Table 1:

Continuous heart rate monitoring analytics and outcome studies.

Investigators	Study N Site(s)	Inclusion criteria	Results/Conclusions
Griffin et al (19)	633 Two centers	27 0/7 – 37 weeks	Abnormal HRC (reduced variability, decelerations) is a valid tool for early diagnosis of impending LOS or sepsis like illness.
Griffin et al (42)	337 Single center	27 0/7 – 35 weeks	HRC along with clinical signs of illness can add independent information in the diagnosis of LOS.
Moorman et al (29)	3003 Multicenter	<1500 grams	Display of HRC index is associated with 22% decreased mortality and trend towards increased ventilator free days in comparison to control subjects with recording of HRC index without display.
Fairchild et al (30)	2989 Multicenter	<1500 grams	40% decreased mortality within 30 days of septicemia with HRC index display due to earlier diagnosis.
Stone et al (31)	97 Multicenter	<1500 grams	Abnormal HRC occurs prior to diagnosis of medical and surgical NEC and can help with early diagnosis and treatment.
Addison et al (33)	65 Single center	<1500 grams	Cumulative frequency of abnormal HRC score is associated with increased risk of cerebral palsy and delayed early cognitive development.
Fairchild et al (68)	1065 Two Center	<1500 grams	Best metric for predicting LOS/NEC was cross correlation(X-Corr)-HR-SpO2 and a 3-variable vital sign model.
Fairchild et al (46)	629 Single center	<1500 grams	High cross correlation (X-Corr)-HR-SpO2 is associated with apnea and adverse events including NEC and LOS.
Sullivan et al (34)	566 Single center	<1500 grams	HRC index on day of life 1 and 7 compares favorably to established risk scores to predict death and morbidities (LOS, BPD, severe IVH, NEC and severe ROP).
Doheny et al (32)	70 Single center	28 0/7 –34 6/7 weeks	HF-HRV can be a potential non-invasive biomarker for NEC diagnosis.
Fairchild et al (38)	384 Single center	<1000 grams	Increased HRC index is associated with abnormal brain imaging and can predict adverse neurologic outcomes.
Vergales et al (39)	37–64 Single center	Term gestation	Low HRV (and corresponding high HRC index) is associated with worse EEG, MRI and 2 year Bayley neurodevelopmental outcomes.
Goel et al (37)	102 Single center	All Ventilated infants	HRC index is higher in infants with extubation failures compared to infants with successful extubation. Infants with failed extubation had lower gestational age, extubated at lower corrected gestational age, longer duration of ventilation prior to extubation and culture positive sepsis.
Sullivan et al (35)	274 Single center	<1500 grams	Sepsis, respiratory deterioration, surgical procedures and other infectious or inflammatory conditions are associated with large increase in HRC index.

HRC, heart rate characteristics; LOS, late onset sepsis; NEC, necrotizing enterocolitis; X-Corr-HR-SpO2, cross correlation of heart rate and oxygen saturation; BPD, bronchopulmonary dysplasia; ROP, retinopathy of prematurity; IVH, intraventricular hemorrhage; HUS, head ultrasound; MRI, magnetic resonance imaging