Suzanne Vobecky

Thirty years of experience with epicardial pacing in children

Due to underlying cardiovascular anatomy and size, epicardial pacing may be the preferred method of pacing in small children. To assess long-term safety, we reviewed all epicardial pacemakers implanted in children between 1971 and 2001. We found that 122 patients, with a median age of 5.4 years, had a total of 181 pacemakers and 260 electrodes implanted over a total follow-up of 789 patient-years. Of the total, 12 patients died after the first implantation, with one death attributable to dysfunction of the pacemaker. Reintervention was required in 75 patients after 5.0 +/- 3.2 years, due to depletion of the battery in 45 patients (60%), fracture or dysfunction of electrodes in 27 patients (36%), and infection in 3 patients (4%). In univariate analyses, risk factors for reintervention were an approach via a median sternotomy, with a relative risk of 2.3 (p = 0.0087), and an indication for pacing other than atrioventricular block, with a relative risk of 1.7 (p = 0.0314). In multivariate analyses, the approach via the median sternotomy independently predicted the need for reintervention, with a relative risk of 2.1, and 95% confidence intervals from 1.1 to 4.1 (p = 0.0256). The longevity of the second pacemaker and/or its electrode, assessed in 26 patients, was 3.7 +/- 2.6 years, not shorter than the first implantation (p = 0.4037). We conclude that epicardial pacing is a reliable means of achieving permanent pacing in children, with low morbidity and mortality. A substantial proportion, nonetheless, requires reintervention within five years, warranting meticulous follow-up.

Treatment of Isolated Ventricular Septal Defects in Children: Amplatzer Versus Surgical Closure

BACKGROUND Isolated hemodynamically significant ventricular septal defects (VSD) were previously treated surgically. Since the introduction of percutaneous (PC) devices, the management of isolated VSD has evolved. In our center, Amplatzer devices have been implanted for selected isolated perimembranous VSD since 2002. METHODS The charts of all isolated PC perimembranous VSD closures and all surgical closures performed since 2002 were reviewed retrospectively. Clinical, electrocardiographic, and echocardiographic data were analyzed. The preclosure, immediate postclosure, and 1-month, 6-month, and 12-month postclosure results were assessed. RESULTS Thirty-seven patients underwent PC closure, and 34 had surgical treatment. Mean follow-up was 42.1 ± 26.0 months. The PC group was significantly older (p < 0.01) and larger in size (p < 0.001). Surgical patients had more severe congestive heart failure and a significantly lower VSD gradient (p < 0.004). At follow-up, there were no differences in the incidence of residual shunting between the two groups (p = 0.92). All valvular regurgitations improved over time, except for 3 aortic regurgitations (5.4%) in the PC group that got worse. Two permanent pacemakers were implanted for early complete heart block in the PC group, and one was implanted in the surgical group (p = 0.94). CONCLUSIONS The surgical results in our population were excellent. The selection of patients with perimembranous VSD remains a challenge to avoid post-PC intervention complications such as heart block and aortic insufficiency. For isolated VSD, PC closure, which avoids the morbidity of open heart surgery, should be considered as part of the therapeutic armamentarium.

Experience in a single centre with percutaneous aortic valvoplasty in children, including those with associated cardiovascular lesions

BACKGROUND We report the experience in a single institution with balloon aortic valvoplasty for congenital aortic stenosis. Unlike most other reported series, we included patients with associated lesions involving the left side of the heart. METHODS Between November, 1986, and November, 2006, we performed 161 interventions on 143 patients, of whom 33 were neonates, 33 infants, and 77 children, just over one-quarter (28.6%) having associated lesions. RESULTS The overall reduction in peak-to-peak gradient of 60 ± 24% (p < 0.01), was more effective in primary versus secondary intervention (63 ± 24% versus 47 ± 23%; p < 0.03), and in those with fused bifoliate as opposed to truly bifoliate valves (66 ± 17% versus 53 ± 30%; p = 0.01). Patients with associated lesions were younger (40.89 ± 60.92 months versus 81.9 ± 72.9 months; p = 0.001), and were less likely to achieve a final pressure gradient of less than 20 mmHg (35.0% versus 61.2%; p < 0.01). Overall mortality was higher in cases with associated lesions (27.5% versus 1.9%; p < 0.0001) but not catheter-related death (2.5% versus 1.9%; p = 1.0). Reintervention was more frequently required in infants (p = 0.02) but not in cases with associated lesions (p = 0.35). CONCLUSIONS Balloon valvoplasty is a safe and effective method for the treatment of congenital aortic stenosis. Prior surgery to the aortic valve, reintervention, associated cardiovascular lesions, and the anatomy of the valve predict a less effective reduction in the gradient. Major complications and catheterization-related death are mainly secondary to very young age, but not to associated cardiac lesions.

