ABSTRACT
In other cardiomyopathies, cardiac magnetic resonance imaging (CMR)-derived myocardial delayed enhancement (MDE), a marker of myocardial fibrosis, is a risk factor for sudden cardiac death (SCD). In Duchenne muscular dystrophy (DMD), the prognostic value of MDE for ventricular arrhythmias and death is unknown. This study aimed to evaluate associations between MDE and electrocardiographic (ECG) changes, ventricular remodeling, risk of arrhythmias, and death in DMD. This retrospective study included all subjects with DMD who had undergone a CMR between January 2006 and December 2011 and had available ECG and 24-h Holter records from the same period. Left ventricular (LV) MDE was semiquantitatively graded from 0 to 4. Comparisons of demographic and clinical characteristics between MDE and no-MDE groups were made. Cox regression analysis was performed to assess factors associated with death. This study investigated 32 boys with a median age of 13.8 years (range, 7.2-17.4 years) and found MDE present in 25 (78 %) of the boys. Compared with the no-MDE subjects, the MDE subjects were older (15.7 ± 3.3 vs 12.1 ± 4.8 years) and had a wider QT dispersion (QTd: 74 ± 30 vs 55 ± 33 ms), a higher incidence of ventricular tachycardia (40 vs 0 %), a lower LV ejection fraction (46 ± 12 vs 56 ± 9 %), a larger LV end-diastolic volume (124 ± 58 vs 68 ± 14 ml/m(2)), and a larger end-systolic volume (57 ± 29 vs 28 ± 10 ml/m(2)) (p < 0.05 for all). During the study period, six of the subjects (19 %) died. The factors associated with mortality were increased age, advanced grade of MDE, higher LV end-systolic volume, lower LV ejection fraction, use of beta-blockers, and ventricular tachycardia. Myocardial fibrosis detected by CMR is an independent predictor of adverse cardiac remodeling, ventricular arrhythmias, and death in DMD. Cardiac MRI using MDE can be applied as a screening tool to detect patients at risk for ventricular arrhythmias, more advanced disease, adverse LV remodeling, and death.
Subject(s)
Arrhythmias, Cardiac/etiology , Electrocardiography, Ambulatory , Heart Ventricles/physiopathology , Muscular Dystrophy, Duchenne/complications , Ventricular Dysfunction, Left/etiology , Ventricular Remodeling , Adolescent , Arrhythmias, Cardiac/diagnosis , Arrhythmias, Cardiac/physiopathology , Child , Follow-Up Studies , Heart Ventricles/pathology , Humans , Magnetic Resonance Imaging, Cine , Male , Muscular Dystrophy, Duchenne/diagnosis , Prognosis , Retrospective Studies , Ventricular Dysfunction, Left/diagnosis , Ventricular Dysfunction, Left/physiopathologyABSTRACT
There is growing awareness that the Norwood procedure with the Sano modification is prone to early right ventricular to pulmonary artery (RV-PA) conduit stenosis resulting in systemic oxygen desaturation, increased interstage morbidity, and death. We report our experience with endovascular stent placement for conduit stenosis and compare the outcomes at stage II surgery between stented and nonstented infants. The medical records of all patients with hypoplastic left heart syndrome who received an RV-PA conduit at Norwood palliation from May 2005 to January 2010 were reviewed. The preoperative anatomy, demographics, operative variables, and outcomes pertaining to the Norwood and subsequent stage II surgeries were obtained and compared between stented and nonstented infants. The pre- and post-stent oxygen saturation, stenosis location, type and number of stents implanted, concomitant interventions, procedure-related complications, and reinterventions were collected. Of the 66 infants who underwent the Norwood procedure with RV-PA conduit modification, 16 (24%) received stents. The anatomy, demographics, and outcome variables after the Norwood procedure were similar between the stented and nonstented infants. The age at catheterization was 93 ± 48 days, and the weight was 4.9 ± 1.2 kg. The oxygen saturation increased from 66 ± 9% before intervention to 82 ± 6% immediately after stenting (p <0.0001). No interstage surgical shunt revisions were performed in either group. Age, weight, pre-stage II echocardiographic variables, oxygen saturation, and operative and outcome variables, including mortality, were similar between the 2 groups. In conclusion, endovascular stent placement for RV-PA conduit stenosis after the Norwood procedure leads to improved systemic oxygen levels and prevents early performance of stage II surgery without compromising stage II outcomes.