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 199 records · Page 11Linked to original sources
PubMedDate not supplied

Adults with congenital complete heart block: 25-year follow-up.

Complete congenital heart block has been recognized since 1846, yet the prognosis of the disease has not been determined by comprehensive long-term studies. We reviewed 14 cases of complete congenital heart block at The Cleveland Clinic Foundation. The patients were followed for a mean of 25 years (range, 20 to 32 years). Ten patients had structurally normal hearts, and 4 had varying degrees of congenital heart disease. The patients were evaluated with regard to symptoms, and indications for permanent pacemaker implantation were studied. Seven patients received permanent pacemakers. Ages at the time of pacemaker implantation ranged from 15 to 38 years (mean, 25 years). Overall, the patients in our study tended to lead normal productive lives. The main indications for pacemaker implantation were symptoms alone. Guidelines for prophylactic pacemaker implantation have yet to be determined, and the development of these guidelines is difficult due to small numbers of patients at isolated centers. A large international study is needed to set these guidelines.

Adult↗
PubMed2001

A case of familial atrioventricular heart block affected by alteration of the autonomic nervous system.

Familial atrioventricular heart block affected by the autonomic nervous system has rarely been documented. We describe a 35-year-old man who had first-degree atrioventricular heart block with a PR interval of 0.46 s. He had a family history of 2 members with complete heart block and 1 with documented atrial standstill. The man's P-R interval was shortened by exercise and phenylephrine administration. In the electrophysiolgic study, a "split His" with an H-H' of 220 ms was recognized. Such a case of familial atrioventricular heart block with abnormal His-Purkinje conduction affected by the autonomic nervous system is very rare and worthy of description.

Adult↗
PubMed1993

Chloroquine retinopathy in Nigerian patients with heart block.

Twenty-six patients with heart block were examined for evidence of chloroquine retinopathy. Detailed histories of chloroquine intake showed that 50% (13 of 26) of these patients were chloroquine abusers. Retinal changes typical of chloroquine retinopathy were seen in 53.8% (7 of 13) of the chronic chloroquine abusers. Patients with heart block of unknown cause should have their fundi examined so that signs of chloroquine retinopathy may be sought.

Adult↗
PubMed1992

Therapeutic guidelines for congenital complete heart block presenting in pregnancy.

Congenital complete heart block presenting for the first time in pregnancy is a therapeutic challenge. Most of the reports are from an era when pacemaker therapy was in its infancy. Although isolated case reports have appeared, there are no definite guidelines for the management of such patients. We describe three cases of congenital complete heart block presenting in pregnancy. All the patients delivered normally with temporary pacing support during labor. Two of the three women remained symptomatic during the postpartum period when they were being weaned off the pacing support, so they were discharged with permanent pacemaker implantation. The third woman remained symptom-free during pregnancy, labor, and the postpartum period and was discharged without a permanent pacemaker; she is being followed with routine and 24-hour ambulatory electrocardiography. We review the literature in an attempt to formulate a therapeutic policy for such patients.

Adult↗
PubMed1987

Congenital heart block and cardiac anomalies in the absence of maternal connective tissue disease.

The association of congenital heart block with maternal connective tissue disease and autoimmunity has been recently reported. Two cases of heart block were diagnosed in utero at 23 and 24 weeks' gestation. Both mothers had extensive workups for connective tissue disease that were negative. Two-dimensional and Doppler echocardiography were performed in utero and both infants had left atrial isomerism, atrioventricular canal defects, and severe hydrops in addition to heart block. Review of the recent literature identifies a subset of congenital heart block in which the mothers have no evidence for connective tissue disease, and the fetus or neonate has complex cardiac malformations and hydrops. The common features in these babies are atrioventricular canal defects and isomerism. No reports of congenital heart disease among the children of mothers with connective tissue disease fit this description. Our recent experience and literature review emphasize the previously known association between congenital heart block and congenital heart disease. This association is especially important in light of the poor prognosis for this group of fetuses and neonates.

Adolescent↗
PubMed2001

Late occurrence of heart block after radiofrequency catheter ablation of the septal region: clinical follow-up and outcome.

