An unusual cause of repolarization abnormality after congenital heart surgery: A case report.

We present a case of a young boy who developed persistent tachycardia despite fluid resuscitation, antipyretics, and analgesia after a Fontan procedure. Review of telemetry and ECGs revealed repolarization abnormalities, including the appearance of T-wave alternans, for which an uncommon cause was ultimately identified.

Life-threatening cardiac arrhythmia and sudden death during electronic gaming: An international case series and systematic review.

BACKGROUND: Electronic gaming has recently been reported as a precipitant of life-threatening cardiac arrhythmia in susceptible individuals. OBJECTIVE: The purpose of this study was to describe the population at risk, the nature of cardiac events, and the type of game linked to cardiac arrhythmia associated with electronic gaming. METHODS: A multisite international case series of suspected or proven cardiac arrhythmia during electronic gaming in children and a systematic review of the literature were performed. RESULTS: Twenty-two patients (18 in the case series and 4 via systematic review; aged 7-16 years; 19 males [86%]) were identified as having experienced suspected or proven ventricular arrhythmia during electronic gaming; 6 (27%) had experienced cardiac arrest, and 4 (18%) died suddenly. A proarrhythmic cardiac diagnosis was known in 7 (31%) patients before their gaming event and was established afterward in 12 (54%). Ten patients (45%) had catecholaminergic polymorphic ventricular tachycardia, 4 (18%) had long QT syndrome, 2 (9%) were post-congenital cardiac surgery, 2 (9%) had "idiopathic" ventricular fibrillation, and 1 (after Kawasaki disease) had coronary ischemia. In 3 patients (14%), including 2 who died, the diagnosis remains unknown. In 13 (59%) patients for whom the electronic game details were known, 8 (62%) were war games. CONCLUSION: Electronic gaming can precipitate lethal cardiac arrhythmias in susceptible children. The incidence appears to be low, but syncope in this setting should be investigated thoroughly. In children with proarrhythmic cardiac conditions, electronic war games in particular are a potent arrhythmic trigger.

Long-term Outcomes of Children Operated on for Anomalous Left Coronary Artery From the Pulmonary Artery.

BACKGROUND: We examined the outcomes of children (<18 years) operated on for anomalous left coronary artery from the pulmonary artery (ALCAPA). METHODS: We linked patients undergoing ALCAPA repair between 1982 and 2003 in the Pediatric Cardiac Care Consortium with the National Death Index and the Organ Procurement and Transplantation Network to examine their outcomes through 2019. RESULTS: We identified 228 children (median age, 6.0 months) operated on for ALCAPA. At the time of repair, 38.6% had severe mitral regurgitation (MR), and 71.4% had severe left ventricular (LV) dysfunction. Repair included primarily coronary reimplantation in 173 and the Takeuchi procedure in 34; concurrently, 18 underwent mitral valve (MV) operation. In-hospital death occurred in 31 (13.6%) and was not associated with MR severity (P = .846); however, among patients with moderate or severe MR, risk of death was 28% lower when undergoing MV operation (P = .033). After adjustment for other risk factors, only infant operation reached statistical significance for in-hospital death (adjusted odds ratio, 12.99; 95% CI, 1.61-104.59; P = .016). Among those discharged alive with long-term data available (n = 155), the 30-year transplant-free survival reached 95.5% (95% CI, 92.3%-98.8%) and was not associated with the degree of preoperative MR or LV dysfunction. Coronary reimplantation was associated with better long-term survival compared with other surgical techniques (adjusted odds ratio, 0.11; 95% CI, 0.02-0.74; P = .023). CONCLUSIONS: Favorable long-term outcomes can be expected after coronary artery reimplantation for ALCAPA, even in patients with severe LV dysfunction at presentation. MV operation predicted decreased risk for in-hospital mortality in patients with moderate/severe MR, but MR severity predicted neither in-hospital nor longer-term outcomes.

An interesting response to adenosine during right ventricular pacing. What is the mechanism?

