Objectives: To assess the relation between initial ECG findings, presence of risk factors, coronary angiography findings, and clinical outcomes in patients with acute myocardial infarction complicated by cardiogenic shock (CS).
Design: Data from a total of 5572 acute myocardial infarction patients admitted to the four tertiary hospitals during a period of 3 years were analyzed. CS on admission was present in 358 patients (6.4%). They were divided into four groups based on the admission ECG: ST-segment elevation (STEMI), ST-segment depression (STDMI), bundle branch block (BBBMI), and other ECG acute myocardial infarction.
Results: CS developed most frequently among BBBMI patients (in 12.1% of all BBBMIs, p < 0.001 vs. STEMI), followed by STEMI (6.7%), STDMI (4.4%), and other ECG acute myocardial infarction (2.3%). The risk of CS development was similar in patients with left bundle branch block (LBBB) (13.3%) and right bundle branch block (RBBB) (11.2%). The one-year mortality was highest among RBBBMI patients (66.7%, p < 0.001), followed by LBBBMI (48.6%), other ECG (47.1%), STEMI (41.7%), and STDMI patients (38.1%).
Conclusions: RBBB on admission ECG is associated with the highest risk of CS development, frequent left main coronary artery affection, and unsuccessful revascularization. It is also an independent predictor of one-year mortality.