A novel method for the quantitative evaluation of diurnal respiratory instability in patients with heart failure: A pilot study

Cheyne-Stokes Breathing as a Predictive Indicator of Heart Failure in Patients With Obstructive Sleep Apnea; A Retrospective Case Control Study Using Continuous Positive Airway Pressure Remote Monitoring Data

Objective

We conducted a retrospective case control study to examine whether remote monitoring of Cheyne-Stokes breathing (CSB) was useful for predicting the onset of heart failure (HF) in patients with obstructive sleep apnea (OSA) on continuous positive airway pressure (CPAP).

Methods

Among patients with OSA treated at our hospital, 33 patients with HF that occurred between July 2014 and May 2021 [11 patients with acute HF (AHF); 22 patients with chronic HF (CHF) exacerbation] were included in the HF group. Of the 618 stable patients, 149 patients with a 30-days average CSB rate (CSB%) ≧1% were included in the non-HF control group. The chronologic change of CSB% were compared among the AHF, CHF and Control groups. Furthermore, of the 149 patients in the non-HF control group, 44 patients were matched for CSB%, body mass index, and sex in a ratio of 1:2 to 22 patients with CHF. The average cycle length (CL) of CSB was compared among three groups: CHF in stable period (CHF-stable group), CHF in exacerbation period (CHF-exacerbation group), and control group. In addition, according to the status of HF, receiver operating characteristic (ROC) curves were generated to determine the optimal cut-off points for variation of CSB% and CL.

Results

Chronological change in CSB% among the three groups was significantly different. Standard deviation of CSB% (SD CSB%) before onset HF was significantly higher in both the AHF and CHF groups than in the control group. The CL of CSB was significantly longer in the CHF group than in the control group and was longer during the exacerbation period than during the stable period. The optimal cut-off value of CL that could differentiate patients with and without the onset of HF was 68.9 s.

Conclusion

The HF group demonstrated greater CSB variations and longer CL than the non-HF control group. Furthermore, the CL was longer during the exacerbation period of HF even in the same patient. These results suggest that remote monitoring of CPAP device data for CSB variations and CL might allow early prediction of the onset and exacerbation of HF.

Breathing irregularities before sleep onset on polysomnography in patients with heart diseases

PURPOSE

Severe cardiac dysfunction can manifest with diurnal breathing irregularity. However, it remains to be clarified whether or not diurnal breathing irregularity is observed in patients with heart diseases, including relatively mild chronic heart failure (CHF), compared to those without heart diseases.

METHODS

In this cross-sectional study, consecutive inpatients who were admitted for evaluation of sleep-disordered breathing were enrolled. We extracted 3.5 min of stable respiratory signals before sleep onset using polysomnography, analyzed the airflow data using fast Fourier transform, and quantified breathing irregularities using Shannon entropy S.

RESULTS

A total of 162 subjects were evaluated. Among these, 39 subjects had heart diseases, including ischemic heart disease (IHD), atrial fibrillation (Af), CHF, and a history of aortic dissection. The values of Shannon entropy S of airflow signals in subjects with heart diseases were significantly higher than in those without heart diseases (p < 0.001). After excluding CHF, the Shannon entropy S was also significantly higher in subjects with heart diseases than in those without heart diseases (p < 0.001). The values of Shannon entropy S were significantly correlated with plasma brain natriuretic peptide levels (r = 0.443, p < 0.001). Although the values were also significantly correlated with body mass index, the presence of heart diseases was independently associated with breathing irregularity in the multiple logistic analysis. Matching analysis revealed consistent differences between subjects with heart diseases and without heart diseases.

CONCLUSION

Breathing irregularity was observed before sleep onset in subjects with heart diseases who underwent polysomnography to diagnose sleep-disordered breathing.