Cheyne-Stokes respiration in heart failure: cycle length is dependent on left ventricular ejection fraction

Cheyne-Stokes respiration (CSR) is common in patients with congestive heart failure (CHF) and is associated with poor prognosis. The aim of this study was to analyse the characteristics of CSR in patients with varying degrees of impaired left ventricular ejection fraction (LVEF).

A total of 104 patients with CSR (apnea-hypopnea index [AHI]15/h) and exertional dyspnea were divided into FIVE groups according to their LVEF (<20% upto 50%). A subgroup of 22 patients was studied twice: 15 in whom LVEF improved between studies and 7 in whom LVEF deteriorated. Using cardiorespiratory polygraphy recordings, cycle length (CL), apnea length (AL), ventilation length (VL), time to peak ventilation (TTPV), circulatory delay (CD) and VL:AL ratio were determined.

There was no relationship between AHI and impairment of LVEF, but the characteristics of CSR were related to LV function. Comparing the groups with the best LVEF (>50%) and the worst LVEF (<20%), there were significant increases in CL (49+/-17-86+/-23s), AL (21+/-9-31+/-10s), VL (28+/-10-55+/-17s), TTPV (19+/-5-32+/-11s), VL:AL ratio (1.5+/-0.4-1.9+/-0.7s) and CD (29+/-8-49+/-16s). In the subgroup of patients who were studied twice, improvement in EF was associated with a decrease in these parameters.

The current classification of CSR in CHF patients using AHI may be overly simplistic. Parameters such as CL, VL, TTPV and CD are related to cardiac function and could potentially be used for disease monitoring.