A de novo mutation of the beta cardiac myosin heavy chain gene in an infantile restrictive cardiomyopathy

Here we report the first pediatric case of restrictive cardiomyopathy secondary to a de novo mutation in the cardiac myosin heavy chain gene MYH7. The clinical course is characterized by an early onset of disease, mild hypertrophy of the left ventricle and a very short evolution to death. Because of the location of the mutation in the hinge region between the rod part and the globular head of the myosin molecule, it is possible that restrictive cardiomyopathy resulted from an impairment of flexion/extension of myosin heads during the contraction/relaxation cycle.

The challenge of renal function in heart transplant children

Renal dysfunction may occur after pediatric heart transplantation and impacts on long-term prognosis. This study aims to review the incidence and mechanisms of chronic nephropathy following heart transplantation, and suggest therapeutic directions. The proportion of pediatric heart-transplant recipients with impaired renal function varies from 22 to 57%, and end-stage renal failure from 3 to 10%, depending on the method used for estimating the glomerular filtration rate. The pathophysiology of renal dysfunction is in part due to calcineurin inhibitor-induced renal vasoconstriction, through activation of the intrarenal renin-angiotensin system, TGF-beta1 upregulation and TGF-beta1 gene polymorphisms. Overproduction of angiotensin II, associated with angiotensin-converting-enzyme genotype, might be associated with poor prognosis and pharmacological factor gene polymorphisms, and may contribute to variation of calcineurine inhibitor exposure in the kidney. Strategies to prevent renal dysfunction include reducing calcineurine inhibitor exposure or delaying calcineurine inhibitor administration from the early post-transplant period. Calcium channel blockers and angiotensin-converting-enzyme inhibitors, blockade of angiotensin II, or anti-TGF-beta1 antibodies might limit nephrotoxicity. No accurate marker can predict the potential of renal lesions to develop. Lowering calcineurine inhibitors levels with immunosuppressive agents that are either less nephrotoxic or non-nephrotoxic should be formally studied. Of high interest is the impact of genetic polymorphism on the development of renal dysfunction.

Current patterns of infective endocarditis in congenital heart disease

OBJECTIVE

To assess the changing profile of infective endocarditis in patients with congenital heart disease.

METHODS

All cases diagnosed from 1966 to 2001 (revised Duke criteria) were retrospectively reviewed and categorised in periods I (< 1990) and II (>or= 1990).

RESULTS

153 episodes occurred, 81 in period I and 72 in period II. Mean age of affected patients was higher in period II. Non-operated ventricular septal defect, Rastelli correction and palliated cyanotic heart disease increased. Infective endocarditis in corrective surgery changed to patients with prosthetic material. Post-surgical cases decreased. Dental problems were the leading cause (period I 20% v II 33% of cases) with a large variety of pathological organisms (multiple species of Streptococcus). Cutaneous causative infections increased (5% to 17%) with different species of Staphylococcus. Negative blood cultures lessened (20% to 7%, p = 0.03). Streptococci were the most common causative organisms in both periods. Severe heart failure and cardiac complications lessened (20% to 4% and 31% to 18% during periods I and II, respectively). Early surgery was more frequent in period II (32% v 18.5%, p = 0.02). One- and 10-year survival was 91% v 97% in period I and 89% v 97% in period II, respectively (NS).

CONCLUSION

Current targets include complex cyanotic disease, congenital heart disease corrected with prosthetic material and small ventricular septal defect. Postoperative cases lessened; dental and cutaneous causes increased. Survival was unchanged. Prophylactic measures targeted at dental and cutaneous sources should be emphasised.

Sinus venosus-type atrial septal defect: a rare curable cause of recurrent transient neurological deficits

BACKGROUND AND PURPOSE

Sinus venosus defect is a rare cardiac abnormality, provoking an interatrial shunting outside the interatrial septum. Echographic diagnosis is difficult and may require examination by a specialized cardiologist.

SUMMARY OF CASE

We report the case of a young woman who presented with repeated episodes of hemiparesis.

CONCLUSIONS

Surgical correction of sinus venosus defect led to disappearance of neurological symptoms.

