[Acute effects of cardiac resynchronization therapy on breathing during sleep in patients with severe chronic heart failure--a pilot study].

BACKGROUND

Sleep-related breathing disorders (SDB), especially Cheyne-Stokes respiration (CSR), have prognostic relevance in patients with chronic heart failure (CHF). Thus, we investigated acute effects of cardiac resynchronization therapy on breathing during sleep.

METHODS

Beside a cardiopulmonary investigation, breathing during sleep was analysed polygraphically/polysomnographically on the night before and during the second night after implantation of a biventricular pacemaker for cardiac resynchronization.

PATIENTS: We investigated 16 consecutive patients with severe CHF (NYHA class III-IV) and widened QRS complexes (QRS > 150 ms) with the indication for cardiac resynchronization therapy independent of this study.

RESULTS

Cardiac resynchronization therapy shortened the QRS time in each and every patient (QRS: 167.3 +/- 21.7 ms to 113.0 +/- 19.0 ms; p < 0.001) as a marker for successful resynchronization. Initially, SDB were diagnosed in 11 of the 16 patients studied (69 %), with 7 patients having CSR (44 %) and 4 patients (25 %) having CSR and obstructive sleep apnoea. With cardiac resynchronization therapy, no significant acute changes were seen regarding nocturnal breathing/breathing disorder, heart frequency, or oxygen saturation.

CONCLUSIONS

The established positive effects of cardiac resynchronization therapy are rather due to a chronic improvement of cardiopulmonary interactions (remodelling, circulatory time, or chemosensitivity) than to acute effects, as investigated in this study.