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At least 19 recordsLinked to original sources
PubMed1976

Progressive improvement of His-Purkinje conduction during recovery from catheter-induced heart block.

Complete heart block developed during HBE studies in a patient with left bundle branch block, after inadvertent catheter-induced trauma to the right bundle branch. Normal intraventricular conduction (HV interval) was documented during the initial part of the study, and was demonstrated to be markedly prolonged after the appearance of heart block. Conduction through the right bundle branch improved over a short period of time as manifested by steplike shortenings of the HV interval, until the original conduction velocity was re-established. This case strongly supports the concept that the His-Purkinje system is capable of varying its conduction velocity and further demonstrates that, in patients with bundle branch block, a prolonged HV interval indicates disease of the remaining bundle branch.

Bundle of His↗
PubMed1975

De subitaneis mortibus. X. Familial congential heart block.

Complete heart block was found shortly after birth in a brother and sister (not twins). Both were treated by electronic pacing because of symptoms attributable to inadequate cardiac output and electrical instability of heart. The boy has done well with his artificial pacemaker and is now six years old. His sister died of complications due in part to the large size of her pacemaker and small size of her body. At necropsy special studies of her heart included the centers for normal impulse formation and concuction. The primary abnormalities were at the junction of atrial septum with atrioventricular (A-V) node, and at the origin of the two bundle branches from the His bundle. The A-V node was isolated by collagen at all its margins except its junction with the His bundle. The proximal His bundle was essentially normal, but from that point on through the initial protions of both the left and right bundle branches there was extensive caseous degeneration which interrupted any possible conduction. These findings are discussed in relation to fetal and postnatal development of the human A-V node, and the His bundle and its branches; and in the context of a recently observed mathematical relationship between sinus rate and two forms of experimentally produced A-V junctional escape rhythms.

Atrioventricular Node↗
PubMed1976

Prolonged His-Q interval in chronic bifascicular block. Relation to impending complete heart block.

Although prolonged infra-His conduction time in bifascicular block is suspected of denoting trifascicular disease, adquate documentation is lacking concerning the correlation between lengthened His-Q interval (H-Q) and the risk of development of complete heart block (CHB). H-Q in conducted sinus beats in patients with bifascicular block associated with Mobitz II or intermittent CHB represents the approximation of maximal H-Q prolongation prior to onset of trifascicular block. To assess this relationship between prolongation of H-Q and trifascicular block, His bundle electrocardiography (HBE) was performed in 50 patients with chronic bifascicular block exhibiting Mobitz II block or transient CHB. Mobitz II or episodic CHB was shown in all patients: within two days prior to HBE in 45/50 patients; in 39/50 patients during HBE; and following HBE in five patients. In 49/50 patients H-Q was prolonged (greater than 55 msec) and in 47 this interval was substantially lengthened (65 msec or greater). Since marked H-Q prolongation in conducted sinus beats was documented in nearly all patients with bifascicular block associated with intermittent complete trifascicular block, we conclude that a considerably lengthened H-Q interval in bifascicular block is not only a usual prerequisite but strong evidence, for impending complete heart block.

Adult↗
PubMed1979

Treatment of heart block due to sarcoid heart disease.

The role of glucocorticosteroid therapy for myocardial sarcoidosis is not well defined. This report shows the effect of prednisone therapy on atrioventricular (AV) conduction in a patient with myocardial sarcoidosis and AV block. On three separate occasions AV block was documented prior to prednisone therapy. On the first two occasions the patient had first and second degree AV block which by His bundle electrogram initially was shown to be in the AV node. On the third occasion the patient developed complete heart block. On each occasion treatment with prednisone resulted in improved AV conduction. The results indicate that prednisone therapy can be beneficial in the treatment of AV block due to myocardial sarcoidosis.

Adult↗
PubMed1975

Hemodynamic changes during ventricular pacing in patients with complete heart block and aortic and mitral valvular heart disease.

Increasing the heart rate to near normal in patients with complete heart block (CHB) and slow ventricular rates may lead to greater improvement in ventricular function than when the heart rate is increased from normal to more rapid heart rates. Improvement in ventricular function is usually manifested by a decrease in left ventricular end-diastolic pressure (LVEDP) and volume and by an increase in contractility. In patients with both CHB and valvular heart disease improvement in ventricular function during pacing may be modified by the nature of the valvular disease. Hemodynamic data from six patients with both valvular heart disease and CHB were compared with those from ten patients with CHB and normal cardiac valves. Hemodynamic studies were performed at slow or idioventricular rates and again after increasing the heart rate to more nearly normal levels by ventricular pacing. When obstruction to left ventricular inflow (mitral stenosis) co-existed with CHB, increasing the heart rate resulted in a reduction of an elevated LVEDP to normal. This resulted in only a small increase in left atrial pressure in spite of a striking increase in the mean left atrial-ventricular gradient. When obstruction to left ventricular outflow prevailed (aortic stenosis), improvement in cardiac function was manifested mainly by a decrease in LVEDP and was accompanied by a decrease in left ventricular stroke work. When a large regurgitant volume (aortic insufficiency) was added to a ventricle which has enlarged subsequent to CHB, there was striking elevation in ventricular filling pressures which returned to more nearly normal levels when the heart rate was increased. This was accompanied by a reduction in regurgitant stroke volume in the patient in whom it was measured. Thus, an increase in heart rate may be especially beneficial to those patients with CHB who also have valvular lesions which contribute to an increase in LVEDP and end-diastolic volume. Careful hemodynamic evaluation is helpful in determining appropriate therapy in these patients.

