Abstract 340 Characterization of left bundle branch block - acute myocardial infarction and comparison to STEMI: Analysis of the Cologne myocardial infarction registry

Background: ST-segment myocardial infarction (STEMI) is a life-threatening disease despite diagnostic algorithms and optimized treatment. Patients with suspected acute myocardial infarction (AMI) and left bundle branch block (LBBB) represent a challenging subgroup because LBBB-pattern might confound the diagnosis of STEMI. Patients with new or pre-existing LBBB and clinical signs of AMI are treated as STEMI patients with immediate transfer to percutaneous coronary intervention (PCI) in accordance with current guideline recommendations. This registry study aimed to characterize LBBB-AMI patients and to evaluate their treatment outcome in comparison to STEMI patients.

Methods: The Cologne infarction network is a metropolitan cooperation of sixteen hospitals and the emergency medical service (EMS). The registry study includes patients with either STEMI or suspected LBBB-AMI treated between September 2005 and April 2020. Data on pre- and in-hospital treatment were extracted and treatment intervals were calculated. Data were described using median (interquartile range) or percentages, and analyzed using Student’s t-test, Fisher’s exact test and Chi square test.

Results: 4494 patients were eligible for analysis. Of these, 4169 (92.8%) patients had STEMI and 325 (7.2%) had LBBB-AMI. 46.1 % of LBBB patients required resuscitation and 19.7% needed prolonged circulatory support by vasopressors during the preclinical course. Corresponding rates for STEMI group were 12.4% and 8.4% (p< 0.001). The concordance of pre- and in-hospital ECG diagnosis was 96.6% (LBBB) and 97.8% (STEMI, p=0.039). 98.2% (LBBB) and 99.2% (STEMI) of patients underwent coronary angiography. 79.1% of LBBB patients had an indication for PCI, of these 88.2% underwent stent-implantation. Corresponding rates for STEMI patients were 91.1% regarding PCI indication and 94.3% stent-implantation rate (p<0.001). Peri-procedural complication rate was 33.1% (LBBB) and 7.6% (STEMI, p<0.001). The median symptom-to-contact time was 80 minutes (20 - 300) for LBBB group and 90 minutes (30 - 300) for STEMI patients (p=0.016). The EMS needed 25 minutes (19 - 40, LBBB) and 20 minutes (15 - 28, STEMI) from arrival to departure (p<0.001). Contact-to-balloon time was 95.5 (75 - 129.3, LBBB) and 85 minutes (69 – 107.8, STEMI, p<0.001). Door-to-balloon time was 45 (34 - 70) minutes in LBBB- and 47 (33 - 68) minutes in STEMI patients (p=0.857). Median needle to balloon-time was 20 minutes in both groups (p=0.107). The median duration of hospitalization was 7 (LBBB) and 5 (STEMI) days (p<0.001).

Conclusion: The in-hospital treatment until revascularization was comparable between the groups, but the diagnosis of LBBB resulted in a significant treatment delay during the pre-hospital period despite quicker consultation of the EMS. This delay may reflect difficulties in diagnosis, but seems to be at least particularly caused by higher incidence of resuscitation in LBBB patients. On the one hand LBBB patients less often required PCI or stent revascularization. On the other hand they had a more complicated course resulting in a prolonged hospital stay. Future studies should evaluate tools to raise diagnostic specificity and identify those LBBB patients with the need for coronary angiography and percutaneous coronary intervention.

