Left bundle branch block with intermittent right axis deviation Evidence for left posterior hemiblock accompanying predivisional left bundle branch block

A case of complete left bundle branch block with several episodes of intermittent marked right axis deviation is presented. All possible causes of the intermittent development of additional right axis deviation, such as electrolyte imbalances, lateral wall infarct, intermittent Wolff-Parkinson-White conduction, right bundle branch block, right ventricular hypertrophy and pulmonary embolism, were excluded. We conclude that the explanation for left bundle branch block with intermittent right axis deviation in our patient was the coexistence of left posterior hemiblock and predivisional left bundle branch block.     

Left bundle branch block: a continuously evolving concept

Eppinger and Rothberger in 1909 and 1910 first acknowledged the importance of the conduction system, yet a confusion of the pattern of left bundle branch block with right bundle branch block resulted which persisted for 25 years. In left bundle branch block, right ventricular endocardial activation begins before, and is often completed before, initiation of left ventricular endocardial activation. Most likely, right to left septal activation then follows, resulting in left ventricular endocardial activation. Although it is hazardous to make definitive diagnoses of infarction in the presence of left bundle branch block, clues do exist. Benign left bundle branch block is rare; usually disease becomes manifest. Electrocardiographic criteria of hypertrophy are not as helpful in older patients with chronic left bundle branch block (mainly because of the very high incidence of left ventricular hypertrophy) as in younger patients with block of nonatherosclerotic origin. Left bundle branch block is often associated with other abnormalities of the conduction system. Fascicular blocks may mask or mimic myocardial infarction. Left posterior fascicular block is most often an indicator of left ventricular myocardial deficit if right ventricular enlargement is eliminated. Mortality is higher in patients with associated left axis deviation than in those with a normal axis, although the incidence of progression of atrioventricular (AV) block is low. In symptomatic patients with prolonged His to ventricular intervals, the incidence of progression of AV block is higher (12%). Preexisting left bundle branch block in the absence of clinical evidence of heart disease is rare, yet carries with it a slightly increased mortality. Newly acquired left bundle branch block carries a 10-fold increase in mortality; the incidence of sudden death as the first manifestation of heart disease is increased 10-fold.     

Changing axis deviation with changing bundle branch block and new-onset of atrial fibrillation during acute myocardial infarction

Paroxysmal atrial fibrillation is considered a frequent complication of acute myocardial infarction.It has been rarely reported alternating right and left bundle branch block associated with atrial fibrillation. It has also been rarely reported changing axis deviation with left bundle branch block also during atrial fibrillation and acute myocardial infarction. We present a case of changing axis deviation with changing bundle branch block and new-onset of atrial fibrillation in a 96-year-old Italian man with acute myocardial infarction.     

On axis deviation in human bundle branch block

Fifty-four cases with records showing both normal intraventricular conduction and bundle branch block have been collected; 192 records were available, ninety showing bundle branch block, ninety-two showing normal intraventricular conduction, and ten showing both bundle branch block and normal conduction.The axis deviation has been measured in each record and the average position of the electrical axis of QRS during normal conduction compared with that during bundle branch block.When right or left bundle branch block appeared or disappeared there was a significant change in the direction of the electrical axis of QRS (15° or more) in less than one-half of the cases, and the average change was 12° to the left in left bundle branch block and 12° to the right in right bundle branch block.When a significant change of axis was associated with the appearance of bundle branch block, the direction of the change was always to the left when the block was of the left bundle branch and, except in one case, to the right when the right bundle branch was blocked.Even in cases in which a significant change of axis was found, the general pattern of the bundle branch block electrocardiogram conformed closely to the pattern with normal intraventricular conduction.Factors, other than the bundle branch block, that might have caused a shift of the electrical axis have been discussed; it is believed that they did not materially influence the averaged results.It is concluded that the axis deviation and the general pattern of the electrocardiogram are not greatly modified by the appearance of bundle branch block, and that the axis deviation associated with right and left bundle branch block is due principally to the position of the electrical axis of QRS before the bundle branch block appeared.Certain implications arising from this conclusion have been briefly discussed.     

