Right bundle branch block: are we looking in the right direction?

Abstract

This editorial refers to ‘Right bundle branch block: prevalence, risk factors, and outcome in the general population: results from the Copenhagen City Heart Study’, by B.E. Bussink et al. , doi:10.1093/eurheartj/ehs291 The right bundle branch is a long, thin, and discrete structure composed of high-velocity conduction Purkinje fibres. It is located in the right side of the interventricular septum and occupies a subendocardial position in its superior and inferior thirds and deeper in the middle third. There are no ramifications in most of its course, but it starts to branch as it reaches the base of the anterior papillary muscle. The appearance of a right bundle branch block (RBBB) alters the ventricular activation sequence, produces a QRS prolongation, and changes the orientation for R- and S-wave vectors, thus generating a typical electrocardiogram (ECG) pattern ( Figure 1 ). Figure 1 Right bundle branch block produces a change in the normal activation of the heart. The prevalence of RBBB in the general population is estimated at between 0.2% and 0.8%, and it clearly increases with age.1 It may be associated with different cardiac structural diseases such as ischaemic heart disease, myocarditis, hypertension, congenital heart disease, cor pulmonale, and pulmonary embolism. Its prognosis depends on the type and severity of the associated heart condition; for example, in patients with ischaemic heart disease the presence of RBBB is a well-established mortality predictor.2–4 The same is true for patients with heart failure where at least two different studies showed a worse prognosis for patients with RBBB hospitalized with this condition.5,6 Nevertheless, all previously published data suggest an excellent prognosis in patients free of heart …