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PubMed2006

Specificity and effector mechanisms of autoantibodies in congenital heart block.

Complete congenital atrio-ventricular (AV) heart block develops in 2-5% of fetuses of Ro/SSA and La/SSB autoantibody-positive pregnant women. During pregnancy, the Ro/SSA and La/SSB antibodies are transported across the placenta and affect the fetus. Emerging data suggest that this happens by a two-stage process. In the first step, maternal autoantibodies bind fetal cardiomyocytes, dysregulate calcium homestasis and induce apoptosis in affected cells. This step might clinically correspond to a first-degree heart block, and be reversible. La/SSB antibodies can bind apoptotic cardiomyocytes and thus increase Ig deposition in the heart. The tissue damage could, as a second step, lead to spread of inflammation in genetically pre-disposed fetuses, progressing to fibrosis and calcification of the AV-node and subsequent complete congenital heart block. Early intrauterine treatment of an incomplete AV-block with fluorinated steroids has been shown to prevent progression of the heart block, making it clinically important to find specific markers to identify the high-risk pregnancies.

Animals↗
PubMed1979

Polymyositis and complete heart block.

The development of complete heart block is described in a patient with polymyositis. The implantation of a permanent pacemaker has controlled the heart block, but the progression of the underlying disease despite treatment with relatively high dosage of corticosteroids makes the outlook uncertain.

Adult↗
PubMed1992

Disposition of the atrioventricular conduction tissues in the heart with isomerism of the atrial appendages: its relation to congenital complete heart block.

OBJECTIVES: Our goal was to compare histologically the mechanisms producing congenital complete heart block in normally structured hearts and in hearts with isomerism of the atrial appendages. BACKGROUND: It is known that several different histologic patterns can underscore the existence of congenital complete heart block in the normally structured heart, and that block is particularly frequent in the setting of isomerism of the atrial appendages. The histologic findings in the latter setting were compared and contrasted with those found in the normally structured heart. METHODS: Serial section techniques were used to study 14 hearts with isomerism of the atrial appendage (12 with left isomerism and 2 with right isomerism) and 7 normally structured hearts. RESULTS: Discontinuity between the atrioventricular (AV) node and the ventricular conduction tissues was found in 10 of the 12 hearts with left isomerism; the other 2 hearts had a normally formed conduction axis and heart block was not present in these cases. In both hearts with right isomerism, "slings" of ventricular conduction tissue connected dual AV nodes; congenital complete heart block was not present in either case. In six of the seven cases with a normally structured heart, anti-Ro antibodies had been found in the maternal serum. All six of these hearts had discontinuity between the atrial tissues and the ventricular conduction axis. Intraventricular discontinuity was found in the seventh case, in which anti-Ro antibodies were not found in the mother. CONCLUSIONS: The pattern of congenital complete heart block in cases with left isomerism is discontinuity between the AV node and the conduction axis, in contrast to the pattern of atrial-axis discontinuity produced in the normally structured heart when anti-Ro antibodies are found in the maternal serum.

Abnormalities, Multiple↗
PubMed1995

Therapeutic trial of sympathomimetics in three cases of complete heart block in the fetus.

BACKGROUND: A total of 36 fetuses with isolated congenital complete heart block and structurally normal hearts have been seen in the department of fetal echocardiography since 1980. Although the prognosis is good in the majority of cases, those who develop intrauterine cardiac failure have a high mortality. The aim of this study was to investigate the contribution to management of sympathomimetic therapy by comparing two possible agents administered to the mothers. METHODS AND RESULTS: The effect of two sympathomimetic agents, isoprenaline and salbutamol, was compared in three patients with isolated complete heart block. Fetal heart rate and indexes of cardiac function were monitored during therapy. Maternal cardiovascular status was also regularly assessed. Dosage of isoprenaline increased from 1 to 12 micrograms/min, and salbutamol increased from 4 to 64 micrograms/min during the trial. No significant change was detected with isoprenaline therapy, but all fetuses showed an increase in heart rate and improvement in ventricular function with salbutamol. Salbutamol was maintained until delivery in one case with evidence of cardiac failure, with resolution of fetal hydrops. All three delivered in good condition close to term. Two of three required pacing in the neonatal period. CONCLUSIONS: We conclude that salbutamol can be effective in the treatment of fetal complete heart block and should be considered in patients with this condition where there is evidence of deteriorating cardiac function.

Albuterol↗
PubMed1988

Pathology of primary congenital complete heart block.

Studies were done on the hearts of 4 infants and 2 adults with the clinical diagnosis of congenital complete heart block (CCHB) and on the hearts of 6 control patients of similar age groups but without any significant arrhythmia. All 6 patients with CCHB had absence of the fibers [approaches to atrioventricular node (AVN)] connecting the atrium and the AVN and common bundle (CB), as well as having partial or complete absence of the AVN. The mothers of 2 of the 4 infants with CCHB had antibodies to Ro antigen, and one mother (with Ro antibody) had evidence of having had active systemic lupus erythematosus (SLE). One infant developed SLE before the age of 1 yr. In one of the 2 adult cases with CCHB, the patient had evidence of having developed his CHB after birth, and the other adult patient probably had his CCHB since birth. It was suggested that these findings--and others in the literature--could be explained by there being two factors that lead to the occurrence of idiopathic heart block, whether it be truly congenital or acquired later in life: (a) a genetic predisposition to the condition together with (b) a precipitating injury. Thus, a patient with a genetic predisposition to insults to his conducting fibers might develop CCHB in utero due to some insult (e.g., due to damage by circulating anti-DNA antibodies in patients with SLE or by other unknown insults); or the "weak" fibers could be affected later in life by many different injuries--whether viral, hypersensitivity, anoxic, or due to aging.

