SPC365

Chronotropic incompetence - still on time to make a difference ?

Session: Sessão de Posters 27 - Reabilitação cardíaca
Speaker: João Fernandes Pedro

Congress: CPC 2024
Topic: J. Preventive Cardiology
Theme: 29. Rehabilitation and Sports Cardiology
Subtheme: 29.2 Cardiovascular Rehabilitation
Session Type: Cartazes
FP Number: ---
Authors: João Fernandes Pedro; Ana Margarida Martins; Ana Beatriz Garcia; Catarina Gregório; Paula Sousa; Bruno Bento; Laura Santos; Maria Clarissa Rodrigues; Nelson Cunha; Inês Aguiar-Ricardo; Fausto J. Pinto; Ana Abreu

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Introduction: </strong></span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">Chronotropic incompetence (CI) is prevalent among individuals with cardiovascular disease. This phenomenon is frequently noted in cardio-pulmonary exercise testing (CPET) in patients participating in cardiac rehabilitation (CR) programs and often attributed to a combination of factors, notably the administration of beta-blockers (BB).&nbsp;</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">Recent evidence casted doubt over long term beta-blocker use on ischemic pts with preserved ejection fraction and some large scale trials as BETAMI and DANBLOCK are undergoing to clarify BB role in this specific population.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Aim:</strong></span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"> This study aimed to evaluate alterations in the chronotropic response observed in consecutive patients undergoing CPET and to explore the impacts of BB on this physiological parameter.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Methods:</strong></span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"> We conducted a single centre, prospective study of consecutive patients who were submitted to CPET. CI was defined as chronotropic index (max HR-resting HR/predicted HR-resting HR)&lt;0,8 and chronotropic deficit ((predicted HR-max HR)/predicted HR)&lt;0,2.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Results: </strong></span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">446 patients were analysed (80,5% males; mean age of 60</span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">11; 83,4% ischemic patients). In our population, 95,8% had CI assessed during the CPET. 79% (n= 347) were under BB therapy, from which 68.3% (n=222) without heart failure with reduced ejection fraction. Most pts used either low (bisoprolol 2,5mg or equivalent) or intermediate (bisoprolol 5mg or equivalent) BB dose (30% and 28,7% respectively). During a mean follow-up of 2,5&plusmn;1,8 years, most pts (60,7%) maintained drug dosage, 8,7% increased and only 4,9% stopped.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">The use of BB was associated with CI (p=0.002), chronotropic index &lt; 80% (p&lt;0.001) and with chronotropic deficit &gt;20% (p=0.019). This was independent of the dosage of BB used. All of these pts were associated with a poorer exercise capacity as assessed by CPET and measured by VO2/kg (AUC:0.767 95% 0.67-0.87, p&lt;0.001) (Fig1), a known strong prognostic surrogate in this pts. There was however no significant difference regarding VO2/kg between pts with low or high BB dosage (mean 17.3 vs 17.8 mL/kg, p=0.513).</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000"><strong>Conclusion:&nbsp;</strong></span></span></span><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">As mentioned, recent meta-analysis questioned the benefit for long term beta-blocker use on ischemic pts with preserved ejection fraction; indeed most patients with preserved ejection were under beta-blocker therapy. In this subpopulation the rate of CI was similarly high and positively associated with BB use and lower values of oxygen consumption.</span></span></span></p>

<p style="text-align:justify"><span style="font-size:11pt"><span style="font-family:Calibri,sans-serif"><span style="color:#000000">CI is highly prevalent in our population and it is directly related to related to BB use. Its broad use in pts with coronary artery disease and preserved LVEF is being questioned and those who display CI may be ideal candidates to halt this therapeutic. </span></span></span></p>