We describe an interesting case in which single dose of adenosine during RV pacing elicited a series of abrupt transitions in the retrograde activation behaviour in an 11-year-old child undergoing electrophysiology study for Wolff-Parkinson-White syndrome.

Permanent conduction system pacing for congenitally corrected transposition of the great arteries: A Pediatric and Congenital Electrophysiology Society (PACES)/International Society for Adult Congenital Heart Disease (ISACHD) Collaborative Study.

BACKGROUND: Congenitally corrected transposition of the great arteries (CCTGA) is associated with spontaneous atrioventricular block and pacing-induced cardiomyopathy. Conduction system pacing is a potential alternative to conventional cardiac resynchronization therapy (CRT). OBJECTIVE: The purpose of this study was to determine the outcomes of conduction system pacing for CCTGA. METHODS: Retrospective data were collected from 10 international centers. RESULTS: His bundle (HBP) or left bundle branch pacing (LBBP) was attempted in 15 CCTGA patients (median age 23 years; 87% male). Previous surgery had been performed in 8 and chronic ventricular pacing in 7. Conduction system pacing (11 HBP, 2 LBBP 2; nonselective in 10, selective in 3) was acutely successful in 13 (86%) without complication. In 9 cases, electroanatomic mapping was available and identified the distal His bundle and proximal left bundle branches within the morphologic left ventricle below the pulmonary valve separate from the mitral annulus. Median implant HV interval was 42 ms (interquartile range [IQR] 35-48), R wave 6 mV (IQR 5-18), and threshold 0.5 V (IQR 0.5-1.2) at median 0.5 ms. QRSd was unchanged compared to junctional escape rhythm (124 vs 110 ms; P = .17) and decreased significantly compared to baseline ventricular pacing (112 vs 164 ms; P <.01). At a median of 8 months, all patients were alive without significant change in pacing threshold or lead dysfunction. New York Heart Association functional class improved in 5 patients. CONCLUSION: Permanent conduction system pacing is feasible in CCTGA by either HBP or proximal LBBP. Narrow paced QRS and stable lead thresholds were observed at intermediate follow-up. Unique anatomic characteristics may favor this approach over conventional CRT.

Mortality Following Pediatric Congenital Heart Surgery: An Analysis of the Causes of Death Derived From the National Death Index.

Background Prior research has focused on early outcomes after congenital heart surgery, but less is known about later risks. We aimed to determine the late causes of death among children (<21 years of age) surviving their initial congenital heart surgery. Methods and Results This is a retrospective cohort study from the Pediatric Cardiac Care Consortium, a US-based registry of interventions for congenital heart defects (CHD). Excluding patients with chromosomal anomalies or inadequate identifiers, we matched those surviving their first congenital heart surgery (1982-2003) against the National Death Index through 2014. Causes of death were obtained from the National Death Index to calculate cause-specific standardized mortality ratios (SMRs). Among 31 132 patients, 2527 deaths (8.1%) occurred over a median follow-up period of 18 years. Causes of death varied by time after surgery and severity of CHD but, overall, 69.9% of deaths were attributed to the CHD or another cardiovascular disorder, with a SMR for CHD/cardiovascular disorder of 67.7 (95% confidence interval: 64.5-70.8). Adjusted odds ratios revealed increased risk of death from CHD/cardiovascular disorder in females [odds ratio=1.28; 95% confidence interval (1.04-1.58); P=0.018] with leading cardiovascular disorder contributing to death being cardiac arrest (16.8%), heart failure (14.8%), and arrhythmias (9.1%). Other major causes of death included coexisting congenital malformations (4.7%, SMR: 7.0), respiratory diseases (3.6%, SMR: 8.2), infections (3.4%, SMR: 8.2), and neoplasms (2.1%, SMR: 1.9). Conclusions Survivors of congenital heart surgery face long-term risks of premature mortality mostly related to residual CHD pathology, heart failure, and arrhythmias, but also to other noncardiac conditions. Ongoing monitoring is warranted to identify target factors to address residual morbidities and improve long-term outcomes.

