Abstract 1609: Infarct size and Transmurality as Predict Response to Cardiac Resynchronization Therapy in Patients with Ischemic Cardiomyopathy
Aim: To determine whether myocardial scarring, quantified using late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR), predicts response to cardiac resynchronisation therapy (CRT).
Methods and results: 45 patients with ischemic cardiomyopathy [age 67.1 ± 10.4 yrs (mean ± SD)] underwent assessment of 6-min walking distance (6MWD) and quality of life (QoL) before and after CRT. Scar size (% left ventricular mass), location and transmurality were assessed prior to CRT using LGE-CMR. Responders (survival for 1 year with no heart failure hospitalizations, and improvement by ≥1 NYHA classes or ≥25% 6-MWD) had a higher LVEF (p=0.048), smaller (<33%) scars (p=0.009) and fewer scars with ≥51% transmurality (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 transmurality <51% were higher than in those with ≥51% (89% vs 46%, p<0.01). Amongst patients with posterolateral scars, a transmurality ≥51% was associated with a particularly poor response rate (23%), compared to 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 ischemic cardiomyopathy, a scar size ≥33%, a transmurality ≥51% and pacing over a posterolateral scar are associated with a suboptimal response to CRT.