Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Heart Block”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 451 records · Page 25Linked to original sources

Importance of the immune response to the Ro/La particle in the development of congenital heart block and neonatal lupus erythematosus.

Previous studies have suggested a role for anti-Ro antibodies in the pathogenesis of neonatal lupus erythematosus (NLE). We reexamined the role of the immune response to the Ro/La particle in the development of NLE using newer and more definitive assay techniques. All 15 infants with congenital heart block and NLE had both anti-Ro and anti-La antibodies. Of 8 patients with cutaneous NLE alone, 2 had anti-Ro antibodies alone while the remaining 6 had both anti-Ro and anti-La antibodies. One woman gave birth to 2 children; one had both Ro and La antibodies and developed congenital heart block, the other had only anti-Ro and anti-U1RNP antibodies and was clinically normal. Our study demonstrates that the presence of anti-Ro and anti-La antibodies define the immune response that is associated with the development of congenital heart block of NLE.

Antibodies, Antinuclear↗

Transdifferentiation of cardiac fibroblasts, a fetal factor in anti-SSA/Ro-SSB/La antibody-mediated congenital heart block.

The signature lesion of autoantibody-associated congenital heart block (CHB) is fibrosis of the conducting tissue. To date, participation of myofibroblasts in the cascade to injury has been unexplored. The importance of myofibroblast/macrophage cross-talk is demonstrated by the novel finding of these cell types in the heart of a neonate dying of CHB. This clue to pathogenesis prompted consideration of the mechanism by which maternal anti-SSA/Ro-SSB/La Abs initiate an inflammatory response and promote fibrosis. Isolated cardiocytes from 16-24 wk abortuses were rendered apoptotic by exposure to poly (2-) hydroxyethylmethacrylate; flow cytometry confirmed surface expression of Ro/La. Apoptotic cardiocytes were incubated with affinity-purified Abs to 52 and 60 kDa Ro from CHB mothers (opsonized) or IgG fractions from healthy donors (nonopsonized). Macrophages cultured with opsonized apoptotic cardiocytes expressed proinflammatory markers, supported by a three-fold increase in active alpha(V)beta(3) integrin. Fetal cardiac fibroblasts exposed to supernatants obtained from macrophages incubated with opsonized apoptotic cardiocytes (but not nonopsonized) dramatically increased expression of the myofibroblast marker alpha-smooth muscle actin (SMAc). The "opsonized" supernatant reversed an inhibitory effect of the "nonopsonized" supernatant on proliferation of fibroblasts (120 vs 69%, p < 0.05). Parallel experiments examined the effects of two cytokines and their neutralizing Abs on fibroblasts. TGFbeta1 increased SMAc staining but decreased proliferation. TNF-alpha did not affect either readout. Addition of anti-TGFbeta1 Abs to the "opsonized" supernatant blocked SMAc expression but increased proliferation, while anti-TNF-alpha blocking Abs had no effects. These data suggest that transdifferentiation of cardiac fibroblasts to a scarring phenotype is a pathologic process initiated by maternal Abs.

Antibodies, Antinuclear↗

Skeletal muscle pathology in chronic heart block.

Skeletal muscle samples, mainly from the deltoid, were studied morphologically and histochemically in 35 patients with chronic heart block and from nine elderly control subject. The average age of the first group was 67-7 (range 11-94) years. Abnormalities were present in 20 cases, no difference being found between patients with idiopathic and secondary heart block. In 15 samples there was increased oxidative enzyme activity in some muscle fibres, and in six there was fibre type grouping. Six had unexplained type 11 fibre atrophy and two had a predominance of type 1 fibres. Tubular aggregates were conspicuous in one biopsy specimen, and in another, rod bodies were found. Minor abnormalities were also seen in the control group. In the absence of any consistent pattern many of these changes were attributed to ageing.

Adolescent↗

Return of normal conduction after paroxysmal heart block. Report of a case with major discordance of electrophysiological and pathological findings.

This report describes a 52-year-old male with paroxysmal heart block as well as left and right bundle branch block, resulting in Stokes-Adams attacks. The patient experienced a return to 1:1 atrioventricular (A-V) conduction with narrow QRS within 48 hours of the attacks and heart block never recurred. Electrophysiological studies three weeks later revealed a narrow QRS, a normal H-V interval (36 msec), 1:1 A-V conduction up to an atrial paced rate of 210 beats/min, and normal refractory periods with atrial extrastimulus techniques (His-Purkinje system refractory periods less than 370 msec). The patient died from a cerebral embolus incurred during diagnostic left heart catheterization two days after electrophysiological studies. Postmortem examination revealed calcific aortic stenosis with calcific impingement upon the pars membranacea resulting in compression of the distal His bundle and marked disruption of the proximal portions of both bundle branches. This report documents a major limitation of electrophysiological studies, this limitation being that these studies may be totally normal on one occasion in a patient with pathologically significant chronic conduction disease, which may become clinically manifest on another occasion.