Trends in Long-Term Mortality After Congenital Heart Surgery.

BACKGROUND: Congenital heart surgery has improved the survival of patients with even the most complex defects, but the long-term survival after these procedures has not been fully described. OBJECTIVES: The purpose of this study was to evaluate the long-term survival of patients (age <21 years) who were operated on for congenital heart defects (CHDs). METHODS: This study used the Pediatric Cardiac Care Consortium data, a U.S.-based, multicenter registry of pediatric cardiac surgery. Survival analysis included 35,998 patients who survived their first congenital heart surgery at <21 years of age and had adequate identifiers for linkage with the National Death Index through 2014. Survival was compared to that in the general population using standardized mortality ratios (SMRs). RESULTS: After a median follow-up of 18 years (645,806 person-years), 3,191 deaths occurred with an overall SMR of 8.3 (95% confidence interval [CI]: 8.0 to 8.7). The 15-year SMR decreased from 12.7 (95% CI: 11.9 to 13.6) in the early era (1982 to 1992) to 10.0 (95% CI: 9.3 to 10.8) in the late era (1998 to 2003). The SMR remained elevated even for mild forms of CHD such as patent ductus arteriosus (SMR 4.5) and atrial septal defects (SMR 4.9). The largest decreases in SMR occurred for patients with transposition of great arteries (early: 11.0 vs. late: 3.8; p < 0.05), complete atrioventricular canal (31.3 vs. 15.3; p < 0.05), and single ventricle (53.7 vs. 31.3; p < 0.05). CONCLUSIONS: In this large U.S. cohort, long-term mortality after congenital heart surgery was elevated across all forms of CHD. Survival has improved over time, particularly for severe defects with significant changes in their management strategy, but still lags behind the general population.

Outcomes after surgical coronary artery revascularisation in children with congenital heart disease.

OBJECTIVE: Surgical coronary revascularisation in children with congenital heart disease (CHD) is a rare event for which limited information is available. In this study, we review the indications and outcomes of surgical coronary revascularisation from the Pediatric Cardiac Care Consortium, a large US-based multicentre registry of interventions for CHD. METHODS: This is a retrospective cohort study of children (<18 years old) with CHD who underwent surgical coronary revascularisation between 1982 and 2011. In-hospital mortality and graft patency data were obtained from the registry. Long-term transplant-free survival through 2014 was achieved for patients with adequate identifiers via linkage with the US National Death Index and the Organ Procurement and Transplantation Network. RESULTS: Coronary revascularisation was accomplished by bypass grafting (n=72, median age 6.8 years, range 3 days-17.4 years) or other operations (n=65, median age 2.6 years, range 5 days-16.7 years) in 137 patients. Most revascularisations were related to the aortic root (61.3%) or coronary anomalies (27.7%), but 10.9% of them were unrelated to either of them. Twenty in-hospital deaths occurred, 70% of them after urgent 'rescue' revascularisation in association with another operation. Long-term outcomes were available by external linkage for 54 patients surviving to hospital discharge (median follow-up time 15.0 years, max follow-up 29.8 years) with a 15-year transplant-free survival of 91% (95% CI 83% to 99%). CONCLUSIONS: Surgical coronary revascularisation can be performed in children with CHD with acceptable immediate and long-term survival. Outcomes are dependent on indication, with the highest mortality in rescue procedures.

Long-Term Transplant-Free Survival After Repair of Total Anomalous Pulmonary Venous Connection.

