Influence of atrial fibrillation on oxygen uptake and exercise tolerance in cardiovascular patients; close association with heart rate response

Abstract

To investigate the effect of atrial fibrillation (AF) on the oxygen uptake and exercise tolerance, we evaluated cardiopulmonary exercise test (CPET) data in AF patients and heart rate-matched controls with sinus rhythm (cSR) who received ambulatory cardiac rehabilitation. We compared CPET data between AF (N = 27) and cSR patients (N = 106) who had similar HRs at rest and the peak points. Oxygen uptake (VO2)/kg and relative O2 pulse (ml/bpm/kg) at rest and the anaerobic threshold (AT) level was not different between AF and cSR patients, but these parameters above the AT level were significantly lower in AF than in cSR patients. Concisely the parallel increase of relative O2 pulse during exercise was blunted above the respiratory compensation level (Rc) in the AF group. In addition, the HR change during exercise was inversely correlated with the increase of the O2 pulse above the AT level and this inverse correlation was more prominent in AF patients than in cSR patients. In conclusion, the value of VO2 was significantly lower above the AT level in AF patients. The trend of O2 pulse above the AT level was strongly associated with the detrimental response of HR increase and the response was markedly exaggerated in the AF patients.

Clinical impact of newly developed atrial fibrillation complicated with longstanding ventricular fibrillation during left ventricular assist device support: A case report

“…Right atrial contraction contributes to approximately 15-30% of the RV stroke volume; however, its contribution differs across patients with heart failure. The development of AF generally decreases the cardiac output [7], whereas the derangement of AF in cardiac output is somewhat counteracted under LVAD support. Enriquez et al have demonstrated no significant differences in peak VO 2 during a cardiopulmonary exercise test between patients with and without AF under LVAD Fig.…”

Early improvement of daily physical activity after catheter ablation for atrial fibrillation in an accelerometer assessment: A prospective pilot study

“…AF itself is a reason for decreased physical activity. Increased heart rate at rest causing a reduction of stroke volume and loss of atrial function can be considered to be associated with decreased physical function in patients with AF (Pardaens et al, 1997; Takano et al., 2019). Furthermore, the uncomfortable symptoms related to AF due to irregularity or tachycardia rhythm may also limit their daily activity and physical function (Nabauer et al., 2009).…”

“…These unfavorable symptoms can restrict physical activity and quality of life in the patients (Dorian et al., 2000). Patients with AF exhibited decreased oxygen uptake and exercise tolerance in a cardiopulmonary exercise test and treadmill test than in patients with sinus rhythm (Singh et al., 2006; Takano et al., 2019). Excessive increase in heart rate response to exercise, hemodynamical impairment of rhythm regularity, and loss of atrial contraction could be possible explanations for the lower level of physical activity in patients with AF.…”

Clinical importance of respiratory muscle fatigue in patients with cardiovascular disease

“…peak respiratory exchange ratio was over 1.1. [ 12 ] For all the subjects, expired gases were continuously measured on a breath-by-breath basis.…”