A CRT-D is recommended when someone needs both ICD protection and cardiac resynchronisation therapy. This typically applies to people with heart failure where:
- The left ventricle’s pumping function is significantly reduced (usually an ejection fraction of 35% or below)
- The ECG shows a wide QRS complex, indicating that the two ventricles are not contracting in synchrony
- Symptoms persist despite optimal medical therapy
In this group of patients, biventricular pacing can improve symptoms, exercise capacity, and quality of life, and in some cases can partially reverse the structural changes in the heart. Clinical evidence shows that approximately two in three eligible patients experience meaningful benefit from CRT.
Not everyone who has had a cardiac arrest has heart failure, and not everyone with heart failure needs a CRT-D. A standard ICD may be perfectly appropriate. The decision is made by a specialist cardiologist or electrophysiologist based on your ECG, echocardiogram results, symptoms, and other clinical factors. If a CRT-D has been recommended for you, your team will explain the specific reasons.