Acute myocardial infarction and left bundle branch block with changing axis deviation

Changing axis deviation has been reported also during atrial fibrillation or atrial flutter. Changing axis deviation has been also reported during acute myocardial infarction associated with atrial fibrillation too or at the end of atrial fibrillation during acute myocardial infarction. Left bundle branch block is usually associated with normal or left axis deviation. Rarely the ECG shows a LBBB with changing QRS morphology and changing axis deviation. There are several possible explanations for the intermittent shift in the QRS axis in the presence of complete left bundle branch block. The most plausible explanation is the coexistence of left posterior hemiblock and predivisional left bundle branch block. We present a case of a left bundle branch block with changing axis deviation in a 93-year-old Italian woman admitted to the Cardiology Unit with an acute myocardial infarction.     

Hyperkalemia-induced bundle branch block and complete heart block

Hyperkalemia was associated with complete heart block in one patient that resolved by first showing right bundle branch block and marked left axis deviation (left anterior hemiblock). Then the right bundle branch block resolved, leaving the marked left axis deviation that was present before the hyperkalemic episode. Another patient with hyperkalemia had right bundle branch block with marked left axis deviation, both of which disappeared with correction of the hyperkalemia. These findings suggest that hyperkalemia can depress conduction in the His-Purkinje system and raise the possibility that hyperkalemia may induce complete heart block distal to the atrioventricular junction.     

Hereditary bundle branch system defect. A new genetic entity?

A familial survey demonstrated mendelian inheritance in three large kindreds with conduction abnormalities and heart block. The trait was autosomal dominant, with varying expressivity and penetrance, apparent male preponderance, and congenital onset. Manifestations included right bundle branch block, left axis deviation, and right bundle branch block associated with left axis deviation. Complete heart block proved almost always to be a late event, and developed in all documented cases from bilateral bundle branch block. An r' pattern, most likely representing a right ventricular conduction delay, is discussed.     

Characteristics and prognosis of incomplete right bundle branch block: an epidemiologic study

A cohort of 1,960 white men aged 40 to 56 years without initial apparent heart disease and with 11 years of annual rest electrocardiograms and 20 year mortality data was followed in the Chicago Western Electric Company Study. Incomplete right bundle branch block was found in 134 men (6.8%) at entry. During follow-up, 222 men developed such block, an incidence rate of 13.6%. Left axis deviation of -30 degrees or less was more frequent in men with than in those without incomplete block at entry (8.2 versus 2.4%). Men with left axis deviation also had a higher incidence of incomplete right bundle branch block. Similarly, men developing incomplete block had a significantly greater risk of developing left axis deviation. The associations between incomplete block and left axis deviation were unrelated to age and body weight. Men with incomplete block had a significantly greater likelihood of developing complete right bundle branch block. The 11 year incidence rate of complete block was 5.1% for men with baseline incomplete block and 0.7% for those without. Complete block developed in 2 of 220 incident cases of incomplete block but in none of the 440 control men matched by age and duration of follow-up. Although incomplete right bundle branch block was not related to an increased risk of death in 20 years from coronary heart disease and cardiovascular diseases, the study data suggest that such block is frequently a manifestation of primary abnormality of the cardiac conduction system in middle-aged men.     

Histological findings of the right and left ventricular myocardium and clinical follow up in idiopathic ventricular tachycardia

In order to evaluate the etiology of so-called idiopathic ventricular tachycardia, endomyocardial biopsies were performed in four patients with electrocardiographically documented recurrent and sustained ventricular tachycardia. During the episodes of ventricular tachycardia, standard ECG showed a QRS pattern of right bundle branch block with left axis deviation in two patients and left bundle branch block in two patients. The episodes were associated with palpitation, dyspnea and hypotension in all cases. No organic heart disease was detected by physical examination, chest X-ray films, echocardiograms, left ventriculograms or coronary cineangiograms. His bundle electrograms showed blocks at various sites in the atrioventricular conduction system. The biopsy specimens revealed nonspecific myocardial degeneration in the right and left ventricles. These findings suggest mild but wide-spread myocardial damage in both the working myocardium and the conduction system. The clinical course of these patients appeared benign according to follow-up data of one to nine years' duration. None developed overt clinical signs of dilated, hypertrophic or restrictive cardiomyopathy.     

