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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.

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