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Left bundle branch pacing (LBBP) is emerging as an alternative to His bundle pacing that overcomes the latter's limitations. Several studies have reported on the safety, efficacy, and electrophysiological properties of LBBP, while postoperative success rates range from 80.5% to 94%. The left posterior fascicle is composed of broad bands of fibers coursing inferiorly and posteriorly toward the papillary muscle, while the anterior fascicle is a thin, tendon-like structure. We report a case of a 70-year-old man in whom left posterior fascicular pacing was done after LBBP failed. We were able to demonstrate all the features of left posterior fascicular capture, including fascicular potential and a left anterior hemiblock pattern, using surface 12-lead electrocardiography. Left posterior fascicular pacing could be an alternative technique when attempts to deploy LBBP fail.

Bifascicular block is defined as complete left bundle-branch block, complete right bundle-branch block with left anterior hemiblock or left posterior hemiblock (QRS > 120 ms).

A 65-year-old diabetic and hypertensive woman was admitted for evaluation of syncope. Her baseline electrocardiogram revealed normal sinus rhythm with left anterior hemiblock. Her treadmill test, holter monitoring and external loop recorder examinations were normal. Right sided carotid sinus massage (CSM) revealed 2:1 atrioventricular block (AV) (Mobitz II type) while left sided CSM had no effect. Permanent pacemaker implantation was performed (DDIR, St Jude Medical, USA). Mobitz II type AV block due to CSM reflects enhanced vagal efferent tone on AV node and his bundle fibre.

Regular exercise activity, especially the aerobic type, is responsible for structural and functional cardiac remodeling with a variety of associated ECG patterns, known as athlete’s heart [1, 2].

We report a case of 82-year-old female with total masquerading bundle branch block. We discuss the problems with ECG analysis.

Aims The role of right bundle branch block (RBBB) for the induction of left ventricular (LV) asynchrony is discussed controversially. The objective of this study was to assess presence and degree of LV asynchrony in patients with RBBB, left bundle branch block (LBBB), or left anterior hemiblock (LAH) and normal LV function. Methods We included 15 patients with RBBB, 13 patients with RBBB and concomitant LAH, 10 patients with pure LBBB, and 100 healthy controls into this study. All patients had normal LV function. Interventricular asynchrony was assessed as the difference of the right and LV ejection delay. Intraventricular delay was obtained by tissue synchronicity imaging-guided tissue Doppler imaging measurement. Results Interventricular and left intraventricular asynchrony were linked to the presence of an LBBB. No left intraventricular asynchrony was noted during pure RBBB; interventricular delays were negative (aortic flow preceding pulmonary flow) in the presence of RBBB. Conclusion In patients with normal LV function, intraventricular asynchrony depends on the presence of an LBBB and interventricular asynchrony is inversed in the presence of RBBB. (PACE 2013; 36:63–68)

The aim of this study is to present the criteria for the diagnosis of incomplete or partial block within the anterior and posterior divisions of the left bundle-branch (LBB). To disclose incomplete left anterior hemiblock (LAH) and incomplete left posterior hemiblock (LPH), clinical cases of pathologic and physiologic intermittent or transient block in the divisions of the LBB are analyzed. When dealing with the diagnosis of incomplete LAH, an ÂQRS shift in the same or in successive tracings in a patient, showing electrical axis at +50°, +40°, +30°, and 0° covering the whole range up to -45° or even more negative, makes the diagnosis of incomplete to complete block in the anterior division of the LBB. Conversely, when LPH is the case, a progressive change of the ÂQRS from a normal axis to the right, up to +120° in the same or subsequent tracings in a short period, can only be explained by increasing the degrees of LPH. When a partial or incomplete LAH or LPH is present and the ÂQRS direction can be considered normal in clinical practice, it is difficult or even impossible to reach a diagnosis. That is, small degrees of block in the divisions of the LBB totally overlap normal variants.

