Left Ventricular Scar and Prognosis in Chronic Chagas Cardiomyopathy

Abstract

Background: Patients with chronic Chagas cardiomyopathy (CCC) have pronounced myocardial fibrosis, which may predispose to sudden cardiac death, despite well-preserved global left ventricular (LV) systolic function. Cardiac magnetic resonance can assess myocardial fibrosis by late gadolinium enhancement (LGE) sequences.

Objectives: This prospective study evaluated if the presence of scar by LGE predicted hard adverse outcomes in a cohort of patients with CCC.

Methods: A prospective cohort of 140 patients with CCC (52.1% female; median age 57 years [interquartile range: 45 to 67 years]) were included. Cardiac magnetic resonance cine and LGE imaging were performed at enrollment with a 1.5-T scanner. The primary endpoint was the combination of cardiovascular death and sustained ventricular tachycardia. The secondary endpoint was the combination of cardiovascular death, sustained ventricular tachycardia, or cardiovascular hospitalization during follow-up.

Results: After a median of 34 months (interquartile range: 24 to 49 months) of follow-up, 11 cardiovascular deaths, 3 episodes of sustained ventricular tachycardia, and 20 cardiovascular hospitalizations were recorded. LGE scar was present in 71.4% of the patients, with the lateral, inferolateral, and inferior walls most commonly affected. Patients with positive LGE had lower LV ejection fraction and higher LV end-diastolic volume and LV mass than patients without LGE. No difference in other cardiovascular risk factors was noted. Patients with scar had higher event rates compared with those without scar for the primary (p = 0.043) and the secondary (p = 0.016) endpoint. In multivariable analysis, age and LGE area were related to primary outcome; age and lower LV ejection fraction were related to the secondary outcome. The pattern of LGE myocardial fibrosis was transmural, focal, or diffuse scar in approximately one-third of patients with positive LGE, and no pattern was specifically related to outcomes.

Conclusions: In patients with CCC, presence of scar by LGE is common and is strongly associated with major adverse outcomes.

Keywords: Chagas; Chagas heart disease; MRI; clinical events; late gadolinium enhancement; scar.