We aimed to determine whether mechanical dyssynchrony assessed by Equilibrium RadioNuclide Angiography (ERNA) may predict response to CRT.

70 patients were consecutively enrolled. ERNA, echocardiography and electrocardiogram were performed before biventricular pacemaker implantation. Positive response to CRT was defined as an improvement in NYHA class in patients alive and not readmitted for HF within 6 months.

Mean age was 65±9 years, 74 % of patients were men, 84 % were in NYHA class III or IV. Main HF aetiologies were ischemic (36%) or dilated (50 %). ERNA left ventricular ejection fraction was 21±9%, QRS duration was 161±34 ms. 96% of patients received an ACE inhibitor or an angiotensin II receptor antagonist, 66% a beta-blocker and 36% an aldosterone antagonist. Non-response rate was 31.5%. Interventricular delay assessed by ERNA was greater in non-responders versus responders in univariate analysis: respectively 92±39 ms and 57±46 ms, p = 0.005. QRS duration, interventricular and intraventricular delay assessed by echocardiography, intraventricular delay assessed by ERNA, were not significantly different between the two groups.

In conclusion, by contrast to other methods, interventricular delay assessed by ERNA before implantation may help to identify responders and non-responders to CRT.