In recent years there has been a growing interest in using cardiac pacing as additive treatment in severe heart failure. It is estimated that 30% of patients with severe heart failure have intraventricular conduction disturbances mechanically characterised by a discoordinate ventricular contraction pattern and wide QRS complexes.1Multisite biventricular pacing, which restores the synchronisation of the ventricular contraction, could be expected to be beneficial in such patients. A clinical benefit from biventricular pacing in heart failure was first suggested by Bakker and colleagues.2 Thereafter acute and short term haemodynamic benefits, including decreases in filling pressures and mitral regurgitation and improvements in diastolic filling and cardiac output, from biventricular pacing were demonstrated.3 ,4 It is, however, by no means clear whether acute and short term haemodynamic benefits will translate into long term or indeed into clinical improvements. Moreover, randomised trials are needed to establish the true value of this treatment.

Results from uncontrolled studies suggest that multisite pacing improves selected heart failure patients.5 The largest of these is the Insync study. It comprised 68 patients with severe heart failure of mixed aetiology. All patients had severe heart failure, New York Heart Association (NYHA) functional class III–IV, and a QRS duration of at least 150 ms. …