Early changes in myocardial repolarization and coronary perfusion after cardiopulmonary bypass surgery for ASD repair in children

Abstract

BackgroundIn adults, impaired myocardial repolarization and increased risk of arrhythmia are known consequences of open heart surgery. Little is known, however, about post-operative consequences of cardiopulmonary bypass surgery in children. The aim of this study was to assess ventricular repolarization and coronary perfusion after bypass surgery for atrial septal defect (ASD) repair in children.MethodsTwelve patients with ASD were assessed one day before and 5–6 days after ASD repair. Myocardial repolarization (corrected QT interval, QTc, QT dispersion, QTd, and PQ interval) was determined on 12-lead electrocardiograms. Coronary flow in proximal left anterior descending artery (peak flow velocity in diastole, PFVd) was assessed by transthoracic Doppler echocardiography.ResultsTen of the 12 (83%) children had normal myocardial repolarization before and after surgery. After surgery, QTc increased 1-9% in 5 (42%) patients, decreased 2-11% in 5 (42%) patients and did not change in 2 (16%) patients. Post-op QTc positively correlated with bypass time (R=0.686, p=0.014) and changes in PFVd (R=0.741, p=0.006). After surgery, QTd increased 33-67% in 4 (33%) patients, decreased 25-50% in 6 patients (50%) and did not change in 2 (16%) patients. After surgery, PQ interval increased 5-30% in 4 (33%) patients, decreased 4-29% in 6 (50%) patients and did not change in 1 (8%) patient. Post-op PQ positively correlated with bypass time (R=0.636, p=0.027). As previously reported, PFVd significantly increased after surgery (p<0.001).ConclusionsChanges in QTc, PQ and PFVd are common in young children undergoing surgery for ASD repair. Post-op QTc significantly correlates with bypass time, suggesting prolonged cardiopulmonary bypass may impair ventricular repolarization. Post-op QTc significantly correlates with PFVd changes, suggesting increased coronary flow may also impair ventricular repolarization. The clinical significance and reversibility of these alternations require further investigations.

QTc Prolongation after Ventricular Septal Defect Repair in Infants

“…Some studies show that early transmural ischemia results in QTc prolongation 6)12-14). In this study, prolonging of cross-clamp time showed a definite correlation to QTc prolongation, and prolonged bypass time also showed a tendency towards QTc prolongation.…”

Incidence and Related Risk Factors of Junctional Ectopic Tachycardia in Infants after Cardiac Surgery for Congenital Heart Disease

“…We cannot conclude whether ERP directly caused postoperative JET from this single-center retrospective study. However, some studies have shown that CPB surgery can change electrophysiological properties, including myocardial repolarization and QTc interval in children [32,33]. In particular, infants have unique calcium transients in the atrial myocytes [34].…”

Refractory ventricular fibrillations after surgical repair of atrial septal defects in a patient with CACNA1C gene mutation - case report

“…Diagnostic difficulty is due to the fact that patients with LQTS and ASDs occasionally show a RBBB preoperatively or after surgical correction of tetralogy of Fallot, and this ECG abnormality can mask the prolonged QT time [ 1 ]. It has also been reported that QT interval is prolonged after surgical correction of ASD in 42% of patients due to increased coronary flow after the correction [ 13 ]. Thus, physicians should carefully evaluate patients’ family medical history, especially when they present RBBB and a strong family history of arrhythmias.…”