LEFT BUNDLE BRANCH BLOCK AND VENTRICULAR

The quantification of ventricular dyssynchrony is a key factor in identifying patients with severe heart failure who may benefit from cardiac resynchronisation with biventricular pacing (BVP). Echocardiographic techniques appear to offer superior sensitivity and specificity than the ECG in selecting these patients. This paper reviews the scope of current echocardiographic techniques for guiding both patient selection and optimisation of device programming following implantation. B iventricular pacing (BVP) or cardiac resynchronisation therapy (CRT) is an adjuvant treatment for patients with symptomatic, drug refractory heart failure, providing both acute and long term haemodynamic and functional improvements.1–4 The 12 lead ECG has formed the mainstay of patient selection for BVP. A broad QRS complex provides a marker for electrical delay that may correlate with the mechanical dyssynchrony that BVP can correct. However, this selection strategy results in a failure of 20–30 % of implanted patients to respond clinically5 and excludes a number of patients with a narrow QRS complex who may benefit from BVP. In addition, devices are costly and implants time consuming and not without risk, an 8 % serious adverse event rate having been recently reported.4 Therefore, non-invasive screening techniques that offer superior sensitivity and specificity for diagnosing ventricular dyssynchrony or incoordination are essential for patient selection. It is likely that the answers to many of these key issues in BVP lie in the expanding role of echocardiographic techniques. This paper aims to review the use of echocardiography in guiding patient selection and in the process of therapy optimisation