Adolescent↗
PubMed1992

Incidence and prognostic implications of heart block complicating inferior myocardial infarction treated with thrombolytic therapy: results from TIMI II.

OBJECTIVES: The aim of this study was to determine the incidence and significance of second- or third-degree heart block among patients with inferior myocardial infarction treated with thrombolytic therapy. BACKGROUND: Data from the prethrombolytic era suggest that heart block occurs in approximately 20% of patients with acute inferior myocardial infarction and is associated with a marked increase in mortality. Little is known about the incidence and prognostic implications of heart block among patients receiving thrombolytic therapy. METHODS: We studied 1,786 patients with acute inferior myocardial infarction enrolled in the Thrombolysis in Myocardial Infarction (TIMI) II Trial who received recombinant tissue-type plasminogen activator (rt-PA) within 4 h of the onset of symptoms. RESULTS: Heart block occurred in 214 patients (12%); 113 (6.3%) had heart block on presentation and 101 (5.7%) developed heart block in the 24 h after treatment with rt-PA. Patients with heart block at entry were slightly older and a greater proportion had cardiogenic shock. The 21-day mortality rate among patients with heart block at entry was 7.1% (8 of 113), compared with 2.7% (45 of 1,673) among patients without heart block at study entry (relative risk 2.6, p = 0.007). However, heart block was not independently associated with 21-day mortality after adjustment for other variables, including shock. Mortality and other adverse cardiac events in the following year were similar among patients with and without heart block. Among patients without heart block at study entry, coronary angiography among patients randomly assigned to coronary catheterization 18 to 48 h after admission revealed that the infarct-related artery was occluded in 28.2% (11 of 39) of patients who developed heart block versus 15.5% (112 of 723) of patients without heart block (p = 0.04). The 21-day mortality rate was increased among patients in whom heart block developed after thrombolytic therapy (9.9% [10 of 101] versus 2.2% [35 of 1,572] of patients without heart block, relative risk 4.5, p less than 0.001). Analysis of the increased mortality among patients who developed heart block suggests that mortality was due to severe cardiac dysfunction; no patient was considered to have died as a result of the heart block or its treatment. CONCLUSIONS: Heart block is common among patients with inferior infarction given thrombolytic therapy and is associated with increased mortality. These clinical and anatomic data provide insight into the mechanism of heart block and increased mortality among such patients.

Female↗
PubMedDate not supplied

Early and late postoperative complete heart block in pediatric patients submitted to open-heart surgery for congenital heart disease.

The incidence of complete heart block (CHB) following open-heart surgery for congenital heart disease is about 1%. Most of postoperative CHBs are the consequence of procedures involving the closure of ventricular septal defect; they usually occur immediately after surgery or early in the postoperative period; in few cases they also may occur many months or years after surgery. Early postoperative CHB can be transient or permanent. Permanent pacing is generally not recommended in the former. On the contrary, if CHB persists after at least two weeks of temporary pacing, permanent pacing is needed because the block is usually due to His bundle damage or to trifascicular damage and this is associated with excessive bradycardia and risk of asystole. Late postoperative CHB can be due to the recurrence of previous transient early postoperative CHB or to the progression of postoperative His-Purkinje conduction troubles suggesting trifascicular damage. Permanent pacing is obviously needed in case of documented late postoperative CHB. The prophylactic use of permanent pacing in patients at risk of late postoperative CHB is still a controversial point. Electrophysiologic studies should be performed in such patients. The occurrence of second degree AV block within or below the bundle of His during atrial pacing at rate lower than 200/min can be considered a good marker of impending CHB. In this case prophylactic permanent pacing should be recommended, especially in patients with coexisting problems of troublesome or malignant tachyarrhythmias who have to be treated with antiarrhythmic drug therapy that may favour the progression to CHB.

Adolescent↗
PubMed2001

Heart block in patients after bariatric surgery accompanying sleep apnea.

BACKGROUND: Heart block and bradycardia during sleep has been reported in patients with obesity. The occurrence of bradyarrhythmias in patients after undergoing bariatric surgery has not been reported. METHODS: Over a period of 6 months, 3 patients who underwent laparoscopic weight reduction surgery developed prolonged heart block during sleep. Clinical course and follow-up are presented. RESULTS: All 3 patients were diagnosed with sleep apnea. For 2 of these patients this was a new diagnosis. The episodes of heart block coincided with their episodes of sleep apnea. During follow-up of at least 6 months, no patient has had any adverse consequences related to their nocturnal heart block. CONCLUSION: Heart block during sleep is sometimes seen in patients undergoing bariatric surgery. The cause is sleep apnea, which often is worsened in the postoperative state due to narcotic analgesics. These patients require treatment of their sleep apnea, not pacemakers.