BACKGROUND: Long-term survival, risk of transplantation, and causes of death after repair of total anomalous pulmonary venous connection (TAPVC) remain unknown. By linking the Pediatric Cardiac Care Consortium with the National Death Index and the United Network for Organ Sharing, we evaluated long-term transplant-free survival in children undergoing repair of TAPVC. METHODS: We identified 777 infants within the Pediatric Cardiac Care Consortium who underwent TAPVC repair (median 21 days; interquartile range, 5 to 80) and had sufficient personal identifiers for linkage with the National Death Index and United Network for Organ Sharing. Sixty-six deaths, ten cardiac transplantations, and one bilateral lung transplantation had occurred by the end of 2014. Data collected included age and weight at time of procedure, TAPVC type, associated cardiac lesions, and postoperative length of stay. The study cohort was divided into simple and complex TAPVC based on the presence of an associated cardiac lesion. Parametric survival plots were constructed, and risk factor analyses were performed to identify demographic and clinical characteristics associated with long-term outcomes. RESULTS: Mortality or need for transplantation was 9.7% with a median follow-up of 18.4 years and a median age of death or transplant of 0.74 years. The risk of mortality and transplant after TAPVC repair was highest during the first 18 months after hospital discharge. Cardiac causes accounted for the majority of deaths. Multivariate regression models for transplant-free survival demonstrated that complex TAPVC, mixed TAPVC, and postoperative length of stay were associated with increased risk of death/transplant. CONCLUSIONS: Transplant-free survival after TAPVC repair is excellent, with most deaths or transplant events occurring early. Factors associated with the worst long-term outcomes included complex TAPVC, mixed TAPVC, and prolonged postoperative length of stay.

Hereditary arrhythmias and cardiomyopathies: decision-making about genetic testing.

PURPOSE OF REVIEW: The modern field of clinical genetics has advanced beyond the traditional teachings familiar to most practicing cardiologists. Increased understanding of the roles of genetic testing may improve uptake and appropriateness of use. RECENT FINDINGS: Clinical genetics has become integral to the management of patients with hereditary arrhythmia and cardiomyopathy diagnoses. Depending on the condition, genetic testing may be useful for diagnosis, prognosis, treatment, family screening, and reproductive planning. However, genetic testing is a powerful tool with potential for underuse, overuse, and misuse. In the absence of a substantial body of literature on how these guidelines are applied in clinical practice, we use a case-based approach to highlight key lessons and pitfalls. Importantly, in many scenarios genetic testing has become the standard of care supported by numerous class I recommendations; genetic counselors can improve accessibility to and appropriate use and application of testing. SUMMARY: Optimal management of hereditary arrhythmias and cardiomyopathies incorporates genetic testing, applied as per consensus guidelines, with involvement of a multidisciplinary team.

Congenital Diaphragmatic Hernia with Liver Herniation into the Pericardial Sac in a 30-Week Gestation Infant.

Anterior diaphragmatic defects with pericardial involvement are extremely rare and diagnostically challenging entities encountered perinatally. While a majority of diaphragmatic defects occur in isolation, others are associated with multiple defects forming a complex of syndromes such as Pentalogy of Cantrell. Liver herniation into the pericardial sac poses a particular challenge and can mimic a pericardial tumor on prenatal ultrasound, yielding a different management course. The following case is an unusual presentation of a 30-week gestation female with an anterior midline diaphragmatic defect with liver herniation mimicking as a pericardial tumor, diagnosed at time of autopsy. Postmortem studies also found multiple congenital anomalies including an atrioventricular septal defect and midline gumline defect suggesting at least a partial Pentalogy of Cantrell or variant. Early recognition and screening for associated anomalies are essential for management in this subset of patients.

Factors Affecting Length of Postoperative Hospitalization for Pediatric Cardiac Operations in a Large North American Registry (1982-2007).

