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Chronotropic Incompetence — EECC MCQ

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ModerateArrhythmia & ElectrophysiologyChronotropic IncompetenceEECC

A 72-year-old woman presents with intermittent dizziness and near-syncope on exertion. Her resting ECG shows sinus rhythm at 62 bpm with normal PR interval. Exercise testing reveals failure of her heart rate to exceed 95 bpm despite achieving maximal exertion (predicted peak HR 148 bpm). What is the diagnosis?

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Correct answer: D — Chronotropic incompetence

Chronotropic incompetence (CI) is defined as the inability to achieve an adequate heart rate response to exercise, typically failing to reach 80% of age-predicted maximum heart rate (220 - age) or a chronotropic index <0.8. This patient achieved only 95/148 bpm (64% of predicted), confirming CI. It is a common cause of exercise intolerance in the elderly and may be a manifestation of sinus node dysfunction. The 2021 ESC Pacing Guidelines recognise CI as a potential indication for rate-adaptive pacemaker implantation (AAIR or DDDR with rate response) when symptomatic and drug causes (beta-blockers, calcium channel blockers) have been excluded.

Reference: ESC (2021): Guidelines on Cardiac Pacing and CRT