Mubadda A. Salim

Plastic bronchitis occurring late after the Fontan procedure : Treatment with aerosolized urokinase

Objective To describe the use of aerosolized urokinase in a patient with plastic bronchitis after a Fontan procedure. Design Case report. Setting Pediatric intensive care unit in a university-affiliated children’s hospital. Patients Report of one patient with acute respiratory failure secondary to plastic bronchitis. Interventions Aerosolized urokinase, multiple bronchoscopies, corticosteroids, mucolytics, bronchodilators, and atrial pacing. Measurements and Main Results Airway obstruction secondary to recurring casts improved with the treatments. Histologic analysis of the casts demonstrated less fibrin after treatments with aerosolized urokinase. No adverse events were noted. Conclusions The addition of aerosolized urokinase to this patient’s treatment regimen helped to resolve life-threatening airway obstruction secondary to fibrin casts.

Pulmonary/systemic flow ratio in children after cavopulmonary anastomosis

OBJECTIVES This study attempted to provide a formula for calculation of the pulmonary/systemic flow ratio in children after bidirectional cavopulmonary anastomosis. BACKGROUND With the bidirectional cavopulmonary anastomosis, only the superior vena cava blood is oxygenated by the lungs. The inferior vena cava flow recirculates into the systemic circulation. The ratio of these flows will determine systemic arterial saturation. METHODS According to the Fick principle, 1) Systemic cardiac output (liters/min) = Pulmonary venous flow + Inferior vena cava flow; 2) Systemic blood oxygen transport (ml/min) = Pulmonary venous blood oxygen transport + Inferior vena cava blood oxygen transport. By substituting the first equation into the second, Pulmonary/systemic flow ratio = (Systemic saturation - Inferior vena cava saturation)/(Pulmonary venous saturation - Inferior vena cava saturation). RESULTS We applied the third formula to data obtained from 34 catheterizations in 29 patients after bidirectional cavopulmonary anastomosis. Mean [+/- SD] age at operation was 1.70 +/- 1.43 years, and mean age at catheterization was 2.95 +/- 1.65 years. The pulmonary/systemic flow ratio calculated for all 29 patients was 0.58 +/- 0.09. Of 17 patients with aortography, 10 had systemic to pulmonary collateral vessels. Patients with collateral vessels had a significantly higher pulmonary/systemic flow ratio (0.61 +/- 0.07 vs. 0.53 +/- 0.07, respectively, p < 0.02) and systemic saturation (88 +/- 4% vs. 82 +/- 4%, respectively, p < 0.002) than those without collateral vessels. The pulmonary/systemic flow ratio in those patients with no collateral vessels was similar to the previously reported echocardiographically derived superior vena cava/systemic flow ratio in normal children. CONCLUSIONS The pulmonary/systemic flow ratio after bidirectional cavopulmonary anastomosis can be calculated. Pulmonary blood flow in these patients determines systemic saturation and accounts for the majority of venous return in young children.

The fate of homograft conduits in children with congenital heart disease: an angiographic study

The use of homograft conduits in the repair of congenital heart disease is widely accepted. We reviewed the catheterization and angiographic data from 20 patients with homograft conduits. All conduits were to the pulmonary arteries. The age at operation was 4.7 +/- 5.6 years (mean +/- standard deviation) and at follow-up catheterization, 7.8 +/- 6.7 years. At implantation, conduit cross-sectional area and Z value were 219 +/- 96 mm2 and 3.5 +/- 1.8, respectively. At subsequent catheterization, the conduit diameters were measured in two projections at the shaft, annulus, valve opening, and insertion into the pulmonary artery. The transconduit gradient was 47 +/- 26 mm Hg. The cross-sectional areas were 149 +/- 56 mm2 at the shaft, 151 +/- 92 mm2 at the annulus, 108 +/- 116 mm2 at the valve opening, and 127 +/- 84 mm2 at the pulmonary artery insertion. The Z values were -0.9 +/- 2.5, -0.9 +/- 2.8, -3.8 +/- 4.0, and -2.0 +/- 3.4, respectively. The cross-sectional areas and the Z values at the levels of measurement were significantly smaller than the corresponding values at implantation. The change in cross-sectional areas and Z values exceeded what would be expected from growth alone. These data indicate that there is a decrease, with time, in the functional lumen of homograft conduits, and this may have implications for follow-up strategy after implantation.

