Chronotropic index
Chronotropic index is calculated as follows
[A] (peak heart rate – resting heart rate) / ((220 – age)[B] (peak heart rate – resting heart rate) / ((220 – resting heart rate)
[C] (peak heart rate – resting heart rate) / age + resting heart rate)
[D] (peak heart rate – resting heart rate) / ((220 – age) – resting heart rate)
Chronotropic index of less than ——— % is considered a sign of chronotropic incompetence
[A] 50%
[B] 60%
[C] 70%
[D] 80%
Chronotropic index – [(HRmax − HRrest) / (220 − Age − HRrest)] × 100
Failure to achieve a chronotropic index higher than 80% defines chronotropic incompetence and predicts a poor prognosis
The above formula is not useful in case of – Atrial fibrillation
