Incomplete Right Bundle Branch Block Research Articles

Possible risks of general anesthesia in patients with intraventricular conduction disturbances.

In order to assess the risk of complete AV block in patients with intraventricular conduction disturbances who undergo general anesthesia, 20 patients with various conduction defects (7 LBBB, 1 RBBB and 1st degree AV block, 1 incomplete RBBB, 9 RBBB + LAH and 2 RBBB + LPH) were studied by means of His bundle recording and corrected sinus node recovery time (CSNRT) before and after the subministration of thiopental (0.2 g I.V.), succinylcholine (1 mg/kg I.V.), Fluothane (1%) and Ethrane (1.6%). Nineteen patients displayed signs of dizziness or syncope; both the sinus rate and the CSNRT, did not undergo significant variations. A slight and not significant variation of intranodal conduction during sinus rhythm was observed after Fluothane administration (AH was prolonged by 8%). A less evident negative dromotropic action of thiopental and Ethrane was only revealed by atrial pacing. No significant variations were demonstrated in His-ventricular conduction after administration of the various drugs. The maximum average increase (1.5%) of the H-V interval was observed after administration of succinylcholine. Acute AV block distal to the His bundle appeared in three patients after succinylcholine administration.

The IVIC syndrome: a new autosomal dominant complex pleiotropic syndrome with radial ray hypoplasia, hearing impairment, external ophthalmoplegia, and thrombocytopenia.

The IVIC syndrome is an autosomal dominant condition affecting mainly the upper limbs. It is described from 19 living members of one family of mostly Caucasoid descent; it came to Venezuela from the Canary Islands 140 years ago. The new mutation appeared six generations ago. It has complete penetrance and wide expressivity for a radial ray defect which may vary from an almost normal thumb to a severely malformed upper limb. When present, the thumb has a long/slender metacarpal and a short distal phalanx, reflected in a typical metacarpophalangeal (MP) pattern profile. Anthropometry reveals delayed growth in the forearms, clavicles, and cranium during adolescence, and permanently in the spine; the maturation of the face, tibiae, and feet is normal. The radial carpal bones are always affected, some being still hypoplastic at advanced ages. Constant palmar dermatoglyphic anomalies are a high a-b ridge count, a distally placed or absent t triradius, and an increased frequency of patterns in the second interdigital area. Extraocular muscles are involved almost always, producing strabismus. Hearing is bilaterally impaired due to a mixed congenital loss, either total or partial. Mild thrombocytopenia and leukocytosis are present before the age of 50 years. There is neither associated ectodermal dysplasia nor heart involvement [except for occasional mild, incomplete right bundle branch block (IRBBB)]; imperforate anus occurs in about 10% of affected persons. The possible pathogenetic relationship to the thalidomide embryopathy and to the Holt-Oram syndrome, among others, is discussed.

Interpretation of the body surface isopotential maps of patients with right bundle branch block. Determination of the region of the delayed activation within the right ventricle.

Body surface isopotential maps were produced by computer processing of the 85 electrocardiograms obtained from the entire thorax of 28 patients with complete or incomplete right bundle branch block (RBBB). We divided the map patterns into the following 3 groups. Type I map pattern (10 cases): at the early stage of QRS, the maximum was located in the left chest. It shifted to the left from the normal position; at the instant of 44 msec, on the average, after the onset of QRS breakthrough minimum appeared over the left chest. Its appearance was delayed and its site shifted to the left as compared with the normal; at the late stage, the positive zone covered extensively the right chest and the right back; terminally, the maximum was positioned along the right parasternum. Type II map pattern (13 cases): at the early stage of QRS, the maximum was in the left chest as in Type I; breakthrough minimum appeared at 38 msec on the average, later than in the normal, but the site of breakthrough minimum varied from the left chest as in Type I to the midsternal region as in the normal; at the late stage, the positive zone covered the upper part of the right chest and the right back, less extensively than in Type I; the terminal maximum was in the upper sternal region. Type III map pattern (5 cases): the map pattern passed normally until the late stage, but thereafter a small positive zone survived over the upper sternal region. In Type I the delayed activation was presumed to occur all over the right ventricle, in Type II mainly over the smaller area of the right anterior free wall, and in Type III over the localized area of the outflow tract. Patients with complete RBBB showed Type I pattern. Patients with incomplete RBBB showed Type II or Type III pattern, although electrocardiograms failed to differentiate Type II patients from Type III patients. These findings suggest that the electrocardiographic pattern of incomplete RBBB probably arises from the various mechanisms.

Incomplete right bundle branch block and vital capacity.

Right bundle branch block (RBBB) is occasionally encountered in young persons who lack any other evidence of overt cardiac disease (Hiss and Lamb, 1962; Lancaster, Schechter, and Massing, 1972). The block may be complete or incomplete, the latter being more common. Right bundle branch block has been studied in relation to body weight, obesity, serum cholesterol and glucose levels, and blood pressure, but the results have been negative (Ostrander, 1964; Kannel et al., 1962). Data presented here suggest that incomplete RBBB is related to vital capacity.

