Successful 2-Stage Pacemaker Implantation for Atrioventricular Block in a Low-Birth-Weight Infant with Congenital Heart Disease: Case Report.

Congenital heart block is a potentially life-threatening condition with high morbidity and mortality, especially in the presence of congenital heart disease. We present the case of a low-body-weight premature infant with complex single ventricle congenital heart disease and high-grade atrioventricular block. A 2-staged pacing approach provided atrio-ventricular synchrony and allowed her to grow until a permanent dual-chamber pacemaker system could be implanted.

An intra-aortic guide wire: what "knot" to do.

We report a rare complication of central venous catheter placement in a 5-month-old baby.

Reanastomosis and rehabilitation of interrupted left pulmonary artery derived from atretic ductus.

True absence of a branch pulmonary artery is rare. We identified a patient initially diagnosed with an absent left pulmonary artery at a previous hospital. Due to disagreement in the initial diagnosis, she had a diagnostic catheterisation, which revealed an isolated left pulmonary artery off the left innominate artery via a ductus. The ductus was recanalised with serial stenting and balloon dilatation followed by reanastomosis to the main pulmonary artery. In a patient who initially is diagnosed with an absent pulmonary artery, an alternative diagnosis, such as this case report, should be considered.

Timing of adding blood to prime affects inflammatory response to neonatal cardiopulmonary bypass.

Complications from systemic inflammation are reported in neonates following exposure to cardiopulmonary bypass. Although the use of asanguinous primes can reduce these complications, in neonates, this can result in significant haemodilution, requiring addition of blood. This study investigates whether the addition of blood after institution of bypass alters the inflammatory response compared with a blood prime. Neonatal swine were randomised into four groups: blood prime, blood after bypass but before cooling, blood after cooling but before low flow, and blood after re-warming. All groups were placed on central bypass, cooled, underwent low flow, and then re-warmed for a total bypass time of 2 hours. Although haematocrit values between groups varied throughout bypass, all groups ended with a similar value. Although they spent time with a lower haematocrit, asanguinous prime groups did not have elevated lactate levels at the end of bypass compared with blood prime. Asanguinous primes released less tumour necrosis factor α than blood primes (p=0.023). Asanguinous primes with blood added on bypass produced less interleukin 10 and tumour necrosis factor α (p=0.006, 0.019). Animals receiving blood while cool also showed less interleukin 10 and tumour necrosis factor α production than those that received blood warm (p=0.026, 0.033). Asanguinous primes exhibited less oedema than blood primes, with the least body weight gain noted in the end cool group (p=0.011). This study suggests that using an asanguinous prime for neonates being cooled to deep hypothermia is practical, and the later addition of blood reduces inflammation.

Development of chylous ascites in an infant with ventricular septal defect: a case report.

This case report describes chylous ascites associated with a CHD in a 4-month-old infant. Although atraumatic chylous ascites are a rare clinical finding, the recognition and treatment of chylous ascites influence the timing of cardiac surgery.

A modification of the pulmonary autograft procedure to prevent late autograft dilatation.

Although the pulmonary autograft procedure for aortic valve replacement is a commonly utilized option for children, its use is diminishing in adult-aged patients. One commonly cited concern is the tendency for the pulmonary autograft to dilate in the aortic position. This article reviews a technique we have used in 36 patients since October, 2004 that stabilizes the autograft so that it cannot dilate. There have been no operative or late deaths and the autograft has continued to function in 34 patients. Two patients have undergone autograft replacement because of early failure, which we believe was likely related to technical considerations in our early technique (first reported in the 2005 STCVS Pediatric Cardiac Surgery Annual). The technical modifications described in this article have produced a more reliable and reproducible technique and have not resulted in any autograft failures in our experience. One patient with Marfan's syndrome and a bicuspid aortic valve is symptom- and dilation-free 8 years post op, with no autograft or pulmonary homograft insufficiency, normal activity and a stable aortic root by serial echocardiography. Our results suggest that this technique might be applicable for selected adult patients in whom autograft growth is not necessary and for whom the risk of autograft dilatation would provide a reason to avoid a pulmonary autograft procedure.

Neonatal ascending aortic thrombus: successful medical treatment.

Neonatal aortic thrombosis is a potentially life-threatening condition with significant morbidity and mortality if undiagnosed and untreated. The most common location of arterial thrombosis in neonates is in the abdominal aorta and is associated with umbilical artery catheterisation. There are only a few previous reports of thrombosis in the ascending aorta. We describe a case of ascending aortic thrombosis in a neonate who underwent successful thrombolytic therapy.

Anomalous left coronary artery from the pulmonary arteryin an adult.

Anomalous left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital heart defect that usually presents before the age of 1 year. Several surgical options exist for the correction of ALCAPA; however, debate continues regarding the optimal repair technique in adult populations. We report the case of successful surgical repair of ALCAPA with a direct aortic implantation technique in a 44-year-old mother of 4 children.

Critical COVID-19 Complicating Recovery From Surgical Repair of Congenital Heart Disease.

