Sleep-disordered breathing in heart failure and the effect of cardiac resynchronization therapy.

Respiratory disturbances during sleep are common in patients with heart failure (HF) and can trigger the occurrence of sleep apnoea or deteriorate pre-existing breathing disorder. This in turn may lead to worsening of the HF itself. Optimal treatment for HF has been found to reduce respiratory disturbances during sleep significantly, whereas cardiac resynchronization therapy (CRT), achieved by biventricular pacing, appears to cause a further reduction in episodes of central type apnoea, although it may also have an effect on episodes of obstructive type. The beneficial effect of CRT is due to the patients' haemodynamic improvement and in the HF amelioration, and not due to some other effect resulting from the electrical stimulation of the heart. However, this therapeutic intervention by itself is insufficient for the effective treatment of respiratory disturbances during sleep and should be considered as an adjunctive treatment in addition to other established therapies.