PO-05-137 ECG MORPHOLOGY IS A DETERMINANT OF SURVIVAL IN PULSELESS ELECTRICAL ACTIVITY

Abstract

Sudden cardiac arrest (SCA) due to pulseless electrical activity (PEA) has a poor prognosis and identification of cases with a higher likelihood of survival could facilitate the resuscitation process. In PEA, QRS frequency and morphology can vary significantly. To investigate if the frequency and morphology of the QRS can predict survival outcomes in PEA. The study population is drawn from two prospective, community-based studies of out-of-hospital SCA in the U.S.: Oregon SUDS from the Portland, OR metro area (Pop. approx. 1 million; since 2002) and Ventura PRESTO from Ventura County CA (Pop. approx. 850,000, since 2015). In the present study, we included SCA cases resuscitated by EMS that had EMS recording of the ECG available, and PEA was the presenting rhythm. We analyzed QRS frequency, regularity, and width of the presenting PEA rhythm in a subset of 347 PEA-SCA cases (34 survivors and 313 non-survivors). The mean age of the subjects was 70.3±15.5 years and 60.2% were male. The prevalence of QRS frequency >60 bpm was 23.1% and QRS width <120 ms was 32.6%. Females were more likely to have a narrow QRS complex than males (39.9% vs. 27.8%; p=0.02) but there was no sex difference in the QRS frequency. Those with QRS frequency >60 bpm had a higher survival rate than those with QRS frequency <60 bpm (17.5% vs. 7.5%: p=0.02). In addition, cases with QRS width <120 ms had a higher survival rate in comparison to cases with QRS width >120 ms (17.7% vs. 6.0%; p=0.001). Cases with both narrow QRS complex (<120 ms) and fast frequency (>60 bpm) had the highest survival rate (10/38, 26.3%). There was no difference in the survival rate between regular and irregular rhythms. PEAs with electrical activity >60 bpm and narrow QRS complex were associated with higher survival. These results suggest that resuscitation efforts are most likely to be beneficial in PEA-SCA cases that present with a narrow and fast QRS pattern.