This case highlights the need for accurate and rapid testing for severe acute respiratory syndrome coronavirus 2 and also underscores the need for caregivers to remain vigilant for coronavirus disease 2019 in the postoperative setting despite negative preoperative testing.

Pentalogy of Cantrell with double-outlet right ventricle: a case of surgical correction.

Pentalogy of Cantrell is characterised by a combination of severe defects in the middle of the chest including the sternum, diaphragm, heart, and abdominal wall. Mortality rate after cardiac surgery is usually high. We report a successful total correction of the cardiac defects in a case of Pentalogy of Cantrell with a double-outlet right ventricle prior to abdominal wall defect repair.

Thoracoscopic Resection of Left Atrial Appendage Aneurysm in a 16-Year-Old Boy.

We report a case of a left atrial appendage aneurysm (LAAA) in a 16-year-old boy presenting with supraventricular tachycardia (SVT). The aneurysm was detected incidentally on a routine echocardiogram performed before an electrophysiology study for evaluation and management of the SVT. The aneurysm was successfully resected under cardiopulmonary bypass through video-assisted thoracoscopic surgery. This type of surgery is a useful approach for LAAA in the pediatric population.

Use of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

Our aim was to evaluate the potential use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. The DexAide titanium stator was replaced by a zirconia stator in several blood pump builds, without changing the remaining pump hardware components. In vitro pump performance and efficiency were evaluated at a predetermined pump speed and flow. Motor power consumption decreased by 20%, and DexAide battery life was extended to over 12 h on two fully charged batteries. The zirconia stator was also successfully evaluated in a severe start/stop test pre- and postexposure of the zirconia to accelerated simulated biologic aging. This study's outcomes indicated the advantages of zirconia as an alternate journal bearing material for the DexAide device.

In vivo evaluation of zirconia ceramic in the DexAide right ventricular assist device journal bearing.

Zirconia is a ceramic with material properties ideal for journal bearing applications. The purpose of this study was to evaluate the use of zirconium oxide (zirconia) as a blood journal bearing material in the DexAide right ventricular assist device. Zirconia ceramic was used instead of titanium to manufacture the DexAide stator housing without changing the stator geometry or the remaining pump hardware components. Pump hydraulic performance, journal bearing reliability, biocompatibility, and motor efficiency data of the zirconia stator were evaluated in six chronic bovine experiments for 14-91 days and compared with data from chronic experiments using the titanium stator. Pump performance data including average in vivo pump flows and speeds using a zirconia stator showed no statistically significant difference to the average values for 16 prior titanium stator in vivo studies, with the exception of a 19% reduction in power consumption. Indices of hemolysis were comparable for both stator types. Results of coagulation assays and platelet aggregation tests for the zirconia stator implants showed no device-induced increase in platelet activation. Postexplant evaluation of the zirconia journal bearing surfaces showed no biologic deposition in any of the implants. In conclusion, zirconia ceramic can be used as a hemocompatible material to improve motor efficiency while maintaining hydraulic performance in a blood journal bearing application.

Valve-sparing replacement of the aortic root for a 2-year-old child with Loeys-Dietz syndrome.

Loeys-Dietz syndrome is a newly recognized constellation that presents with aortic aneurysm or dissection similar to Marfan's syndrome. We describe successful surgical treatment in a 2-year-old with the syndrome in whom we performed a valve-sparing replacement of the aortic root because of significant dilation of the aortic root and the ascending aorta.

Thoracic duct embolization in kaposiform lymphangiomatosis.

An 11-year-old girl with kaposiform lymphangiomatosis presented with recurrent chylous pericardial effusions that were refractory to pericardial drainage and medical therapy. Magnetic resonance imaging demonstrated a prominent lymphatic duct with anterior mediastinal extension into the left clavicular region and a region of high signal that was favored to represent a low-flow lymphatic malformation. The patient underwent direct access thoracic duct lymphangiography with thoracic duct embolization and sclerotherapy of the large left-sided neck and pericardial lymphatic malformation. After the procedure, her pericardial effusions resolved, and she has remained asymptomatic for 15 months.

Human clinical fitting study of the DexAide right ventricular assist device.

The DexAide right ventricular assist device (RVAD) has been developed as an implantable RVAD. The purpose of this study was to determine the final design and optimal anatomical placement of the DexAide RVAD when implanted simultaneously with either of two commercially available left ventricular assist devices (LVADs) in patients. A mock-up DexAide RVAD was used to assess configuration with each of two types of commercially available LVADs at the time of LVAD implantation in three human clinical cases. The pump body of the DexAide RVAD was placed either in the preperitoneal space or in the right thoracic cavity. The DexAide RVAD placed into the right thoracic cavity is suitable for use with the Novacor or HeartMate II LVADs. The results of this study will guide the finalization of the inflow cannula and optimal placement of the DexAide RVAD for human clinical trials.

Preoperative risk factors for mortality after biventricular assist device implantation.