INTRODUCTION: There are few data regarding the occurrence of delayed heart block at least 24 hours after radiofrequency catheter ablation (RFCA) of AV nodal reentry or posteroseptal accessory pathways (APs). We investigated the late occurrence of heart block in this population, the clinical outcome, and whether findings at electrophysiologic study could have predicted its development. METHODS AND RESULTS: Two of 418 patients with AV nodal reentry undergoing RFCA using a posterior approach and 1 of 54 patients with RFCA of a posteroseptal AP developed late heart block. Anterograde and retrograde AV nodal conduction before and after RFCA were normal. Patients received 12, 15, and 32 RFCA lesions, respectively, using a mean maximum power of 44 W. The RFCA sites were the posterior septum for posteroseptal AP and the posterior and mid-septum for patients with AV nodal reentry, with no His electrogram ever recorded at the ablation site. During RFCA, junctional tachycardia occurred with 1:1 VA conduction in the patient with a posteroseptal AP, but occasional intermittent single retrograde blocked complexes were present in both patients with AV nodal reentry. No rapid junctional tachycardia or >1 consecutive retrograde blocked complex was ever observed during RFCA. Persistent high-degree AV block with junctional escape developed 2 days after RFCA in the posteroseptal AP patient. A permanent pacemaker was implanted, and normal conduction was noted 16 days after RFCA. Both patients with AV nodal reentry complained of fatigue, mainly on exertion, 3 to 4 days after RFCA, and ECG-documented exercise-induced variable AV block was obtained. Because heart block resolved in our initial patient, a prolonged monitoring period was allowed. Symptoms disappeared at 13 and 8 days, and a follow-up treadmill test showed normal PR interval and no heart block. No recurrence of heart block has been seen in any of these three patients. CONCLUSION: Late unexpected heart block after RFCA of AV nodal reentry and posteroseptal AP is rare, often resolves uneventfully in 1 to 2 weeks, and no specific electrophysiologic findings predicted its occurrence. Prolonged clinical observation is preferable to immediate pacemaker implantation in such patients.

Adult↗
PubMedDate not supplied

Threshold, enzymatic, and pathologic changes associated with prolonged transcutaneous pacing in a chronic heart block model.

Previous studies have shown that 30 minutes of transcutaneous cardiac pacing (TCP) can induce mild, clinically insignificant myocardial damage. Longer use of TCP may cause more severe cardiac damage which might result in an increase in the capture threshold for subsequent transvenous cardiac pacing (TVP). To assess this possibility, we examined changes induced by TCP in a canine chronic heart block model. Heart block was induced in conditioned dogs (n = 8) by His bundle ablation. Seven to 10 days after induction of heart block, six animals were paced. Cardiac enzymes were drawn before pacing and at 4, 24, 48, and 72 hours after pacing. Although there was a significant rise in CK at 4 and 24 hours (P less than 0.05), there was no detectable rise in the MB fraction in any of the paced animals. There was no elevation of LDH after pacing, although three animals did develop an LDH1/LDH2 isoenzyme flip indicative of myocardial damage. Animals were sacrificed 72 hours after pacing and their hearts were examined for gross and microscopic changes. The hearts of the paced animals revealed subendocardial, subepicardial, and perivascular areas of basophilic degeneration involving less than 1% of the myocardium in four of six animals. No evidence of such damage was seen in two heart-blocked control animals not undergoing pacing. TVP and TCP capture thresholds assessed before and after a 60-minute TCP pacing period showed no significant change. Hence, use of TCP for a 60-minute period prior to TVP appears to be a safe emergency pacing technique.

Animals↗
PubMed1978

Preservation of pre-excitation despite acute myocardial infarction complicated by complete heart block.

In a 53-year-old man with ventricular pre-excitation (normal PR interval, QRS interval of 0.12 seconds and delta-waves) acute inferior wall myocardial infarction was complicated by, successively, first-degree atrioventricular block, second-degree atrioventricular block (Wenckebach type) and complete heart block. The QRS pattern of pre-excitation was preserved throughout these events. The classification of ventricular pre-excitation is reviewed and the correlation between the various electrocardiographic patterns (the Wolff-Parkinson-White syndrome and its variants and the Lown-Ganong-Levine syndrome) and the anomalous conduction pathways of Kent, James and Mahaim are discussed. In this case the best possible explanation for preservation of pre-excitation during complete heart block was the existence of accessory fibres of Mahaim.

Acute Disease↗
PubMed1994

Autoantibody-associated congenital heart block: outcome in mothers and children.