Adams-Stokes Syndrome↗

Congenital complete heart block and SSA antibodies: obstetric implications.

Mothers with known or occult rheumatic disorders may be delivered of infants with congenital complete heart block. The more frequent use of ultrasonography during pregnancy now allows early detection of heart block in utero. The transplacental passage of SSA or SSB antibodies, of the IgG class, may mediate or be associated with immune damage to the fetal cardiac conduction system, as reported in our two patients. Maternal and/or newborn screening for SSA and SSB antibodies in selected patients permits an early presumptive diagnosis and will assist perinatal planning, particularly for immediate newborn cardiac pacemaker implantation. Early serologic detection of such antibodies may also assist family counseling of mothers at risk and should promote investigation of techniques to modify the immune status of these mothers. SSA- or SSB-positive maternal/fetal pairs should be prospectively managed by the obstetrician, neonatologist, and rheumatologist.

Adult↗

Lyme disease presenting as heart block.

Lyme disease is now recognized as an infectious process capable of involving multiple organs including the cardiovascular system. We recently treated a boy whose complaints on admission related only to symptomatic heart block that was severe enough to require transvenous pacing. This boy was subsequently determined to have had Lyme Disease after his medical testing was reevaluated for possible tick exposure. In rare instances symptomatic heart block may be the sole presenting complaint of Lyme Disease in children.

Child↗

The health of mothers of children with cutaneous neonatal lupus erythematosus differs from that of mothers of children with congenital heart block.

PURPOSE: Neonatal lupus erythematosus is caused by the transplacental passage of maternal autoantibodies. The aim of this study was to determine the risk of connective tissue disorders in mothers of children with cutaneous neonatal lupus erythematosus, as compared with the risk in mothers of children with congenital heart block, which is also often caused by maternal autoantibodies. SUBJECTS AND METHODS: We prospectively studied all mothers of children with cutaneous neonatal lupus erythematosus during a 14-year period at the Hospital for Sick Children, Toronto, Ontario, Canada. We identified 28 mothers, of whom 24 were eligible for study. The health and antibody status of the mothers were determined at the birth of the child and at followup. RESULTS: All mothers had anti-Ro antibodies at the time of birth. Initially 10 mothers were healthy and 14 mothers had either a defined (n = 9) or an undifferentiated (n = 5) autoimmune disorder. At a mean follow-up of 7 years, 13 (1 of whom had died) had a defined connective tissue disease, and 5 had an undifferentiated autoimmune disorder. Only 6 (25%) remained asymptomatic. By comparison, 36 (56%) of 64 mothers of children with congenital heart block were asymptomatic at follow-up (P <0.005). CONCLUSIONS: The majority of mothers of children with cutaneous neonatal lupus erythematosus had a defined or undifferentiated autoimmune disorder at the time of the child's birth, and others developed these conditions during follow-up. The health of these mothers appears to differ from that of mothers of children with congenital heart block.

Adult↗

Complete heart block in an Inuit family.

An Inuit family from Cape Dorset, Northwest Territories is described; six had documented complete heart block, one high grade atrioventricular block, one bi- or trifascicular block and all suffered syncope. One other member received a pacemaker for unknown reasons. Two of three middle-aged relatives had minor conduction abnormalities. All younger family members who were examined had no conduction problems. This suggests a heritable form of adult onset complete heart block, the largest series reported in the English literature.

Aged↗

Systolic and diastolic effects of variable atrioventricular delay in patients with complete heart block and normal ventricular function.

This study was designed to demonstrate the effects of varying the atrioventricular delay (AVD) on ventricular diastolic filling dynamics and the resultant stroke volume in patients with complete heart block and normal cardiac function. We studied 7 patients with normal cardiac function in whom a dual chamber pacemaker had been implanted because of complete heart block. Doppler and M-mode echocardiography was performed at 70, 100, 140, 180, and 220 ms, AVD with the device in DDD mode at a rate of 80 beats/min. The effects of these variable intervals on the contribution of the E and A waveform to the diastolic filling, on the stroke volume, and on the systolic intervals were evaluated. Optimization of this interval, with a 19% increase in stroke volume was achieved in the group of patients at an AVD of 140 ms. When considered individually, the AVD associated with the largest stroke volume, was 100 ms in 2 patients and 140 ms in the remaining 5. At this individual optimal AVD the ventricular septal contraction occurred 31 +/- 14 ms, before the end of the transmitral flow. The optimal AVD is, therefore, the one which synchronizes the ventricular and atrial systole so that the first ventricular septal contraction occurs after the peak of the A wave, just before the end of the transmitral flow. Because of the different functional cardiovascular status of the single patient, this parameter should be individualized; this can be clinically important as it may lead, in this patient population, to an improvement of the stroke volume up to 42%.