Latent coronary insufficiency in young athletes.

Abstract Staff and students at the Norwegian College of Physical Education and Sport, totalling 170 males and females of mean age 24 years, have been subjected to a bicycle ergometer test with post‐exercise ECG recordings. Sixteen athletes needed further evaluation for the following reasons: 1) ST depression of more than 1 mm. 2) Ventricular extrasystoles in the immediate post‐exercise tracing. 3) A possibly incomplete RBBB. 4) Inadequate heart rate in the immediate post‐exercise tracing. On reexamination with a graded, submaximal bicycle ergometer test with in‐ and post‐exercise ECG recordings, 8 persons were found to have a normal response, 4 ECG changes of functional type, 2 ventricular extrasystoles, mainly as bigeminy, which disappeared on high work loads, and 3 ECG changes of ischemic type. Selective coronary angiography was performed on the 3 athletes with latent coronary insufficiency and showed normal coronary arteriogram in 1 and a hypoplasia of the circumflex coronary artery in 2. Problems of ECG of athletes and evaluation of the coronary arteriograms are discussed.

Incomplete Right Bundle-Branch Block

Incomplete right bundle-branch block (IRBBB) usually is thought to be associated with abnormalities of the peripheral Purkinje system. This paper discusses the results of a study of six dogs from the same family and three nonrelated dogs with congenital IRBBB. Cardiac catheterization data were normal, and no evidence or history of cardiac disease was found before or after death. The depolarization sequence of ventricular epicardial activation was determined, and delays in right ventricular (RV) epicardial activation times were observed. Multipoint intramural electrodes were used to study intramural activation of the ventricular septum and free walls. The "electrical thickness" near the base of the RV mass was more than double that of the normal RV mass (9 vs 4 mm). Conduction along the right bundle branch (RBB) was analyzed during cardiopulmonary bypass, and electrograms recorded simultaneously from six sites along the RBB demonstrated that conduction velocity down the bundle was normal. The normal time of activation of the endocardial RV Purkinje fibers demonstrated that conduction in the right peripheral Purkinje system also was normal. Therefore, IRBBB in these dogs did not result from conduction abnormalities within the RV specialized conduction system. Interestingly, six of these dogs were members of the F 1 generation from a mating of a female beagle with pulmonary stenosis and a male beagle with ventricular septal defect. Both defects as well as IRBBB were observed in the F 2 generation. The present findings suggest that IRBBB may be a developmental variation in thickness of the RV free wall rather than an abnormality of the RV conduction system in cases without apparent heart disease. The developmental variant appears to have a genetic basis.

Mass examination in Mitoh district

Mass examination was carried out in935individuals aged40to90yeas. Blood pressure was measured and electrocardiograms recorded in all cases. Blood was sampled for the determination of serum total cholesterol, and urine for the determination of albumin and sugar. The results can be summarized as follows:1) Systolic blood pressure of 150 to 199 mmHg was found in90% in the5th decade, 25% in the 6th decade, 41% in the 7th decade, 44% in the 8th decade and 39% in the9th decade. Systolic blood pressure higher than 200 mmHg was found in 2% in the5th decade, 4% in the 6th decade, 6% in the 7th decade, 18% in the 8th decade and 29% in the 9th decade. 2) Coronary insufficiency was divided into3grades: an upstroke of the ST-T segment is more horizontal than normal with an exaggerated U wave in mild coronary insufficiency, the ST segment is depressed with a biphasic T wave in moderate coronary insufficientcy, and the ST segment is more depressed with a negative T wave in marked coronary insufficiency. Moderate-coronary insufficiency was found in 4.2% in 5th decade, 18.7% in the 6th decade, 19.9% in the 7th decade, 14.9% in the 8th decade and 19.2% in the9th decade. Marked coronary insufficiency was found in 0.4% in the 5th decade, 1.5% in the 6th decade, 2.2% in the 7th decade, 4.2% in the 8th decade and 10.3% in the 9th decade. 3) Diagnosis of left ventricular hypertrophy was made by Sokolow-Lyons' voltage criteria of SV1+RV5>35mm. Left ventricular hypertrophy was found in 7.6% in the 5th decade, 10.5% in the 6th decade, 15.1% in the 7th decade, 12.2% in the8th decade and16.6% in the9th decade. 4) Incomplete RBBB was found in 5.1% in the5th decade, 2.6% in the6th decade, 3.7% in the 7th decade, 4.2% in the 8th decade and 0% in the9th decade. This indicicates that incomplete RBBB in younger adults is due to functional rightventricular overload as in the athlete's heart and that in senile subjects due to organic arteriosclerotic changes of the conduction system. Percentage occurrence of atrial and ventricular premature beats increased with advance in age. 6) Serum total cholesterol was related neither to blood pressure nor to age. 7) Proteinuria was found in 5% of the subjects studied. Among them, hypercholesterolemia was found in 1 of 6 cases in the 5th decade, 2 of 7 cases in the6th decade, 11 of 20 cases in the 7th decade, 9 of 18 cases in the 8th decade and 3 of 4 cases in the 9th decade. 8) In subjects with proteinuria, moderate to marked coronary inssfficiency was found in 5 of 8 cases in 6th decade, 9 of 20 cases in the 7th decade, 11 of 21cases in the 8th decade and 3 of 4 cases in the 9th decade. Namely, abnormal electrocardiograms were observed in 47.1% of those with proteinuria. This indicates that myocardial ischemia occurs more frequently in those with renal. arteriosclerosis than. those without it. 9) Glucosuria was found in 106 of 935 subjects studied. Hypercholesterolemia higher than 200mg/dl was found in 72.7% of those with glucosuria. Abnormal electrocardiograme such as moderate to marked coronary insufficiency, left ventricular hypertrophy and myocardial infarction were found in 57.6% of those with glucosuria. This indicates that abnormalities in. carbohydrate metabolism accelerate aging process of the heart. 10) Abnormal electrocardiograms including mild coronary insufficiency of our criteria amounted to 49.0% in the5th decade, 69.6% in the 6th decade, 82.8% in the 7th decade, 89.2% in the 8th decade and 94.9% in the 9th decade. This indicates that electrocardiographic abnormalities increase with advance in age, and the occurrence of electrocardiographic abnormalities is much higher than previously reported when the changes of the U wave are taken into consideration.

