Minute Ventilation

Chronotropic Incompetence (CI)

CI is defined as the inability to achieve the optimal heart rate during activity. If cardiac device patients can’t get their heart rate to increase, it makes it difficult to exercise and perform everyday activities like walking to the mailbox or holding a grandchild. Patients with CI have a higher risk of mortality1,2 and may not be able to achieve a high enough heart rate for normal activities.

Typical Necessary Heart Rate for Activity

Typical necessary heart rate for activity

CI Prevalence by Condition

CI Prevelence by Condition


While common across the entire heart failure patient population, CI is especially prevalent in patients requiring cardiac resynchronization therapy (CRT).


CI Prevelence by Study Population

  Population Number CI%
HF Brubaker et al.3 State of the Art 25-75%*
Witte et al.4 237 43%
Al-Najjar et al.5 411 46%
Jorde et al.6 278 46%
CRT Samara et al.7 238 77%
Ujeyl et al.8 122 56-89%
*Substantial variability likely influenced by the criteria employed to determine CI and differing patient characteristics (age, disease severity, type/dose of medications).

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VISIONIST™ X4 CRT-P: Indications, Safety and Warnings