Surgical treatment of congenital heart disease represents a major cause of pediatric hospitalization and healthcare resource use. Larger centers may provide more efficient care with resulting shorter length of postoperative hospitalization (LOH). Data from 46 centers over 25 years were used to evaluate whether surgical volume was an important determinant of LOH using a competing risk regression strategy that concurrently accounted for deaths, transfers, and discharges with some time interactions. Earlier discharge was more likely for infants and older children compared to neonates [subhazard ratios at postoperative day 6 of 1.64 (99 % confidence interval (CI) 1.57, 1.72) and 2.67 (99 % CI 2.53, 2.80), respectively], but less likely for patients undergoing operations in Risk Adjustment for Congenital Heart Surgery categories 2, 3, 4, and 5/6 compared to category 1 [subhazard ratios at postoperative day 6 of 0.66 (99 % CI 0.64, 0.68), 0.34 (95 % CI 0.33, 0.35), 0.28 (99 % CI 0.27, 0.30), and 0.10 (99 % CI 0.09, 0.11), respectively]. There was no difference by sex [non-time-dependent subhazard ratio 1.019 (99 % CI 0.995, 1.040)]. For every 100-operation increase in center annual surgical volume, the non-time-dependent subhazard for discharge was 1.035 (99 % CI 1.006, 1.064) times greater, and center-specific exponentiated random effects ranged from 0.70 to 1.42 with a variance of 0.023. The conditional discharge rate increased with increasing age and later era. No sex-specific difference was found. Centers performing more operations discharged patients sooner than lower volume centers, but this difference appears to be too small to be of clinical significance. Interestingly, unmeasured institutional characteristics estimated by the center random effects were variable, suggesting that these played an important role in LOH and merit further investigation.

Catecholaminergic polymorphic ventricular tachycardia in children: analysis of therapeutic strategies and outcomes from an international multicenter registry.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation are not well validated. We sought to define treatment outcomes in children with catecholaminergic polymorphic ventricular tachycardia. METHODS AND RESULTS: This is a Pediatric and Congenital Electrophysiology Society multicenter, retrospective cohort study of catecholaminergic polymorphic ventricular tachycardia patients diagnosed before 19 years of age. The cohort included 226 patients, including 170 probands and 56 relatives. Symptomatic presentation was reported in 176 (78%). Symptom onset occurred at 10.8 (interquartile range, 6.8-13.2) years with a delay to diagnosis of 0.5 (0-2.6) years. Syncope (P<0.001), cardiac arrest (P<0.001), and treatment failure (P=0.008) occurred more often in probands. ß-Blockers were prescribed in 205 of 211 patients (97%) on medication, and 25% experienced at least 1 treatment failure event. Implantable cardioverter defibrillators were placed in 121 (54%) and was associated with electrical storm in 22 (18%). Flecainide was used in 24% and left cardiac sympathetic denervation in 8%. Six deaths (3%) occurred during a cumulative follow-up of 788 patient-years. CONCLUSIONS: This study demonstrates a malignant phenotype and lengthy delay to diagnosis in catecholaminergic polymorphic ventricular tachycardia. Probands were typically severely affected. ß-Blockers were almost universally initiated; however, treatment failure, noncompliance and subtherapeutic dosing were often reported. Implantable cardioverter defibrillators were common despite numerous device-related complications. Treatment failure was rare in the quarter of patients on flecainide. Left cardiac sympathetic denervation was not uncommon although the indication was variable.

Age-dependent sex effects on outcomes after pediatric cardiac surgery.

BACKGROUND: Sex has been linked to differential outcomes for cardiovascular disease in adults. We examined potential sex differences in outcomes after pediatric cardiac surgery. METHODS AND RESULTS: We retrospectively analyzed data from the Pediatric Cardiac Care Consortium (1982-2007) by using logistic regression to evaluate the effects of sex on 30-day within-hospital mortality after pediatric (<18 years old) cardiac operations and its interaction with age, risk category, z-score for weight, and surgical year for the whole cohort. Of 76 312 operations, 55% were in boys. Unadjusted mortality was similar for boys and girls (5.2% versus 5.0%, P=0.313), but boys were more likely to have cardiac surgery as a neonate and to have more complex operations. After adjustment, the overall test of any association between postsurgical mortality and sex was significant (P=0.002), but the overall test of any interaction was not (P=0.503). However, a potential age-dependent sex effect on postsurgical mortality was observed among infants subjected to high-risk operations, with girls doing worse during the first 6 months of life. CONCLUSIONS: Patient sex has a significant effect on mortality after pediatric cardiac operations, with an increased risk of death in early infancy for girls after high-risk cardiac operations. This age-dependent relationship supports a sex-related biological effect on postoperative cardiovascular stress.