Left bundle branch block and cardiovascular morbidity and mortality in hypertensive patients with left ventricular hypertrophy: the Losartan Intervention For Endpoint Reduction in Hypertension study

BACKGROUND: Whether left bundle branch block is associated with cardiovascular events in hypertension with electrocardiographic left ventricular hypertrophy is unknown. METHODS: Hypertensive patients with electrocardiographic-left ventricular hypertrophy were randomized to losartan-based or atenolol-based treatment and followed for 4.8 years in the losartan intervention for endpoint reduction in hypertension study. Cox regression models controlling for significant covariates assessed the association of left bundle branch block with cardiovascular events. RESULTS: At baseline, 564 patients had left bundle branch block and 8567 patients did not. Left bundle branch block was associated with higher heart rate, electrocardiographic-left ventricular hypertrophy, and prior cardiovascular disease (all P < 0.005). In univariate Cox regression analysis, left bundle branch block was not associated with the composite endpoint, stroke, or myocardial infarction (all P > 0.05), and was associated with cardiovascular (8.3 versus 4.5%, P < 0.001) and all-cause mortality (12.1 versus 8.6%, P < 0.005). After adjusting for significant covariates Cox regression analyses showed that left bundle branch block was independently associated with 1.6-fold more cardiovascular death (95% confidence interval 1.12-2.27, P < 0.05), 1.7 fold more hospitalization for heart failure (95% confidence interval 1.15-2.56, P < 0.01), 3.5 fold more cardiovascular death within 1 h (95% confidence interval 1.89-6.63, P < 0.001), and 3.4 fold more cardiovascular death within 24 h (95% confidence interval 1.83-6.35, P < 0.001). CONCLUSION: In hypertension with electrocardiographic-left ventricular hypertrophy, left bundle branch block identifies patients at increased risk of cardiovascular mortality, sudden cardiovascular death, and heart failure.     

Complex arrhythmias in a patient with predominantly right ventricular cardiomyopathy

A 23-year-old man presented with ventricular tachycardia. The electrocardiogram revealed right bundle branch block plus right axis deviation. It also showed frequent episodes of asystole, 2: 1 sinuatrial block and couplets of left bundle branch block morphology. Electrophysiologic study demonstrated sinuatrial entrance block, with an HV interval of 65 msec. It was also possible to induce sustained ventricular tachycardia of left bundle branch block pattern with normal QRS axis. Subsequent investigations were consistent with the diagnosis of right ventricular cardiomyopathy with mild left ventricular involvement.     

Pathologic correlations in three cases of bilateral bundle branch disease with unusual electrophysiologic manifestations in two cases.

Examination of the conduction system in three patients with bifascicular block who had electrophysiologic studies forms the basis for this report. Patients 1 and 2 had left bundle branch block and Patient 3 right bundle branch block and left axis deviation. The H-V interval was prolonged in each case (70, 65 and 60 msec, respectively). Serial section examination of the conduction system revealed sclerodegenerative involvement of both bundle branches in all cases. In Case 1, atrial extrastimulus testing converted left to right bundle branch block; in Case 2, it delineated a sinus echo zone with repetitive sinus nodal reentrance. In the latter case serial section revealed extensive amyloid infiltration of the approaches to the sinoatrial (S-A) node and the atrial preferential pathways. In Case 3, with right bundle branch block and left axis deviation, serial section revealed greater involvement of the anterior part of the main left bundle branch than of the posterior portion as well as involvement of the second part of the right bundle branch. The study revealed excellent correlation between electrophysiologic and pathologic findings in three cases of intraventricular conduction disease and demonstrated an anatomic basis for the electrophysiologic findings resembling alternating bilateral bundle branch block. Sinus nodal reentrance may be related to disease in the approaches to the S-A node thereby causing delay in perinodal tissue allowing sinus reentrance. Finally in Case 3, the anatomic substrate for left axis deviation may lie in a greater involvement of the anterior portion than of the posterior portion of the main left bundle rather than in the corresponding portions of the periphery.     