The JT interval as a depolarization independent measurement of repolarization: lessons from catheter ablation of the Wolff-Parkinson-White syndrome.

In patients with Wolff‐Parkinson‐White syndrome (WPW), preexcitation precludes accurate assessment of the ventricular repolarization by the QTC. In patients with long QT syndrome, it has been demonstrated that the JTC does not change when depolarization abnormalities develop. We hypothesized that this phenomenon should also be applicable to WPW patients. To test this, we assessed the surface ECG of 29 patients (16 males, 13 females) with WPW pre‐ and postablation. The QRS, QT, and JT intervals were measured pre‐ and postablation at 50 mm/s paper speed in leads II and V2. QTC and JTC were calculated according to Bazetts formula. The average age was 12.8 ± 4.9 years (range 1.5–21). All patients had no residual preexcitation on postablation ECG. Early and late follow‐up ECGs were obtained at 32 ± 34 days and 388 ± 197 days postablation, respectively. Both the QRS and the QTC intervals shortened significantly on the postablation versus preablation ECGs (QRS: 115 ± 23 ms vs 89 ± 15 ms, respectively; P < 0.0001), (QTC: 454 ± 26 vs 423 ± 23, respectively; P < 0.0001). The preablation JTC interval did not change, postablation (319 ± 21 vs 323 ± 23, respectively; P > 0.2). Also, the JTC interval did not change between early and late follow‐ up, postablation. JTC: is an independent measure of repolarization, not related to depolarization. JTC may be a useful tool in assessing repolarization in patients with WPW and other depolarization abnormalities.

Sports and Marfan Syndrome: Awareness and Early Diagnosis Can Prevent Sudden Death.

Marfan syndrome is an autosomal dominant disorder of the connective tissues. Its major manifestations are in the cardiovascular, musculoskeletal, and ocular systems. Recognizing the phenotypic presentation of tall stature, long limbs and fingers, chest deformity, myopia, midsystolic click, and systolic or diastolic murmur can lead to early diagnosis. Morbidity and mortality are primarily caused by cardiovascular involvement. The goal of medical therapy is to retard the aortic root dilation that leads to sudden death from dissection or rupture. Surgical interventions for mitral valve regurgitation and resection of aortic aneurysms are highly effective. In addition, individuals with Marfan syndrome should be restricted from participation in certain sports.

Serum electrolytes in children with neurocardiogenic syncope treated with fludrocortisone and salt.

We examined the changes in serum electrolytes of patients with syncope treated with salt and fludrocortisone. The most significant change was an increase in serum bicarbonate concentration, with minimal alteration of sodium, potassium, and chloride concentrations; none was clinically significant.

QT interval response to exercise in children with syncope

R ecurrent syncopal episodes in children and adolescents are a common occurrence. Qrthostatic testing is widely accepted as a useful method for evaluating these patients.ls2 The response to the orthostatic challenge can be vasodepressor (an initial decrease in blood pressure followed by bradycardia), cardioinhibitory (asystole for several seconds or severe bradycardia), or mixed. Autonomic dysfunction has been postulated as a possible underlying mechanism for these syncopal episodes; cardiac and peripheral vascular autonomic control appear to play a role.3*4 Patients with tilt test-induced syncope (tilt+) have been noted to have a significantly greater prolongation in their corrected QT interval (QTc) in response to isoproterenol infusion than those who did not develop syncope in response to the same tilt test (tilt--).l Moreover, subjects with autonomic dysfunction, i.e., familial dysautonomia, have a prolongation of the QTc with changes in position as well as a failure of QTc shortening with exercise.5 This study evaluates the response of the QTc to exercise in tilt+ and tiltpatients. We hypothesize that the effects on cardiac repolarization observed with isoproterenol infusion in tilt+ patients will also be seen in the tilt+ subjects in response to exercise (presumably because of endogenous catecholamines). The 14 patients (8 females and 6 males, mean age 12.9 years [range 6.5 to 171) who were evaluated had a history of at least 1 episode of syncope. All patients had a thorough history and physical examination. All except 1 patient with mitral valve prolapse had a normal cardiac examination. Echocardiograms were obtained in 12 patients. With the exception of the patient with mitral valve prolapse, all echocardiograms were normal. No patient had an arrhythmia at rest. Three of the patients had a neurologic evaluation that included clinical evaluation as well as electroencephalogram, computerized tomography, or magnetic resonance imaging of the head; all were normal.