MYOCARDIAL-ISCHEMIA AND SPINAL ANALGESIA IN PATIENTS WITH ANGINA-PECTORIS

We have studied prospectively myocardial ischaemic events by Holter mo nitoring of ST-segment depression in patients with angina pectoris giv en spinal analgesia for minor surgery compared with a reference day of normal daily activities. Monitoring was undertaken continuously for 2 4 h on both days, starting just before anaesthesia on the day of surge ry. On the reference day, seven of 14 patients had 27 ischaemic events with mean max ST-depression of 0.15 mV and total duration of 143 min, compared with 10 of 14 patients with 70 ischaemic events with mean ma x ST-depression of 0.22 mV and total duration of 1078 min (P < 0.01 fo r all). On the day of surgery, the first ichaemic event occurred a mea n 338 min (range 75-480 min) after spinal analgesia, and the duration of all first events was 480 min. On this day, the first ischaemic even t was associated with increased heart rate (103 beat min-1 (range 66-1 31 beat min-1) compared with 92 (60-122) beat min-1 during all events (P=0.011)). In patients with angina pectoris, myocardial ischaemia did not occur immediately after the onset of spinal analgesia, but severa l hours later, corresponding to the cessation of block. This could be explained by increased cardiac pre- and afterload, probably further ag gravated by the volume load.