Daniel A. Kveselis

Effect of preterm birth on pulmonary function at school age : A prospective controlled study

OBJECTIVEnTo assess long-term pulmonary outcome of a regional cohort of children born at < 32 weeks gestation compared with a matched term control group.nnnSTUDY DESIGNnAll 125 surviving children born at 24 to 31 weeks gestation during a 1-year period and a sociodemographically matched term control group were evaluated at age 7 years.nnnRESULTSnPreterm children with previous bronchopulmonary dysplasia (BPD) were twice as likely to require rehospitalization during the first 2 years of life than were preterm children without BPD (53% vs 26%, P < .01). At 7 years of age the BPD group had more airway obstruction than did both preterm children without BPD and the term control group (significantly reduced mean forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow, 25% to 75% vital capacity, all, P < .001). Lung function among preterm children without previous BPD was similar to that of the term control group. Bronchodilator responsiveness was observed twice as often in preterm children with previous BPD (20 of 43, 47%) compared with preterm children without BPD (13 of 53, 25%) or the term control group (23 of 108, 21%, P < .001). These differences remained significant after adjustment was done for birth weight and gestational age.nnnCONCLUSIONnPreterm children without BPD demonstrate pulmonary function at school age similar to that of children in a healthy term control group, whereas preterm children with previous BPD demonstrate abnormal pulmonary function.

Procainamide for Rate Control of Postsurgical Junctional Tachycardia

Abstract. This study was conducted to determine the efficacy of procainamide therapy for rapid rate control of postoperative junctional tachycardia (JT). Postoperative JT is one of the most difficult forms of tachycardia to manage. Reported success with a variety of treatments of JT in infants and children has been inconsistent and limited. Rate control using procainamide was achieved in 17 children having rapid JT (heart rate >200 beats/min) between 1986 and 1997. In the first 5 patients (protocol A), following a loading dose of 3 mg/kg over 20 minutes, a continuous procainamide infusion was initiated at a rate of 20 μg/kg/min. The infusion dose was increased in 10 μg/kg steps every 30 minutes to 40–120 μg/kg/min until the heart rate decreased below the target rate of 180 beats/min. In the other 12 patients (protocol B), after a higher loading dose of 10 mg/kg the infusion rate was increased every 10–15 minutes until the heart rate decreased below the target rate of 180 beats/min. Procainamide decreased JT rates in all patients but the response was significantly faster in protocol B. In the patients treated with protocol A, pretreatment JT rates ranged from 203 to 240 (213 ± 17) beats/min and decreased to 195 ± 10 beats/min at 2 hours (p= ns), 186 ± 8.8 at 4 hours (p < 0.02), and 179 ± 8 at 6 hour postinitiation of PA. In protocol B, pretreatment JT rates ranged from 201 to 240 (218 ± 17) beats/min and decreased to 183 ± 20 beats/min at 2 hours (p < 0.001) and 171 ± 12 at 4 hours after starting the procainamide therapy. The mean duration to decrease JT rates below the target rate of 180 beats/min was 3.2 ± 1.1 hours in protocol B compared to 6.4 ± 3.8 hours in protocol A (p < 0.02). Eight of 12 patients in protocol B achieved rate control below the target rate of 180 beats/min within 4 hours despite remaining on significant inotropic support. The procainamide infusion rates to maintain heart rates below 180 beats/min were 40–120 (68.4 ± 22.1) μg/kg/min. No proarrhythmia, bradycardia, or significant hypotension was observed. In this series procainamide provided safe, effective, and rapid rate control of JT occurring in the immediate postoperative period.

Exaggerated blood pressure response to exercise in children with increased low-density lipoprotein cholesterol.

Arterial vascular responses are characteristically altered with hypercholesterolemia: conduit vessels manifest increased stiffness, and conduit and resistance vessels demonstrate impaired endothelium-dependent dilation and augmented vasoconstriction to neurohumoral stimulation. These changes should be reflected in an exaggerated blood pressure increase in response to exercise. To evaluate this hypothesis, we compared the blood pressure response to treadmill exercise in children with hypercholesterolemia and children with normal lipid levels. In a preliminary retrospective study, 15 hypercholesterolemic boys 10 to 18 years old underwent treadmill exercise testing, and their blood pressure results were compared with those of 32 normolipidemic children in the same age group who had undergone treadmill exercise electively in the same time period. In the second phase, 10 hypercholesterolemic boys and 10 normolipidemic age-matched boys were evaluated prospectively according to the same protocol. Treadmill exercise involved a modified Bruce protocol with heart rate and blood pressure measured before exercise, immediately after exercise, and throughout recovery. Office blood pressures were normal in all children, with no significant difference between groups. With treadmill exercise, all subjects achieved >95% of predicted maximum heart rate and endurance times, maximum oxygen consumption, and maximum respiratory ratio did not differ between groups. Results of the retrospective and prospective groups were similar and were therefore combined. Children with increased low-density lipoprotein (LDL) cholesterol had significantly higher systolic and diastolic blood pressures immediately before treadmill exercise (systolic 120 +/- 13 mm Hg vs 113 +/- 13 mm Hg, p < 0.03; diastolic 68 +/- 8 mm Hg vs 63 +/- 9 mm Hg, p < 0.01). After exercise, blood pressures were again significantly higher in the subjects with high LDL cholesterol (systolic 182 +/- 20 mm Hg vs 160 +/- 23 mm Hg, p < 0.0003; diastolic 77 +/- 12 mm Hg vs 72 +/- 9 mm Hg, p < 0.03). At the end of recovery, systolic blood pressures remained significantly higher in subjects with high LDL cholesterol (120 +/- 9 mm Hg vs 112 +/- 12 mm Hg, p < 0.005). In this study, children with severely increased LDL cholesterol had an exaggerated blood pressure response to exercise when compared with normolipidemic control subjects. The study findings suggest that control of arterial vascular tone may already be altered in children with hypercholesterolemia.

