Post-hoc diagnosis of congenital long QT syndrome in patients with tetralogy of Fallot

This report describes two patients diagnosed with congenital long QT syndrome after surgical repair of tetralogy of Fallot. Despite the fact that both patients had preoperative electrocardiograms demonstrating QT prolongation, neither was diagnosed until long after their surgeries, when they or their relatives presented with symptoms of long QT syndrome. A brief discussion highlights the reasons why long QT syndrome may be overlooked in patients with structural heart defects and the clinical importance of identifying these patients preoperatively.

Evolution of heart rate control after transplantation: conduction versus autonomic innervation

In cardiac transplantation, the donor organ is not initially innervated and demonstrates decreased heart rate variability (HRV). However, HRV may improve after several months. The mechanism for HRV improvement has not been elucidated; autonomic "reinnervation" of the donor heart has been proposed. The role of atrioatrial conduction from recipient to donor organ has not been evaluated. We prospectively evaluated cardiac transplant patients with a limited electrophysiology study at the time of their surveillance biopsies. Recordings were made of recipient and donor signals, observing conduction properties between recipient and donor atria. Holter recordings were analyzed and HRV was determined using spectral analysis techniques, recording mean RR interval, low-frequency power (LF), high-frequency power (HF), and the LF/HF ratio. These were compared to published norms. From November 1999 to May 2000, 21 patients (6 female) who underwent cardiac transplantation participated at a median age of 101 months (range, 4.1-217 months). Time posttransplant ranged from 26 days to 71 months. Holter data were available for 20 patients and demonstrated dissociated P waves in 13 (65%). The mean heart rate on Holter was 111 beats per minute (bpm) (range, 85-161 bpm). We were able to record distinct recipient atrial signals in 16 of 21 (76%) patients. The average recipient tissue heart rate was 55% that of the donor heart rate. We documented atrioatrial association in only 1 patient. HRV did not reach normal values for most patients and did not increase with time posttransplantation. The LF values were in the normal range for most patients, whereas 3 patients had normal HF values and 2 patients had values just below normal. Recipients of heart transplantation have a predominantly sympathetic influence of HRV. These preliminary data suggest that atrioatrial conduction does not play a role in reestablishing normal heart rate control following pediatric cardiac transplantation.

Predictors of refractory tachycardia in infants with supraventricular tachycardia

Reentrant supraventricular tachycardia (SVT) is the most common arrhythmia in infants. There are few predictors as to which patients will have recurrent or refractory SVT. We retrospectively reviewed records of all infants with SVT evaluated at The Hospital for Sick Children, Toronto, between January 1, 1995, and December 31, 1999. Patients with reentrant SVT documented in infancy and structurally normal hearts were included. Patients were placed in two groups: the "simple" group consisted of patients with SVT completely controlled by not more than one medication, and the "complex" group consisted of patients with recurrent episodes requiring at least one medication change for control. Forty-two cases were analyzed-23 in the simple group and 19 in the complex group. One patient in each group died. Age at presentation was 50.4 +/- 13.2 days for the simple group versus 10.2 +/- 2.5 days for the complex group (p <0.01). Complex patients were treated with a median of three medications and were more likely to have echocardiographically reduced ventricular function. The surface electrocardiogram RP interval during SVT was significantly longer in complex patients (p <0.001). There were no differences between the groups in gender, cycle length in SVT or sinus rhythm, the presence of pre-excitation, initial medication choice, or duration of therapy. Recurrent SVT in infancy is associated with younger age and/or ventricular dysfunction at presentation and also with slower ventriculoatrial conduction. The similar duration of therapy for simple and complex patients suggests that the early clinical course of SVT in infancy is not predictive of long-term outcome.

Spontaneously terminating apparent ventricular fibrillation during transesophageal electrophysiological testing in infants with Wolff-Parkinson-White syndrome

This article describes two infants with Wolff-Parkinson-White (WPW) syndrome in whom apparent VF occurred without antecedent AF or atrial flutter during routine transesophageal electrophysiological testing. Remarkably, this arrhythmia terminated spontaneously in both infants. The documentation of self-limited apparent VF, or polymorphic ventricular tachycardia close to VF, in transesophageal testing adds another dimension to the management of WPW.

