What is a prerequisite for FDA approval of CRT in patients?

The prerequisite for FDA approval for Cardiac Resynchronization Therapy (CRT) in patients primarily revolves around ensuring that patients meet appropriate criteria without severe illness. This means that candidates for CRT should typically have left ventricular ejection fraction (LVEF) of 35% or less, New York Heart Association (NYHA) functional class III or IV heart failure symptoms, and a QRS duration that is prolonged, indicating a potential benefit from the therapy.

This criterion ensures that the patients selected for CRT are those who can genuinely benefit from this intervention, as their heart failure condition requires significant enhancement or resynchronization to improve cardiac output and relieve symptoms. The focus on not having severe concomitant illnesses is crucial, as those conditions may complicate the patient's recovery or response to the therapy, potentially skewing the results or introducing additional risks.

In contrast, having significant concomitant illnesses would detract from the patient's candidacy because these conditions might interfere with the efficacy or safety of CRT. Age limitations, like being under 50, are not inherently a standard prerequisite for CRT, as older patients can also benefit from this treatment. Likewise, a family history of heart failure, while relevant in terms of assessing risk, is not a requirement for determining eligibility for CRT.