Why the study?
Chronotropic incompetence in patients taking beta-blockers is associated with poor prognosis, but its impact on exercise capacity remains unclear.
Does chronotropic incompetence reduce exercise capacity in patients taking beta-blockers?
Population
140 consecutive patients taking beta-blockers referred for cardiopulmonary exercise testing
Comparison
Chronotropic incompetence (CI ≤ 62%) vs CI > 62%
Design
Observational study
Key result
In patients taking beta-blockers, chronotropic incompetence was associated with significantly lower exercise capacity (18.3 vs. 24.0 mL/kg/min, p<0.001), regardless of beta-blocker dose.
Authors
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May warrant chronotropic assessment in beta-blocker patients with low exercise capacity; leaves open whether rate-targeted interventions improve tolerance.
Observational (n=140)
Does chronotropic incompetence reduce exercise capacity in patients taking beta-blockers?
Absolute Event Rate: 18.3% vs 24%
p-value: p=<0.001
Chronotropic incompetence is highly prevalent in patients taking beta-blockers and is independently associated with significantly reduced aerobic exercise capacity, regardless of beta-blocker dose.
Smarż et al. (2021) conducted an observational in Patients taking beta-blockers (n=140). Chronotropic incompetence (chronotropic index ≤ 62%) vs. No chronotropic incompetence was evaluated on Exercise capacity assessed as peak oxygen uptake (mL/kg/min) (p=<0.001). In patients taking beta-blockers, chronotropic incompetence was associated with significantly lower exercise capacity (18.3 vs. 24.0 mL/kg/min, p<0.001), regardless of beta-blocker dose.
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