OBJECTIVE: To determine the initial clinical status and the long-term outcome of mothers and their children with autoantibody-associated congenital heart block. DESIGN: Dynamic, longitudinal cohort study. PATIENTS: 55 children with isolated congenital heart block, their 52 mothers, and 5 other women currently carrying fetuses with congenital heart block. All maternal sera contained antibodies to SSA/Ro alone or to both SSA/Ro and SSB/La. MEASUREMENTS: Clinical information obtained from mailed questionnaires, telephone interviews, primary physicians, and chart reviews. RESULTS: When congenital heart block was identified in the children, 23 women were asymptomatic, 15 had systemic lupus erythematosus, 8 had the Sjögren syndrome, and 11 had an undifferentiated autoimmune syndrome. Follow-up ranged from 1 week to 20 years (median, 3.7 years). Eleven (48%) of the 23 initially asymptomatic mothers developed symptoms of a rheumatic disease (0.15 status changes/patient-year of follow-up; 6 (26%) developed an undifferentiated autoimmune syndrome, 2 (9%) developed the Sjögren syndrome, and 3 (13%) developed systemic lupus erythematosus. One mother with the Sjögren syndrome progressed to systemic lupus erythematosus. Four (16%) of 25 subsequent pregnancies in 22 women were complicated by heart block. Seventeen affected children died, 12 within 1 month of birth. Pacemakers were implanted in 37 (67%) of the 55 children, 27 within 3 months after birth. CONCLUSION: The development of rheumatic disease in asymptomatic mothers identified by the birth of a child with congenital heart block is common but not universal. The risk for congenital heart block in subsequent pregnancies is low. One third of the children with autoantibody-associated congenital heart block die in the early neonatal period and, of those who survive, most require pacemakers.

Adult↗
PubMed1980

Reflex heart block. Baroreflex, chemoreflex and bronchopulmonary reflex causes.

Reflex heart block was studied in 20 dogs anesthetized with sodium pentobarbital and in 5 trained unanesthetized dogs. Three different vagal reflexes were produced: the Marey response during hypertension caused by administering methoxamine, a cardiogenic hypertensive chemoreflex activated by injection of serotonin into the left atrium and the Hering-Breuer reflex observed during normal respiration of unanesthetized dogs. In every dog during any of the three reflexes heart block was consistently observed after the normal slowing response of the sinus node had been selectively eliminated by the direct perfusion of 10 microgram of atropine into the sinus node artery. This was a uniform response despite its being variously produced by a pressor reflex, a chemoreflex or an extracardiac bronchopulmonary reflex. Transient heart block is therefore to be anticipated during reflexes with vagal efferent components if for any reason the sinus node is incapable of slowing suitably. The possible clinical relevance of these experimental observations is discussed.

Animals↗
PubMed1988

Heart block and paragonimiasis.

Intracardiac granulomas can cause complete heart block. A case of complete heart block is reported in a patient who had had paragonimiasis 30 years before and who had radiographic evidence of calcified granulomas in the heart and lungs.

Calcinosis↗
PubMed1979

Myocardial infarction complicated by heart block--treatment and long-term prognosis.

A number of 597 patients with acute myocardial infarction (AMI) were treated with continuous ECG monitoring of the heart rhythm in a coronary care unit for at least three days. We found 84 patients with heart block, 39 with complete, 29 with at most second degree and 16 with at most first degree heart block. The treatment was primarily conservative; 22 of the 39 patients with complete heart block were given isoproterenol and two received temporary pacemakers. Survival was traced over two years in the whole patient group with myocardial infarctions. Heart block implied a worsened prognosis over the two years, but survival was independent of the degree of heart block. Among those with complete heart block, survival did not differ from that of a comparable patient series from Copenhagen, where all patients were given pacemakers. This does not support indiscriminate artificial pacing of patients with AMI and complete heart block. Our results ought to be controlled in a randomized study.

Aged↗
PubMed1995

Familial atrioventricular heart block of adult onset: electrocardiogram and HLA typing analysis.

A family was investigated because of heart block and sinus arrhythmia. The electrical characteristics were: (1) adult onset in all members; (2) complete heart block with atrial fibrillation in 2, and first- or second-degree heart block in 7 members; and (3) sinus arrhythmia in 3 members. Human leukocyte antigen (HLA) typing was performed. HLA A2, B39, Cw7, and DR12 were positive in 4 of 5 members in the heart block group. In the sinus arrhythmia group, HLA DR12 was positive in all members. In the normal group, none of these HLA typings was positive except one. These findings indicate a tighter relationship between heart block and the HLA locus than previously thought.

Adult↗