BACKGROUND: A right ventricular assist device is a treatment option for patients with severe right ventricular failure after left ventricular assist device (LVAD) implantation. Recognition of risk factors for mortality after biventricular assist device (BiVAD) implantation is important for patient selection and optimal outcomes. METHODS: We reviewed our experiences between 1991 and 2005 in 44 patients who were supported by both an LVAD and a right ventricular assist device. RESULTS: Thirteen patients (30%) survived until heart transplantation, and 31 patients (70%) died while on support. The multivariate analysis shows that post-LVAD extracorporeal membrane oxygenation and worsening renal function are associated with the highest postoperative mortality. The univariate analysis also included previous thoracic surgery and ischemic cardiomyopathy as potential preoperative indicators for poor outcome after BiVAD implants. No differences were observed in the rates for the need of preoperative support with a ventilator, an intra-aortic balloon pump, or extracorporeal membrane oxygenation, or in the rates of postoperative complications between survivors and nonsurvivors. CONCLUSIONS: BiVAD implantation remains one of the challenges in treating severe heart failure. Previous cardiac surgery, elevated creatinine, and post-LVAD extracorporeal membrane oxygenation were risk factors for mortality after BiVAD implantation. Dialated Cardiomyopathy on the other hand was associated with a more favorable outcome.

Phasic coronary blood flow patterns in dogs vs. pigs: an acute ischemic heart study.

BACKGROUND: Canine and porcine hearts have been widely used to investigate diagnoses, interventions, and surgical therapies for ischemic heart disease. Dogs and pigs are known to vary with regard to the anatomic distribution of their coronary arteries. However, the mechanisms of these differences and the differing phasic coronary blood flow patterns between the two species are not well characterized. MATERIAL/METHODS: Phasic coronary blood flow patterns and hemodynamic data were analyzed using three flow probes placed around the left anterior descending (LAD), left circumflex (LCX), and right coronary (RCA) arteries in both canine and porcine models. RESULTS: Systolic left ventricular pressure, arterial pressure, and systemic vascular resistance in dogs were higher than in pigs. Likewise, total coronary blood flow, LAD flow, and LCX flow were higher in dogs than in pigs. LCX flow was higher in dogs, but RCA flow was higher in pigs. Diastolic fraction and diastolic/systolic peak velocity ratio of the LAD, LCX, and RCA showed no significant differences at baseline between dogs and pigs. Systolic LAD flow in dogs decreased after the creation of an LAD stenosis, whereas systolic LAD flow in pigs increased. CONCLUSIONS: Coronary blood flow patterns in dogs and pigs are quite different. These findings are potentially relevant to understanding the physiology of myocardial blood perfusion in dogs and pigs with ischemic heart disease.

Innovative, replaceable heart valve: concept, in vitro study, and acute in vivo study.

The purpose of this study was to evaluate the feasibility of our innovative, replaceable heart valves that can be easily detached from the sewing ring at the time of repeat replacement. The prototype devices consist of the base magnet ring assembly and the valve magnet ring assembly that utilize magnetic coupling force for the locking mechanism. Magnetic coupling strength was evaluated in vitro. Prototype bioprosthetic valves were implanted acutely in three sheep to confirm the feasibility of the replaceable mitral valve. The static separation force of prototype size #25 was 12.5 lb, meeting the design goal. In situ attachment and detachment of the valve magnet ring assembly from the base magnet ring assembly were very easily accomplished in all animals. The magnetic coupling did not decouple even under extremely high left ventricular pressures. We have demonstrated the feasibility of this innovative concept of a replaceable mitral valve.

Heart rate variability in a progressive heart failure model with rapid ventricular pacing.

BACKGROUND: Heart rate variability (HRV) is an indicator of autonomic nervous system functionality and a recognized predictor of cardiac death; however, the changes in HRV occurring in progressive heart failure are not fully understood. The purpose of this study was to evaluate the progressive changes of autonomic system activity in progressive heart failure by rapid ventricular pacing in an animal model. METHODS: Heart failure was induced in 13 mongrel dogs (27.8 +/- 3.7 kg) by rapid ventricular pacing (230 beats/min) for 4 weeks and maintenance of pacing at a reduced rate (190 beats/min) for 2 weeks. Time domain analysis and spectral analysis of HRV were performed with the MemCalc system after 30 minutes of pacing cessation every week. Hemodynamic and echocardiographic data were obtained before and after induction of heart failure. RESULTS: Cardiac output decreased significantly (3.6 L/min versus 1.6 L/min, P < .001) after 6 weeks of ventricular pacing. Significantly increased were the heart rate (126 beats/min versus 138 beats/min, P < .05), left ventricular end-diastolic pressure (9.1 mm Hg versus 30.9 mm Hg, P < .001), and pulmonary capillary wedge pressure (8.0 mm Hg versus 18.7 mm Hg, P < .001). High-frequency components progressively decreased. Low-frequency components progressively decreased except at 5 weeks after the pacing. A ratio of low- to high-frequency components increased in moderate heart failure and decreased in severe heart failure. CONCLUSIONS: Changes in the high-frequency component and low-frequency component are important for assessing heart failure in progressive heart failure. Serial follow-up measurements of HRV might be helpful for patients with such disease.