What is the clinical evidence from this study?

Study design: Observational. Population: Patients taking beta-blockers referred for cardiopulmonary exercise testing (n=140). Intervention: Chronotropic incompetence (chronotropic index ≤ 62%) vs. No chronotropic incompetence. Primary outcome: Exercise capacity (peak oxygen uptake, mL/kg/min) (p=<0.001).

What question did this study set out to answer?

To assess the effect of chronotropic incompetence on aerobic exercise capacity in patients undergoing beta-blocker therapy.

July 17, 2020Open Access

Chronotropic incompetence in patients taking beta-blockers was associated with significantly lower exercise capacity (peak VO2 18.3 vs. 24.0 mL/kg/min) compared to those without it.

Q: What are the key findings of this study?

Q: What question did this study set out to answer?

To assess the effect of chronotropic incompetence on aerobic exercise capacity in patients undergoing beta-blocker therapy.

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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

Patients with chronotropic incompetence vs without chronotropic incompetence

Design

Retrospective cohort study

Key result

Chronotropic incompetence in patients taking beta-blockers was associated with significantly lower exercise capacity (peak VO2 18.3 vs. 24.0 mL/kg/min) compared to those without it.

Authors

MTMaciej Tysarowski KSKrzysztof Smarż BZBeata Zaborska

Discussion

Member takes

Overview

Chronotropic incompetence may limit exercise capacity on beta-blockers; hypothesis-generating for prospective trials of rate optimization.

Key Points

To assess the effect of chronotropic incompetence on aerobic exercise capacity in patients undergoing beta-blocker therapy.
Retrospectively analyzed N=140 consecutive patients taking beta-blockers referred for cardiopulmonary exercise testing.
Defined chronotropic incompetence as a chronotropic index ≤ 62%, calculated from resting, peak, and maximum predicted heart rates, and measured exercise capacity as peak oxygen uptake.
Chronotropic incompetence occurred in 80.7% (113/140) of patients and was associated with significantly lower peak oxygen uptake compared to preserved chronotropic response (18.3 ± 5.7 vs. 24.0 ± 5.3 mL/kg/min, p < 0.001).
Multivariate analysis showed exercise capacity correlated positively with chronotropic index (β = 0.14, p < 0.001) and male sex (β = 5.12, p < 0.001), negatively with age (β = -0.17, p < 0.001) and heart failure (β = -3.35, p < 0.001), with no association observed for beta-blocker dose.

Study Design

Type

Observational (n=140)

Multicenter

Structured PICO

Does chronotropic incompetence reduce exercise capacity in patients taking beta-blockers?

Population

140 patients taking beta-blockers referred for cardiopulmonary exercise testing, with a mean age of 61 years and 27% female.

Exposure

Presence of chronotropic incompetence (defined as chronotropic index ≤ 62%)

Comparator

Absence of chronotropic incompetence (chronotropic index > 62%)

Outcome

Exercise capacity expressed as peak oxygen uptake (peak VO2; mL/kg/min) during symptom-limited cardiopulmonary exercise testingsurrogate

Main Result

Absolute Event Rate: 18.3% vs 24%

p-value: p=<0.001

In patients taking beta-blockers, chronotropic incompetence is a strong independent predictor of reduced exercise capacity, suggesting chronotropic index should be routinely incorporated into exercise stress testing.

Limitations

Single-center, observational, retrospective study
Relatively small group of mostly male patients
Included a diverse group of patients with and without heart failure
Brain natriuretic peptide plasma concentration values were not available
Data on physical activity status and quality of life were not available
single-center, observational, retrospective study
relatively small group of mostly male patients
diverse group of patients with and without heart failure
data on physical activity status and quality of life were not available

Cite This Study

Tysarowski et al. (2020) conducted an observational in Patients taking beta-blockers referred for cardiopulmonary exercise testing (n=140). Chronotropic incompetence (chronotropic index ≤ 62%) vs. No chronotropic incompetence was evaluated on Exercise capacity (peak oxygen uptake, mL/kg/min) (p=<0.001). Chronotropic incompetence in patients taking beta-blockers was associated with significantly lower exercise capacity (peak VO2 18.3 vs. 24.0 mL/kg/min) compared to those without it.

synapsesocial.com/papers/6a6e2f15febe604dd707e898 https://doi.org/10.1101/2020.07.15.20149005

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July 17, 2020Open Access

Chronotropic incompetence in patients taking beta-blockers was associated with significantly lower exercise capacity (peak VO2 18.3 vs. 24.0 mL/kg/min) compared to those without it.

View Full Paper

Ask AI

Bookmark

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

Patients with chronotropic incompetence vs without chronotropic incompetence

Design

Retrospective cohort study

Key result

Chronotropic incompetence in patients taking beta-blockers was associated with significantly lower exercise capacity (peak VO2 18.3 vs. 24.0 mL/kg/min) compared to those without it.

Authors

MTMaciej Tysarowski KSKrzysztof Smarż BZBeata Zaborska

Discussion

Member takes

Overview

Chronotropic incompetence may limit exercise capacity on beta-blockers; hypothesis-generating for prospective trials of rate optimization.

Key Points

To assess the effect of chronotropic incompetence on aerobic exercise capacity in patients undergoing beta-blocker therapy.
Retrospectively analyzed N=140 consecutive patients taking beta-blockers referred for cardiopulmonary exercise testing.
Defined chronotropic incompetence as a chronotropic index ≤ 62%, calculated from resting, peak, and maximum predicted heart rates, and measured exercise capacity as peak oxygen uptake.
Chronotropic incompetence occurred in 80.7% (113/140) of patients and was associated with significantly lower peak oxygen uptake compared to preserved chronotropic response (18.3 ± 5.7 vs. 24.0 ± 5.3 mL/kg/min, p < 0.001).
Multivariate analysis showed exercise capacity correlated positively with chronotropic index (β = 0.14, p < 0.001) and male sex (β = 5.12, p < 0.001), negatively with age (β = -0.17, p < 0.001) and heart failure (β = -3.35, p < 0.001), with no association observed for beta-blocker dose.

Study Design

Type

Observational (n=140)

Multicenter

Structured PICO

Does chronotropic incompetence reduce exercise capacity in patients taking beta-blockers?

Population

140 patients taking beta-blockers referred for cardiopulmonary exercise testing, with a mean age of 61 years and 27% female.

Exposure

Presence of chronotropic incompetence (defined as chronotropic index ≤ 62%)

Comparator

Absence of chronotropic incompetence (chronotropic index > 62%)

Outcome

Exercise capacity expressed as peak oxygen uptake (peak VO2; mL/kg/min) during symptom-limited cardiopulmonary exercise testingsurrogate

Main Result

Absolute Event Rate: 18.3% vs 24%

p-value: p=<0.001

Limitations

Single-center, observational, retrospective study
Relatively small group of mostly male patients
Included a diverse group of patients with and without heart failure
Brain natriuretic peptide plasma concentration values were not available
Data on physical activity status and quality of life were not available
single-center, observational, retrospective study
relatively small group of mostly male patients
diverse group of patients with and without heart failure
data on physical activity status and quality of life were not available

Cite This Study

synapsesocial.com/papers/6a6e2f15febe604dd707e898 https://doi.org/10.1101/2020.07.15.20149005

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