PhD Scientific Days 2023

Clinical Medicine I.

Incidence rates of the different initial rhythms during out-of-hospital cardiopulmonary resuscitation and mortality of patients presenting ST elevation myocardial infarction

Text of the abstract

Introduction
Mortality risk of patients presenting with ST-elevation myocardial infarction (STEMI) is extensively researched. Yet, prehospital mortality of them has been rarely studied.
Aims
We investigated the outcomes of STEMI patients with different initial rhythms during cardiopulmonary resuscitation (CPR) using the database of the National Ambulance Service.
Methods
We analysed data of 632 patients between November 2018 and June 2021 who required CPR because of out-of-hospital cardiac arrest (OHCA) with ST elevation being present either on the initial ECG or on that after return of spontaneous circulation. Endpoint was admission to hospital alive. Pearson’s chi-squared test and Mann-Whitney U test were used for statistical analysis.
Results
Of the 632 patients, 102 (16.1%) died before arriving at the hospital. The age of survivals was median 63 years (IQR 53 to 70), while that of patients who died was 70 years (IQR 60 to 77, p<0.001). The sex rate was not different, as 33/197 (16.8%) of women and 59/369 (16.0%) of men died before hospital admission (p=0.812).
Initial rhythm was documented in 469 cases (74.2%). Among these patients, the out-of-hospital mortality was 95/469 (20.3%). Of them 73 patients (76.8%) had a non-shockable initial rhythm (pulseless electric activity or asystole, PEA/ASY), whereas 22 patients (23.2%) died due to an initial shockable rhythm (ventricular tachycardia or fibrillation, VT/VF).
92.5% (273/295) of the cases with VT/VF reached the hospital alive, while patients with an initial PEA/ASY survived only in 58.0% (101/174, p<0.001).
Anterior STEMI patients had an initial PEA/ASY in 26% (46/177), whereas patients with inferior STEMI had non-shockable rhythm in 40.3% (77/191, p=0.004).
An initial shockable rhythm was present in 44.4% (131/295) of the anterior STEMI cases and 90.8% (119/131) of them reached the hospital alive. In contrast, patients with VT/VF had inferior STEMI in 41.8% (114/273) and 97.4% (111/114) of them were admitted to the hospital alive (p=0.033).
Conclusion
Patients with inferior STEMI may have a higher risk for cardiac arrest due to a non-shockable rhythm than patients with an anterior STEMI. However, patients with an inferior STEMI and an initial shockable rhythm may have better chances to reach the hospital alive. For individual prediction, more data and complex statistical methods are needed.

Funding: Dominika Szabó was supported by a scholarship from the European Union „Development of scientific workshops of medical, health sciences and pharmaceutical educations”, project identification number: EFOP-3.6.3-VEKOP-16-2017-00009