Two-ventricle repairs in the unbalanced atrioventricular canal defect spectrum with midterm follow-up.

OBJECTIVES: Unbalanced atrioventricular (AV) canal defects include a hypoplastic ventricle (HV) and AV valve (HAVV) precluding complete 2-ventricle repairs (2VRs). Catch-up growth would solve this problem and was induced by increasing HAVV flow. The objectives were to assess reliability of HV and HAVV growth and provide 5- to 15-year 2VR follow-up. METHODS: From 1990 to 2005, 23 consecutive infants (13 females and 10 males) with echo-diagnosed unbalanced AV canal defects (n = 20) or subsets (n = 3) underwent 2VRs. HV volumes (18 left and 5 right) and HAVV sizes estimated from biplane echoes and z values (standard deviation from expected) were determined. Hypoplasia was defined by a z value of less than -2.0. Three operative approaches were used: (1) Staged repairs (n = 9) had complete AVV repairs with partial atrial septal defect and ventricular septal defect closures, which increased HAVV flow and maintained stability. The septal defects were closed later. (2) An asymmetric valve partition (n = 8) was used to increase HAVV size. (3) For moderate hypoplasia, HAVV flow was increased and ASDs/VSDs were left for stability (n = 6). Follow-up at 5 to 19 years was done locally. RESULTS: Staged repairs began at 20 to 328 days (average, 129 days) and were completed 5 to 145 days later (average, 101 days). Midterm survival was 87% (20/23) after 1 central nervous system bleed after trial weaning from extracorporeal membrane oxygenation and 2 later deaths from hyperkalemia. Reoperations for AVV regurgitation (n = 3), AVV stenosis (n = 1), and mitral valve replacement (n = 1) were satisfactory. On follow-up, all hypoplastic structures (HV and HAVV) had grown to normal size. Two patients "doing well" were lost to follow-up. Survivors have satisfactory 2VRs, with 15 of 18 taking no cardiac failure medications. CONCLUSIONS: Reliable HV/HAVV catch-up growth was induced, and all midterm 2VRs were satisfactory.

Frequency of superior vena cava obstruction in pediatric heart transplant recipients and its relation to previous superior cavopulmonary anastomosis.

The risk factors for superior vena cava (SVC) obstruction after pediatric orthotopic heart transplantation (OHT) have not been identified. This study tested the hypothesis that pretransplant superior cavopulmonary anastomosis (CPA) predisposes patients to SVC obstruction. A retrospective review of the Pediatric Cardiac Care Consortium registry from 1982 through 2007 was performed. Previous CPA, other cardiac surgeries, gender, age at transplantation, and weight at transplantation were assessed for the risk of developing SVC obstruction. Death, subsequent OHT, or reoperation involving the SVC were treated as competing risks. Of the 894 pediatric OHT patients identified, 3.1% (n = 28) developed SVC obstruction during median follow-up of 1.0 year (range: 0 to 19.5 years). Among patients who developed SVC obstruction, 32% (n = 9) had pretransplant CPA. SVC surgery before OHT was associated with posttransplant development of SVC obstruction (p <0.001) after adjustment for gender, age, and weight at OHT and year of OHT. Patients with previous CPA had increased risk for SVC obstruction compared with patients with no history of previous cardiac surgery (hazard ratio 10.6, 95% confidence interval: 3.5 to 31.7) and to patients with history of non-CPA cardiac surgery (hazard ratio 4.7, 95% confidence interval: 1.8 to 12.5). In conclusion, previous CPA is a significant risk factor for the development of post-heart transplant SVC obstruction.

Surgical volume and center effects on early mortality after pediatric cardiac surgery: 25-year North American experience from a multi-institutional registry.

