036 COMPARISON OF CLINICAL CHARACTERISTICS AND OUTCOMES IN PATIENTS WITH LEFT BUNDLE BRANCH BLOCK VERSUS ST ELEVATION MYOCARDIAL INFARCTION REFERRED FOR PRIMARY PCI

• Published in: Heart (British Cardiac Society) Vol. 99; no. suppl 2; pp. A26 - A27
• Main Authors: Mannakkara, N N, Mozid, A M, Showkathali, R, Sheikh, A S, Tang, K H, Robinson, N M, Kabir, A M, Jagathesan, R O, Sayer, J W, Kelly, P A, Aggarwal, R K, Clesham, G J, Davies, J R, Gamma, R A
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Cardiovascular Society 01.05.2013; BMJ Publishing Group LTD
• ISSN: 1355-6037; 1468-201X
• DOI: 10.1136/heartjnl-2013-304019.36

Aims Current national and international guidelines continue to recommend activation of the primary percutaneous coronary intervention (PPCI) pathway in patients presenting with chest pain and presumed new-onset left bundle branch block (LBBB). Previous research has suggested that a lower proportion of patients presenting with LBBB require emergency intervention. In this study we have compared baseline clinical characteristics, angiographic findings and subsequent outcome in patients with LBBB versus ST-elevation myocardial infarction (STEMI) referred to our tertiary centre for PPCI. Table 1 Clinical characteristics Risk factor LBBB (n=155) STEMI (n=1720) p Value Mean age (±SD) 70.35±11.9 64.95±14.0 <0.0001 Male 87 (56.1%) 1228 (71.4%) <0.0001 Hypertension 70 (45.2%) 668 (38.8%) 0.127 Hypercholesterolaemia 52 (33.5%) 512 (29.8%) 0.327 Diabetes mellitus 26 (16.8%) 201 (11.7%) 0.063 Previous MI 36 (23.2%) 205 (11.9%) <0.0001 Previous CABG 10 (6.5%) 44 (2.6%) 0.005 Methods All patients accepted for PPCI within the period of September 2009 to November 2011 were included in the study. Patient data obtained from our Cardiac Services Database System (Phillips CVIS) were analysed and angiographic images reviewed on our Cardiac Image Database (McKesson Horizon). Mortality data were gathered from the Summary Care Record (SCR) database. Statistical comparisons of continuous variables were made by an unpaired t test. Categorical variables were compared using the χ2 test. A p value of <0.05 was considered to indicate statistical significance. Results During the study period, 1875 patients were referred for PPCI of whom 155 (8.3%) had LBBB. Compared with STEMI, patients with LBBB were significantly older, more likely to be female and have prior history of MI and CABG (table 1). Patients with LBBB had similar door-to-balloon (DTB) and call-to-balloon (CTB) times. PCI was performed in 40 (26%) patients with LBBB although an acutely occluded culprit vessel was found in only 19 (12.2%) patients (table 2). Furthermore, 85 (54.8%) patients had non-flow limiting coronary artery disease and of those with significant disease 12 (7.7%) patients required CABG (figure 1). Overall, an acute coronary syndrome (defined as ischaemic chest pain with positive troponin) was confirmed in only 67 (43.2%) of patients presenting with LBBB. 30-day mortality was similar between LBBB and STEMI patients (table 2). However, during a mean follow-up period of 2.1 years, overall mortality was significantly higher in the LBBB group compared to STEMI (HR 2.01, 95% CI 1.26 to 3.20) (figure 2). Conclusions Our study shows that, in contrast to STEMI, only a small proportion of patients presenting with chest pain and LBBB had an acutely occluded coronary artery. Although short-term mortality was similar between the two groups, long-term outcome was significantly worse in patients with LBBB. Further work is needed to identify those patients presenting with LBBB who are most likely to have an acute coronary occlusion, in order to facilitate the appropriate use of emergency coronary angiography and PPCI. Table 2 Clinical outcomes Outcome LBBB (n=155) STEMI (n=1720) p Value Door-to-balloon time (min±SD) 40±17 37±25 0.710 Call-to-balloon time (min±SD) 128±36 120±47 0.263 Acute coronary occlusion 19 (12.2%) 1096 (63%) <0.0001 PCI performed 40 (26%) 1430 (83%) <0.0001 30-day mortality (all) 8 (5.2%) 120 (6.9%) 0.391 30-day mortality (PCI) 3/40 (7.5%) 94/1430 (6.6%) 0.825 30-day mortality (no PCI) 5/115 (4.3%) 26/290 (8.9%) 0.115 Overall mortality 32 (27.8%) 240 (13.9%) 0.023 Figure 1 Clinical outcome in patients with LBBB. Figure 2 Kaplan-Meier comparison of survival curves.