Abstract Purpose Infants and children with congenital heart defects, inherited arrhythmia syndromes, and congenital cardiac conduction disorders often receive epicardial implantable electronic devices. Unfortunately, once an epicardial device is implanted, the patient is no longer eligible to receive MRI exams due to an elevated risk of RF heating. Here we show that a simple modification in the trajectory of epicardial leads can substantially and reliably reduce RF heating during MRI at 1.5 T, with benefits extending to abandoned leads. Methods Electromagnetic simulations were performed to assess RF heating of two common epicardial lead trajectories exhibiting different degrees of coupling with MRI incident electric fields. Experiments in anthropomorphic phantoms implanted with commercial cardiac implantable electronic devices (CIEDs) confirmed the findings. Results Simulations of an epicardial lead with a trajectory where the excess length of the lead was looped and placed on the anterior surface of the heart showed a 9-fold reduction in 0.1g-averaged SAR compared to the lead with excess length looped on the inferior surface of the heart. Repeated experiments with a commercial epicardial device confirmed the results, showing a 16-fold reduction in the average temperature rise for fully implanted systems with leads following low-SAR trajectories, and a 20-fold reduction in RF heating on an abandoned lead. Conclusion Surgical modification of epicardial lead trajectory can substantially reduce RF heating at 1.5 T, with benefits extending to abandoned leads.
Anomalous aortic origin of a coronary artery (AAOCA) is a known cause of sudden death. Our hypothesis was that longer intramural length and smaller ostial diameter correlate with preoperative symptoms. If true, this would assist in the decision for surgical indications. We also assessed the accuracy of preoperative imaging to predict intramural length.Retrospective analysis of patients who underwent AAOCA unroofing from 2006 to 2014. Patients had preoperative computed tomography angiography (CTA) or magnetic resonance imaging (MRI). Intramural length was measured. Intramural lengths and ostial diameters were also measured intraoperatively (operating room [OR]). Symptoms were noted. Intramural lengths and ostial diameters were compared between patients with and without preoperative symptoms. The accuracy of intramural length measured by CTA/MRI versus the length measured in the OR was assessed using a Bland-Altman analysis.Sixty-six patients underwent surgical repair of AAOCA. Fifty-two (79%) patients were symptomatic and 14 (21%) were asymptomatic. Mean age was 12.4 ± 4.0 years. There was no mortality. There was strong agreement between intramural length measured by CTA/MRI and measured in the OR. There was no significant difference in AAOCA intramural length in the symptomatic (8.6 ± 3.5 mm) and asymptomatic (8.9 ± 2.8 mm, P = .77) patients, which were measured both by CTA/MRI and intraoperatively (symptomatic 7.3 ± 2.5 mm, asymptomatic 6.9 ± 2.8 mm; P = .62). There was also no significant difference in AAOCA ostial diameters between groups (symptomatic = 1.9 ± 0.5 mm, asymptomatic = 1.6 ± 0.5 mm; P = .09).Preoperative CTA/MRI was very accurate in predicting the length of surgical unroofing. There was no demonstrable correlation between preoperative symptoms and intramural AAOCA length or AAOCA ostial diameter.
Anomalous origin of a branch pulmonary artery from the ascending aorta (AOPAA) has been reported to exist with tetralogy of Fallot (TOF), interrupted aortic arch, aortopulmonary window, isthmic hypoplasia, and ventricular septal defects. Right pulmonary artery origin from the ascending aorta (AORPA) occurs from abnormal migration of the right sixth aortic arch. The right pulmonary artery (RPA) usually arises near the sinotubular junction from the right or posterior aspect of the ascending aorta. Anomalous origin of the left pulmonary artery (AOLPA) occurs when the left pulmonary artery (LPA) arises from the persistent aortic sac as a result of absence of the left sixth arch with persistence of the left fifth arch. Advanced medical imaging with computed tomography angiography (CTA) or magnetic resonance imaging (MRI) is quite useful for operative planning. The repair is performed via a median sternotomy approach with the use of hypothermic cardiopulmonary bypass.
Interrupted aortic arch (IAA) is a rare congenital defect resulting from the loss of luminal continuity between the ascending and descending aorta. Classification is determined by the location of the interruption. Nearly all patients have a ventricular septal defect (VSD) and patent ductus arteriosus. Patients with IAA should be evaluated for microdeletion of chromosome 22q11 and DiGeorge syndrome. Diagnosis may be made by prenatal ultrasound or with postnatal echocardiography. Advanced medical imaging (catheterization, CT) may aid diagnosis and operative planning. Prior to operative repair, ductal patency is maintained with a PGE1 infusion and lower body perfusion is optimized. After resuscitation of the patient, surgical repair with a direct aortic anastomosis and correction of associated cardiac anomalies (VSD) is performed. Following repair of IAA, patients should be monitored for development of late complications of arch obstruction, left ventricular outflow obstruction, and bronchial obstruction.
