Characteristics and long-term outcome of echocardiographic super-responders to cardiac resynchronisation therapy: 'real world' experience from a single tertiary care centre.

Background: The individual benefit from cardiac resynchronisation therapy (CRT) varies largely among patients.

Aims: To compare different definitions of echocardiographic super-response to CRT regarding their ability to predict the incidence of adverse events.

Methods: Three definitions of super-response to CRT were evaluated in 110 consecutive patients with CRT implantation: (1) an absolute increase in ejection fraction of ≥ 10%; (2) a decrease in left ventricular end-systolic volume of ≥ 30%; and (3) a decrease in left ventricular end-diastolic volume of ≥ 20%. The primary endpoint was a combination of time to death, heart transplantation, ventricular assist device implantation and hospitalisation for heart failure. Secondary endpoints included time to first appropriate implantable cardioverter defibrillator (ICD) discharge during follow-up.

Results: All three definitions of super-response were highly predictive of a reduced risk for reaching the primary combined endpoint (3-year estimators: 64% ± 7% vs 82% ± 7% for ejection fraction ≥ 10%; 63% ± 8% vs 92% ± 5% for end-systolic volume ≥ 30%; and 62% ± 8% vs 94% ± 4% for end-diastolic volume ≥ 20%; all p<0.001). In all three analyses, super-responders had a significantly shorter time from diagnosis of heart failure until the time point of CRT implantation. However, even super-responders, independent of the definition, did experience appropriate ICD discharges during follow-up.

Conclusions: All three definitions of super-response are highly predictive for a favourable outcome after CRT. However, even patients with pronounced reverse left ventricular remodelling experience appropriate ICD discharges during follow-up.