Heart rate recovery improvement in patients following acute myocardial infarction: exercise training, β-blocker therapy or both
Heart rate recovery (HRR) is a strong mortality predictor. Exercise training (ET) and β-blocker therapy have significant impact on the HRR of patients following myocardial infarction (MI). However, the combination of ET and β-blocker therapy, as well as its effectiveness in patients with a more compromised HRR (≤12 bpm), has been under-studied. Male patients (n = 64) post-MI were divided: Training + β-blocker (n = 19), Training (n = 15), β-blocker (n = 11) and Control (n = 19). Participants performed an ergometric test before and after 3 months of intervention. HRR was obtained during 5 min of recovery and corrected by the cardiac reserve (HRRcorrCR). Compared to pre-intervention, HRRcorrCR was significantly increased during the 1st and 2nd minutes of recovery in the Training + β-blocker group (70·5% and 37·5%, respectively; P<0·05). A significant improvement, lasting from the 1st to the 4th minute of recovery, was also observed in the Training group (47%, 50%, 25% and 8·7%, respectively; P<0·05). In contrast, the β-blocker group showed a reduction in HRRcorrCR during the 2nd and 3rd minutes of recovery (−21·2% and −16·3%, respectively; P<0·05). In addition, interventions involving ET (Training + βb, Training) were significantly more effective in patients with a pre-intervention HRR ≤ 12 bpm than for patients with HRR > 12 bpm. Combination of β-blocker therapy with ET does not compromise the effect of training and instead promotes HRR and aerobic capacity improvement. In addition, this combination is particularly beneficial for individuals presenting with a more compromised HRR. However, chronic administration of β-blocker therapy alone did not promote improvement in HRR or aerobic capacity.