Echocardiography and pulmonary function testing in childhood onset systemic lupus erythematosus

The aim of this paper was to investigate the frequency of echocardiography (ECHO) and pulmonary function test (PFT) abnormalities in childhood onset systemic lupus erythematosus (SLE), and to determine the relationship of these abnormalities to disease activity. The charts of 50 patients with childhood onset SLE attending a pediatric rheumatology clinic were reviewed for ECHO and PFT studies. The frequency and description of ECHO and PFT abnormalities were documented. Possible associations of PFT and ECHO abnormalities with clinical cardiopulmonary disease, radiographic findings, and measures of lupus disease activity were evaluated. Forty patients (80%) had at least one ECHO study. Twenty-seven (68%) had an abnormal initial study. Nine of 14 patients with an initial abnormal ECHO had normal findings on repeated study. Three abnormalities were considered moderately severe. Thirty-three patients (66%) had at least one PFT performed. Sixteen (48%) were abnormal initially. Four of these 'abnormal' studies were repeated and the abnormalities persisted. Nine patients (27%) were considered to have a severe abnormality. Thirty-one children (62%) had both studies performed. An initial abnormal ECHO and abnormal PFT was found in 10 (32%) of these children. No relationship between ECHO or PFT abnormality and any measure of disease activity (physician's global assessment, anti DNA, C3 or ESR) could be found. Occult cardiac and pulmonary disease as demonstrated by ECHO or PFT occurs frequently in childhood onset SLE. If we wish to understand the natural history of these abnormal heart and lung findings, it will be necessary to do serial testing with ECHO and PFTs in this population.

Balloon angioplasty of right ventricular outflow tract conduits

Palliation of complex congenital heart disease, requiring reconstruction of the right ventricular outflow tract (RVOT), is standard practice. Survival of the homograft is a limiting factor. We examined the role of balloon angioplasty (BAP) in prolonging conduit life. Twelve patients underwent 15 BAP procedures between February 1989 and October 1997. The median age at conduit insertion was 28 months with detection of a significant echo gradient 42 months later. Calcification of homografts, with attendant obstruction and valve dysfunction, was present in all patients. BAP was performed within 1 month of echocardiography and reduced the gradient from a median of 57 to 38 mmHg (p < 0.0005). Echocardiographic follow-up showed persistent gradients (median 68 mmHg) and 11/12 patients went on to conduit replacement after BAP. Only one patient had replacement deferred as a result of BAP. Complications requiring intervention occurred in 20% of the procedures and included bleeding and an unusual balloon fracture. Although BAP can reduce the pressure gradient across the RVOT conduit, the effect is transient and the delay of surgery is not due to improved hemodynamic function. Approximately 10% of cases will benefit from BAP alone, but given the high rate of complications, we do not recommend this procedure as a means of prolonging conduit life.

Early and intermediate-term complications of self-expanding stents limit its potential application in children with congenital heart disease

OBJECTIVES

We report on the early and intermediate-term follow-up results of self-expanding Wallstent (Schneider, Switzerland) implanted in children with congenital heart disease.

BACKGROUND

The inherent shortcomings of balloon-expandable stents prompted the trial of an alternative stent.

METHODS

Twenty patients underwent 22 implantations of 25 self-expanding Wallstents between December 1993 and June 1997 in two institutions. The mean age and weight were 10.8+/-4.5 years and 30.5+/-14.2 kg, respectively. The patients were divided into two groups: 1) Group I comprised 17 patients with pulmonary arterial stenoses, 2) Group II comprised four patients with venous stenoses (one belonged to both groups). Sixteen patients underwent recatheterization at a median of 5.8 months (range 0.5 to 31, mean 8.1 months) after stenting. Hemodynamic and angiographic changes after the interventional procedures and complications were documented.

RESULTS

All the stents were successfully deployed in the intended position. In Group I, the narrowest diameter of the stented vessel increased from 4.1+/-1.5 to 8+/-2 mm (95% increase, p < 0.0001) while the systolic pressure gradient across decreased from 24.6+/-15.8 to 12.1+/-11.4 mm Hg (51% decrease, p = 0.001). In Group II, the dimensional changes of the narrowest segment increased from 4.3+/-0.5 to 7.5+/-0.4 mm (75% increase, p = 0.003), and the pressure gradient reduced from 5.0+/-2.9 to 0.9+/-1.0 mm Hg (82% decrease, p = 0.04) across the stented venous channel. Distal migration of two optimally positioned stents occurred within 24 h of implantation. At recatheterization, significant neointimal ingrowth (>30% of the expanded diameter) was noted in 7 (28%) of the 25 implanted stents. This responded poorly to balloon dilation. Predisposing factors for the neointimal ingrowth included stents of smaller diameter (<9 mm) and longer period after implantation.

CONCLUSIONS

Self-expanding Wallstent could be deployed easily and safely to relieve vascular stenoses in children. The complications of distal migration, significant neointimal ingrowth and its unyielding design to overdilation limit its application to this patient group.

