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

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.

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.

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.

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).