Clin Res Cardiol (2022). https://doi.org/10.1007/s00392-022-02002-5
Characterization of left bundle branch block - acute myocardial infarction and comparison to STEMI: Analysis of the Cologne myocardial infarction registry
S. Macherey-Meyer¹, M. Meertens¹, C. Adler¹, S. Braumann¹, H. Christ², S. Heyne³, S. F. Nießen³, T. Tichelbäcker¹, I. Ahrens⁴, F. M. Baer⁵, F. Eberhardt⁶, M. Horlitz⁷, J.-M. Sinning⁸, A. Meissner⁹, S. Baldus¹, S. Lee¹, für die Studiengruppe: KIM eV
¹Klinik für Kardiologie, Angiologie, Pneumologie und Internistische Intensivmedizin, Universität zu Köln, Medizinische Fakultät und Uniklinik, Köln; ²Universität zu Köln, Institut für Medizinische Statistik und Bioinformatik, Köln; ³Klinik III für Innere Medizin, Universität zu Köln, Medizinische Fakultät und Uniklinik Köln, Köln; ⁴Klinik für Kardiologie und internistische Intensivmedizin, Krankenhaus der Augustinerinnen, Akademisches Lehrkrankenhaus, Köln; ⁵Medizinische Klinik & Kardio-Diabetes-Zentrum Köln, St. Antonius Krankenhaus, Köln; ⁶Kardiologie & Internistische Intensivmedizin, Ev. Krankenhaus Köln-Kalk, Köln; ⁷Klinik für Kardiologie, Elektrophysiologie u. Rhythmologie, Krankenhaus Porz am Rhein gGmbH, Köln; ⁸Innere Medizin III - Kardiologie, St. Vinzenz-Hospital, Köln; ⁹Medizinische Klinik II, Kliniken der Stadt Köln gGmbH, Krankenhaus Merheim, Köln;
Background: ST-segment myocardial infarction (STEMI) is a life-threatening disease despite diagnostic algorithms and optimized treatment. Patients with suspected acute myocardial infarction (AMI) and left bundle branch block (LBBB) represent a challenging subgroup because LBBB-pattern might confound the diagnosis of STEMI. Patients with new or pre-existing LBBB and clinical signs of AMI are treated as STEMI patients with immediate transfer to percutaneous coronary intervention (PCI) in accordance with current guideline recommendations. This registry study aimed to characterize LBBB-AMI patients and to evaluate their treatment outcome in comparison to STEMI patients. Methods: The Cologne infarction network is a metropolitan cooperation of sixteen hospitals and the emergency medical service (EMS). The registry study includes patients with either STEMI or suspected LBBB-AMI treated between September 2005 and April 2020. Data on pre- and in-hospital treatment were extracted and treatment intervals were calculated. Data were described using median (interquartile range) or percentages, and analyzed using Student’s t-test, Fisher’s exact test and Chi square test. Results: 4494 patients were eligible for analysis. Of these, 4169 (92.8%) patients had STEMI and 325 (7.2%) had LBBB-AMI. 46.1 % of LBBB patients required resuscitation and 19.7% needed prolonged circulatory support by vasopressors during the preclinical course. Corresponding rates for STEMI group were 12.4% and 8.4% (p< 0.001). The concordance of pre- and in-hospital ECG diagnosis was 96.6% (LBBB) and 97.8% (STEMI, p=0.039). 98.2% (LBBB) and 99.2% (STEMI) of patients underwent coronary angiography. 79.1% of LBBB patients had an indication for PCI, of these 88.2% underwent stent-implantation. Corresponding rates for STEMI patients were 91.1% regarding PCI indication and 94.3% stent-implantation rate (p<0.001). Peri-procedural complication rate was 33.1% (LBBB) and 7.6% (STEMI, p<0.001). The median symptom-to-contact time was 80 minutes (20 - 300) for LBBB group and 90 minutes (30 - 300) for STEMI patients (p=0.016). The EMS needed 25 minutes (19 - 40, LBBB) and 20 minutes (15 - 28, STEMI) from arrival to departure (p<0.001). Contact-to-balloon time was 95.5 (75 - 129.3, LBBB) and 85 minutes (69 – 107.8, STEMI, p<0.001). Door-to-balloon time was 45 (34 - 70) minutes in LBBB- and 47 (33 - 68) minutes in STEMI patients (p=0.857). Median needle to balloon-time was 20 minutes in both groups (p=0.107). The median duration of hospitalization was 7 (LBBB) and 5 (STEMI) days (p<0.001). Conclusion: The in-hospital treatment until revascularization was comparable between the groups, but the diagnosis of LBBB resulted in a significant treatment delay during the pre-hospital period despite quicker consultation of the EMS. This delay may reflect difficulties in diagnosis, but seems to be at least particularly caused by higher incidence of resuscitation in LBBB patients. On the one hand LBBB patients less often required PCI or stent revascularization. On the other hand they had a more complicated course resulting in a prolonged hospital stay. Future studies should evaluate tools to raise diagnostic specificity and identify those LBBB patients with the need for coronary angiography and percutaneous coronary intervention.
https://dgk.org/kongress_programme/jt2022/aP2020.html