[Long QT syndrome in children: analysis of the Lyon series]

Congenital long QT syndrome is a rare and serious disorder in children. In addition to the clinical and electrocardiographical diagnostic criteria, molecular biochemistry has identified six genes which are implicated in this pathology. Our study involved a retrospective analysis of 23 patients aged less than 21 with congenital long QT syndrome, followed up for an average of two years. Genotypes were obtained for all of the patients. There were unfortunately two deaths, one of which had a mutation in the SCN5A gene. The other patient had a double mutation of the SCN5A and KCNE2 genes. Symptomatic patients had QT and QTc intervals noticeably longer than the asymptomatic patients, although this difference was not shown to be significant. LQT3 patients as well as those with a double mutation were affected more severely because two of the three LQT3 patients and one of the two patients with a double mutation suffered a cardiac arrest. Three patients in our study showed no mutation. Nevertheless, two of them suffered a severe cardiac event. This confirms the limits of genetic diagnosis, which could be envisaged in all cases. All of the clinical and ECG data should be combined with the genetic analysis in order to confirm the diagnosis.

[Propionibacterium acnes infective endocarditis. Study of 11 cases and review of literature]

BACKGROUND

Propionibacterium acnes, a gram positive, anaerobic, skin commensal bacillus, is too often considered a biologic fluid contaminant, of blood cultures in particular. Its implication has been shown in various infections, including brain abscess, ocular infections, osteitis, and acne. It is also the cause of infective endocarditis (IE).

METHODS

Retrospective, observational study of 11 patients with P. acnes IE, hospitalised between 1993 and 2001 at the Louis Pradel Hospital, Lyon-Bron, and review of 20 published cases.

RESULTS

P. acnes IE is rare, though its prevalence is probably underestimated. It is most likely to affect men (71%), and affects all ages (children 4/31 cases). An entry point, probably cutaneous, is rarely confirmed. P. acnes IE often develops on valve prosthesis (42%), and embolisms are common (61%). The infective site is usually aortic (55%). The often-subtle symptoms and slow growth of the organism in vitro complicate the diagnosis, which is often made at a late stage, when valvular and peri-valvular destruction has become major. Despite the high sensitivity of P. acnes to most antimicrobials, a surgical intervention is very often needed (81%). The mortality is relatively high (15% to 27%). Examination of pathologic specimens by polymerase chain reaction increases the sensitivity and speed of its detection. The identification of P. acnes in a biologic specimen, valvular tissue in particular, requires a thorough knowledge of the clinical context before concluding to contamination, and mandates close surveillance of the patient. P. acnes can be the cause of IE long before it has been detected.

[Neonatal forms of congenital long QT syndrome]

The neonatal congenital long QT syndrome (LQTS) is rare and of bad prognosis due to the presence of severe ventricular arrhythmia and conduction abnormalities.

METHODS

we included 24 propositus newborns from our population with LQTS. Genetic study was possible in 19 cases.

RESULTS

the diagnosis of LQTS was made according to a QT prolongation associated with a sinusal neonatal bradycardia (n=9) or a 2/1 AV block (n=15). The onset presentation consisted of syncope (n=2), torsades de pointes (n=7), cardiovascular collapse (n=5), cardiac arrest (n=1). The mean QTc was at 550+60 ms. During the neonatal period the treatment consisted of beta-blocking agents in all cases, associated with a definitive pacemaker implantation in 10 cases with 2/1 AV block. Three newborns with a 2/1 AV block died during the first month of life (one case due to a septecemia after implantation of a pacemaker, and two who were waiting for that implantation). All survivors remained asymptomatic during a follow-up period of 7 years. In all cases with a 2/1 AV block we identified mutations in HERG (n=8). Newborns with isolated sinusal bradycardia presented all a mutation in KCNQ1 (n=9).

CONCLUSION

the LTQS with 2/1 AV block is preferably associated with mutation in HERO with a bad initial prognosis.

