https://doi.org/10.1007/s00392-025-02625-4
1Herzzentrum der Universität zu Köln Klinik für Kardiologie, Angiologie, Pneumologie und Internistische Intensivmedizin Köln, Deutschland; 2Universitätsmedizin der Johannes Gutenberg-Universität Mainz Zentrum für Kardiologie Mainz, Deutschland; 3Herzzentrum der Universität zu Köln Klinik III für Innere Medizin Köln, Deutschland; 4Universitätsklinikum Köln Herzzentrum - Kardiologie Köln, Deutschland; 5Krankenhaus der Augustinerinnen, Akademisches Lehrkrankenhaus Klinik für Kardiologie und internistische Intensivmedizin Köln, Deutschland; 6St. Antonius Krankenhaus Medizinische Klinik & Kardio-Diabetes-Zentrum Köln Köln, Deutschland; 7Ev. Krankenhaus Köln-Kalk Kardiologie & Internistische Intensivmedizin Köln, Deutschland; 8Krankenhaus Porz am Rhein gGmbH Klinik für Kardiologie, Elektrophysiologie u. Rhythmologie Köln, Deutschland; 9Cellitinnen Krankenhaus St. Vinzenz Köln Innere Medizin III - Kardiologie Köln, Deutschland; 10Kliniken der Stadt Köln gGmbH, Krankenhaus Merheim Medizinische Klinik II Köln, Deutschland; 11Universitätsklinikum Köln Köln, Deutschland; 12Klinikum Leverkusen Klinik für Akut- und Notfallmedizin Leverkusen, Deutschland; 13Universitätsklinikum Köln Klinik III für Kardiologie, Angiologie, Pneumologie und Internistische Intensivmedizin Köln, Deutschland
Background: Triage of patients with suspected acute myocardial infarction (AMI) and left bundle branch block (LBBB) is a frequent dilemma. LBBB-AMI patients less often have acute coronary occlusion compared to ST-segment elevation myocardial infarction (STEMI). Nonetheless, the European guideline authors recommend a pragmatic immediate invasive - “STEMI-like” - strategy in the presence of ischemic symptoms in suspected LBBB-AMI. This results in unnecessary catheterization laboratory activations and potential harm.
Clinical identification of LBBB-AMI patients without necessity of immediate invasive management is crucial. Those without evidence of hemodynamic, electric or respiratory instability – so called “stable” - might be a group of interest.
Objective: Stable patients with suspected LBBB-AMI and ischemic symptoms were analyzed to assess outcomes compared to matched ST-segment elevation myocardial infarction (STEMI) patients, and to evaluate effectiveness of the pragmatic triage strategy.
Methods: All stable patients referred for intended primary percutaneous coronary intervention (PCI) in a multicentric STEMI network between January 2005 and December 2020 were analyzed. They were stratified according to LBBB or STEMI ECG pattern. Patients with pulmonary oedema or sustained ventricular arrhythmia and those requiring vasopressors, intubation or resuscitation were excluded. Propensity score matching (PSM) was performed using a 1:3 ratio. Odds ratios (OR) and 95% confidence intervals were calculated using a conditional logistic regression model for categorial outcomes and a mixed linear regression model for continuous variables.
The need for emergency PCI was defined as the presence of a culprit lesion in combination with myocardial injury (peak creatine kinase >2 upper limit of normal).
Results: Overall, 344 (7.5%) patients with LBBB-AMI and 4219 (92.5%) with STEMI were registered (see A). After exclusion of unstable patients and following PSM, 744 patients (n=187 LBBB-AMI, n=557 STEMI) remained for adjusted analysis.
Treatment outcomes are summarized in B. In detail, in-hospital mortality was comparable between LBBB-AMI and STEMI (6.5 vs. 5.4%, p=0.197). Cardiogenic shock was present in 6.9% and 4.1% of patients (p=0.078). A culprit lesion was diagnosed in 78.4% of LBBB-AMI and 86.7% of STEMI patients during coronary angiography. Corresponding rates for stent implantation were 71.3% and 79.8% (p=0.03). Following PCI, 21.8% of LBBB-AMI and 14.3% of STEMI patients had slow-flow or no reflow in the culprit vessel (p=0.007).
In the final adjudication on the need of timely PCI, 56.4% of stable LBBB-AMI patients in the matched cohort had a culprit lesion in combination with myocardial injury. Retrospectively these were appropriately triaged (see C). The corresponding rate was 72.0% in STEMI patients (p<0.001).
Conclusion: Six of ten stable suspected LBBB-AMI patients triaged within a STEMI network required timely PCI – defined by the presence of a culprit lesion and acute myocardial injury. This still supports routine emergency coronary angiography in the presence of ischemic symptoms in these patients. Notably, three of ten stable STEMI patients did not meet criteria for emergency PCI, retrospectively. A more selective triage is warranted for both groups.
Moreover, future prospective trials should address the impact of the worse angiographic outcome following PCI in LBBB-AMI on mid- and long-term prognosis.