Cardiac resynchronization therapy guided by late gadolinium-enhancement cardiovascular magnetic resonance.

ABSTRACT

BACKGROUND: Myocardial scarring at the LV pacing site leads to incomplete resynchronization and a suboptimal symptomatic response to CRT. We sought to determine whether the use of late gadolinium cardiovascular magnetic resonance (LGE-CMR) to guide left ventricular (LV) lead deployment influences the long-term outcome of cardiac resynchronization therapy (CRT). METHODS: 559 patients with heart failure (age 70.4 ± 10.7 yrs [mean ± SD]) due to ischemic or non-ischemic cardiomyopathy underwent CRT. Implantations were either guided (+CMR) or not guided (-CMR) by LGE-CMR prior to implantation. Fluoroscopy and LGE-CMR were used to localize the LV lead tip and and myocardial scarring retrospectively. Clinical events were assessed in three groups +CMR and pacing scar (+CMR+S); CMR and not pacing scar (+CMR-S), and; LV pacing not guided by CMR (-CMR). RESULTS: Over a maximum follow-up of 9.1 yrs, +CMR+S had the highest risk of cardiovascular death (HR 6.34), cardiovascular death or hospitalizations for heart failure (HR 5.57) and death from any cause or hospitalizations for major adverse cardiovascular events (HR 4.74) (all P < 0.0001), compared with +CMR-S. An intermediate risk of meeting these endpoints was observed for -CMR, with HRs of 1.51 (P = 0.0726), 1.61 (P = 0.0169) and 1.87 (p = 0.0005), respectively. The +CMR+S group had the highest risk of death from pump failure (HR 5.40, p < 0.0001) and sudden cardiac death (HR 4.40, p = 0.0218), in relation to the +CMR-S group. CONCLUSIONS: Compared with a conventional implantation approach, the use of LGE-CMR to guide LV lead deployment away from scarred myocardium results in a better clinical outcome after CRT. Pacing scarred myocardium was associated with the worst outcome, in terms of both pump failure and sudden cardiac death.