Arrhythmias & electrophysiologyCohort study
Beta-Blockers and Exercise Performance in Children With Long QT Syndrome
- retrospective chart review
- linear mixed-effects model
- validation cohort
Authors' conclusion
In children with LQTS, we did not observe any relationship between higher nadolol doses and objective measures of effort (peak RER) or cardiopulmonary fitness (peak Vo2), despite a linear dose-response between nadolol dose and %PHR. These results suggest that treatment with nadolol for LQTS does not affect most patients' peak exercise performance. These data were validated in patients from an earlier era who had been prescribed atenolol.
Study context
- Population
- Children and young people with long QT syndrome (LQTS) taking beta-blockers who underwent treadmill cardiopulmonary exercise tests (CPETs)patients with LQTS, 220 CPETs evaluated
- Participants
- 93 children
- Exposure
- whether objective measures of cardiopulmonary fitness are influenced by beta-blocker dose in LQTS
Main finding
As reported in the abstract
%PHR decreased per 1 mg/kg/d increase in beta-blocker dose
13%
Observational data: associations, not effects.
Further findings
Measures of cardiopulmonary fitness (peak Vo2, peak respiratory exchange ratio (RER)) by nadolol dose
- No correlation between nadolol dose and measures of cardiopulmonary fitness; neither peak Vo2 nor peak RER was correlated with nadolol dose
Blood pressure at peak exertion by nadolol dose
- Decrease at peak exertion per 1 mg/kg increase in nadolol dose
- <9 mm Hg
- only mild blood pressure changes
Peak Vo2 and peak RER by atenolol dose
- Increased atenolol dose associated with stable peak Vo2 and peak RER
Age at first CPET
- Mean age at first CPET
- 12 ± 3.9 years
Original publication
Summarised from the published abstract; every number is checked against it