Myocardial infarction at the background of left bundle branch block in the record-3 registry-management and prognosis

Abstract

Purpose. To study prognostic value of left bundle brunch block (LBBB) in patients with verified myocardial infarction in real clinical practice. Material ana methods. This analysis has been based on data from the RECORD-3 registry. This registry enrolled consecutive patients hospitalized in participating centers with suspected acute coronary syndrome. Among 2368 included patients 91 (3.84%) had LBBB on admission ECG ("new" in 25 [27.4%], "old" in 28 [30.8%]), and of "undetermined duration" in 38 [41.8%]). Myocardial infarction (Ml) was verified in 871 patients, 48 of them (5.5%) had LBBB. Results. MI patients with compared with those without LBBB were significantly older (70.5 vs. 64 years, p=0.01l), more often had history of MI and cerebral catastrophes, effort angina, symptoms of chronic heart failure and renal pathology. Patients with LBBB twice more often complained of dyspnea/suffocation and had significantly lower mean ejection fraction (44 vs 52%, p=0.00l). At prehospital stage, they less often received aspirin, Clopidogrel, ß-adrenoblockers. Patients with LBBB more often required artificial pulmonary ventilation (APV) and temporary cardiac pacing, and were less often subjected to reperfusion strategy (52.1 vs. 85%, p<0.00l). Coronary angiography was carried out in 37.5 and 64.1% (p<0.00l), primary percutaneous coronary intervention was performed in 25 and 46.4% (p=0.0004) of patients in groups with and without LBBB, respectively. Patients with LBBB had more than 2 times higher risk of death during hospitalization (14.6 vs. 6.3%, p<0.027), without significant difference between "new" and "old" block. Multifactorial regression analysis revealed the following independent factors of unfavorable prognosis: necessity of APV, requirement in pressor drugs during first 24 hours and thereafter, heart rate on day two. Conclusion. High hospital mortality of patients with MI with LBBB was due to not simply the presence of LBBB on ECG but older age, severity of condition at admission, and high number of concomitant diseases.