Is the left bundle branch pacing a choice to conquer the right bundle branch block?—A case report

In patients with preserved ejection fraction or right bundle branch block (RBBB) pattern requiring a high percentage of ventricular pacing, His‐bundle pacing (HBP) might be an alternative to biventricular pacing, although the high threshold occasionally occurs. We provided a case of the intrinsic RBBB correction by capturing intra‐Hisian left bundle branch (LBB) or distal His‐bundle with different output settings. LBB pacing had the advantage of a much lower threshold while remained most synchrony as HBP. LBB pacing might be a promisingly safe and effective procedure for patients with high‐grade atrioventricular (AV) block and RBBB pattern.     

When should we diagnose incomplete right bundle branch block?

An rSr' pattern with QRS duration of less than 0.12 s in theright precordial leads can be due to incomplete right bundlebranch block (which may progress to complete right bundle branchblock) or can be a normal electrophysiological variant. To identifyother ECG features that may help to distinguish between thesetwo possibilities, ECGs of 15 patients who progressed from normalto complete right bundle branch block through an intermediaterSr' pattern of incomplete right bundle branch block were analysed.The following features in the right precordial leads (V₁, V₂)that preceded or accompanied the appearance of the rSr' wereidentified: diminution of the S wave depth (100%), inversionof ratio of the S wave depth to SV₁,/SV₂ (93%), slurring ofthe downstroke or upstroke of the S wave (27%) and prolongationof the QRS duration to 0.10 s (73%). When a further 79 subjectswith rSr' pattern in the right precordial leads and QRS durationof <0.12 s were divided into those with SV₁/SV₂ ratio >1.0 and those with SV₁/SV₂ < 1.0, compared with the latterthe subjects with SV₁/SV₂ ratio > 1.0 were found to be significantlyolder (59.8±18.4 years vs 32.8±18.1 years, P<0.001),to exclusively show S wave slurring (37% vs 0%), and to morelikely have a QRS duration 0.10s (74% vs 7%). The findings indicatethat when faced with a single ECG showing an rSr' pattern inthe right precordial leads and QRS duration 0.12 s, severalother features, and in particular the relative sizes of theS waves in V₁ and V₂, may be useful in distinguishing rSr' dueto incomplete right bundle branch block from ‘normal’rSr'.     

Septal branch aneurysm during coronary computed tomography angiography: a cause of right bundle branch block?

A 59-year-old male was referred to our institution for a cardiologyconsultation due to unexplained dizziness and recent episodesof near syncope. He had previously been diagnosed with rightbundle branch block (RBBB) (Panel A),     

Intermittent left bundle branch block: What is the mechanism?

We present an illustrative case of a patient with intermittent left bundle branch block (LBBB) that underwent electrophysiological study with detailed multielectrode recordings of the right and left septum. The case elucidates the nature and location of conduction block and provides further insight into the underlying mechanisms of LBBB.     

Wenckebach pattern in right bundle branch block – benign or not?

A Mobitz type I block (Wenckebach phenomenon) with narrow QRS complex is almost always due to a lesion in the AV node. In a type I block with wide QRS complex (>0.12 sec), the block can be in the His-Purkinje system in 60–70% of the cases. Even though the progressive PR prolongation with every conducted beat suggests Wenckebach phenomenon, one needs to pay attention to the accompanying QRS complex. In the setting of persistent right bundle branch block, axis change of subsequent conducted beat before an unconducted p suggests alternating fascicular block, giving clue to unreliable infra-Hisian conduction; and in the setting of symptoms, a pacemaker should be implanted. Infra-Hisian Wenckebach block is rare with only sparse literature reports. The present case report adds to these, suggesting that wide QRS with Wenckebach block on surface ECG may indicate infra-Hisian conduction abnormalities.     

“Pseudo” Hisian extrasystole arising from the proximal portion of the left bundle branch

The diagnosis of a Hisian extrasystole is based on simple electrocardiographic features and both an extrasystole arising from the His-Bundle (“true” Hisian extrasystole) and also one from the proximal portion of the bundle branch (“pseudo” Hisian extrasystole) would be diagnosed as Hisian extrasystoles [1]. Here we report a case of “pseudo” Hisian extrasystole arising from the proximal portion of the left bundle branch and the successful catheter ablation was achieved in the right coronary cusp.     

New formula for defining “normal” and “prolonged” QT in patients with bundle branch block

Objectives

To predict the QT interval in the presence of normal QRS for patients with left bundle branch block (LBBB).

Epidemiological and evolutionary characteristics of heart failure in patients with left bundle branch block – A Moroccan center-based study

Background

In patients with heart failure, left bundle branch block (LBBB) seems to be associated with an increased risk of cardiovascular mortality.

Purpose

The purpose of this study is to determine the in-hospital outcome of congestive heart failure patients with LBBB versus those without.

Methods

We conducted a prospective observational study at the Department of Intensive Care and Rhythmology at the Mohammed V Military Hospital of Rabat, where 330 patients were admitted for heart failure between January 2008 and September 2012. Screening out patients with missing data yielded a cohort of 274 patients. Among the 274 patients, only 110 had LBBB and a left ventricular ejection fraction lower than 50%. We randomly selected a subset of 110 patients diagnosed as non-LBBB to ensure a significant statistical comparison between LBBB and non-LBBB patients. We therefore considered two groups in our analysis: 110 heart failure (HF) patients with LBBB and 110 HF patients without LBBB. Patients with incomplete records were excluded.

Results

Male gender was dominant in both groups (82.7% vs. 66.7%, p = 0.005). Patients with LBBB had a higher prevalence of idiopathic dilated cardiomyopathy (39.1% vs. 4.8%, p < 0.001); and a higher prevalence of previous hospitalization for heart failure (64.5% vs. 23.3%, p < 0.001). The left ventricular ejection fraction was significantly lower in the group with LBBB (25.49% vs. 39.53%, p < 0.001). Age, cardiovascular risk factors, rhythmic and thromboembolic complications did not significantly differ. In patients with LBBB, 61.8% received cardiac resynchronization therapy performed both during the index hospital stay (50.9%) and previously (10.9%). Hospital outcome was marked by 20 in-hospital deaths in the group with LBBB and eight deaths in the group without LBBB (p = 0.008).

Conclusion

Our analysis emphasizes increased in-hospital mortality and higher disease severity, over a short period of stay, in heart failure patients with left bundle branch block.     

Is there an association between left bundle branch block and coronary slow flow in patients with normal coronary arteries?

Slow flow in angiographically normal coronary arteries is not a rarely seen problem. It is unknown whether it is related with conduction disorders. In this study we investigated the frequency of conduction disorders in patients with normal coronary artery and slow flow. The study included 36 (22 female; mean age 63 +/-11 years) patients who have normal coronary arteries and slow flow in coronary angiography. Patients' 12-lead electrocardiograms were analyzed for the presence of bundle branch block. Twenty-two of 36 patients (61%) demonstrated left bundle branch block. Twelve patients (33%) had normal intraventricular conduction. Only 2 of 36 patients (6%) had right bundle branch block. Microvascular disease has been implicated in coronary slow flow. However, according to the results of this study there is a close association between especially left bundle branch block and coronary slow flow. A causal relation should be sought between them with future studies.