Despite being rarely performed in patients with non-shockable cardiac rhythms, coronary angiography led to a substantial survival benefit with a favorable neurological outcome, according to a study in PLOS One.

Lead author Eunsil Ko and colleagues studied 670 adult patients who suffered out-of-hospital cardiac arrest (OHCA) and were transferred to 27 hospitals within a nationwide Korean registry. A total of 401 patients (60 percent) showed initial non-shockable rhythms on electrocardiograms (ECGs), while the remaining 40 percent demonstrated shockable rhythms, which can be treated using defibrillation.

Only 13 percent of those with initial non-shockable rhythms—including pulseless electrical activity and asystole—received coronary angiography, but those patients were 3.6 times more likely to survive to 30 days with good neurological outcome. Coronary angiography was also associated with a 3.7-fold likelihood of 30-day survival with favorable cognitive function in patients with an initial shockable rhythm.

Overall, patients with shockable rhythm were 3.2 times more likely to survive to 30 days with good neurological outcomes than those with non-shockable rhythms, but the findings supported the use of coronary angiography in all cases regardless of initial ECG readings.

“CAG (coronary angiography) enables early identification and revascularization of coronary arterial occlusion, which lead to improve clinical outcomes in shockable OHCA,” Ko and coauthors wrote. “In this study, PCI was performed in nearly 40 percent of patients who underwent CAG irrespective of initial rhythm. Performing CAG may have a similarly beneficial effect on clinical outcomes in non-shockable OHCA.”

The authors said 2015 American Heart Association Guidelines and European Society of Cardiology guidelines recommend coronary angiography routinely for OHCA patients regardless of initial rhythm. But Ko and colleagues said they were unaware of any other studies that separately analyzed the clinical outcomes of OHCA patients using different ECG categories in relation to angiography.