[Characteristics of infectious endocarditis in ventricular septal defects in children and adults]

The aim of this retrospective study was to analyse cases of infectious endocarditis (IE) of native or repaired ventricular septal defects (VSD) to determine its incidence, the circumstances of its occurrences, the outcome and prognosis of this complication. From 1966 to 2002, 36 IE occurred in 19 boys and 17 girls: the age at diagnosis was 13.4 +/- 11.8 years; 26 had an isolated VSD and 10 had VSD associated with a minor lesion. Eleven of the 36 cases (30.5%) had been previously operated: repair of an isolated VSD with a patch in 5 cases, associated with a Crafoord procedure for coarctation of the aorta in 2 cases, three times with conservative treatment of associated aortic regurgitation (AR) and with ligature of patent ductus arteriosus (PDA) in 1 case. Twenty-five of the 36 cases (69.5%) had not been operated before: 21 isolated type 1 VSD; 2 VSD + AR, 1 VSD with PDA (undiagnosed), 1 VSD with valvular pulmonary stenosis (PS). The portal of entry was post-surgical in 7 out of 36 cases (19.4%): 4 VSD patches, 2 VSD patches + Crafoord and 1 VSD patch with ligature of PDA. The source of infection was dental in 14 out of the 36 cases (38.9%): one isolated VSD repair with residual shunt, 11 native VSDs, and 2 cases of unoperated VSD + AR. The other infectious causes (15 = 41.7%) were ENT (2 cases), skin (2 cases), gastrointestinal (2 cases), pulmonary (1 case) or unknown (8 cases), on operated lesions (3 VSD patches + AR) or native lesions (12 cases: 10 isolated VSDs, 1 VSD with PSD and 1 VSD with PS). Twelve episodes occurred (33.3%) despite antibiotic prophylaxis, 7 out of 7 post-surgical and 5 out of 14 dental cases. The commonest localisation was the tricuspid valve (10 cases, always in isolated VSD). Embolism was observed in 60% of right heart endocarditis (always multiple) and in 55% of IE of the left heart (single embolism). Early surgery was required in 6 patients (16.7%). The risk of early surgery was higher in patients with VSDs associated with other lesions (4 out of 10 = 40%) than in isolated VSD (2 out of 26, 7.7%, p = 0.027). Thirteen patients underwent secondary surgery after an average interval of 2.96 years, median 0.86 years (from 4 months to 22.8 years) for VSD repair (10 cases), aortic valve replacement (2 cases) and aorto-aortic conduit (1 case). The global follow-up period was 7.4 +/- 8.3 years, from 28 days to 27.9 years (median 3.3 years). Five deaths were observed on average 3.7 +/- 6.2 years after the episode of IE (median 6 months): 2 were early, occurring less than 6 months after IE and directly related to the infective episode. The survival was 97.1% at 1 month, 94.3% at 6 months, 91.4% at 1 year and 86.6% at 5 and 10 years after IE. VSD is a benign cardiac lesion, the prognosis of which can be severely compromised by infectious endocarditis: surgical repair reduces the risk but does not totally exclude it because of minor associated abnormalities. Prophylactic antibiotic therapy and the diagnosis of latent infectious problems, particularly dental, remains essential before and after cardiac surgery.

Long QT syndrome in neonates: conduction disorders associated with HERG mutations and sinus bradycardia with KCNQ1 mutations

OBJECTIVES

We hypothesized that neonatal long QT syndrome (LQTS) with 2:1 atrioventricular block (AVB) could be related to HERG mutations.

BACKGROUND

Early onset of LQTS is rare but carries a high risk of life-threatening events such as ventricular arrhythmias and conduction disorders. There are no data on possible gene specificity.

METHODS

We analyzed the characteristics and outcomes of 23 neonate probands from our LQTS population. Samples of DNA were available in 18 cases.

RESULTS

Long QT syndrome was diagnosed because of corrected QT interval (QTc) prolongation (mean QTc of 558 +/- 62 ms) and neonatal bradycardia attributable to sinus bradycardia (n = 8) or 2:1 AVB (n = 15). Symptoms included syncope (n = 2), torsades de pointes (n = 7), and hemodynamic failure (n = 6). Three infants with 2:1 AVB died during the first month of life. During the neonatal period, all living patients received beta-blockers (BB) and 13 had a combination of BB and permanent cardiac pacing. Under treatment, patients remained asymptomatic, with a mean follow-up of seven years. Mutations were identified in HERG (n = 8) and KCNQ1 (n = 8), and one child had three mutations (HERG, KCNQ1, and SCN5A). Conduction disorders were associated with LQT2, whereas sinus bradycardia was associated with LQT1.