Loss of Sinus Rhythm After Total Cavopulmonary Connection

BACKGROUNDnTotal cavopulmonary connection (TCPC) to repair functional single ventricle involves the sinus node area, in contrast to the Fontan procedure. We compared ECG findings after TCPC and Fontan to evaluate the impact of the cavopulmonary connection on sinus rhythm postoperatively.nnnMETHODS AND RESULTSnThe Fontan group consisted of 17 patients repaired at 7.8 +/- 3.1 years of age (mean +/- SD): 11 for tricuspid or pulmonary atresia (TA/PA) and 6 for single ventricle. The TCPC group consisted of 19 patients repaired at 5.1 +/- 3.2 years of age (mean +/- SD) (P < .001): 9 for TA/PA, 4 for single ventricle, and 6 for hypoplastic left heart syndrome. Mean follow-up after Fontan was 7.7 +/- 2.7 years versus 2.8 +/- 1.6 years for TCPC (P < .001). Preoperative ECGs on all TCPC patients showed sinus rhythm (SR), whereas 16 of 17 Fontan patients had SR and one had nonsinus atrial rhythm (NSAR) since birth. On the first postdischarge ECG, 12 of 19 TCPC patients (63%) were in SR, 4 were in junctional rhythm (JR), and 3 were in NSAR. In comparison, 15 of 17 Fontan patients (88%) were in SR with 1 of 17 in NSAR and 1 in supraventricular tachycardia (P < .05 with chi 2 test). By 2 years postoperatively, only 6 of 15 TCPC patients available for follow-up (40%) were in SR, with 7 of 15 in JR and 2 of 15 in NSAR. By contrast, 13 of 17 Fontan patients (76%) remained in SR, with 1 in NSAR and 3 in JR (P < .05 with chi 2 test). TCPC patients with loss of SR did not differ from other patients in the group in age at repair, preoperative diagnosis, or surgeon performing the procedure.nnnCONCLUSIONSnThis significant incidence of loss of SR temporally related to surgery suggests that operative compromise of the sinus node area is common with TCPC.

Modified technique for balloon valvuloplasty of critical pulmonary stenosis in the newborn

OBJECTIVESnWe report our experience in eight consecutive neonates who underwent attempted balloon dilation as an initial therapy for critical valvular pulmonary stenosis, and we review in detail technical modifications that improved the success rate.nnnBACKGROUNDnBalloon dilation of the pulmonary valve has become the treatment of choice for valvular pulmonary stenosis in children and adults. There are few reports of its effectiveness in critical pulmonary stenosis in the newborn. In this setting, application of the technique of balloon dilation has been limited by the ability to advance the necessary guide wires and catheters across the stenotic, often near-atretic, pulmonary valve.nnnMETHODSnThe pulmonary valve was crossed in all patients. When this could not be accomplished with an end-hole catheter, a soft guide wire was advanced directly across the pulmonary valve through the end-hole catheter positioned in the right ventricular outflow tract below the valve. Initial predilation was achieved in all patients by using a coronary dilation catheter in an effort to facilitate introduction of the definitive balloon dilation catheter. Definitive dilation with a balloon diameter of > or = 110% of the diameter of the pulmonary valve annulus was possible in six patients.nnnRESULTSnRight ventricular pressure declined from a mean value of 108 +/- 32 mm Hg to a mean value of 49 +/- 11 mm Hg after balloon dilation, with no change in heart rate or aortic pressure in these six patients after definitive balloon dilation.nnnCONCLUSIONSnThe results of this small series suggest that critical valvular pulmonary stenosis in the newborn can be successfully treated by transluminal balloon valvuloplasty.

Double-Outlet Right Ventricle (Tetralogy of Fallot Type) Associated with Anomalous Origin of the Left Coronary Artery from the Right Pulmonary Artery: Report of Successful Total Repair in a 2-Month-Old Infant

Abstract. The case reported herein demonstrates the rare association of double-outlet right ventricle (tetralogy of Fallot type) with anomalous origin of the left coronary artery from the pulmonary artery. It is the first reported successful total surgical repair in an infant.