Global longitudinal strain to predict myocardial fibrosis in patients in carbon monoxide poisoning

Abstract

Abstract Background Carbon monoxide (CO) inhibits oxygen delivery and subsequently causes ischemic changes that can lead to myocardial damage. Late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) reflects myocardial fibrosis and detects subclinical myocardial damage in patients with acute CO poisoning. However, CMR is expensive and hard to perform in patients with neurologic deficit. Therefore, this study aims to investigate which echocardiographic parameters could predict the presence of myocardial fibrosis represented by LGE in CO intoxication patients. Methods This prospective observational study included 128 consecutive patients (Mean age: 52.2±16.2) with acute CO poisoning and elevated troponin I (defined as >0.045 ng/mL) at the emergency department of a tertiary university hospital. All participants underwent hyperbaric oxygen therapy (HBOT). CMR and conventional echocardiography with 2D speckle-tracking were performed within 7 days. Subjects were categorized into late gadolinium enhancement (LGE) and no LGE group according to the CMR findings. Results Mean left ventricular (LV) ejection fraction (EF) and global longitudinal strain (GLS) were 57.0±10.0% and −16.3±3.7% respectively. LGE was observed in 89 (69.5%) patients and the most common pattern was mid-wall involvement. Clinical characteristics such as age, sex, shock, time elapsed from rescue to HBOT, and the level of troponin I were not different between groups with LGE and without LGE. Among echocardiographic parameters, LV EF was not significantly different between groups (LGE: 56.0±10.5% vs 59.3±8.1%, p=0.089). LV GLS was more impaired in patients with LGE compared to those without LGE (−15.7±3.8% vs −17.9±3.0%, p=0.003). In multivariate logistic analysis, LV GLS was independently associated with the presence of LGE [Odds ratio (OR) 1.279, 95% confidence interval (CI) (1.047–1.563), p=0.016], but not LV EF. Conclusion In patients with acute CO poisoning and elevated troponin I, LV GLS predicted the presence of LGE in CMR. These finding suggest that subclinical myocardial dysfunction represented by LV GLS may reflect the burden of CO induced myocardial fibrosis. Funding Acknowledgement Type of funding sources: None.