What does chronotropy affect?

Chronotropy specifically refers to the effects on heart rate. It is a term derived from the Greek word "chronos," meaning time, and it describes how quickly or slowly the heart beats. Positive chronotropic effects increase heart rate, while negative chronotropic effects decrease it.

Heart contractility, or the strength of the heart's contractions, is influenced by a different aspect known as inotropy, not chronotropy. Cardiac output is the volume of blood the heart pumps per minute and depends on both heart rate and stroke volume, but it is not directly affected by chronotropy alone. Similarly, blood pressure is influenced by multiple factors, including vascular resistance and heart rate, but it is not the primary focus of chronotropic effects. Therefore, the answer identifying heart rate as the correct aspect influenced by chronotropy precisely captures the essence of the term.