The Annals of Thoracic Surgery, Vol 47, 586-588, Copyright © 1989 by The Society of Thoracic Surgeons
Anticipation of bypass surgery: can it induce silent myocardial ischemia?
S Plawes, S Charlap, A Greengart, G Hollander, J Shani and E Lichstein
Department of Medicine, Maimonides Medical Center, Brooklyn, New York 11219.
Psychological stress has been demonstrated to induce myocardial ischemia.
To determine whether stressful events before a coronary artery bypass
grafting procedure precipitate myocardial ischemia, silent or symptomatic,
and whether this can have an effect on the prognosis, 26 patients were
evaluated before a bypass operation with continuous Holter monitor
recording. Specific events monitored were signing surgical consent,
receiving preoperative medications, shaving and preparing, and transfer to
the operating room. A positive Holter result was defined as an ST segment
depression of 1 mm or more lasting one minute or longer. Six patients (23%)
were found to have one or more episodes of substantial ST segment
depression, with a total of ten episodes lasting 208 minutes recorded. All
episodes were silent and not associated with an increase in mean heart
rate. The majority of episodes occurred randomly, although three episodes
did occur between 5 and 6 AM at the time of transport to the operating
room. This appeared to be related more to the circadian rhythm than to the
stress of transport. No perioperative or postoperative myocardial
infarctions occurred, and all patients were alive at 30 days. In
conclusion, silent myocardial ischemia present in the immediate
preoperative period does not appear to be related to specific preoperative
events. Frequency of early morning ischemia may warrant changes in the
medication schedule to provide additional protection during these hours.
