When should CRT therapy be performed in patients with heart failure?

Cardiac Resynchronization Therapy (CRT) is indicated for patients with heart failure who have a left ventricular ejection fraction (LVEF) of less than or equal to 35%. This measure reflects significant systolic dysfunction and identifies patients who might benefit from the improved synchronization of heart contractions provided by CRT. The therapy aims to improve the heart's pumping efficiency and enhance overall cardiac output, which is crucial for managing heart failure symptoms and improving quality of life.

Choosing to initiate CRT based solely on LVEF is key, as it identifies patients at higher risk for worsened heart failure outcomes. While patients may have symptoms or other factors that suggest CRT could be beneficial, the threshold LVEF provides a more objective and standardized approach to determining candidacy for this intervention.

The other options do not provide the necessary criteria to warrant CRT. For example, patients in NYHA class 1 or 2 on guideline-directed medical therapy (GDMT) might not have severe enough symptoms or heart dysfunction to justify CRT, and a recent diagnosis of cardiomyopathy or a normal heart rate without arrhythmia alone does not necessarily correlate with the need for CRT therapy. Therefore, LVEF is a critical marker used by healthcare providers to guide their decision-making