CSA, typically associated with symptomatic HF, is widely observed in clinical practice and associated with a poor outcome. Currently, PAP is the standard treatment for CSA. Clinical trials using PAP for treating CSA have yielded contradictory outcomes [
15,
16]. The CANPAP trial was a randomized, outcome study that assessed the efficacy of CPAP treatment for CSA in HF subjects; this study revealed no benefits of CPAP [
17]. A post hoc examination of the trial’s data suggested that mortality could be reduced if CPAP therapy is associated with an early and considerable reduction in AHI. The mean AHI in the adaptive servo-ventilation (ASV) group at 12 months was 6.6 e/h [
18]. The incidence of the primary endpoint was not substantially different between the ASV and control groups. In the ASV group, overall mortality and cardiovascular mortality were considerably greater than in the control group [
19]. When compared with PAP, the benefit of PNS includes a natural breathing pattern by a diaphragmatic stimulation. As a result, physiological effects of diaphragmatic stimulation do not have similar negative hemodynamic effects on cerebral hemodynamics as PAP breathing (e.g., increased intrathoracic pressure affecting right and left ventricular preload and afterload) [
20‐
22]. Prospective self-controlled studies such as PNS comparison can be recommended to the same patient, with a pause after PAP treatment [
23]. The recent approval of the PNS system in Europe and USA provides new hope for patients with CSA. Fudim et al. used pooled individual data from the pilot (
n = 57) and pivotal (
n = 151) studies of the Remedē System in patients with predominant moderate to severe CSA. At 6 months, PNS reduced AHI by a median of − 22.6 e/h (25th and 75th percentiles; − 38.6 and − 8.4, respectively); PNS decreases CSA severity and sleep quality considerably. Significant and long-term reductions in key predictors of CSA severity, such as AHI, CAI, and 4% ODI, established the feasibility and therapeutic efficacy of PNS for CSA [
24‐
26]. The degree of AHI and the reduction in AHI are related, for example, to improved outcomes in patients with obstructive or CSA. It remains to be determined whether reductions in crucial sleep parameters, symptoms, and heart function by the Remedē System can have a positive effect on cardiovascular results [
18,
27]. Implant success and procedural complication rates were improved from the pilot study to the pivotal phase. Increased operator experience, improved leads, and updated implantation techniques may contribute to the rate of implant success [
28].
Our study showed that PNS can be utilized to treat CSA in individuals with HF, leading to a substantial decrease in AHI. Those with the most severe sleep apnea, as defined by an AHI > 30 e/h, have the highest mortality rates [
29]. In our study, the proportion of subjects with severe sleep apnea decreased from 66 to 44% when PNS was administered. During the therapeutic night, five patients (55%) had an AHI < 15 e/h. Previous research divided 151 suitable patients into treatment (
n = 73) or control (
n = 78) groups. Six months later, those in the treatment group had an AHI reduction from baseline that was higher than or equal to 55%, whereas those in the control group did not achieve this reduction. Significant improvement in reducing the severity of CSA, improvements in arousal indices as well as in rapid eye movement sleep, PGA scores, and ESS were observed with PNS. Consistent improvements in oxygenation and quality of life support the clinical relevance of this therapy, making PNS a potential treatment for CSA [
25]. The results of the trial showed that only two patients were unable to adapt to the treatment. The therapy was well tolerated. The first implantation success rate was very high. Despite lead dislodgement, it was comparable to other implantable devices using the transvenous lead technique. A total of 138 (91%) of 151 patients experienced no serious-related side events at 12 months [
25]. Our study did not detect an increased mortality in HF patients after PNS; however, past studies have shown a signal of increased mortality in CSA patients treated with PNS [
19,
30]. In Dariusz’s research, only five major adverse events occurred during the 12 months of follow-up. There were no deaths as a result of serious adverse events linked to the device or procedure. None of these incidents were fatal [
31]. The safety of any new medical device must be evaluated over time.
Our study had limitations. This is a single-center and non-randomized trial. We only evaluated a two-night therapy with a limited sample size, and all patients were men (a high prevalence of CSA in male patients with HF). The design of the study did not allow us to fully evaluate the potential complications of this therapy, such as its potential to interfere with pre-existing implanted cardiac devices. In addition, a few individuals were excluded due to issues with the lead placement. Notably, many patients with HF who have CSA may also have obstructive apnea; future randomized, controlled trials are needed to obtain stronger evidence.