrombotic therapy and were increased in patients with reduced LV function, akinetic myocardial segments, and LV thrombus. They were present in all 3 patients with stroke and may represent a predictor of clinical embolic events.
Nadareishvili
Z G
ZG
Stroke Research Unit, Sunnybrook & Women's College Health Sciences Centre, University of Toronto, Canada. znadareishvilili19@hotmail.com
Choudary
Z
Z
Joyner
C
C
Brodie
D
D
Norris
J W
JW
D000368:Aged; D005260:Female; D006801:Humans; D020766:Intracranial Embolism / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications* / Q000188:drug therapy / Q000473:pathology; D011446:Prospective Studies; D020521:Stroke / Q000209:etiology; D015912:Thrombolytic Therapy; D017585:Ultrasonography, Doppler, Transcranial