Peripheral blood flow responses to exercise after successful correction of coarctation of the aorta

OBJECTIVES The purpose of this study was to characterize peripheral flow kinetics in response to progressive discontinuous maximal exercise in 10 patients who underwent repair of coarctation of the aorta and 11 age-matched healthy adolescents. BACKGROUND An impairment of leg blood flow has been suggested on the basis of exaggerated femoral muscle lactate accumulation in patients with successful repair of coarctation. Few data are available describing blood flow kinetics of the exercising leg in such patients. METHODS Duplex ultrasound provided transcutaneous measurements of peak systolic and end-diastolic flow velocities of the femoral, humeral and renal arteries at rest and immediately after mild, moderate and maximal exercise intensities for computation of mean velocity, resistance index and femoral blood flow. RESULTS Femoral mean velocity and femoral blood flow increased linearly with exercise intensity in both groups, but the slope of this increase was significantly lower in patients. Similarly, humeral mean velocity increased significantly less in patients than in control subjects. Femoral resistance index sharply decreased from that at rest (patients [mean +/- SE] 1.4 +/- 0.04; control subjects 1.4 +/- 0.03) to mild exercise intensity in both groups (patients 0.69 +/- 0.03; control subjects 0.72 +/- 0.03). A further decrease was observed at maximal exercise in patients (0.60 +/- 0.04, p = 0.08) but not in control subjects (0.69 +/- 0.02). CONCLUSIONS These observations suggest that despite a greater exercise-induced femoral vasodilation, patients with successful correction of coarctation of the aorta demonstrate an impaired lower limb blood flow in response to strenuous dynamic exercise. In the absence of stenosis at rest, this alteration could result from exaggerated flow turbulence in the descending aorta distal to the site of correction because of loss of elasticity at the site of the resection of the coarcted segment.

Left Atrial Inexcitability in Children With Congenital Lupus‐Induced Complete Atrioventricular Block

Background Congenital atrioventricular block is a well‐established immunologic complication of maternal systemic lupus erythematosus. We sought to further characterize the electrophysiological manifestations of maternal systemic lupus erythematosus on neonatal atria. Methods and Results Cases of isolated congenital atrioventricular block treated at our center over the past 41 years were identified. Data were extracted from clinical charts, pacemaker interrogations, ECGs, echocardiograms, and histopathological reports, when available. Of 31 patients with isolated congenital atrioventricular block, 18 were negative for maternal antibodies and had normal epicardial atrial sensing and pacing thresholds. In contrast, 12 of 13 patients with positive maternal antibodies had epicardial pacemakers, 5 (42%) of whom had left atrial (LA) inexcitability and/or atrial conduction delay. In 3 patients, the LA could not be captured despite high‐output pacing. The fourth patient had acutely successful LA appendage and left ventricular lead placement. At early follow‐up, an increased delay between the surface P‐wave and intracardiac atrial depolarization was observed, indicative of atrial conduction delay. The fifth patient exhibited LA lead dysfunction, with atrial under‐sensing and an increased capture threshold, 2 weeks after implantation. Biopsies of LA appendages performed in 2 patients showed no evidence of atrial fibrosis or loss of atrial myocytes. Conclusions Herein, we report previously undescribed yet prevalent electrophysiological ramifications of maternal systemic lupus erythematosus, which extend beyond congenital atrioventricular block to encompass alterations in LA conduction, including LA inexcitability. These manifestations can complicate epicardial pacemaker implantation in newborns. In the absence of histological evidence of extensive atrial fibrosis, immune‐mediated functional impairment of electrical activity is suspected.

