Exercise hemodynamics during different modes of exercise in patients with definitive and non-definitive arrhythmogenic cardiomyopathy

Abstract Background Scarce prospective data exist on exercise response to low or moderate intensity endurance or resistance exercise in definitive and non-definitive arrhythmogenic cardiomyopathy (ACM). Proarrhythmogenic effects may be triggered by compromised exercise hemodynamics. Knowledge of acute exercise response to guideline-adherent and prolonged low to moderate intensity exercise could improve tailored exercise prescriptions in these patients. Purpose To invasively assess individual hemodynamic response of patients with definitive and non-definitive ACM to low or moderate intensity endurance, isometric and dynamic resistance exercise. Methods We included 20 patients fulfilling criteria for borderline and non-definitive ACM with preserved left ventricular ejection fraction (≥50%) to undergo invasive exercise right heart catheterization during isometric handgrip exercise (one minute at 70% of the one repetition maximum, 1-RPM) and dynamic biceps curls (at 70% of 1 RPM for one minute) as well as low to moderate intensity endurance exercise. Endurance exercise was performed for 20 and 40 minutes at a continuous workload of the first ventilatory threshold during supine bicycle ergometry. Troponin T levels were assessed at the end of each exercise modality. Between each exercise modality a five-minute break was performed. Results Thirteen non-sedentary patients with definitive (mean age 42.8 ± 8.8 years) and seven with non-definitive ACM (mean age 42.3± 14.3 years, p=0.985) were included. The majority (n=14) of patients consisting of plakophilin-2 mutation carriers. Right ventricular work (RVWi, 1.10±0.35kg/m2/min vs. 0.76±0.32kg/m2/min, p.001, Figure 1A) and power output (RVCPOi, 0.18±0.06 W/m2 vs. 0.13±0.05 W/m2, p.001,Figure 1B) index, mean pulmonary artery pressure (16.6±4.4mmHg vs. 14.0±4.8mmHg, p=0.02, Figure 1C) as well as cardiac index (CI, 4.9±1.1L/min/m2 vs. 4.0±1.1L/min/m2, p.001, Figure 1D) were higher during endurance compared to resistance exercise. Isometric handgrip yielded higher pulmonary capillary wedge pressures (PAWP) compared to other modalities (p.001, Figure 2A). Troponin T levels increased steadily across exercise modalities (Figure 2B, p.001). Hemodynamic variables did not differ between 20 and 40min of low to moderate endurance exercise. In addition, no differences were found between definitive and non-definitive ACM across all tested variables. Conclusions No hemodynamic differences between 20 and 40 minutes of endurance exercise were observed, which may suggest that extended low to moderate intensity endurance exercise could be feasible in selected ACM patients. In addition, dynamic rather than isometric resistance exercise may be preferred due to lower hemodynamic strain. The clinical significance of the low, but steady increase in troponin during prolonged exercise warrants further investigation.Figure 1For image description, please refer to the figure legend and surrounding text. Figure 2For image description, please refer to the figure legend and surrounding text.