Adult↗

Complete heart block mimicking seizure disorder.

Two patients are described who presented with seizures. Electrocardiogram revealed complete heart block with ventricular asystole lasting four to 10 seconds in each case. These Stokes-Adams episodes were controlled with temporary transvenous pacing. Although there was full clinical recovery in each case, both patients continue to have right bundle branch block (RBBB) and left anterior hemiblock (LAH) 1-1/2 years after their initial presentation.

Adams-Stokes Syndrome↗

Mid-systolic click, late systolic murmur syndrome associated with complete heart block.

A 60 year old woman is presented who had the mid-systolic click, late systolic murmur syndrome, documented by phonocardiogram and left ventricular angiography. During an episode of non-anginal chest pain, advanced heart block was demonstrated and permanent transvenous pacemaker therapy was subsequently instituted. The association of the mid-systolic click, late systolic murmur syndrome and heart block is reviewed. It is suggested that 24-hour continuous electrocardiographic monitoring, as well as exercise stress testing, be included in the evaluation of patients with this syndrome.

Angiocardiography↗

Cross-reactive maternal autoantibodies and congenital heart block.

Epitopes with linear sequences recognized by anti-La autoantibodies from seven mothers of children with congenital heart block were recently defined. Eight of these epitopes share sequence identity with three other proteins in addition to the original autoantigen, La. The three proteins are human cardiac myosin beta heavy chain, laminin B1 chain and the M6 protein of Streptococcus pyogenes. Affinity purified anti-La antibodies from a further three mothers bound to the La antigen and also to human cardiac myosin and mouse laminin. Affinity purified antibodies from three mothers of healthy children bound to the La antigen but showed minimal binding to either human cardiac myosin or mouse laminin. Cardiac myosin inhibited the binding of CHB-related anti-La antibodies to both La and myosin. These data support a role for maternal autoantibodies crossing the placenta and recognizing foetal cardiac antigens accessible at a critical developmental stage during gestation. We suggest that this would lead to complement fixation, inflammation and the subsequent pathology associated with congenital heart block.

Amino Acid Sequence↗

Transient complete heart block following percutaneous balloon pulmonary valvuloplasty: treatment with systemic corticosteroids.

Balloon pulmonary valvuloplasty is a safe and effective treatment for congenital pulmonic valve stenosis. This report describes a child who developed complete atrioventricular (AV) block following balloon pulmonary valvuloplasty. The child was treated with a 10-day course of systemic corticosteroids. The heart block gradually resolved during the first week following the procedure and has not recurred. Heart block is a known complication of right heart catheterization and has been described following balloon pulmonary valvuloplasty. Systemic corticosteroids have been used to treat AV block of various etiologies and may have contributed to the child's recovery in this case.

Catheterization↗

Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela.

OBJECTIVE: We report 16 infants with complete congenital heart block (CHB) who developed late-onset dilated cardiomyopathy despite early institution of cardiac pacing. BACKGROUND: Isolated CHB has an excellent prognosis following pacemaker implantation. Most early deaths result from delayed initiation of pacing therapy or hemodynamic abnormalities associated with congenital heart defects. METHODS: A multi-institutional study was performed to identify common clinical features and possible risk factors associated with late-onset dilated cardiomyopathy in patients born with congenital CHB. RESULTS: Congenital heart block was diagnosed in utero in 12 patients and at birth in four patients. Ten of 16 patients had serologic findings consistent with neonatal lupus syndrome (NLS). A pericardial effusion was evident on fetal ultrasound in six patients. In utero determination of left ventricular (LV) function was normal in all. Following birth, one infant exhibited a rash consistent with NLS and two had elevated hepatic transaminases and transient thrombocytopenia. In the early postnatal period, LV function was normal in 15 patients (shortening fraction [SF] = 34 +/- 7%) and was decreased in one (SF = 20%). A cardiac pacemaker was implanted during the first two weeks of life in 15 patients and at seven months in one patient. Left ventricular function significantly decreased during follow-up (14 days to 9.3 years, SF = 9% +/- 5%). Twelve of 16 patients developed congestive heart failure before age 24 months. Myocardial biopsy revealed hypertrophy in 11 patients, interstitial fibrosis in 11 patients, and myocyte degeneration in two patients. Clinical status during follow-up was guarded: four patients died from congestive heart failure; seven required cardiac transplantation; one was awaiting cardiac transplantation; and four exhibited recovery of SF (31 +/- 2%). CONCLUSIONS: Despite early institution of cardiac pacing, some infants with CHB develop LV cardiomyopathy. Patients with CHB require close follow-up not only of their cardiac rate and rhythm, but also ventricular function.

Cardiomyopathy, Dilated↗