CONCLUSIONS

Two-to-one AVB seems preferentially associated with HERG mutations, either isolated or combined. Long QT syndrome with relative bradycardia attributable to 2:1 AVB has a poor prognosis during the first month of life. In contrast, sinus bradycardia seems to be associated with KCNQ1 mutations, with a good short-term prognosis under BB therapy.

[Genetics and congenital heart diseases]

We describe in this article the recent data on the genetics of congenital heart defects (CHD) organised by type of CHD although each predisposing genetic factor is associated with a whole variety of CHD types. The recent progress resulting from animal models, molecular cytogenetics and CHD familial cases studies allow a better understanding of the determinism of CHD. This lead in term to improved counselling of parents of affected children and of CHD adults who would like to become parents. Nevertheless, more progress is needed to reach a better accuracy in prediction.

Non-invasive detection of coronary artery disease by dobutamine-stress echocardiography in children after heart transplantation

BACKGROUND

Coronary vasculopathy is the main cause of cardiac graft failure. Because yearly coronary angiography is invasive in children, a non-invasive method for detecting graft vasculopathy is needed. The aim of this study was to test dobutamine-stress echocardiography in a pediatric population to determine its feasibility, safety and reliability in the detection of graft coronary artery disease.

METHODS

Eighteen patients, aged 2 days to 16.8 years at transplantation (mean 8.4 years), underwent 44 dobutamine-stress echocardiography (DSE) exams, at a follow-up of 1.1 to 11.8 years (mean 5.1 years). Selective coronary angiography was performed for comparison. Echocardiographic recordings were obtained in 4 standard views of the left ventricle and measurements carried out within the frames of a 16-segment model. Segmental scores of contractility were obtained for each segment and a total segmental contractility index was calculated at each stage.

RESULTS

All patients reached the maximum dose stage. Maximum heart rate was 57% to 90% of predicted maximum. Maximum systolic blood pressure reached 190 mmHg. Segmental scores were normal in 37 and abnormal in 7 cases. Echographic results were concordant with angiography in 82% and discordant in 18% of the cases (4 negative DSEs with minor angiographic lesions, 2 positive DSEs with normal angiography), but there was no significant angiographic lesion with normal DSE.

CONCLUSIONS

DSE is a safe and highly feasible non-invasive technique in transplanted children. A normal DSE study successfully predicts the absence of significant coronary artery disease in the post-transplant population.

[Pediatric cardiac transplantation. Long-term results and problems]

The aim of this study was to establish an assessment for cardiac transplantation by retrospective analysis of data from two French centres. Screening for acute rejection was ensured by systematic myocardial biopsies for patients aged over 10 years, and by clinical non-invasive follow up, ECG and Doppler echo in the younger ones. Coronaropathy was screened for by coronarography or stress echography. Eighty three cardiac transplantations were performed in 82 patients aged 9.2 +/- 6 years. The follow up was 5.8 +/- 4.8 years. Survival was 86% at 1 month, 76% at 1 year, 73% at 5 years and 60% at 10 years and did not differ for age at transplantation (p = 0.88) or the initial pathology (p = 0.25). Twenty-nine patients died in the period between 3 days to 11 years, of which 13 were during the first month and 9 after one year (of which 4 were acute rejections and 2 coronaropathies). The incidence of acute rejection was 1.8 episodes per patient; 42% were late rejections, through non-compliance for half of them. Systematic biopsy was useful in the first 3 months post transplant. Eight patients (9.6%) presented with coronaropathy of the graft, progressive for 5 of them. Renal function was altered in 12% of cases, especially in the patients transplanted before the age of 2 years. The results of paediatric cardiac transplantation are satisfactory. Acute rejection and therapeutic compliance for adolescents, graft coronaropathy, and renal function of infants remain the principal elements for the long term prognosis.

Rabbit antithymocyte globulin as induction immunotherapy in pediatric heart transplantation

BACKGROUND

There is little published data on the use of antithymocyte globulins in children. This retrospective study describes the use of Thymoglobulin (Imtix, SangStat, Lyon, France) in pediatric cardiac transplantation over a 13-year period in a single center that adjusted the dose of Thymoglobulin according to platelet count monitoring and examines the short-term hematological effects as well as longer-term outcomes.

