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

Figures

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  Fig. 1. Enrollment criteria and flow chart of the study. CR, cardiac rehabilitation; CPET, cardiopulmonary exercise test; AF, atrial fibrillation; SR, sinus rhythm; cSR, heart rate-matched controls with sinus rhythm; RER, respiratory exchange ratio; HR, heart rate; VO2, oxygen uptake; N, number of patients.

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  Fig. 2. Changes in the HR, VO2/kg, and relative O2 pulse in the AF and cSR groups during exercise. ¶, statistically significant change from the previous time point of exercise in the cSR group; §, statistically significant change from the previous time point of exercise in the AF group; **, statistically significant difference between the AF and cSR groups; AF, atrial fibrillation; cSR, heart rate-matched controls with sinus rhythm; HR, heart rate; VO2, oxygen uptake; Rest, average of 4 min of rest; Wu; average of 3–4 min after exercise commenced; AT, anaerobic threshold; RC, respiratory compensation point; Peak, exercise peak.

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  Fig. 3. Changes in the HR, VO2/kg, and relative O2 pulse in AF patients after divided into two groups according to O2 pulse trend ratio. ¶, statistically significant change from the previous time point of exercise in the high O2 pulse trend group; §, statistically significant change from the previous time point of exercise in the low O2 pulse trend group; The horizontal axis shows each point during CPET. AF, atrial fibrillation; cSR, heart rate-matched controls with sinus rhythm; HR, heart rate; VO2, oxygen uptake; Rest, average of 4 min of rest; Wu; average of 3–4 min after exercise commenced; AT, anaerobic threshold; RC, respiratory compensation point; Peak, exercise peak.

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  Fig. 4. Correlative relationships between the O2 pulse trend ratio (O2 pulse at Peak/O2 pulse at AT) and HR change from Rest to Peak, Rest to AT and AT to Peak.