Beta-Blocker Continuation or Discontinuation After MI With Preserved Ejection Fraction
She's eighteen months out from an uncomplicated MI with a normal ejection fraction, and the newest trial evidence on long-term beta-blocker use doesn't clearly say she has to keep taking it.
L.F., a 52-year-old woman who teaches high school English, has run every fall marathon in her city for the past nine years, and the eighteen months since her heart attack are the first stretch in nearly a decade her training log doesn't look like the years before it. She had an NSTEMI eighteen months ago — a single blocked vessel, opened with a stent, no complications, no arrhythmia, an ejection fraction that has stayed normal at every echo since. She was started on metoprolol at the time of her MI, as has been standard practice for decades, and has taken it faithfully since.
What brings her back to clinic now isn't a cardiac symptom. It's fatigue she says has never fully lifted, and a marathon pace that hasn't recovered to where it was before her MI despite a training load she insists hasn't changed. She has, in her own methodical way, done her own reading, and arrived with printouts of two recent trials — REDUCE-AMI and ABYSS — both concerning beta-blockers after myocardial infarction in patients with preserved ejection fraction, the population she is now solidly in. The two are not asking the same question, though, and the difference turns out to matter for her. REDUCE-AMI tested whether to start a beta-blocker at all after an MI in patients with an ejection fraction of at least 50 percent. ABYSS tested something much closer to what she is proposing: whether a patient already established on one, a year or more past an uncomplicated MI, can safely come off it. She wants to stop the metoprolol, and she wants a real answer about whether the evidence still supports her staying on it, not a reflexive 'this is standard after a heart attack.'
In clinic, eighteen months out
Beta-blockers after MI have been standard for so long that stopping one can feel like abandoning proven therapy, but the evidence that standard was built on comes almost entirely from an era before routine reperfusion and modern secondary prevention. REDUCE-AMI, in a contemporary post-MI population with preserved EF, found no reduction in death or recurrent MI with beta-blocker use compared to no beta-blocker. I think her case is a reasonable one to actually apply that evidence to, rather than continue by default.
If her EF were reduced, I wouldn't be having this conversation — beta-blockers have clear, well-established mortality benefit in HFrEF regardless of the post-MI trials, and none of the newer evidence touches that population at all.
I'm less ready to extrapolate a single trial, even a well-conducted one, into stopping a therapy she's tolerated and stayed adherent to for eighteen months. And ABYSS, which is the more directly relevant of the two, did not come out the way she is hoping. It was designed to demonstrate that interruption was non-inferior to continuation, and it failed to demonstrate that: the composite of death, myocardial infarction, stroke, or cardiovascular hospitalization occurred in 23.8 percent of the interruption group against 21.1 percent of those who continued, a hazard ratio of 1.16, with the non-inferiority margin not met. Most of the excess sat in cardiovascular hospitalizations. Blood pressure and heart rate both rose after stopping, and quality of life — the very thing patients stop for — did not improve. I'd want to know her fatigue is actually attributable to the drug — not just correlated with the general post-MI recovery timeline, which can itself take longer than patients expect — before concluding stopping it is clearly the right move.
That's fair, and it's exactly why a real trial off the drug, not just her own conviction, is the right next step rather than either dismissing her fatigue or stopping the metoprolol purely because she's asked to.
The honest read of the two together is narrower than either extreme, and she deserves it stated plainly rather than softened. REDUCE-AMI says nobody was obliged to start her on one at her ejection fraction. ABYSS says that stopping an established beta-blocker was not shown to be as safe as continuing it, and that the quality-of-life payoff patients expect did not materialize at the group level. That is a genuine argument against routine discontinuation. What it is not is evidence that her fatigue is imaginary, or that a supervised, monitored trial off the drug is unreasonable in one patient — ABYSS measured group event rates, not whether a particular person's symptoms are drug-related. Given that she's symptomatic on the drug and motivated to stop, I'd taper the metoprolol over several weeks rather than stop it abruptly, and have her track her training pace and any palpitations during the taper. That gives us an actual answer specific to her, not just a trial-level probability applied to an individual.
Agreed: metoprolol tapered over four weeks rather than continued indefinitely or stopped abruptly, with ambulatory rhythm monitoring during the taper given her training intensity.
The taper completes to full discontinuation — justified by her own symptom response, which is what this trial off the drug was designed to test, rather than by the group-level trial data.
The taper stops at whatever dose controlled it, and metoprolol continues at that lower dose rather than resuming the original one by default.
She'll track her marathon-training pace through the taper as her own practical measure, alongside the clinical monitoring.