Congenital complete atrioventricular block

Anesthetic management of a 2-day-old with complete congenital heart block

Maternal connective tissue disorders such as Systemic Lupus Erythematosus (most common), Sjogren's syndrome, mixed connective tissue disorders may lead to the rare condition of complete congenital heart block in the neonate. Rare fetal syndromes such as myocarditis, 18p syndrome, mucopolysaccharidoses and mitochondrial diseases are other causes. The mortality rate of this condition is inversely propotional to the age of presentation being 6 % in the neonatal age group. As the cardiac output in the neonate is heart rate dependent, it is crucial to maintain the heart rate in these patients. Pharamacological interventions with dopamine, isoprenaline, epinephrine and atropine are known for their variable response. Although permanent pacing is the most reliable mode of management, the access to it is often not readily available, especially in the developing countries. In such cases temporary pacing methods become lifesaving. Of all the modalities of temporary pacing (transcutaneous, transesophageal and transvenous) transcutaneous pacing is the most readily available and immediate mode. In this case report we present a two day old neonate with isolated complete congenital heart block and a resting heart rate of 50-55/min in immediate need of palliative surgery for trachea-esophageal fistula (TEF). With pharmacological intervention the heart rate could only be raised to 75-80/min. The surgery was successfully carried out using transcutaneous pacing to maintain a heart rate of 100/min.

Congenital complete heart block: single tertiary centre experience

BACKGROUND

Congenital complete heart block (CCHB) is an uncommon although important and potentially serious condition contributing to neonatal morbidity and mortality.

AIMS

To study the characteristics and outcomes of infants born with CCHB at a single tertiary centre.

METHODS

A retrospective review of all infants with CCHB over the last 20 years was carried out to determine the outcomes, and the indications and timing of pacemaker insertion.

RESULTS

Fifteen live born infants (10 male, 5 female) with CCHB were identified. Their mean (and SD) gestation and birth weight were 37 (3.3) weeks and 3100 (448) grams respectively. Maternal systemic lupus erythematosus (SLE) antibodies were present in eight (53%) pregnancies and two infants had congenitally corrected transposition of the great arteries (cCTGA). The median heart rate/minute at birth was 60 (range 40-80). Thirteen (87%) patients to date required a pacemaker. The median age of insertion of a pacemaker device was six months (range 2 days-16 years). All patients were paced epicardially - six initially with a single chamber and five with a dual chamber pacemaker. At the time of generator change, dual chamber pacemakers were used. The median life of an implanted pacemaker was six years (3-10 years). Except for a patient with cCTGA who has undergone a double switch procedure, all the patients had good systemic ventricular function. There was one death in the group unrelated to CCHB.

CONCLUSIONS

CCHB is a uncommon but potentially serious condition in infancy. While a significant number of infants need a pacemaker, the overall outcome of infants with CCHB in our experience is good.

Acute cardiac failure following pacing in an adult patient with congenital complete heart block

A case of an adult patient with congenital complete heart block is reported in whom acute heart failure followed pacemaker implantation. It is uncertain whether the associated cardiomyopathy was present since birth, although right ventricular pacing was probably responsible for further deterioration of myocardial function. Synchronous pacing of both ventricles might be recommended in these patients.

Cardiac syncope in pediatric patients

OBJECTIVE

To assess the epidemiology of cardiac syncope in children and evaluate the guidelines on its management.

MATERIAL AND METHODS

We analyzed the etiology to syncope and diagnostic workup in consecutive pediatric patients presenting with syncope in our emergency departments or cardiac outpatient clinics between 1997 and 2005, and who were subsequently diagnosed as having cardiac syncope.

RESULTS

A primary cardiac cause was identified in 11 syncopal patients presenting to the emergency room and 14 patients to the cardiac clinic: supraventricular tachyarrhythmia in 9, ventricular tachyarrhythmia in 10, pacemaker dysfunction in 2, and isolated cases of sick sinus syndrome, hypoxic spell, hypertrophic cardiomyopathy, and primary pulmonary hypertension. Some elements suggested potential cardiac disease as a cause of syncope in all cases. The resting electrocardiogram and the echocardiogram were interpreted as positive and relevant to the diagnosis in 17 and 3 patients, respectively. Exercise electrocardiogram and Holter recording provided diagnostic information previously not seen on the resting electrocardiogram in six and three patients, respectively. Three children have died and one child has neurological sequelae following resuscitation.

CONCLUSION

Our data support the premise that careful history taking with special focus on the events leading up to syncope, as well as a complete physical examination, can guide practitioners in discerning which syncopal children need further cardiac investigations.

Sudden death in children and adolescents

OBJECTIVE

To identify the incidence, causes, and characteristics of sudden death at age 1-20 years.

DESIGN

A review of all deaths at age 1-20 years. Death certificates were obtained from the Office for National Statistics, and further information, where appropriate, from coroners, paediatricians, physicians, and pathologists.

SETTING

The resident population of one English health region in 1985-1994.

RESULTS

In a population of 806 500 children and adolescents aged 1-20 years there were 2523 deaths in 10 years. Medical causes accounted for 1017 deaths (40%); 1236 (49%) were unnatural, and 270 (11%) were sudden. These sudden deaths comprised 142 with a previous diagnosis, the commonest being epilepsy 49 (34%), cardiovascular disease 33 (23%), and asthma 30 (21%); 87 attributed to a cause discovered at necropsy, which was respiratory infection in 32 (37%), other infections in 17 (20%), and unsuspected cardiovascular abnormalities in 26 (30%); 41 remained unexplained.