In order to find the three-dimensional distribution of ventricular depolarization potentials in left anterior hemiblock (LAHB) diagnosed by the conventional scalar ECG, 7 subjects with LAHB aged 9 to 62 years old who were otherwise healthy were studied by computer graphic electrocardiography (CGECG).

We report a case of a 62-year-old male with Steinert’s disease who presented with progressive intermittent episodes of lightheadedness five years after he was diagnosed with the disease. On evaluation, he developed a new onset trifascicular block (first degree atrioventricular block, new onset right bundle branch block, and left anterior fascicular block). A dual chamber pacemaker was inserted and lightheadedness improved significantly.

This study was designed to assess the functional and prognostic significance of left anterior hemiblock (LAHB) in patients with no history of myocardial infarction referred for dobutamine stress echocardiography (DSE). BACKGROUND: The significance of isolated LAHB in patients with suspected coronary artery disease (CAD) is unclear. METHODS: We studied 1,187 patients with suspected CAD and no history of myocardial infarction who underwent DSE and were followed for occurrence of cardiac death. RESULTS: Left anterior hemiblock was detected on baseline electrocardiogram in 159 patients (13%). Ischemia occurred more frequently in patients with LAHB (43% vs. 33%, p = 0.02). During a mean follow-up of 5.0 +/- 2.5 years, 125 patients (11%) died of cardiac causes. The annual cardiac death rate was 4.9% in patients with LAHB and 1.9% for patients without (p < 0.0001). Patients with both LAHB and an abnormal DSE had the highest annual cardiac death rate (6.3%). In a Cox multivariable analysis, independent predictors of cardiac death were age, smoking, history of heart failure, diabetes, and ischemia. Left anterior hemiblock was independently associated with increased risk of cardiac death among patients with normal DSE (hazard ratio 1.8, 95% confidence interval 1.1 to 3.8) and in patients with abnormal DSE (hazard ratio 1.7, 95% confidence interval 1.1 to 2.7). CONCLUSIONS: In patients with suspected CAD referred for stress testing, LAHB is associated with increased risk of cardiac death. This risk is persistent after adjustment for major clinical data and abnormalities on the stress echocardiogram. Therefore, isolated LAHB should not be considered a benign electrocardiographic abnormality in these patients.

Subclinical hyperthyroidism is an increasingly recognized entity that is defined as a normal serum free thyroxine and free triiodothyronine levels with a thyroid-stimulating hormone level suppressed below the normal range and usually undetectable. It has been reported that subclinical hyperthyroidism is not associated with CHD or mortality from cardiovascular causes but it is usually associated with a higher heart rate and a higher risk of supraventricular arrhythmias including atrial fibrillation and atrial flutter. Intermittent changing axis deviation during atrial fibrillation has also rarely been reported. We present a case of intermittent changing axis deviation with intermittent left anterior hemiblock in a 59-year-old Italian man with atrial flutter and subclinical hyperthyroidism. To our knowledge, this is the first report of intermittent changing axis deviation with intermittent left anterior hemiblock in a patient with atrial flutter.

The prevalence of eight different ventricular conduction blocks and their association with risk factors and major cardiovascular diseases were studied in a major Finnish population study.Data, including 12-lead electrocardiograms, were collected from 6315 subjects. The prevalence of left bundle branch block (LBBB), right bundle branch block (RBBB), non-specific ventricular block, incomplete LBBB, incomplete RBBB, R-R'-pattern, left anterior hemiblock (LAHB), and left posterior hemiblock (LPHB) was calculated for both genders in three age groups. Their association with risk factors and cardiovascular diseases was studied.R-R'-pattern was the most common ventricular conduction block in all age groups (3.9%, p0.001 for comparison between groups), but it showed no association with cardiovascular diseases. Males had more RBBB (1.5% vs. 0.7%, p0.001), incomplete LBBB (1.8 vs. 0.4, p0.001) and non-specific ventricular block (1.1% vs. 0.1%, p0.001). With increasing age (45 years vs.55 years) LBBB, RBBB and LAHB (0 vs. 2.2%, 0.3 vs. 2.2%, 0.2 vs. 1.9% respectively, p-values0.001) became more prevalent. LBBB, RBBB and non-specific ventricular conduction block were associated with coronary heart disease (angina pectoris in 28.3, 20.3 and 22.9%, respectively) and heart failure (25.0, 10.1 and 11.4%, respectively). LBBB and RBBB were also associated with peripheral vascular disease (8.8%).Ventricular conduction blocks differ in prevalence between sexes and age groups. They also show disparate association with cardiovascular diseases. These differences need to be taken into consideration in everyday clinical practice.

