Abstract P121: Initial QRS Duration and Fatal Clinical Outcome in Patients With a Cardiogenic Shock Complicating ST-segment Elevation Myocardial Infarction
We evaluated initial QRS duration in the admission 12-lead electrocardiogram as a marker to identify the fatal clinical outcome in patients treated with emergent coronary angioplasty for a cardiogenic shock complicating anterior ST-segment elevation myocardial infarction (STEMI).
Methods A total of 38 consecutive Killip class IV patients (28 men, 72±12 years) with a first anterior STEMI were evaluated. Using median levels of initial QRS duration (120 msec), the patients were divided into wide and normal QRS groups (179±38 vs.102±16 msec, p=0.0001), and both groups were compared as to microvascular revascularization and in-hospital mortality. To evaluate myocardial tissue-level reperfusion, severe microvascular injury was defined by the presence of both angiographic myocardial blush grade 0/1 and less than 30 % resolution of ST-segment elevation after angioplasty.
Results In-hospital mortality was 84 % in the wide QRS group as compared with 26 % in the narrow QRS group (p=0.001). ST-segment in lead aVR showed higher in the wide QRS group than in the narrow QRS group (0.10±0.11 vs.0.06±0.07 mV, p=0.019). The sum of ST-segment elevation in leads I, aVL, and V1 to V6 on admission were not different between the two groups. Despite recanalization of culprit coronary lesions in all, the incidence of severe microvascular injury was significantly higher in the wide QRS group than in the narrow QRS group (78 vs. 42 %, p=0.020). Logistic regression analysis demonstrated initial QRS duration, but not ST-segment elevation in aVR, as the independent marker for in-hospital mortality (odds ratio, 6.85, p=0.005).
Conclusions We suggest initial QRS duration as the pivotal marker for subsequent occurrence of severe microvascular reperfusion injury and fatal clinical outcome in patients with a cardiogenic shock complicating STEMI.