Cardiac resynchronisation therapy for chronic heart failure: predicting and measuring ‘response’

Chronic heart failure (CHF) is a complex syndrome involving all organ systems, and frequently affects patients with multiple co-morbidities. The condition is characterised by an inexorable, although variable and unpredictable decline. Cardiac resynchronisation therapy (CRT) can improve symptoms and prognosis in CHF patients with left ventricular (LV) systolic dysfunction (LVSD) and conduction delay.1 National and international guidelines describe simple criteria based on data from randomised placebo-controlled studies to help physicians decide which patients should receive CRT.2 Recently the criteria have expanded to include patients with less severe symptoms.

Despite proven benefits on prognosis, CRT is perceived as an irreversible and expensive treatment (mainly because of reluctance to provide CRT without an implantable defibrillator), not guaranteed to improve symptoms. Patients without symptomatic improvement are classed as ‘non-responders’. This term has undoubtedly slowed uptake of CRT and should now be abandoned. In fact CRT is associated with a greater response rate in terms of symptoms than medical therapy,3 and the vast body of literature, mostly obtained from longitudinal datasets describing complex imaging techniques, has merely proven that in a patient with heart …