Five other clinical parameters along with LVEF can predict Cardiac Arrest

The risk of sudden cardiac death (SCD) is high early after myocardial infarction (MI). During the last decades, medical treatment has evolved, rates of in-hospital revascularization have increased, and the outcome has improved following MI. Yet, current knowledge and guidelines regarding SCD early after MI largely rely on trials and registry studies conducted in the 1990s and early 2000s. For this purpose, researchers of Sweden conducted a retrospective study to assess the incidence of out-of-hospital cardiac arrest (OHCA) within 90 days after MI in a contemporary setting restricted to patients without a prior ICD who had undergone in-hospital coronary angiography. They also assessed the patient characteristics beyond LVEF as possible predictors of OHCA.

Researchers used data from SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based care in Heart Disease Evaluated According to Recommended Therapies) and additional data from the Swedish Cardiopulmonary Resuscitation Registry, and the Swedish Pacemaker and Implantable Cardioverter-Defibrillator (ICD) Registry. A total of 121,379 cases of MI, who had undergone coronary angiography and were discharged alive between 2009 to 2017 without a prior ICD, were followed up to 90 days. Researchers used Cox regression models to assess the associations between clinical parameters and out-of-hospital cardiac arrest (OHCA).

Key findings of the study were:

♦ The median time to OHCA was 11 days (25th and 75th percentiles, 3 and 44 days) after discharge.

♦ Among 121,379 cases, OHCA occurred in 349 (0.29%) and non-OHCA death in 2,194 (1.8%) cases.

♦ During the follow-up period, they observed 301 (86.3%) patients in the OHCA group died.

♦ They also observed a cumulative incidence of OHCA at 30 and 40 days after discharge was 0.19% and 0.21%.

♦ Among OHCA patients, they recorded an initial shockable rhythm in 36.4% of cases.

♦ Researchers identified male sex, diabetes, estimated glomerular filtration rate less than 30 mL/min/1.73 m2, Killip class II or greater, new-onset atrial fibrillation/flutter and impaired left ventricular ejection fraction as independent predictors of out-of-hospital cardiac arrest.

♦ These assigned points, and were grouped into 3 categories, where the incidence of OHCA ranged from 0.12% to 2.0% and non-OHCA death from 0.76% to 11.7%.

♦ When Stratified by LVEF <40% alone they found the incidence of OHCA was 0.20% and 0.76% and for non-OHCA death 1.1% and 4.9%.

The authors concluded, "In this nationwide study, the incidence of OHCA within 90 days after MI was <0.3%. We have shown that the incidence of OHCA is low in a contemporary cohort of post-MI cases. In total, 6 clinical variables including LVEF more accurately predicted OHCA as well as non-OHCA death than an LVEF cut-off of 40% alone".

For further information:

https://www.jacc.org/doi/10.1016/j.jacc.2020.10.033#d14635245e162