So I am Borja Ibanez. I'm a Cardiologist from Madrid, Spain, Scientific Director of the Spanish National Centre for Cardiovascular Research, and Interventional Cardiologist at the University Hospital Fundación Jiménez Díaz. And I'm going to be presenting a summary of our REBOOT-CNIC trials on the role of beta blockers after MI.

What is the background behind the REBOOT-CNIC trial?

We have been treating our patients after myocardial infarction with beta blockers for more than four decades. And this is based on trials which were performed in the early 80s showing a clear mortality reduction for post-MI patients who were treated with beta blockers.

However, treatment for MI at that time was very different from today. Patients were not reperfused, there was no invasive management, of course they didn't have any complete revascularisation, and there were no adjuvant therapies like dual antiplatelet therapy or statins. Since then, treatment for MI has dramatically changed, and in fact, all these things that we have discussed have been implemented.

So there is a question whether, according to current standards, beta blockers that were mainly developed to reduce malignant arrhythmias or heart failure are going to help in the population treated according to today's standards. So these were the rationale for us to design and execute the REBOOT-CNIC trial.

What was the study design, patient population, and key outcomes?

REBOOT was a pragmatic trial meant to be as close as possible to real life. And we enrolled patients after a myocardial infarction, both ST elevation and non-ST elevation MI, with an ejection fraction above 40% and with an invasive management during admission.

So at discharge they were randomised to beta blockers yes or beta blockers no. And according to a pragmatic design, the type of beta blocker and the dose of beta blocker was decided by the [illegible] physician. The primary outcome of our trial was the composite of all-cause death, reinfarction or heart failure hospitalisation, and patients have been followed up for a median time of almost four years, 3.7 years.

So we have observed that there were no differences at all in the primary outcome (death, MI or heart failure hospitalisations) and there were no differences at all in any of the secondary outcomes, which were all cause death, cardiac death, heart failure, infarction and so on.

So in summary, we have observed that there were no benefit of beta blockers in this population. However, it's important to remark that there was a subgroup of patients which was pre specified, which were patients with mildly reduced ejection fraction and ejection fraction between 40 and 50, in which we found that there was a trend towards benefit of beta blockers.

And this is why we team up with another trial released during the congress, which is the BETAMI-DANBLOCK, in a similar population and we pulled together patients with mildly reduced ejection fraction for both trials. And in fact, we have done and presented a meta-analysis showing that this is the only subgroup that benefit from beta blockers.

What are the take-home messages for practice and the next steps?

For clinical practice, it's very important to give very clear messages. So I think that it is clear that patients who have an ejection fraction after MI less than 50%, they still benefit from beta blockers and they should receive beta blockers.

As for patients who have an ejection fraction of 50% or more, there is strong evidence against the benefit of beta blockers. And I'm telling that there is strong evidence because our trial was neutral, no benefit above 50%. Last year it was published the [illegible] trial, again no benefit in ejection fracture above 50%, but in the BETAMI-DANBLOCK there was a sign towards a reduction in reinfarction in this population.

So therefore, what is going to come next? We are planning to perform a new meta-analysis for patients only with preserved ejection fraction and this will be the final answer. My gut feeling is that beta blockers are not going to benefit at all in patients above 50%, but still we have to finalise this meta-analysis and hopefully this will come out in couple of months from now.