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Effect of respiratory pacing on CHF patients with periodic breathing

      Background: A large portion of CHF patients (25%–66%) with NYHA class I to III show sustained daytime periodic breathing (PB) including Cheyne-Stokes. The frequently observed concomitant cyclic oxygen desaturation may further worsen prognosis. The study goal was to explore the acute and sustained changes, in the initially abnormal breathing and SpO2 patterns in CHF patients, in response to device-guided respiratory pacing performed at home or in the lab setting. Patients and Methods: 26 CHF patients (age 58±7 y, NYHA Cl 2.4±0.7, EF 28±9%) with a relatively stable PB underwent, at each visit at the clinic, a 3-phase “acute test”, consisting of spontaneous breathing (“Baseline”), respiratory pacing (“Exercise”) and spontaneous breathing (“Recovery”), 6-minute each. Respiratory pattern, ECG, Blood Pressure and SpO2 were monitored continuously and non-invasively. The respiratory-pacing device (InterCure, Israel) enables patients to achieve slow and deep breathing by synchronizing their inspiration & expiration to guiding tones, generated by the device and controlled by a respiration sensor. The auditory-pacing automatically adjusts the pacing to the patient's ability to slow his/her breathing. A Control intervention was performed in 13/26 patients by substituting the Exercise with a 6-minute non-rhythmic relaxation music. To explore the sustained effects, ten patients were given the pacing device for home use and after a short training were requested to perform the exercise 15-min twice daily: 8 patients came for follow-up visits over a one-year period (3 months mean visit time). Endpoints included mean & variability (SD) over 3-min segments at each phase of the monitored variables. “Acute” outcomes were changes in endpoints between Baseline and Exercise phases at visit 1, while “sustained” outcomes were changes in Baseline endpoints between the 1st and the last follow-up visits. Results: Both acute and sustained responses displayed a reduction of abnormality in both breathing and SpO2 patterns. Acutely, SpO2 was increased from Baseline to Exercise (93.9% vs 95.5%, p = 0.001) while its variability was reduced (0.9% vs 0.4%, p = 0.01). The effect was larger in patients with lower baseline SpO2 (r = 0.76) and greater variability (r = 0.95). In parallel, respiration amplitude increased from its baseline level by +84% (p<0.001), while its variability decreased from 35% to 23% (p<0.01). No change in SpO2 or respiration amplitude was observed using the Control intervention. The sustained response to the routine exercise (n = 8) (Baseline to Baseline) included a reduction of SaO2 variability (1.1% vs 0.4%, p<0.05), greater for higher baseline value (r = 0.92), and a parallel decrease in breathing amplitude variability (31% vs 19%, p = 0.06). Conclusion: Respiratory pacing guided by a device may be effective in normalizing breathing pattern and stabilizing oxygen saturation in CHF. Assessing the efficacy of its therapeutic potential requires further investigation.