Written by Kimiko Dunbar
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Phototherapy may cause myocardial dysfunction, associated with duration of phototherapy and number of phototherapy units.
Should we stop phototherapy sooner?
Phototherapy is the standard of care for neonatal unconjugated hyperbilirubinemia; however, some adverse effects have been reported. This prospective cohort study examined the impact of phototherapy on cardiac function in 40 full-term neonates with unconjugated hyperbilirubinemia versus 40 controls. Authors obtained troponin levels, conventional echo, tissue doppler, and 2D-speckle tracking echocardiography (STE) before and 24 hours after therapy. Control infants had echos performed only once, whereas infants who received phototherapy had echos obtained both before initiation and 24 hours after cessation. 2D-STE differs from conventional echo – it is a non-doppler technique that uses computer software analysis to calculate a more comprehensive assessment of cardiac function. Both systolic and diastolic blood pressures were found to be significantly lower after phototherapy, with a significant increase in heart rate. Troponin levels and conventional echo were unchanged. Using 2DSTE, the study found significant left ventricular global longitudinal strain (2D-LVGLS) pre- and post-phototherapy (−20.6% to −17.9%, p<0.001), respectively. Regression analysis identified phototherapy duration and intensity as predictors of myocardial dysfunction. Importantly, there was no long-term follow-up in this study to assess the impact of LV strain outside of the immediate post-phototherapy period. Further, control neonates only had one echo performed, so it’s impossible to know if there would have been changes to their echo due to something other than phototherapy.
How does this change my practice?
It’s hard to know what to do with this information, since phototherapy is the standard of care. I’d be very interested to see what an 2D-STE echo looks like a few weeks after phototherapy, to understand if there are any meaningful long-term changes. Regardless, I’ll be more thoughtful about repeating levels earlier to facilitate cessation of phototherapy as soon as clinically indicated, given that longer duration of phototherapy is predictive of worse function.
Editor’s note: I am not sure how clinically meaningful this surrogate marker is, but it seems worth learning more about this. ~Clay Smith
Source
Effect of phototherapy on cardiac function in full term neonates with unconjugated hyperbilirubinemia. Pediatr Res. 2025 May 8. doi: 10.1038/s41390-025-04071-4. Epub ahead of print. PMID: 40341252
