SPC365

Chronotropism in CPET - Is incompetence limiting functional capacity?

Session: Posters (Sessão 6 - Écran 4) - Provas de Esforço e Reabilitação
Speaker: Ana Margarida Martins

Congress: CPC 2023
Topic: J. Preventive Cardiology
Theme: 29. Rehabilitation and Sports Cardiology
Subtheme: 29.2 Cardiovascular Rehabilitation
Session Type: Pósters Electrónicos
FP Number: ---
Authors: Ana Margarida Martins; Inês Ricardo; Pedro Alves da Silva; Joana Brito; Beatriz Valente Silva; Beatriz Garcia; Catarina Oliveira; Ana Abrantes; Miguel Raposo; Catarina Gregório; João Fonseca; Daniel Cazeiro; Bruno Bento; Rita Pinto; Nelson Cunha; Fausto J. Pinto; Ana Abreu

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000"><strong>Introduction: </strong></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">Chronotropic incompetence (CI) is defined as the inability to reach 80% of the expected reserve frequency for age during exertion, and it is frequently observed in stress tests of patients undergoing cardiac rehabilitation programs due to a combination of factors, that include the use of betablockers. Despite the theoretical basis for suggesting that a lower peak heart rate is related to a lower tolerance to exertion, we lack data correlating the CI to the maximal functional capacity, measured in cardiopulmonary tests as the maximal oxygen volume consumption (peak VO2).&nbsp;</span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000"><strong>Purpose: </strong></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">To correlate the impact of CI on functional capacity in patients (pts) undergoing a cardiac rehabilitation program and try to find the best value of chronotropic incompetence that could predict a worse prognosis.&nbsp;</span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000"><strong>Methods: </strong></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000"><span style="background-color:#ffffff">Prospective cohort study which included consecutive pts who were </span></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">submitted to cardiopulmonary exercise test (CPET) during 5 years in a tertiary hospital. Demographic data were analyzed and medication with beta blocker was registered. CI and </span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#212121"><span style="background-color:#ffffff">chronotropic index were calculated using the equation (220-age) for estimating maximum HR. </span></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">ROC curve method and Kaplan-Meier survival analysis were used to evaluate the cut-off efficacy.&nbsp;</span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000"><strong>Results: </strong></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">We analyzed 358 CPET and 74,1% patients (n=206) were under beta blocker therapy (7,6% high dose). The majority of the patients had CI (83.5%); CI was more frequent in pts under BB therapy although it didn&rsquo;t reach statistical significance (p=0.12). A low </span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#202124"><span style="background-color:#ffffff">maximum predicted heart rate (mpHR) was associated with low peak VO2 (p</span></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#202124">=0.02</span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#202124"><span style="background-color:#ffffff">) and a mpHR &lt; 61% was the best value to predict peak VO2&lt; 12</span></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">mL/(kg.min)</span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#202124"><span style="background-color:#ffffff"> (</span></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#222222">AUC=0.746, S=72; E=65</span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#202124"><span style="background-color:#ffffff">), despite not showing association with cardiovascular events.&nbsp;</span></span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#212121"><span style="background-color:#ffffff">Regarding the chronotropism, 96.9% of the pts were categorized as having a low chronotropic index . A CI &lt; 0.38 was the best cut-off to predict a peak VO2&lt;12 </span></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">mL/(kg.min) </span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#222222">(AUC=0.81, S=72, E 76) and it was a predictor of all-cause hospitalizations (p=0.015).&nbsp;</span></span></span></p>

<p style="text-align:justify"><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000"><strong>Conclusion: </strong></span></span></span><span style="font-size:12pt"><span style="font-family:Arial"><span style="color:#000000">This study shows a high percentage of pts with CI. A low chronotropic index was associated with low peak VO2 and was a predictor of all-cause hospitalizations.</span></span></span></p>