Abstract 15738: New Left Bundle Branch Block (LBBB) as a Predictor of Coronary Occlusion After Out-of-Hospital Cardiac Arrest (OHCA)

Introduction: In the setting of recent cardiac arrest, it is controversial whether new LBBB with or without Sgarbossa Criteria is an ST elevation (STE) equivalent for predicting acute coronary occlusions. The 2010 AHA guidelines recommend urgent coronary angiography after OHCA when either STE or new LBBB is present. These guidelines are extrapolated from the non-arrest population with few data from OHCA patients. Hypothesis: New LBBB on EKG early after OHCA will have a weaker association with acute coronary occlusion than STE. Methods: This was a retrospective 2 center study of 284 OHCA subjects who underwent early coronary angiography (within 24 hours of resuscitation). The post-resuscitation EKG was reviewed by a study investigator (LK) with cardiology over reading (JJ). Subjects with either STE or new LBBB were identified. Cardiologists performed percutaneous intervention (PCI) at their discretion when a culprit lesion or acute thrombus was found. We calculated the sensitivity and specificity for STE, LBBB, and STE + LBBB (current standard) for predicting PCI and the odds ratio (OR) and 95% confidence intervals (CI) for the association between these EKG findings and PCI. OR were calculated relative to subjects with no STE or LBBB. Results: Of the 284 patients, 125 presented with STE and 19 presented with new LBBB resulting in 144 patients meeting AHA criteria for angiography. None of the LBBB met Sgarbossa Criteria. PCI was performed in 95/125 (76%) of those with STE, 4/19 (21%) of those with LBBB and 99/144 (69%) with either finding. The sensitivity and specificity of STE for PCI were 62% and 77% and the unadjusted OR was 5.82 (95% CI: 3.45, 9.83; p < 0.001). The sensitivity and specificity of ST elevation or new LBBB for PCI was 65% and 66% (OR =3.72 [95% CI: 2.28, 6.09; p < 0.001]). New LBBB was inversely associated with PCI (OR = 0.21 [95% CI: 0.07, 0.66; p = 0.0075]. Survival was higher in those who underwent PCI with STE (OR 8.23 [95% CI: 3.31, 20.48; p <0.0001]) but not in those with LBBB (OR of 0.60 [95% CI: 0.09, 4.01; p=0.5950]). Conclusions: Our findings confirm STE after OHCA is strongly associated with coronary occlusion amenable to PCI, but cast doubt on using new LBBB as an STE equivalent. These findings mirror recent reports about LBBB in non-OHCA patients.