Improved delivery of rate‐adaptive pacing using an impedance‐derived contractility sensor in high‐intensity exercise: A case report.

Effective rate‐adaptive pacing may be difficult in the presence of atrial fibrillation (AF), and is important during high‐intensity exercise. This case presents a 74‐year‐old elite cyclist with AF and a biventricular pacemaker after atrioventricular (AV) node ablation. He reported sudden breathlessness due to heart rate drops, caused by breaching the artefact threshold on the minute‐ventilation sensor. He was exchanged to a generator with an impedance‐derived contractility sensor (closed‐loop stimulation), resulting in resolution of symptoms, and no further rate drops. This is the first description of the utility of closed‐loop stimulation in high‐intensity exercise. [ABSTRACT FROM AUTHOR]