CONCLUSIONS

Half of all sudden deaths in children or adolescents were attributed to an already diagnosed condition. Abnormalities identified at necropsy accounted for one third of sudden deaths. Undiagnosed hypertrophic cardiomyopathy caused less than one death per million person years in the population aged 1-20 years. Unexplained sudden death, which may be caused by primary cardiac arrhythmia, is probably about 10 times more common.

Complete congenital heart block: a review and case study

Complete congenital heart block (CCHB) is a rare disease of the newborn that carries significant morbidity and mortality. It generally occurs as a result of the presence of maternal autoantibodies that are transferred to the fetus and affect the fetal heart, or it may be associated with a congenital structural abnormality of the heart. Infants with CCHB are at risk for diminished cardiac output and the subsequent development of congestive heart failure. Many infants require the placement of a cardiac pacemaker. It is essential that the nurse caring for these infants have a good understanding of the disease process and be familiar with the unique problems that these infants and their families may encounter.

Evaluation and management of bradyarrhythmias in the emergency department

Bradyarrhythmias may be due to varied causes, although acute myocardial infarction, hypoxia, sepsis, and hypothermia should be considered. Emergency department therapy consists of treatment of the underlying cause, pharmacologic interventions, and temporary pacing. This article provides a detailed discussion of the causes and treatment of bradyarrhythmias in the emergency department.

Congenital heart block: HLA differences between affected children and healthy siblings in four Finnish families

Congenital heart block without intracardiac anatomic malformations is a potentially lethal disease affecting children and newborns. The mother often has an autoimmune disorder with autoantibodies against SS-A/Ro and/or SS-B/La antigens. However, only a minority of the children of these mothers develop complete heart block. It is believed that the maternal antibodies are pathogenic, but other immunological mechanisms such as cell-mediated injury cannot be excluded. Maternal cells may recognize fetal antigens adjacent to fetal HLA, and thus some children may be more susceptible to heart block than others, depending on their HLA genetics. The purpose of this study was to evaluate whether there are HLA differences between children with heart block and their healthy siblings. Six affected children in four families and their siblings were studied. MHC class I were typed serologically and class II and some non-HLA alleles were typed by DNA techniques. DQB1*03/04 were seen more often in the affected children than in the siblings. Some other differences were also seen in the other antigens of the MHC area.

Case conference: complete heart block in a young man

A previously healthy 32-year-old man presented to the ED in complete heart block. Ischemic, infectious, and inflammatory conditions were considered in the differential diagnosis. Management options for complete heart block, the etiology of heart block in young adults, and treatment guidelines are reviewed.

Anti-La (SS-B) but not anti-Ro52 (SS-A) antibodies cross-react with laminin--a role in the pathogenesis of congenital heart block?

Cross-reactions between maternally derived autoantibodies and fetal cardiac antigens have been postulated to play a role in the pathogenesis of congenital heart block (CHB). We have explored the cross-reactivity of autoantibodies to the small ribonuclear autoantigens, La/SS-B and Ro/SS-A, with laminin, the major component of cardiac sarcolemmal membrane using affinity-purified antibodies from patients with Sjögren's syndrome (SS). Anti-La antibodies purified from eight of 10 patients cross-reacted significantly with mouse laminin by ELISA. In contrast, purified antibodies to Ro52 from the same 10 patients showed little or no binding to laminin. Laminin inhibited up to 70% binding of anti-La antibodies to La antigen, and La inhibited up to 65% binding of anti-La antibodies to laminin. The cross-reaction was further examined on cryosections of 10 human fetal hearts aged from 8.7 to 14.9 weeks of gestation, two normal adult hearts, and one pathological adult heart with a diagnosis of dilated cardiomyopathy. Anti-Ro52 antibodies did not bind to the surface of cardiac cells. However, anti-La antibodies from seven of 10 patients tested bound to the surface of fetal myocytes from hearts aged 9.4 to 14.9 weeks of gestation, and also to the myocytes from the pathological adult heart but not to normal adult hearts. Preincubation with La antigen abolished the binding of anti-La antibodies to the surface of adult heart myocytes with dilated cardiomyopathy, and pre-incubation with mouse laminin could partially block this binding. These results suggest that molecular mimicry between laminin and La, but not Ro52, may act as a target for specific maternal autoantibodies, and contribute to the pathogenesis of CHB at a critical stage during fetal cardiac development.

Psychophysiologic and behavioral effects of tactile stimulation on infants with congenital heart disease

A within-subjects, counterbalanced, repeated measures design was employed to determine the effects of gender and six different types of verbal and tactile stimuli on the arousal of 24 infants hospitalized for congenital heart disease during their first 6 months of life. Infants were systematically assigned to different sequences of the various stimuli. Measures of arousal included heart rate, blood pressure, respiration, and activity level. Results indicated that the use of touch conducive to neural excitation (i.e., intense, vigorous, extensive touching of highly innervated body areas) produced higher heart rates (p less than .01) and systolic blood pressure (p less than .002) as well as greater activity (p less than .01) than did other types of tactile stimulation or soothing verbal stimulation. Girls appeared more physiologically responsive to touch than boys and a subset of infants showed evidence of distress during more arousing stimulation.