Detection of anticonductive tissue autoantibodies in a patient with chronic intestinal pseudo-obstruction and sick sinus syndrome.

A 26-year-old patient was diagnosed as having chronic intestinal pseudo-obstruction with manometric and histopathologic features suggestive of an intestinal myopathy. Histology was characterized by smooth muscle degeneration without inflammatory or immune cells. The severe gut dysfunction required full parenteral nutritional support. After a few months, the patient developed symptomatic tachy-brady arrhythmia episodes with syncopes. A thorough diagnostic work-up led to a diagnosis of sick sinus syndrome, which was managed by pacemaker implantation and administration of ß-blockers. This led to a partial improvement in tachy-brady arrhythmia episodes. Nonetheless, the patient continued to experience sustained supraventricular tachyarrhythmia runs, poorly responsive to increasing ß-blocker doses. To investigate the origin of the cardiologic impairment, the patient was tested for anticonductive tissue autoantibodies, which were positive, thus supporting a possible autoimmune origin of the dysrhythmia. Other autoantibodies were negative. On the basis of these findings, the patient was treated with high-dose steroids, which were then tapered. The patient responded to the steroid treatment and did not experience further episodes of syncope and tachyarrhythmias. The severe gut dysfunction remained unchanged. This case highlights an association between severe gut dysfunction and cardiac conductive tissue abnormalities, with autoantibodies to conductive tissue possibly causing the dysrhythmia. The severe gut and heart (likely autoimmune-mediated) dysfunction presented in this case provides a basis to further assess a link between intestinal and cardiac abnormal rhythmicity.

Persistent fetal sinus bradycardia associated with maternal anti-SSA/Ro and anti-SSB/La antibodies.

OBJECTIVE: To study the clinical course and outcome of fetal sinus bradycardia (SB) due to maternal antibody-induced sinus node dysfunction. METHODS: We reviewed the maternal, prenatal, and postnatal findings of fetuses with SB associated with elevated maternal anti-SSA/Ro and anti-SSB/La antibodies. RESULTS: Of the 6 cases diagnosed prenatally, 3 had isolated SB persisting after birth and had a good prognosis. Three fetuses with SB and severe myocardial involvement (congenital complete heart block and/or endocardial fibroelastosis) succumbed in utero in spite of treatment. Postmortem histopathology in 1 fetus showed inflammatory destruction of the sinus and atrioventricular nodes. SB was detected incidentally in a 7-year-old girl. She had intermittent heart block with progressive sinus arrest requiring permanent pacemaker. CONCLUSION: Fetal SB associated with maternal autoantibodies may persist in childhood, with a good prognosis in the absence of widespread cardiac involvement.

Antibodies to human sinus node in sick sinus syndrome.

The incidence of autoantibodies against human conducting tissue was studied in 45 pacemaker patients with sick sinus syndrome (SSS), in 17 patients with bradyarrhythmia, and five patients with hypersensitive carotid sinus syndrome. Antibodies against the human sinus node were demonstrated in 29% of patients with SSS and in 24% of patients with bradyarrhythmia; a tenfold risk of SSS could be calculated in patients with this antibody as compared to age-matched controls. At least two subtypes of anti-sinus node antibodies were demonstrated: an antibody absorbable and another one not absorbable with ventricular myocardium. Patients with SSS and prior myocarditis of rheumatic fever have a threefold incidence of that antibody, demonstrating that anti-conducting tissue antibodies are etiologic indicators for former inflammatory heart disease. These antibodies may play a role in the secondary immunopathogenesis of sick sinus syndrome. This hypothesis emerges as an interesting new pathogenetic concept.