Biventricular pacing in patients with severe heart failure: has the time come?

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. 1 Multisite biven-tricular 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 haemody-namic 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. Significant improvements by biventricular pacing were seen in most patients after three and six months of pacing compared to baseline with regard to NYHA class, six minute walk distance, and quality of life. Moreover, pacing reduced the QRS duration significantly and normalised the intraventricular delay as an indication that ventricular resynchronisation had been achieved. Hospital care constitutes a major cost in heart failure management. 6 One recent study demonstrated a reduced need for all cause and heart failure related hospital care in parallel with clinical improvements by biventricular pacing. 7 Even though pacemaker treatment is not inexpensive , neither is hospital care. If biventricular pacing is proven to be eYcient in the long term, it could prove to be cost eVective. Increased sympathetic activity in severe heart failure carries a negative impact on survival. One study indicates that biventricular pacing modifies sympathetic activity in those patients with the highest baseline norepinephrine (nor-adrenaline) concentrations. 8 Moreover an increased vagal influence following biventricular pacing and reduced QT dispersion has been observed. If this is true, biventricular pacing could reduce the risk for ventricular arrhythmias. There are a number of randomised trials on the eYcacy …