chronotropic incompetence
Pronunciation: KRON-oh-trop-ik in-KOM-peh-tens
The inability of the heart rate to increase appropriately with physiological demands, often indicating sinus node dysfunction.
Full Definition
Chronotropic incompetence is a cardiac condition characterized by the inability of the heart rate to increase adequately in response to physiological stress, exercise, or metabolic demands. This condition typically results from sinus node dysfunction, autonomic nervous system abnormalities, or medication effects, particularly beta-blockers or calcium channel blockers. Chronotropic incompetence is often assessed through exercise stress testing, where failure to achieve 85% of age-predicted maximum heart rate suggests impaired chronotropic response. The condition can significantly impact exercise capacity and quality of life, and may require treatment with rate-responsive pacemaker therapy to restore appropriate heart rate response to activity. It is an important consideration in the evaluation of patients with unexplained exercise intolerance.
Usage
Usage note: Often abbreviated as CI in clinical notes, but spell out in formal documentation to avoid confusion.
In Context
- "Exercise testing revealed chronotropic incompetence as the cause of the patient's exertional dyspnea." — Diagnostic workup
- "Rate-responsive pacing improved exercise capacity in this patient with chronotropic incompetence." — Treatment outcome