Influence of right bundle branch block on short- and long-term survival after acute anterior myocardial infarction

The impact of right bundle branch block on long-term prognosis after anterior wall myocardial infarction is unclear. In 932 patients with Q wave anterior infarction, the short- and long-term prognostic significance of the presence of right bundle branch block was analyzed. Compared with 754 patients without block, 178 patients with right bundle branch block after myocardial infarction showed an increased incidence of left ventricular failure (72% versus 52%, p less than 0.001) and increased in-hospital (32% versus 8%, p less than 0.001) and 1 year after hospital discharge (17% versus 7%, p less than 0.001) cardiac mortality rates. The presence of right bundle branch block was an independent predictor of increased in-hospital and 1-year mortality when entered in a multivariate analysis. However, the absence of left ventricular failure identified a subgroup of patients with right bundle branch block with low in-hospital (4%) and 1 year postdischarge (5%) cardiac mortality rates comparable with those of patients with neither failure nor right bundle branch block (1.7% and 4.8%, respectively). In the presence of left ventricular failure, patients with associated right bundle branch block had higher in-hospital (43% versus 14%, p less than 0.01) and 1 year postdischarge (24% versus 9%, p less than 0.01) cardiac mortality rates than those of patients with failure but no right bundle branch block. Thus, the presence of right bundle branch block after anterior myocardial infarction is an independent marker of poor prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left bundle branch block: a hemodynamic and angiographic study

Coronary angiography, left ventriculography, and hemodynamicdata were evaluated in 34 patients with coronary artery diseaseand left bundle branch block. Left axis deviation (mean frontalaxis greater than —30°) was correlated with hemodynamicand angiographic findings. The patients with left bundle branchblock and coronary artery disease were compared with 98 subjectswith ischemic heart disease without conduction disturbances. Left axis deviation, which is common in subjects with coronaryartery disease and left bundle branch block, had no prognostichemodynamic significance. Left bundle branch block associatedwith coronary artery disease did not imply more severe or moreextensive coronary atherosclerosis, even though it revealeda higher frequency of lesions of the left main coronary arteryand more severe myocardial dysfunction, with asynergy especiallyinvolving the anterior areas of the left ventricle.     

Limitations of the electrocardiographic diagnosis of left ventricular hypertrophy: the influence of left anterior hemiblock and right bundle branch block.

We analysed the performance of the electrocardiogram in diagnosing left ventricular hypertrophy in 70 patients with isolated left anterior hemiblock and in 75 patients with right bundle branch block, either isolated (44 cases) or associated (31 cases) with left anterior hemiblock. Left ventricular hypertrophy defined as an echocardiographically determined left ventricular mass greater than 261 g in men and 172 g in women or left ventricular mass index greater than 125 g/m2 in men and 112 g/m2 in women was present in 48 subjects (57%) with isolated left anterior hemiblock and 33 subjects (44%) with right bundle branch block. In patients with isolated left anterior hemiblock the best results were obtained using the SV1 or SV2 + (RV6 + SV6) greater than 25 mm with 74% in sensitivity and 67% in specificity; the criterion SIII + (R + S) maximal in a precordial lead greater than or equal to 30 mm showed a sensitivity of 74% but a specificity of 47%. In the whole group of patients with right bundle branch block none of the criteria nor combination of criteria achieved an acceptable performance (sensitivities ranged from 17% to 41% and specificities ranged from 54% to 85%). When these patients were divided according to the presence or absence of concomitant left anterior hemiblock the electrocardiographic indexes mostly showed, in comparison to whole group, higher values in sensitivity and lower values in specificity in right bundle branch block plus left anterior hemiblock and an opposite behaviour in isolated right bundle branch block.(ABSTRACT TRUNCATED AT 250 WORDS)     

Left bu;ndle branch block with right axial deviation. Clinic and electro-vectorcardiographic study (author's transl)]

Eleven patients whose ECG and VCG showed a left bundle branch block with right axial deviation (between + 90 degrees and + 150 degrees) were studied with clinical and radiological investigations. All of them had pathological abnormalities of cardiopulmonary apparatus and cardiac enlargement, but only one had congestive heart failure. The right axial deviation was due in one case to the vertical position of the heart in the chest and in three cases to conduction defects of the cardiac impulse through the left bundle branch. In the remaining cases the right axial deviation was dubious. The authors present and discuss all possible factors which could cause such deviation of QRS axis in the left bundle branch block.     

