Course of chest pain and its relation to CK release and ST/QRS vector changes in patients with acute myocardial infarction randomized to treatment with intravenous timolol or placebo.

Assessments of hourly pain scores (0 to 4) were made in 135 patients during the initial 24 hours after admission to the hospital. The duration of chest pain and the cumulative pain score obtained by adding the pain scores hour by hour were compared to ST and QRS vector changes and CK release. The cumulative pain score over a 24-hour period after admission correlated to the maximal QRS vector difference (r = 0.51) and the cumulative CK release (r = 0.58). The time until patients had complete relief of pain was closely related to the time during which QRS vector changes were seen to continue (r = 0.73). No corresponding correlation was found between pain duration and CK release time (r = 0.24). The ST decline time correlated to the duration of the first uninterrupted episode of chest pain in the placebo group only (r = 0.50). Pain duration showed no correlation to our indices of infarct size. There was a recurrence of pain in 41% of the patients, of whom 36% had a time-associated further increase of the ST vector magnitude. We conclude that chest pain is an important clinical symptom that signals ongoing necrosis. Furthermore, assessments of a "soft" parameter, such as the cumulative pain score, can add valuable information concerning the severity of myocardial damage.