[ALTERATIONS IN SENSITIVE MEASURES OF CARDIAC FUNCTION IN HEALTHY NEONATES DURING PHOTOTHERAPY]

Phototherapy has been reported to reduce coronary blood flow in neonates but without affecting gross measures of cardiac function. The aim of our current study was to evaluate earlier, more sensitive changes in cardiac function during phototherapy.

Nineteen neonates with jaundice treated with phototherapy had Doppler echocardiographic evaluation, before, during and after phototherapy and were compared to 25 matched controls. Sensitive measures for cardiac performance in this study included left ventricular dimension, ventricular Doppler parameters and regional function assessment.

Phototherapy was associated with a significant increase in heart rate. In addition, atrioventricular valve closure to opening interval decreased significantly during phototherapy while ventricular ejection times tended to decrease. However, left and right ventricular filling parameters and outflow velocity parameters, longitudinal tissue-Doppler annular velocities and myocardial performance indices were not affected by phototherapy and were similar to those in controls. Coronary blood velocities and integrals decreased significantly during phototherapy.

Our study found no differences in early and sensitive measures of cardiac performance including the diastolic and systolic function, despite modestly lower flow in coronary arteries among healthy neonates during phototherapy.