chronotropic incompetence
Pronunciation: KRON-oh-trop-ik
The inability of the heart rate to increase appropriately in response to increased metabolic demand during exercise.
Full Definition
Chronotropic incompetence is defined as failure to achieve 85% of age-predicted maximum heart rate during exercise testing, or an abnormally flat heart rate response to graded exercise. This condition can result from intrinsic sinus node dysfunction, medications (particularly beta-blockers), or autonomic dysfunction. It significantly impairs exercise capacity and quality of life, often necessitating rate-responsive pacemaker therapy. The condition is commonly assessed during exercise stress testing and may be the primary indication for permanent pacing in patients with sinus node dysfunction.
Usage
Usage note: Distinguish from general exercise intolerance by specifying the heart rate response abnormality.
In Context
- "Exercise testing demonstrated chronotropic incompetence with peak heart rate of only 110 bpm." — Exercise stress test report
- "The patient's fatigue was attributed to chronotropic incompetence requiring rate-responsive pacing." — Electrophysiology consultation