Practice variation in the diagnosis of acute rejection among pediatric heart transplant centers: An analysis of the pediatric heart transplant society (PHTS) registry.

BACKGROUND: Freedom from rejection in pediatric heart transplant recipients is highly variable across centers. This study aimed to assess the center variation in methods used to diagnose rejection in the first-year post-transplant and determine the impact of this variation on patient outcomes. METHODS: The PHTS registry was queried for all rejection episodes in the first-year post-transplant (2010-2019). The primary method for rejection diagnosis was determined for each event as surveillance biopsy, echo diagnosis, or clinical. The percentage of first-year rejection events diagnosed by surveillance biopsy was used to approximate the surveillance strategy across centers. Methods of rejection diagnosis were described and patient outcomes were assessed based on surveillance biopsy utilization among centers. RESULTS: A total of 3985 patients from 56 centers were included. Of this group, 873 (22%) developed rejection within the first-year post-transplant. Surveillance biopsy was the most common method of rejection diagnosis (71.7%), but practices were highly variable across centers. The majority (73.6%) of first rejection events occurred within 3-months of transplantation. Diagnosis modality in the first-year was not independently associated with freedom from rejection, freedom from rejection with hemodynamic compromise, or overall graft survival. CONCLUSIONS: Rejection in the first-year after pediatric heart transplant occurs in 22% of patients and most commonly in the first 3 months post-transplant. Significant variation exists across centers in the methods used to diagnose rejection in pediatric heart transplant recipients, however, these variable strategies are not independently associated with freedom from rejection, rejection with hemodynamic compromise, or overall graft survival.

Ventricular arrhythmia in the X-linked cardiomyopathy Barth syndrome.

Barth syndrome is an X-linked disorder characterized by dilated cardiomyopathy, cyclic neutropenia, skeletal myopathy, abnormal mitochondria, and growth deficiency. The primary defect is a mutation in the TAZ gene on the X chromosome at Xq28, resulting in abnormal phospholipid biosynthesis and cardiolipin deficiency. To date, there has been no systematic evaluation of the cardiac phenotype. We report five cases of cardiac arrest and/or placement of an internal cardiac defibrillator with documented ventricular arrhythmia. We suggest that ventricular arrhythmia is part of the primary phenotype of the disorder and that patients should be screened accordingly.

Radiofrequency catheter ablation of supraventricular tachycardia substrates after mustard and senning operations for d-transposition of the great arteries.

OBJECTIVES: The purpose of this study was to determine the efficacy and risks of radiofrequency ablation of various forms of supraventricular tachycardia after Mustard and Senning operations for d-transposition of the great arteries. BACKGROUND: In this patient group, the reported success rate of catheter ablation of intraatrial reentry tachycardia is about 70% with a negligible complication rate. There are no reports of the use of radiofrequency ablation to treat other types of supraventricular tachycardia. METHODS: Standard diagnostic criteria were used to determine supraventricular tachycardia type. Appropriate sites for attempted ablation included 1) intraatrial reentry tachycardia: presence of concealed entrainment with a postpacing interval similar to tachycardia cycle length; 2) focal atrial tachycardia: a P-A interval < or =-20 ms; and 3) typical variety of atrioventricular (AV) node reentry tachycardia: combined electrographic and radiographic features. RESULTS: Nine Mustard and two Senning patients underwent 13 studies to successfully ablate all supraventricular tachycardia substrates in eight (73%) patients. Eight of eleven (73%) patients having intraatrial reentry tachycardia, 3/3 having typical AV node reentry tachycardia, and 2/2 having focal atrial reentry tachycardia were successfully ablated. Among five patients having intraatrial reentry tachycardia (IART) and not having ventriculoatrial (V-A) conduction, two suffered high-grade AV block when ablation of the systemic venous portion of the medial tricuspid valve/inferior vena cava isthmus was attempted. CONCLUSIONS: Radiofrequency catheter ablation can be effectively and safely performed for certain supraventricular tachycardia types in addition to intraatrial reentry. A novel catheter course is required for slow pathway modification. High-grade AV block is a potential risk of lesions placed in the systemic venous medial isthmus.

Chest pain in the adolescent and young adult.

Pediatric cardiologists and cardiologists who examine adults frequently receive referrals of adolescents and young adults with chest pain. Chest pain in this age group is most likely noncardiac in origin, which often creates a diagnostic dilemma for the consultant in terms of the etiology and extent of evaluation. This review presents the noncardiac and cardiac etiologies of chest pain in adolescents and young adults, as well as the key features of a patient's history and physical examination that help delineate cardiac from noncardiac chest pain. In addition, we present recommendations for the cardiac consultant regarding the evaluation and management of adolescents and young adults referred with the complaint of chest pain.

Ductus arteriosus in premature infants beyond the second week of life.

Persistent patency of the ductus arteriosus (PDA), common in premature infants, is associated with severe respiratory distress. The likelihood and significance of finding PDA in premature infants beyond the second week of life is unknown. We retrospectively analyzed all echocardiograms obtained between 1987 and 1992 on infants <35 weeks' gestational age. Of 446 echocardiograms 77 were obtained from infants >/=14 days. Of the 77 infants, 17 (22%) were found to have PDA (group 1) and the remainder did not (group 2). Forty-eight infants had been diagnosed as having PDA prior to 14 days of age. Of these infants, 16 were from group 1. Thus only 1/17 (6%) infants diagnosed as having PDA after 2 weeks did not have a history of PDA. The presence of PDA after 2 weeks did not relate to duration of oxygen therapy, ventilator therapy, or hospital stay. Furthermore, late closure of PDA in a subgroup of 11 infants did not appear to affect these parameters. It was concluded that premature infants beyond the second week of life are unlikely to have PDA if PDA had not been diagnosed during the first 14 days. Closure of PDA beyond the second week may not improve the infant's respiratory status.