Therapeutic hypothermia and myocardium in perinatal asphyxia: a microvolt T-wave alternans and Doppler echocardiography study

OBJECTIVES: This is the first study evaluating the predictive value of myocardial performance on arrhythmia and mortality via tissue-Doppler and microvolt T-wave alternans in infants with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia-rewarming. METHODS: The study included 23 term newborns having criteria for hypoxic-ischemic encephalopathy, and 12 controls. Tissue-Doppler imaging and T-wave alternans were performed in the first six hours after birth in patients from both groups and after hypothermia-rewarming treatment on the fifth day. RESULTS: The basal T-wave alternans values were higher in patients in lead aVF(p < 0.001) which also correlated with existing acidemia (r = 0.517; p = 0.012). Basal T-wave alternans and post‑treatment values of patients were compared in leads V1 (p < 0.001) and aVF (p < 0.001); a significant decrease was found on the fifth day. Moreover, right ventricle diastolic diameter and estimated systolic pulmonary artery pressure of patients in the first 6 hours were higher (p = 0.03, p < 0.001, respectively). Although, the ejection fraction of patients did not decrease, basal values of left and right ventricular systolic and diastolic functions were lower initially, and increased significantly after treatment. CONCLUSION: The global cardiac functions and myocardial performance of newborns with hypoxic-ischemia might be improved with therapeutic hypothermia which can be determined by using T-wave alternans and tissue-Doppler measurements. However, further studies are needed to assess whether these measurements are prognostic in determining the myocardial dysfunction and arrhythmias (Tab. 2, Fig. 3, Ref. 26).