Coil occlusion of the patent ductus arteriosus: lessons learned

PURPOSE

To review the clinical outcomes of catheter-directed coil occlusion (coil occlusion) of persistently patent ductus arteriosus (PDA) at a pediatric tertiary care hospital.

METHODS

A retrospective review of all patients referred to the Cardiac Catheterization Laboratory for coil occlusion at our institution was performed. Twenty-one consecutive patients (12 female) underwent coil occlusion and follow-up between May 1995 and December 1997. We undertook PDA occlusion if: (a) the PDA narrowed to less than 4 mm on echocardiogram and (b) the minimum body weight was approximately 10 kg. Standard right and retrograde left heart catheterization was performed, followed by coil occlusion. Color-flow mapping (CFM) was used intra-procedurally to confirm occlusion of the PDA with a follow-up study several weeks later.

RESULTS

The median age and weight of the patients were 33 months and 13.2 kg, respectively. Fourteen patients received one coil, with six requiring a second coil and one requiring multiple coils. Initial follow-up was at a median of 2.4 months. At latest follow-up, 2 patients still have persistent flow at the ductal level. The coils were deployed without complication or embolization.

CONCLUSIONS

A review of our first 21 cases demonstrated three important lessons: (1) the maximum diameter of the PDA suitable for coil occlusion is approximately 3 mm; (2) CFM must show complete obliteration of flow in the catheterization lab in order to ensure occlusion of the PDA at follow-up; and (3) the Jackson detachable system allows for precise placement of the coil, often within another coil.

Vascular abnormalities in Adams-Oliver syndrome: cause or effect?

We describe a young girl diagnosed with the Adams-Oliver syndrome (AOS) associated with double outlet right ventricle, portal hypertension, and pulmonary hypertension. We hypothesize that a congenital vascular abnormality is the underlying pathogenesis and that the cutaneous defects characteristically seen in AOS represent the most common manifestation of this. We suggest that AOS should not merely be considered a syndrome consisting of aplasia cutis congenita and terminal transverse limb defects but rather a constellation of clinical findings resulting from an early embryonic vascular abnormality.

Vascular abnormalities in Adams-Oliver syndrome: cause or effect?

We describe a young girl diagnosed with the Adams-Oliver syndrome (AOS) associated with double outlet right ventricle, portal hypertension, and pulmonary hypertension. We hypothesize that a congenital vascular abnormality is the underlying pathogenesis and that the cutaneous defects characteristically seen in AOS represent the most common manifestation of this. We suggest that AOS should not merely be considered a syndrome consisting of aplasia cutis congenita and terminal transverse limb defects but rather a constellation of clinical findings resulting from an early embryonic vascular abnormality.

Extracardiac Fontan operation with tube fenestration allowing transcatheter coil occlusion

A fenestration may improve the immediate postoperative course after a Fontan procedure by preserving the cardiac output. We describe a simple and safe technique of fenestration amenable to coil occlusion, which can be carried out in most cardiac catheterization laboratories.

Kawasaki disease in the older child

OBJECTIVES

To determine the prevalence of Kawasaki disease in older children and to evaluate its clinical presentation, time to diagnosis, and outcome in comparison with younger patients with the disease.

METHODOLOGY

A retrospective analysis of all patients discharged with a diagnosis of Kawasaki disease at a pediatric tertiary care hospital over a 12-year period.

RESULTS

A total of 133 patients were included in this study; 7.5% were 9 years of age or older at the time of illness. Patients were grouped by age: infants included children age 1 to 8 years of age and children 9 years of age or older. Older children had a higher frequency of abnormal cardiovascular physical examination (50%) versus children (6%) and infants (10%). The older age group and the infants had a higher prevalence of coronary artery abnormalities and poor left ventricular function than did the 1- to 8-year-olds. Eighty percent of the older children had coronary arteries that were either dilated or aneurysmal, and 30% demonstrated left ventricular dysfunction on initial echocardiography. The number of days to diagnosis after meeting the diagnostic criteria was 5.8 +/- 2.3 for infants, 5.2 +/- 1.5 for older children, and 1.9 +/- 0.3 for children. Older children had a complicated course of Kawasaki disease compared with younger patients.

CONCLUSION

We found a higher prevalence of older children with Kawasaki disease at our center than has previously been reported. Older patients, as well as infants, had a higher rate of coronary artery abnormalities than did the children between 1 and 8 years of age. Older age at the time of illness or a delay in treatment may be important factors in determining cardiac involvement in Kawasaki disease.