UCSF

Myocardial ischemia is dynamic and unpredictable which, if not identified and treated promptly, can lead to devastating outcomes. Pre-hospital electrocardiography may facilitate early intervention by identifying patients with acute coronary syndrome (ACS) promptly. The goal of this dissertation research was to determine the prevalence and clinical significance of electrocardiographic (ECG) abnormalities of ischemia that occur in the pre-hospital setting in patients who contact `911' for chest pain and other anginal equivalent symptoms. While previous investigations have examined the impact of a snapshot 12-lead pre-hospital ECG (PH ECG), this study is the first to analyze ST-segment monitoring triggered 12-lead ECGs that have been acquired in the pre-hospital setting. The diagnostic and prognostic capabilities of PH ECG in the management of ACS have been examined and described.

The first paper is a critical literature review of the scientific literature about pre-hospital electrocardiography. Several themes that emerged from the literature and form the bases of this paper include: clinical effects of PH ECG (timing, roles, effects on patient outcome and characteristics of patients with PH ECG), diagnostic performance, and prognostic/predictive value of PH ECG.

The second paper is a secondary analysis of data from patients (n=620) who activated `911' for chest pain symptoms to determine the sensitivity and specificity of 12-lead ECG ST-segment monitoring in the pre-hospital period for diagnosing acute ACS. Both the PH ECG and the initial hospital ECG data for each patient were included in this study. The sensitivity of the ECG for diagnosing ACS was significantly improved when used in conjunction with the initial hospital ECG.

The third paper is a secondary analysis of data from the same cohort as previously described above, but includes only the PH ECG data for each patient (n=630). The purpose of the study was to determine whether manifestations of acute myocardial ischemia on the PH ECG are predictive of adverse hospital outcomes. Patients with evidence of PH ECG ischemia had a significantly higher proportion of adverse hospital outcomes than those without PH ECG ischemia. Furthermore, PH ECG ischemia was found to be an independent predictor of adverse hospital outcomes.