Significant motor improvement in an infant with congenital heart disease and a rolandic stroke: The impact of early intervention

ABSTRACT Objective: To report the impact of early motor intervention in an infant with congenital heart disease (CHD) and a stroke. Methods and Results: A 35-week newborn with a complex CHD and a normal MRI presented with early motor developmental delay at 2 months. She began an intervention program, which included biweekly motor developmental therapy with a physiotherapist, parental education, and daily home exercises. At 4 months, she underwent cardiac surgery. Following surgery, she was diagnosed with a stroke involving the right sylvian artery territory. She continued her intensive intervention program. The 12-month assessment revealed an evident gain of motor function. Despite MRI evidence of a chronic infarct involving the primary motor cortex, the child had normal motor functions. Conclusion: This case report supports the positive impact of early intervention in infants with CHD and its potential effect on enhancing neuroplasticity, even in children with cerebro-vascular accidents involving areas of motor function.

Neurally Adjusted Ventilatory Assist After Pediatric Cardiac Surgery: Clinical Experience and Impact on Ventilation Pressures

BACKGROUND: After pediatric cardiac surgery, ventilation with high airway pressures can be detrimental to right ventricular function and pulmonary blood flow. Neurally adjusted ventilatory assist (NAVA) improves patient–ventilator interactions, helping maintain spontaneous ventilation. This study reports our experience with the use of NAVA in children after a cardiac surgery. We hypothesize that using NAVA in this population is feasible and allows for lower ventilation pressures. METHODS: We retrospectively studied all children ventilated with NAVA (invasively or noninvasively) after undergoing cardiac surgery between January 2013 and May 2015 in our pediatric intensive care unit. The number and duration of NAVA episodes were described. For the first period of invasive NAVA in each subject, detailed clinical and ventilator data in the 4 h before and after the start of NAVA were extracted. RESULTS: 33 postoperative courses were included in 28 subjects with a median age of 3 [interquartile range (IQR) 1–12] months. NAVA was used invasively in 27 courses for a total duration of 87 (IQR 15–334) h per course. Peak inspiratory pressures and mean airway pressures decreased significantly after the start of NAVA (mean differences of 5.8 cm H2O (95% CI 4.1–7.5) and 2.0 cm H2O (95% CI 1.2–2.8), respectively, P < .001 for both). There was no significant difference in vital signs or blood gas values. NAVA was used noninvasively in 14 subjects, over 79 (IQR 25–137) h. CONCLUSIONS: NAVA could be used in pediatric subjects after cardiac surgery. The significant decrease in airway pressures observed after transition to NAVA could have a beneficial impact in this specific population, which should be investigated in future interventional studies.

High renal regional oxygen saturation in femoral arteriovenous fistula after neonatal cardiac surgery

The use of an indwelling arterial catheter is standard practice in the postoperative monitoring of paediatric cardiac surgery patients. Arteriovenous fistula related to this procedure can be difficult to diagnose. Regional haemoglobin oxygen saturation (rSO2) using near-infrared spectroscopy and central venous oxygen saturation (ScvO2) are monitored to follow the balance between oxygen consumption and delivery. Low values of these parameters are a sign of low cardiac output. High rSO2 and high ScvO2 are less frequently described. We report the discovery of an iatrogenic arteriovenous fistula in a neonate after cardiac surgery who had unexpectedly high values of renal rSO2 and femoral ScvO2. High renal rSO2 after femoral instrumentation should alert the physician to the possibility of arteriovenous fistula.

Right pulmonary artery torsion following surgical reimplantation.

We report the case of a 3-month-old boy with an anomalous origin of right pulmonary artery (AORPA) from the ascending aorta who presented postoperatively with torsion of the right pulmonary artery demonstrated on 3-D volume-rendered CT angiogram. To our knowledge, CT images of this entity have not been reported. This case illustrates a rare surgical complication that can be easily imaged by CT.