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The legend of intravenous beta-blockers post myocardial infarction in the 21st century

2005; Elsevier BV; Volume: 2; Issue: 5 Linguagem: Inglês

10.1016/j.hrthm.2005.02.365

1556-3871

B. Nuta, S. Burtchaell, M A James,

Cardiac pacing and defibrillation studies

Over the last decade the benefit of intravenous beta-blockers in post MI patients has been recognised primarily due to their anti-arrhythmic effect. However, other treatments such as statins, ACE inhibitors, clopidogrel and fractionated heparin may have obscured the benefits of IV beta-blockade. We have prospectively analysed the effects of IV beta-blockers in 500 consecutive post MI patients admitted to our CCU between March 2000 and April 2002. Mean follow-up was 23 months(16-30). A total of 129 patients (25.8%) died, including in-hospital deaths.Although IV beta-blockers were recommended by the hospital protocol, in practice only 121 patients (24.2%) received this treatment. The total mortality amongst the beta-blocker group was significantly lower at 13.2%(16 patients) compared to 29.8% (113 patients), p<0.001. VF was lower in the beta-blocker group although this was not significant(5.8% vs 8.7%), but the incidence of cardiac arrest due to any arrhythmia was significantly lower at 7.4% in the beta-blocker group compared to 14.7% in the other group, p=0.03. Of interest, the chance of surviving the arrest was significantly higher at 66.6% in patients treated with IV beta-blockers compared to the non beta-blocker group at 30.3%, p=0.003. IV beta blockers decreased the incidence of AF during the index admission (9.9% compared to 25.3%, p=0.003) and it is generally accepted that AF is associated with increased mortality.Although in most cases where beta-blockers were avoided this was due to contraindications such as airways disease, severe LV disease was not a discriminatory factor and could not account for the observed differences in outcome between the 2 groups. LV function was similar in both groups, with 37.6% of the beta-blocker group patients demonstrating a low EF of less than 35%, compared to 36.6% of the other group, whilst there was a trend in slightly larger infarcts in the beta-blocker group as measured by the mean CK (2119 vs 1768). These results emphasise the beneficial antiarrhythmic effects of intravenous beta-blockers in the acute MI and should be used more unless there are specific contraindications in this setting.