Continuamos con la serie de casos clínicos en Cardiología Pediátrica revisando los motivos de consulta frecuentes en las consultas de Pediatría de Atención Primaria, presentados de forma breve y práctica y tratando de mostrar la utilidad del electrocardiograma, método diagnóstico del que disponemos en Atención Primaria. En este número se presenta el caso de una niña de 11 años con un soplo cardiaco detectado en una revisión del niño sano. Se discute cómo las características del soplo y los hallazgos electrocardiográficos orientan el manejo de esta paciente. We continue the series of clinical cases in Paediatric Cardiology checking frequent reasons for consultation in the paediatric offices of Primary Care, presenting them in a brief and practical way and trying to show the electrocardiogram usefulness, diagnostic tool available at the primary care office. In this paper we present the case of an 11 years old girl with a heart murmur found in a well child examination exam. The way clinical and electrocardiography findings guide the diagnosis of this patient is discussed.

A case report of a patient with persistent left anterior hemiblock admitted with acute ischemic heart disease is described. At effort during follow-up evaluation, the patient complained of retrosternal pain when the heart rate was 124 beats/min. No pathological ST-T changes were demonstrated at this time. At 133 beats/min, the precordial pain increased, the QRS axis displayed a marked shift to the right, and ischemic ST-T depression was recorded. In discussing this unreported phenomenon, it is pointed out that left anterior hemiblock does not necessarily represent an anatomical block of the atrioventricular bundle but may simply reflect a relative delay in conduction. In addition, acute ischemia may change the physiological behavior of the system resulting in slower conduction through the posterior rather than through the anterior atrioventricular bundle. The influence of left anterior and left posterior hemiblock on ischemic ST-T changes and on the coronary flow distribution is discussed.

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)

Background: Intraventricular conduction disturbances determine complete impairment of impulse propagation along the right or left bundle branch or the two left fascicles. Hypothesis: This study was undertaken to investigate the electrophysiologic significance of QRS axis (QRSA) orientation in bifascicular and trifascicular blocks. Methods: A group of 76 subjects, 43 with right bundle‐branch block (RBBB) and left anterior hemiblock (LAH) (Group A), and 33 with left bundle‐branch block (LBBB) (Group B) was submitted to electrophysiologic evaluation. Results: In Group A, QRSA was inversely related only to intraventricular conduction, while in Group B, QRSA inversely related to infrahisal conduction times. A value of ‐60°. Of the 9 Group B patients with a QRSA 60°, in only 8.3% were both infrahisal (HV1 and HV2) intervals dangerously prolonged, and 23.8% encountered an infrahisal second‐degree AV block during IAS. In Group A, atrioventricular conduction time >200 ms exhibited a better predictive accuracy than QRSA 80 ms. Conclusion: The degree of leftward QRSA deviation seems to reflect the entity of intraventricular conduction delay in patients with RBBB + LAH, while it appears to be directly related to infrahisal conduction prolongation in those with LBBB.

