Self-report. The risk of sudden cardiac death increases in the first period after a heart attack and is strongly associated with reduced ejection fraction (EF) and clinical heart failure. However, two large, randomized trials were unable to demonstrate a net benefit for patients with EF 35 percent or 30 percent who received an implantable defibrillator (ICD) early after a heart attack, possibly due to competing causes of death. Therefore European and American guidelines recommend an initial preventive ICD no later than 40 days after myocardial infarction or 90 days after angiogenesis if the EF remains 35 percent despite optimal medical treatment. Recent decades have improved care and prognosis after myocardial infarction, in part due to increased vascularization and medical treatment. However, the current state of knowledge and guidelines for the prevention of sudden early cardiac death after a heart attack are mainly based on randomized studies and scoring studies conducted in the 1990s and early 2000s.
The purpose of this study was to investigate the incidence and predictive factors of out-of-hospital cardiac arrest (OHCA) within 90 days of myocardial infarction in a contemporary population. Patients without an implantable cardioverter and defibrillator who were cared for for a 2009-2017 heart attack and who underwent coronary X-rays during the period of care were included. We used data from the Swedishhart website, the Swedish Heart Disease Registry and the Swedish Pacemaker Registry. Using Cox models, we investigated the associations between clinical variants and out-of-hospital cardiac arrest.
A total of 121,379 patients were included. OHCA affected 349 (0.29 percent) of them, while 2,194 (1.8 percent) experienced death without an OHCA record. Six variables were found independently associated with cardiac arrest outside of hospital: male gender, diabetes, estimated GFR <30 mL / min / 1.73 m.2, Killip class ≥ II, a newly discovered atrial fibrillation / flutter and an EF with a reference value of 50 percent, categorized as 40–49 percent, 30–39 percent and <30 percent. Scores were assigned to these variables, which were grouped into three categories. According to the three point categories, the incidence of OHCA was 0.12 - 2.0 percent, while the incidence of death without OHCA was 0.76 - 11.7 percent. Divided only by EF 40 percent and EF <40 percent, the OHCA incidence was 0.20 - 0.76 percent and for death with no OHCA recorded 1.1-4.9 percent.
Overall, the incidence of OHCA within 90 days of myocardial infarction was lower than previously shown. Five variants plus EF predicted OHCA, plus death where OHCA was not recorded, better than EF 40 percent and EF <40 percent. Further studies are needed to elucidate the benefits of using variants in addition to EF for long-term prevention of OHCA early after a heart attack.
La Cartettingen 10/9/2021