ECG Abnormalities, Diastolic Blood Pressure, and Adverse Events After Systemic to Pulmonary Artery Shunt in Infants with Congenital Heart Disease.

All patients with Systemic to Pulmonary Artery (SPA) shunt as the index surgical procedure at a single center were studied to determine the association between post-operative ECG repolarization abnormalities, diastolic blood pressure (DBP), and adverse outcomes. Postoperative ECGs were categorized into three grades, Grade 2 defined as ST elevation/depression ≥ 2 mm in ≥ 2 precordial or ≥ 1 mm in ≥ 2 limb leads; Grade 1-T-wave inversion or flattening in ≥ 3 leads; and Grade 0-no criteria for grades 1 or 2. For each patient, time with invasive DBP below 25, 25-29, 30-34, or above 34 mmHg in the first 24 h was calculated. The primary outcome was a pre-discharge composite of death, cardiac arrest, ECMO, unplanned shunt reintervention, and necrotizing enterocolitis after 24 h of surgery. Of the 109 patients included in final analysis, 17 (15.6%) had the composite outcome. Grade 2 ECG abnormality occurred in 12%, and Grade 1 in 37%. There was no association between ECG abnormalities and adverse events. Increasing time with DBP < 30 was not associated with adverse outcomes, while increasing time with DBP 30-34 was associated with decreased odds, and increasing time with DBP > 34 mmHg was associated with increased odds of adverse outcomes on multivariable analysis accounting for indexed shunt size and chromosomal abnormalities. In conclusion, after SPA shunt placement, ECG repolarization abnormalities and low DBP within 24 h were common and not associated with adverse outcomes. Sustained elevation of DBP above 34 mmHg was not protective, especially in patients with high indexed shunt size and chromosomal abnormalities.