Late gadolinium enhancement-cardiovascular magnetic resonance as a predictor of response to cardiac resynchronization therapy in patients with ischaemic cardiomyopathy

Aim To determine whether myocardial scarring, quantified using late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR), predicts response to cardiac resynchronization therapy (CRT). Methods and results A total of 45 patients with ischaemic cardiomyopathy [age 67.1 +/- 10.4 years (mean +/- SD)] underwent assessment of 6 min walking distance (6MWD) and quality of Life (QoL) before and after CRT. Scar size (percentage of left ventricular mass), location, and transmurality were assessed prior to CRT using LGE-CMR. Responders (survived for 1year with no heart failure hospitalizations, and improvement by >= 1 NYHA classes or >= 25% 6MWD) had a higher left ventricular ejection fraction (P=0.048), smaller scars (< 33%) (P = 0.009), and fewer scars with >= 51% transmuratity (P = 0.002). Scar size correlated negatively with change in 6MWD (r = -0.54, P < 0.001) and positively with changes in QoL scores (r = 0.35, P = 0.028). Responder rates in patients with < 33% scar were higher than in those with >= 33% scar (82 vs. 35%, P < 0.01). Responder rates in patients with scar transmuratity < 51 % were higher than in those with >= 51% (89 vs. 46%, P < 0.01). Among the patients with posterolateral scars, a transmurality value of >= 51% was associated with a particularly poor response rate (23%), compared with scars with < 51 % transmurality (88%, P < 0.001). In multivariate analyses, both scar size (P = 0.022) and transmurality (P = 0.004) emerged as predictors of response. In patients with posterolateral scars, pacing outside the scar was associated with a better responder rate than pacing over the scar (86 vs. 33%, P = 0.004). Conclusions In patients with ischaemic cardiomyopathy, a scar size >= 33%, a transmurality 51%, and pacing over a posterolateral scar are associated with a suboptimal response to CRT.