Mortality after pediatric cardiac surgery varies among centers. Previous research suggests that surgical volume is an important predictor of this variation. This report characterizes the relative contribution of patient factors, center surgical volume, and a volume-independent center effect on early postoperative mortality in a retrospective cohort study of North American centers in the Pediatric Cardiac Care Consortium (up to 500 cases/center/year). From 1982 to 2007, 49 centers reported 109,475 operations, 85,023 of which were analyzed using hierarchical multivariate logistic regression analysis. Patient characteristics varied significantly among the centers. The adjusted odds ratio (OR) for mortality decreased more than 10-fold during the study period (1982 vs. 2007: OR, 12.27, 95 % confidence interval [CI], 8.52-17.66; p < 0.0001). Surgical volume was associated inversely with odds of death (additional 100 cases/year: OR, 0.84; 95 % CI, 0.78-0.90; p < 0.0001). In the analysis of interactions, this effect was fairly consistent across age groups, risk categories (except the lowest), and time periods. However, a volume-independent center effect contributed substantially more to the risk model than did the volume. The Risk Adjusted Classification for Congenital Heart Surgery, version 1 (RACHS-1) risk category remains the strongest predictor of postoperative mortality through the 25-year study period. In conclusion, center-specific variation exists but is only partially explained by operative volume. Low-risk operations are safely performed at centers in all volume categories, whereas regionalization or other quality improvement strategies appear to be warranted for moderate- and high-risk operations. Potentially preventable mortality occurs at centers in all volume categories studied, so referral or regionalization strategies must target centers by observed outcomes rather than assume that volume predicts quality.

Surgical Placement of Permanent Epicardial Pacing Systems in Very Low-Birth Weight Premature Neonates: A Review of Data From the Pediatric Cardiac Care Consortium (PCCC).

UNLABELLED: Few studies have characterized the surgical outcomes following epicardial pacemaker placement in very low-birth weight infants with congenital complete heart block. This study was undertaken to review the surgical experience with this patient population based on data from a large multi-institutional registry. METHODS: The Pediatric Cardiac Care Consortium (PCCC) multi-institutional database was retrospectively reviewed to identify premature, low-birth weight neonates that underwent surgical placement of an epicardial pacing system for heart block. We reviewed 179 patients with birth weights less than 1.5 kg that underwent a major operative procedure. Of these, 10 patients underwent surgical placement of an epicardial pacing system for heart block. Patients had heart block in otherwise structurally normal hearts (n = 6) or heart block associated with complex structural congenital cardiac anomalies (n = 4). RESULTS: There were no deaths directly related to the surgical placement of the epicardial pacing system. There were no immediate complications with either lead or generator placement. One generator pocket was revised three months following placement. Survival to discharge was 60%. The four deaths occurred at a mean of 11 days (range 1-45 days) following the procedure. CONCLUSIONS: Neonates born with prematurity and congenital heart block represent a challenging subset of patients with significant mortality. Generator pocket breakdown and infection have been considered barriers to optimal short- and long-term outcomes. Among cases in the PCCC, there were no deaths or major complications that could be attributed to permanent epicardial pacemaker placement. These data suggest that an aggressive surgical strategy may be justified.

Letal, A tumor-associated NKG2D immunoreceptor ligand, induces activation and expansion of effector immune cells.

NKG2D serves as one of the most potent activating receptors for effector lymphocytes. in peripheral tissues. Here we report the characterization of Letal, the first human trans-membrane NKG2D ligand lacking an immunoglobulin-like alpha-3 ectodomain. Letal is constitutively expressed by a variety of normal tissues, and is upregulated in tumor cells of different origins. Unlike other NKG2D ligands, Letal mRNA expression progressively decreased after treatment of tumor cells with retinoic acid. Simultaneous T-cell receptor activation and engagement of Letal stimulated proliferation of CD8(+) cells and dramatically increased IL-2 and IFNgamma secretion. In addition, Letal induced the killing of cancer cells by CD8(+) and NK cells. These results suggest that Letal delivers activating signals to NK cells and promotes tumor immune surveillance by inducing the expansion of anti-tumor cytotoxic lymphocytes.