A novel method to classify exercise response in patients with cardiac amyloidosis - The RoMa classification.

Aims To evaluate the applicability of the RoMa classification in patients with transthyretin cardiac amyloidosis (ATTR-CM) and to assess its association with functional capacity and key cardiopulmonary exercise testing (CPET) parameters.Methods Consecutive adults (≥18 years) with confirmed ATTR-CM from two tertiary centres who completed symptom-limited maximal CPET were included. RoMa classes were defined using predefined cutoffs for percent-predicted peak heart rate (HRpp ≥80%) and percent-predicted peak O2-pulse (O2pp ≥100%): RoMa I (high HRpp/high O2pp), RoMa II (high HRpp/low O2pp), RoMa III (low HRpp/high O2pp), and RoMa IV (low HRpp/low O2pp).Results We evaluated 165 patients (90% male; 77% wild-type ATTR, 20% variant ATTR). RoMa distribution was: RoMa I, n=33; RoMa II, n=73; RoMa III, n=30; and RoMa IV, n=29. Age did not differ across classes (p=0.36). Functional capacity declined across the RoMa strata: median 6MWD decreased from 420 m (RoMa I) to 313 m (RoMa IV) (overall p=0.009; p-trend=0.005), and NYHA class worsened (overall p=0.003; p-trend=0.005). Peak VO2 (% predicted) differed between groups (RoMa I: 93.0; II: 70.8; III: 75.2; IV: 51.9; overall p<0.001; p-trend<0.001), and ventilatory inefficiency increased (VE/VCO2 slope: 34; 39; 37; 47, respectively; overall p<0.001; p-trend<0.001; peak PetCO2: 30; 27; 29; 25, respectively; overall p<0.001; p-trend=0.003). 6MWD correlated with peak VO2 (r=0.626; p<0.001; n=131) and inversely with VE/VCO2 slope (ρ=-0.484; p<0.001; n=130).Conclusion In ATTR-CM, application of the RoMa classification was feasible and identified distinct CPET-derived exercise-response profiles associated with functional impairment. These findings support RoMa as a promising exploratory framework for functional phenotyping in ATTR-CM.This study examined whether the RoMa classification, an exercise-test-based framework, can be used to describe different patterns of exercise limitation in patients with transthyretin cardiac amyloidosis.In 165 patients, RoMa classification was feasible and identified exercise-response profiles associated with differences in walking distance, symptoms, exercise capacity, and breathing efficiency during exercise.These findings support RoMa as an exploratory tool for functional phenotyping in transthyretin cardiac amyloidosis. Further studies are needed before it can be used for prognosis or clinical decision-making.