Complete right bundle branch block (CRBBB) has been reported as the most common sequelae following total correction of tetralogy of Fallot. A review of previous reports and our own experience have led us to believe that it may be related to the fatal ventricular dysrhythmias which often occur during the postoperative follow-up period. Therefore, we have been trying to reduce the incidence of CRBBB, and we describe herein our surgical procedure for the prevention of CRBBB and its results. Of a total 28 consecutive patients who underwent intracardiac repair by this procedure, only 4 (14%) developed surgically induced CRBBB, none of whom developed a left anterior hemiblock. At the time of this report, no severe ventricular arrhythmias have been found in this series during the postoperative follow-up period. These results suggest that our operative procedure is feasible for the prevention of CRBBB. With regard to the relationship between ventricular dysrhythmia and CRBBB, careful observation is necessary throughout the patients' lifetime.

We investigated whether or not left anterior hemiblock is present in patients with left axis deviation using first-harmonic Fourier analysis of gated blood-pool images. Gated blood-pool images were taken in 50 patients without contraction abnormality. They included 14 normal subjects, 8 patients with right bundle branch block (RBBB), 20 with left axis deviation (LAD) and 8 with both RBBB and LAD (RBBB + LAD). ECG gated blood-pool scans were acquired in the anterior and "best septal" left anterior oblique projections. First, the phase images were displayed cinematically as a continuous-loop movie. Next, for quantitative analysis of the phase image, the whole left ventricular and left ventricular high lateral regions of interest were drawn. The "regional phase shift" (RPS) was then defined as (RPS = A-a) where "A" is the mean value of the whole left ventricular phase angles and "a" is that of phase angles in the high lateral region. The left ventricular phase changes and the RPSs in the RBBB and LAD groups were similar to those in the normal group. In the RBBB + LAD group, the latest phase changes occurred in the high anterolateral region. The RPSs of this group were significantly lower than those in the other 3 groups (p less than 0.01). These data suggest that left anterior hemiblock might coexist with RBBB in patients with RBBB + LAD, whereas left anterior hemiblock might not exist in the majority of patients with LAD alone.

To our knowledge, this is the first case reported of total disappearance of exercise-induced ST-segment depression in the presence of transient left anterior hemiblock at peak exercise. An unusual paradoxic increase in T-wave amplitude was also noticed. The significant ST-segment displacement reappeared when the transient left anterior hemiblock disappeared during the recovery phase. Based on current review, the presence of transient left anterior hemiblock during exercise seems to correlate well with the proximal left anterior descending coronary artery disease. Therefore, the presence of transient left anterior hemiblock during exercise with either normalization of exercise-induced ST-segment depression or paradoxic increase in T-wavse amplitude at peak level may be a useful end-point to stop the test for patients who do not reach 2 mm ST-segment depression or who remain asymptomatic.

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 male female ratio was significantly different (P

T-wave changes in spontaneous intermittent and alternating LAH have been described. Attention has been called to the fact that, with the onset of LAH conduction, the T-wave axis shifts oppositely to that of the QRS, thus widening the QRS-T angle in the frontal plane by about 95 degrees. This has the effect of causing T-waves to become upright in leads II, III and AVF, even in those in whom T-waves were previously inverted. This described dicordance of QRS and T-wave axes is considered as evidence that LAH conduction is in fact a true conduction abnormality. As a corollary, an inverted T-wave in leads II, III or AVF in the presence of LAH is a primary abnormality and may be an indication of inferior wall myocardial ischemia or infarction. T-waves are lowered but not inverted in lead I as a result of LAH conduction and precordial leads are variably but not significantly altered.

A selective defect in cardiac conduction in the anterior division of the left bundle branch was induced in a patient by therapy with procainamide hydrochloride. The defect in conduction, when intermittent, resulted in 2:1 Wencklebach sequences and produced a pattern similar to classic electrical alternans. The prognosis in drug-induced alternans is good, and it is important to differentiate it from true electrical alternans.