Aged↗
PubMed1976

Heart block complicating acute inferior wall myocardial infarction.

Heart block was noted in 60 (35 complete and 25 second-degree) of 410 patients with acute inferior wall myocardial infarction. This group with heart block was compared to a control group of 30 patients with acute inferior wall infarction without heart block. The incidences of prior myocardial infarction and hypertension, in addition to the highest level of serum creatine phosphokinase and a maximum degree of ST-segment elevation in the inferior leads, were all greater in patients with heart block, as compared to the controls. The incidences of various complications, including dizziness and syncope, transient hypotension, cardiogenic shock, and congestive heart failure, were also higher in the group with heart block, while sinus nodal distrubances and atrial arrhythmias occurred with equal frequency. The mortality in those with heart block was 28 percent compared to 13 percent for the control. It is concluded that patients with heart block complicating acute inferior myocardial infarction have a greater amount of myocardial necrosis, a higher incidence of complications, and a higher mortality. Insertion of a temporary pacemaker should be considered when specific indications are present and not routinely.

Acute Disease↗
PubMedDate not supplied

Experimental models of complete heart block.

Methods of creating experimental complete heart block developed since 1883 are reviewed in detail. The three most commonly used techniques at present are: (I) Thoracotomy, atriotomy and ligation of the A-V bundle. (II) Thoracotomy and injection of a chemical into the A-V node or bundle. (III) Injection of a chemical through a transvenous catheter into the node or bundle. The results in different species, complications, and variations in procedure are discussed. The bibliography provides a comprehensive index of work performed in animals with experimental complete heart block. We produced complete heart block in sixteen pigs but subsequently eleven died during Stokes-Adams attacks. Pigs have not been used previously as models of heart block for experimental purposes and prophylactic pacing appears mandatory in this species.

Adams-Stokes Syndrome↗
PubMed1975

Fascicular conduction blocks and their relationship to complete heart block in Nigerians.

Following electrocardiographic analysis, isolated or combined blocks in the intraventricular trifascicular system including predivisional left bundle branch block with left posterior hemiblock in Nigerians are presented and the underlying causes reviewed. The rarity of complete heart block, despite the not uncommon fascicular blocks, is of interest and may be related to the population age structure considering the invariably slow rate of degeneration of conduction fibres in the system.

Adolescent↗
PubMed1977

Progressive familial heart block--two types.

Two types of heart block which occur extensively in families in the Republic of South Africa are reported. A type I heart block tends to have the pattern of a right bundle-branch block and/or left anterior hemiblock occurring individually or together, and manifesting clinically when complete heart block supervenes, either with syncopal episodes, Stokes-Adams seizures or sudden death. The condition is inherited as an autosomal dominant gene and appears to be progressive in nature; the risk to life appears to be greatest at 3 particular periods:at or soon after birth, during puberty and the early 20s, and again towards middle age. The type II condition also appears to be progressive and is inherited as an autosomal dominant gene. The pattern, however, tends to develop along the lines of a sinus bradycardia with a left posterior hemiblock, again presenting clinically as syncopal episodes. Stokes-Adams seizures or sudden death when complete heart block supervenes. Both conditions are likely to be widely prevalent throughout the Republic of South Africa. The pathogenesis is discussed in relation to the patterns of the conduction disturbances.

Adult↗
PubMed1977

Congenitally complete heart block. Developmental aspects.

Three cases of congenitally complete heart block are described of hearts in which other minor congenital malformations were not in themselves severe enough to disrupt the atrioventricular conduction system. The cases fitted well into the categorization of complete heart block suggested by Lev. Two exhibited lack of communication between the atrial and conducting tissues, the other had discontinuity of the penetrating atrioventricular bundle. In an attempt to explain why this discontinuity between different segments of the conducting tissues occurs, we re-examined several series of graded human embryos. This investigation suggested that the anulus fibrosus in the normal heart is derived from sulcus tissue of the atrioventricular junction, the endocardial atrioventricular cushions playing a minor role in the separation of atria from ventricles. The relationships between the sulcus tissues and the different components of the atrioventricular junctional area are discussed in terms of an explanation both for the existence of different types of congenitally complete heart block and for persistence of Mahaim (nodo-ventricular and nodo-fascicular) fibers.

Abnormalities, Multiple↗
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↗