Functional significance of atrial remodeling one year after myocardial infarction and its association with exercise performance and cardiac rehabilitation response
B Couto Viana, E Andrade, T Prata-Branco, L AlvesAbstract
Introduction
Atrial remodeling (AR) after acute myocardial infarction (AMI) may reflect the severity of ischemic injury or a chronic substrate linked to cardiovascular risk factors [1,2]. These persistent alterations are markers of increased hemodynamic load and reduced functional reserve [3]. Their influence on recovery during cardiac rehabilitation (CR) remains uncertain.
Purpose
To evaluate the association between AR one year after myocardial infarction and functional performance at the start and completion of a structured CR programme.
Methods
We studied 148 consecutive patients admitted with AMI (2013–2015) to a tertiary care center who subsequently completed a structured CR program initiated about one month after the event and lasting 8–12 weeks. AR was assessed at one year using the Atrial Remodeling Score (ARS) (0 = none; ≥1 = remodeling), integrating: 1) structural—left atrial volume index >34 mL/m²; 2) electrical—presence of at least two of the following abnormalities: P-wave duration ≥120 ms, P-wave terminal force in V1 ≤ –4000 µV·ms, or advanced interatrial block; and 3) biochemical—BNP in the upper tertile (≥56.1 pg/mL). Functional parameters at CR entry and completion were compared across ARS categories.
Results
Baseline characteristics included a mean age of 54.5 ± 10.0 years, 87% male, BMI 27.2 ± 3.2 kg/m², smoking in 74%, dyslipidemia in 64.9%, hypertension in 38.5%, diabetes in 15.6%, and STEMI in 69.6%. AR status was available for 134 patients, of whom 54 (40.3%) had AR. The mean number of CR sessions was 12.7 ± 4.0. At baseline, patients with AR showed lower MET performance (8.13 ± 2.32 vs. 8.75 ± 2.05; p=0.088) and consistent trends toward reduced energy expenditure (p=0.057), higher perceived exertion (p=0.073), and higher double product (p=0.090), indicating a less favorable initial hemodynamic profile. Improvement in METs during CR was significantly greater in the AR group (2.67 ± 1.40 vs. 2.10 ± 1.61; p=0.027). Final functional capacity remained comparable between groups despite persistent AR (10.79 ± 2.30 vs. 10.85 ± 2.15; p=0.97).
Conclusions
AR at one year may represent a structural remnant of more severe ischemic injury or a pre-existing substrate associated with a less favorable early hemodynamic response, identifying patients who begin CR in a more compromised functional state. Nevertheless, these individuals achieved similar—and proportionally greater, owing to a lower baseline—functional gains, indicating that AR does not limit the benefit derived from post-infarction rehabilitation.Graphical AbstractFor image description, please refer to the figure legend and surrounding text.