METHODS

Data for all children who received a heart transplant at the Hôpital Cardiologique at Lyon from 1984 to 2001 and who were given Thymoglobulin as part of their immunosuppressive protocol were extracted. The dose of Thymoglobulin given depended on baseline platelet count and was 2, 1.5, or 1 mg/kg per day over 5 days for the following platelet count groups: greater than 150,000/mm (normal group), 100 to 150,000/mm (mild thrombocytopenia group), and 50 to 100,000/mm (moderate thrombocytopenia group).

RESULTS

Thirty children of median age 14.2 years were given a median cumulative dose of Thymoglobulin of 8 mg/kg per patient; the moderate thrombocytopenia subgroup was given significantly less (6.4 mg/kg) ( P=0.032). Immediate tolerability of Thymoglobulin was good, with no cases of first-dose syndrome, anaphylaxis, or serum sickness. The platelet count decreased at the start of therapy, but recovered after discontinuation, and did not give rise to clinical concern. Patients were followed up for a median of 6.3 years (7 days-15.5 years); actuarial survival was 90%, 86%, and 74.5%, respectively, at 1, 5, and 10 years. In the first year, 50% of patients suffered an episode of rejection. The overall incidence of infection in the month following transplantation was 40%. One lymphoma occurred at 5 months.

CONCLUSIONS

The use of Thymoglobulin in pediatric heart-transplant patients as part of an immunosuppressive protocol, with dose adjustment according to platelet levels, has been shown to be effective in terms of rejection rate and patient survival and safe in terms of the incidence of infections and malignancy.

[Cardiovascular complications of Kawasaki syndrome: results of a French multicenter study]

PATIENTS AND METHODS

Between March 1, 1995 and February 29, 1996, a multicentric prospective study was conducted in France in order to analyze the cardiovascular complications in Kawasaki syndrome, and to describe the echocardiographic features and the outcome of coronary lesions. Forty-nine cases of Kawasaki syndrome were observed.

RESULTS

There were 32 boys and 17 girls (sex ratio: 1:9). The age at diagnosis was under one year in ten cases (20.4%), between one and five years in 27 cases (55.1%) and more than five years in 12 cases (24.5%). The complete diagnostic criteria were present in 42 cases (85.1%). Forty-five children (91.8%) were given intravenous immunoglobulin treatment but only 20 (40.8%) received this treatment within the seven days following the onset of the illness. Cardiovascular complications consisted of: pericardial effusion in 12 cases (24.5%), coronary dilation in seven cases (14.3%), coronary aneurysms of moderate size in seven cases (14.3%,) with hypokinetic left ventricle in two cases. No death was reported. All patients with coronary dilation and four patients with coronary aneurysms had a normal size of coronary arteries at echocardiography within the nine months of the follow-up. Among the three other patients, after a follow-up of two years, one still has a small coronary aneurysm and two have a normal size of coronary arteries.

CONCLUSION

Despite a delayed administration of immunoglobulin therapy in the majority of patients in this study, outcome of coronary lesions was favorable and severe cardiac complications were rare in the acute phase of the Kawasaki syndrome.

[Variation in cholesterol, lipoproteins and triglycerides after heart transplantation in children]

Total cholesterol, HDL and LDL-cholesterol and triglyceride levels may contribute to the development or progression of coronary artery disease of the transplanted heart. The aim of this retrospective study was to determine the short and long-term lipid profiles of transplanted children and to identify factors influencing these dyslipidemias. Twenty-three patients aged 9.5 +/- 5.9 years at cardiac transplantation were followed up for 5.8 +/- 3.1 years. All were on triple therapy with normal diets. The total cholesterol increased by 17% during the first year (4.47 +/- 1.01 mMol/l to 5.25 +/- 1.22 mMol/l at 1 year: p < 0.05) with a peak at 3 months of 5.31 +/- 1.28 mMol/l correlating with the dosage of prescribed corticosteroids. LDL-cholesterol levels increased by 20% during the first year (2.26 +/- 0.67 mMol/l to 3.29 +/- 0.99 mMol/l at 1 year: p = 0.018). HDL-cholesterol levels increased from 1.02 +/- 0.27 mMol/l to a maximum of 1.55 +/- 0.4 mMol/l at 1 year, p < 0.05. Lipoprotein A1, a protecting sub-fraction of HDL, did not change significantly. Changes in triglyceride levels were not significant despite a tendency to hypertriglyceridaemia in the early phases. After one year, serum cholesterol and lipoprotein levels remained higher than the initial values. These results show that cardiac transplant children are exposed to the risk of atherogenic hyperlipidaemia and require systematic lipid profile monitoring, dietary advice and lipid lowering drugs.