A case of persistent atrial standstill associated with muscular dystrophy of the limb girdle type is reported for the first time in the literature, In spite, of advanced myopathy, the patient delivered an apparently normal child. Hemodynamic studies including a normal coronary cinearteriography were performed in the post-partum period. The patient also had clinical and radiological evidence of peptic ulcer which may be the expression of an excessive vagal tone. A congenitial anomaly of the conduction system might explain the association of left anterior hemiblock with persistent atrial standstill, but could not be demonstrated.

Two patients are described who presented with seizures. Electrocardiogram revealed com plete heart block with ventricular asystole last ing four to 10 seconds in each case. These Stokes-Adams episodes were controlled with temporary transvenous pacing. Although there was full clinical recovery in each case, both patients continue to have right bundle branch block (RBBB) and left anterior hemiblock (LAH) 1½ years after their initial presentation.

Inferior myocardial infarction results in Q waves in the inferior leads of the electrocardiogram (ECG). Left anterior hemiblock results in initial r waves in these leads. Thus the diagnosis of one in the presence of the other is difficult. It has been reported that inferior infarction can be diagnosed in the presence of left anterior hemiblock when there is a q wave or q equivalent in lead II, and that part of the inferior wall must be spared, to result in the initial r waves of left anterior hemiblock in leads III and aVF. We examined these concepts in 18 patients with such an ECG, by means of resting myocardial perfusion (thallium-201) scintigraphy. In 15 there were defects in the inferior left ventricular wall consistent with inferior infarction. In all of these patients there was sparing of part of the inferior wall: in nine, sparing of the posterior part, and in six, sparing of the anterior part. We conclude that in apparently isolated left anterior hemiblock, a q wave or q equivalent in lead II is an important sign, indicating the likelihood of associated inferior infarction.

The voltage criteria of left ventricular hypertrophy were studied in 229 hypertensive patients undergoing treatment and 62 patients who were not treated. The limb-lead voltage criterion (R Lead aVL greater than or equal 11 mm.) was found more frequently in patients with radiographic evidence of cardiomegaly than other voltage criteria. This may have been due to a more negative axis in patients with cardiomegaly than in patients without cardiomegaly. It is possible that dilatation of the left ventricle to the left and posteriorly accentuates limb-lead criteria at the expense of V-lead criteria. Left anterior hemiblock occured in less than 10 per cent of the hypertensive patients. In 10 out of 16 patients with left anterior hemiblock, the hemiblock disappeared after treatment of the hypertension for 4 years whereas all five hemiblocks in untreated hypertensives persisted. Development of left anterior hemiblock subsequently occurred in only one patient with treatment and one without treatment over a 4-year period.

A 16-year-old high school boy showed various types of aberrant QRS complexes during supraventricular premature beats. The aberrant beats showed right bundle branch block pattern associated with varying degrees of left axis deviation. Rosenbaum et al explained it by slowing in conduction through the anterior fascicle in a bifascicular nature of human left bundle system. The alternative explanation might be possible if we consider a fan-like left bundle as proposed by Massing et al: namely incomplete or slight left axis deviation results from block of a small group of anterior parts of the fan-like left bundle, whereas marked left axis deviation results from block of a large number of fibers. The initial QRS force also changed to various degrees according to changes of the QRS axis. This case suggested the existence of an incomplete type of left anterior hemiblock, which produced not only an incomplete QRS axis change but also an incomplete change of the initial QRS forces.

Four hundred and fifty-five patients over age 65 with atrioventricular and intraventricular conduction defects were studied for periods of from two to five years (average, twenty-six months). Data on the overall incidence of conduction defects, the sex incidence, the type of block, and the associated electrocardiographic abnormalities are presented. There was no ECG evidence of extension of the blocks based on prolongation of the P-R interval, a shift or an increase in axis, a shift of the block from one branch to another, or an increase in width of the QRS complex. Left bundle-branch block and left anterior hemiblock, either alone or in association with any other fascicular block, were more common in the female patients whereas right bundle-branch block was more common in the male patients.