On the dynamic ST-segment during acute myocardial infarction
Abstract: Acute myocardial infarction is the single most common cause of death for both men and women in Sweden. Great efforts have over the years successfully been made to improve immediate treatment and care, and thereby prognosis. However, inadequacies in use of new knowledge and technology have been reported in this field. We have investigated our own adaptation over time, to new reports on a limited, but central part of immediate treatment. We have also examined bed-side accuracy in use of advanced technology, continuous ST-monitoring, suggested to yield early important information on patients with acute coronary syndromes. We have further investigated the value of dynamic ST-segment changes during the very early phase of acute myocardial infarction and reasoned on implications of these findings.Among 6058 admissions for acute myocardial infarction during 12 years we examined time-trends in use of fibrinolytics and related these to presentations of new knowledge.Among 99 patients included in the TEAHAT study we explored the prognostic value of early ST-segment variability and found an almost linear relationship between ST-variability and one-year mortality.Among 374 patients included in the ASSENT 2 trial we validated the prognostic value of early ST-variability. We also found that evaluation of ST-variability adds important information to evaluation of ST-recovery. Three groups with 0.8%, 4.5% and 9.9% 30-day mortality were identified.Among 177 patients included in the ASSENT PLUS trial we studied ST-variations during the first 24 hours in relation to late angiographic findings. We found that ST-variations independently of ST-recovery predict thrombi and low-grade coronary flow.Among 752 patients included in the ASSENT 2 and ASSENT PLUS trials we prospectively investigated several previously suggested cut-offs for ST-recovery and times for analyses of these. We found that the best predictor of mortality was 50% ST-recovery at 60 minutes, identifying 2 groups with 1.4% vs. 6.1% 30-day mortality. Eighty-eight percent of deaths were correctly predicted.Among 431 patients included in the ASSENT 2 trial we examined bed-side accuracy of continuous ST-monitoring and found that this technology truly yields important on-line information on prognosis.We have shown the dynamics of the ST-segment to yield very important early information on prognosis, probably because they accurately reflect how early, how complete and how sustained blood-flow is restored at the microvascular level, and how the individual is constituted in dealing with future vascular events. We have also shown that much of this information is truly available in real-time, in the clinical setting. The analysis of our own use of fibrinolytics, showed that we were reasonably updated to new knowledge.
This dissertation MIGHT be available in PDF-format. Check this page to see if it is available for download.