Spontaneous closure of congenital coronary artery fistulas

Six cases of full spontaneous closure of congenital coronary artery fistulas, and one case of near closure, as seen by colour Doppler echocardiography, are presented. It is worth reconsidering the classical view that nearly all cases of spontaneous closure are eligible for surgical or percutaneous correction to prevent the development of significant and potentially fatal complications. As the natural course of coronary artery fistulas is still poorly defined, asymptomatic patients, especially those under 7 years old with small shunts, should be periodically followed up by echocardiography rather than be subjected to operative closure, even by catheterisation.

[Dobutamine echocardiography in children after heart transplantation]

Coronary disease of the transplanted heart is the principal cause limiting long-term survival of patients and grafts. In view of the invasive nature of coronary angiography, dobutamine echocardiography has been proposed as a non-invasive diagnostic method for this disease. The aim of this study was to determine the feasibility and reliability of this investigation in transplanted children. Twenty-one echoes were performed with dobutamine infusions in 17 patients transplanted at 10 months to 16.9 years of age (average 8.4 years), and followed up 1.1 to 10.1 years (average 4.4 years): 4 were on antihypertensive drugs but none were treated by betablockers. Dobutamine echocardiography was performed according to the standard protocol used in adults. The maximal level was attained in all cases. No major side effects were observed. The maximal heart rate attained 57 to 89% of the theoretical maximal rate, an increase of 44 to 184% compared with the basal heart rate. The maximal systolic blood pressure rose to 120 to 194 mmHg, an increase of 8 to 109% compared with resting values. The contractility scores and segmental contractile index were normal in 18 cases, abnormal at the maximal level in 2 cases (hypokinesia of segments 8 and 9 and akinesia of segments 10 and 16 with an index of 1.2), abnormal at the lowest levels (hypokinesia of segment 7 with an index of 1.1) and maximal level (hypokinesia of segments 1 and 7 with an index of 1.2) in one case. These results were concordant with coronary angiography performed within 2 to 8 days of echocardiography, and considered as the diagnostic investigation of reference (sensitivity 75%, specificity 100%, positive predictive value 100% and negative predictive value 93%). The authors conclude that dobutamine echocardiography is a non-invasive method easily performed with low risk in transplanted children but its diagnostic performance in coronary disease of the transplanted heart should be confirmed in larger studies.

[Cardiogenetics in the year 2000]

This review article presents the up-to-date of knowledge progression during the past decade in the genetics of cardiopathies. The cardiopathies presented here have all a mendelian type of inheritance but this list is not exhaustive.

The left retro-aortic brachiocephalic vein: morphologic data and diagnostic ultrasound in 27 cases

A left retro-aortic brachiocephalic vein is a rare anatomic entity. A retrospective study was made of 5218 congenital cardiopathies treated between 1982 and 1998 in a medico-surgical department of paediatric cardiology. A left retro-aortic brachiocephalic vein was demonstrated in 27 patients, i.e. an incidence of 0.5%. The chief cardiopathy in these patients was a tetralogy of Fallot in 25 cases (93%). Among these 25 cases of Fallot's tetralogy the aortic arch was rightsided in 19 cases (70%). The paraclinical diagnosis of this anomaly was facilitated by ultrasonography, provided it was sought for. In this series 6 cases (22%) were discovered during surgery without previous ultrasound diagnosis. The embryological origin of the left retro-aortic brachiocephalic v. differs from that of the venous trunk in its classical anatomic form. It derives from the inferior (but not superior) transverse plexuses, connecting the two anterior cardinal veins. One of the main consequences of this anomaly is its possible confusion with other vascular structures, particularly the right pulmonary artery. Such confusion may give rise to inappropriate surgical procedures. The differential diagnosis is facilitated by the use of the Doppler: the venous flow is biphasic and regulated by respiration, whereas the Doppler recording from a pulmonary artery is that of a characteristic systolic arterial flow.