The linear vectorcardiogram

A simple method of linear presentation of the vectorcardiographic parameters is presented. A discussion as to its possible usefulness is included. Illustrative examples of the changes in the linear vcctorcardiogram in specific clinical entities are utilized. These include the normal linear vcctorcardiogram and the linear vector-cardiogram in the presence of myocardial infarction, right bundle branch block, left bundle branch block, Wolff-Parkinson-White syndrome, right ventricular hypertrophy, and left ventricular hypertrophy.     

New onset left bundle branch block with right axis deviation in a patient with Wegener's granulomatosis

Left bundle branch block (LBBB) is usually associated with a normal axis or left axis deviation (LAD). When it is seen in association with right axis deviation (RAD) it is felt to be a marker of diffuse advanced myocardial disease. We report a case of new onset LBBB with RAD in a patient with Wegener's granulomatosis who had an otherwise functionally and structurally normal heart. To our knowledge, this is the first case report of LBBB with RAD without severe cardiomyopathy, as well as the first case report of new onset LBBB as a result of Wegener's granulomatosis.     

Significance of complete left bundle branch block with left axis deviation.

Left axis deviation occurring with complete left bundle branch block may represent divisional left anterior hemiblock in addition to predivisional left bundle branch block. To study this possibility the electrocardiograms of 84 patients with left bundle branch block, in whom previous electrocardiograms were available, were reviewed. There were 49 patients with left bundle branch block and left axis deviation (greater than ? 30 °) (group A) and 35 patients with left bundle branch block and normal frontal axis (group B). The mean age, QRS interval and time Interval between the first and the qualifying electrocardiogram were similar in both groups. The $\text{male}\text{female}$ ratio was significantly different (P < 0.05) and was 26:23 in group A and 9:26 in group B. In group A 24 of 49 patients had a prior electrocardiogram without bundle branch block; in 10 of 24 the pattern indicated hemiblock. Among patients in group B 25 of 35 had a previous electrocardiogram without bundle branch block; a hemiblock pattern was present in only 3 of the 25 (P < 0.05). Seven of 49 patients in group A had a previous electrocardiogram showing left bundle branch block alone whereas 9 of 35 patients in group B had a previous pattern of left bundle branch block. In these seven patients in group A left axis deviation subsequently developed but did not occur in the nine patients In group B. It is concluded that the majority of patients with a left bundle branch block pattern and left axis deviation have left anterior hemiblock separately (either before or after the appearance of left bundle branch block).     

Significance of left axis deviation in patients with chronic left bundle branch block

Forty-nine patients with chronic left bundle branch block and a normal frontal axis were compared with 53 patients with left bundle branch block and left axis deviation. The following clinical variables were more frequent (P < 0.05) in patients with left axis deviation: greater age, exertional angina, congestive heart failure, cardiomegaly, cardiac functional class II to IV, coronary artery disease and presence of organic heart disease. Absence of organic heart disease (primary conduction disease) was seen only in patients with a normal axis. Patients with left axis deviation had longer (P < 0.05) mean P-R, A-H and H-V intervals and atrial and atrioventricular (A-V) nodal effective refractory periods. All patients were prospectively followed up for 30 to 2,271 days with a mean ± standard error of the mean follow-up period of 538 ± 72 for the group with a normal axis and 604 ± 72 days for the group with left axis deviation (difference not significant). A-V block developed in three patients (6 percent) with left axis deviation and in none of those with a normal axis. The cumulative 4 year mortality rate for the entire group approached 75 percent. The patients with left axis deviation had greater cardiovascular mortality (P < 0.05).In conclusion, among patients with left bundle branch block, those with left axis deviation have a greater incidence of myocardial dysfunction, more advanced conduction disease and greater cardiovascular mortality than those with a normal axis.