OBJECTIVE Guidelines recommend treating patients with a new or presumed new left bundle-branch block (LBBB) similar to those with an acute ST-segment elevation myocardial infarction. It is often unclear which emergency department (ED) patients with potentially ischemic symptoms actually have an acute myocardial infarction (AMI), even in the setting of LBBB. Our null hypothesis was that in ED pa...

BACKGROUND The purpose of this study was to assess the independent contribution of left bundle branch block (LBBB) on long-term mortality in a large cohort with symptomatic heart failure (HF) requiring hospitalization. METHODS AND RESULTS We studied a prospective cohort of 21 685 cases of symptomatic HF requiring hospitalization in the Register of Information and Knowledge about Swedish Heart...

AIMS Left ventricular (LV) dilatation, hypertrophy, and septal perfusion defects are frequently observed in patients with left bundle branch block (LBBB). We investigated whether isolated LBBB causes these abnormalities. METHODS AND RESULTS In eight dogs, LBBB was induced by radio frequency ablation. Two-dimensional echocardiography showed that 16 weeks of LBBB decreased LV ejection fraction ...

Background Left bundle branch block (LBBB) is a marker of increased delay between septal and left ventricular (LV) lateral wall electrical activation, and is a predictor of which patients will benefit from cardiac resynchronization therapy (CRT). Recent analysis has suggested that one third of patients meeting conventional ECG criteria for LBBB are misdiagnosed and new strict LBBB criteria have...

IMPORTANCE The benefits of cardiac resynchronization therapy (CRT) in clinical trials were greater among patients with left bundle-branch block (LBBB) or longer QRS duration. OBJECTIVE To measure associations between QRS duration and morphology and outcomes among patients receiving a CRT defibrillator (CRT-D) in clinical practice. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort 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 Rhyth...

Background Response to cardiac resynchronization therapy (CRT) depends both on dyssynchrony and (regional) contractility. We hypothesized that septal deformation can be used to infer integrated information on dyssynchrony and regional contractility and thereby predict CRT response. Methods and Results In 132 CRT-candidates with left bundle branch block (LBBB)like ECG morphology (left ventricula...

Even among those with true left bundle branch block (LBBB), about a third do not have a favourable response to cardiac resynchronization therapy (CRT). Thus all LBBB are not created equal and the pattern may be due to factors beyond delayed electrical activation (hypertrophy, dilatation, scar, isolated fascicular block). While a more strict definition of LBBB has been recently proposed [1], oth...

Abnormal interventricular septal motion, with pre-ejection posterior motion and anterior motion away from the posterior left ventricular wall during ejection, was demonstrated by echocardiography in 14 out of 17 cases with complete left bundle branch block (LBBB). Two of 14 cases had intermittent LBBB and showed abnormal septal motion only during LBBB. Of the control group of 49 patients withou...

AIMS Several studies have reported a poor outcome with cardiac resynchronization therapy (CRT) in non-left bundle branch block (LBBB) patients. Although the left ventricular (LV) lead location is an important determinant of the clinical outcome, there is scant information regarding its role in non-LBBB patients. This study sought to examine the impact of electrical and anatomical location of th...