Adult↗
PubMedDate not supplied

Complete heart block in thalassemia major: a case report.

Cardiac complications of iron overload are the most common cause of death in patients with thalassemia major. These complications include recurrent pericarditis, refractory congestive heart failure and rhythm disorders. The usual rhythm disturbances are supraventricular or ventricular premature contractions and first-or second-degree heart block. Complete heart block is a very rare complication of thalassemia major. Herein, we report a case of complete heart block with thalassemia major. The patient also had serious congestive heart failure. Management of the heart block with pacemaker brought no clinical improvement, and she died in the second month of hospitalization.

Adolescent↗
PubMed1986

The natural history of primary first-degree atrioventricular heart block.

The long-term prognosis of first-degree heart block in the absence of organic heart disease has not been clearly defined. We addressed this question in a 30-year longitudinal study of 3983 healthy men. We identified 52 cases that were present on entry into the study and 124 incident cases during follow-up. The incidence rose steadily after age 40 and was 1.13 per 1000 person-years over the entire period. Two thirds of the cases had only moderate prolongation of the PR interval (0.22 to 0.23 second). We compared four age-matched controls with each case for histories of scarlet fever, rheumatic fever, diphtheria, smoking, blood pressure, and body-mass index. No significant differences (P greater than 0.05) were found. Likewise, mortality from all causes did not differ between cases and controls. Although somewhat higher rates of morbidity and mortality from ischemic heart disease were observed in the cases than in the controls, the differences were not significant. Progression to higher grades of heart block occurred in only two cases. In view of the prognostic findings and the rare occurrence of advanced degrees of heart block, we conclude that primary first-degree heart block with moderate PR prolongation is a benign condition. This conclusion may not apply, however, to persons with more marked prolongation of the PR interval, a very rare condition.

Adult↗
PubMedDate not supplied

Congenital complete heart block and successful vaginal delivery.

BACKGROUND: Congenital complete heart block is an uncommon fetal arrhythmia characterized by complete dissociation of the atrial and ventricular contractions. CASES: Two patients were diagnosed with isolated congenital complete heart block in the second trimester of pregnancy. Successful vaginal delivery was achieved by both. CONCLUSION: A monitoring protocol algorithm to be used by the clinician in managing term patients with isolated complete congenital heart block is presented. Vaginal delivery can be safely accomplished in patients with isolated congenital complete heart block, with the use of ultrasound and fetal scalp blood sampling to assess fetal well-being during labor and delivery.

Adult↗
PubMed1998

1:1 atrioventricular conduction in congenital complete heart block.

A female neonate with congenital complete heart block developed atrioventricular conduction through an accessory pathway. Despite sinus rhythm and an adequate heart rate she developed severe dilated cardiomyopathy and died at age 14 months. This case illustrates that underlying heart block can be present in individuals with asymptomatic Wolff-Parkinson-White syndrome and that the dilated cardiomyopathy that occasionally accompanies autoimmune congenital heart block is not primarily caused by bradycardia.

Atrioventricular Node↗
PubMed1994

Intrapartum fetal surveillance of congenital heart block with pulse oximetry.

BACKGROUND: In cases of fetal congenital heart block, the fetal heart rate (FHR) pattern is uninterpretable, often leading to an operative delivery. Reflectance pulse oximetry, a new technique that continuously measures the fetal arterial oxygen saturation (SaO2) during labor, is potentially useful in intrapartum monitoring of fetuses with this condition. CASES: Two fetuses with congenital heart block were monitored with reflectance pulse oximetry and fetal scalp blood sampling. The first patient delivered spontaneously. Adequate signal quality was achieved during 73% of the study time. Mean +/- standard deviation (SD) SaO2 was 53 +/- 14%. Fetal outcome was good. The second patient was delivered by cesarean because of arrest of labor. Oxygen saturation values were obtained during 89% of the study time. The mean SaO2 was 42 +/- 13%. There was a period of 8 minutes with SaO2 values below 20%. Capillary blood pH dropped from 7.33 to 7.25; SaO2 values then returned to levels above 30% and the capillary blood pH normalized. The neonate was born in good condition. CONCLUSION: In fetal congenital heart block, adequate surveillance with FHR monitoring during labor is not possible; therefore, continuous information on fetal oxygenation may be valuable in assessing the fetal condition and may prevent unnecessary obstetric interventions.

Adult↗
PubMed1998

Fetal complete heart block: an expectant management.

Fetal complete heart block is a rare cardiac arrhythmia occurring in prenatal life. The diagnosis usually requires a multimodality approach of imaging technology especially M-mode and Doppler ultrasound. The management guideline is not conclusive. We presented 2 cases of fetal complete heart block diagnosed prenatally. The fetuses were closely monitored conservatively and delivered at term. Permanent cardiac pacemakers were performed neonatally with satisfactory outcomes.

Adult↗