Abstract
BACKGROUND: Exercise Oscillatory Ventilation (EOV) and a steep ventilatory efficiency (VE/VCO2) slope are features of ventilatory inefficiency on cardiopulmonary exercise testing (CPET), both associated with poor prognosis in patients with heart failure (HF). The prevalence in patients with co-existent atrial fibrillation (AF) and the impact of catheter ablation (CA) is unknown. OBJECTIVES: To characterize ventilatory inefficiency in patients with persistent AF and Left Ventricular Systolic Dysfunction (LVSD) and assess the impact of CA. METHODS: Patients with persistent AF and Left Ventricular Ejection Fraction (LVEF) < 50% undergoing first-time CA were prospectively enrolled. Echocardiography and CPET were performed at baseline and 6 months post-CA. EOV was defined using the Kremser-Corrà criteria, and VE/VCO2 slope gradient > 30 was considered abnormal. RESULTS: A total of 53 participants were enrolled (mean LVEF of 34 ± 9%). A total of 10 (19.2%) exhibited EOV at baseline. These patients had larger indexed left atrial (41.6 ± 13.1 mL/m(2) vs. 33.3 ± 9.3 mL/m(2), p = 0.03) and ventricular volumes [65.7 mL/m(2) (57.1, 89.0) vs. 46.7 mL/m(2) (39.8, 61.4), p = 0.03]. The partial pressure of end-tidal carbon dioxide (P(ET)CO(2)) at peak exercise increased (33.7 ± 6.1 mmHg to 41.2 ± 5.8 mmHg, p < 0.001) and correlated with improvement in HF symptoms (p = -0.003) and objective HF markers. A total of 25 (48.1%) had an abnormal VE/VCO2 gradient. The EOV pattern resolved in eight (80%) participants due to a reduction in EOV burden (71.1 ± 11.9% vs. 48.8 ± 14.8%, p = 0.006) and the component amplitude of minute ventilation cycles (2.6 L/min (2.5,3.2) vs 2.2 L/min (1.8,2.6), p = 0.028). Fewer patients had an abnormal VE/VCO2 gradient after CA [25 (48.1%) vs. 16 (34.0%), p = 0.004]. CONCLUSIONS: Ventilatory inefficiency is common in patients with AF and LVSD. CA improves both EOV and VE/VCO2 in AF-induced cardiomyopathy. Improvement in P(ET)CO(2) is also seen and correlates with HF symptom burden.