Atrial dissociation followed by A-V dissociation in a case of decompensated cor pulmonale.

A 40-year-old male with chronic cor pulmonale developed atrial dissociation on September 17, 1968 and died on the following day. Before death atrial dissociation changed into A-V dissociation with incomplete RBBB. When the PR interval was shortest, the sinus cycle seemed to be reset by the retrograde conduction of the nodal impulse. Although the retrograde P wave was obscure, an atrial reciprocal rhythm by way of the sinus node was proposed as one of the mechanisms which may explain this phenomenon. In order to discuss the probability of an atrial reciprocal rhythm by way of the sinus node, a case of ventricular premature beats with retrograde P waves occasionally followed by atrial or ventricular echoes was also presented.

Evolution of clinical, radiological, and electrocardiographic changes following experimental atrial septal defect

Incomplete RBBB associated with atrial septal defect is a developmental abnormality that results from mild right ventricular hypertrophy, particularly in the outflow tract region. This electrocardiographic finding appeared five to ten months after surgical creation of the atrial defect in eight puppies. At 11 months, widening of the QRS appeared suddenly at the same time that the pulmonary valve closure became louder, sharper, and delayed so that the defect could be detected clinically. Gradual spontaneous narrowing of a surgically created atrial septal defect in the experimental animal was suspected from the appearance of respiratory variation in splitting of the second sound, even though the splitting was still greater than normal. Complete spontaneous closure of the defect in the experimental animal or surgical repair in man is immediately followed by decreased intensity and a softer quality of the pulmonary component of the second heart sound, although the radiological and electrocardiographic evidence of the previous defect persists.

CLINICAL STUDY OF INCOMPLETE RIGHT BUNDLE BRANCH BLOCK ABOUT ITS PATTERN OF MITRAL VALVULAR DISEASE

It is well known that incomplete right bundle branch block (I.R.B.B.B.) appears in the heart diseases with right ventricular hypertrophy, and recently it was suggested by Cabrera that diastolic overloading of the right ventricle produces frequently I.R.B.B.B., and an intermediary factor of the relation between I.R.B.B.B. and diastolic overloading is a dilatation of the right ventricle.In order to ascertain this theory, the comparison was made between E.C.G. and Xray in mitral valvular disease and the following were the results:1. Electrocardiographic polyphasic QRS patterns in V1 lead which were encountered statistically more frequently in mitral valvular disease than control group, were difined as I.R.B.B.B. pattern.2. Among 535 cases of mitral valvular disease, while heart-lung ratios were not so great so far as the patients with electrocardiographic right ventricular hypertrophy (R.V.H.), they were remarkably great concerned with the patients of I.R.B.B.B. patterns.3. The value of the longest distance between right phrenicocardiac angle and left third arch of cardiac silhouette divided by thorathic transverse diameter was difined as right ventricular index (R.V.I.). R.V.I. of the patients with I.R.B.B.B. patterns was statistically greater than that of the patients with R.V.H. patterns.4. During clinical course, I.R.B.B.B. patterns appeared hand in hand with the enlargement of cardiac silhouette and disappeared following the reduction of the enlargement in several cases.