Epidemiological Characteristics Of Heart Failure Combined With Sleep Apnea And Safety And Efficacy Of Phrenic Nerve Stimulation Therapy

Objectives:Sleep-disordered breathing (SDB) is common in patients with chronic heart failure secondary to non-valvular heart disease; however, the prevalence and charactheristics of SDB in patients with rheumatic valvular heart disease (RVHD) are unclear. This study was designed to determine the prevalence, characteristics, and risk factors for SDB in RVHD patients.Methods:A cross-sectional study was conducted in260RVHD patients. The following data were recorded:types of heart valve lesions, electrocardiographic, echocardiographic, arterial blood gas analysis findings, baseline medication,6-minute walk test (6MWT) distance and sleep parameters.Results:Compared to patients with single left-sided valve lesions, patients with left-and right-sided valve lesions had a higher prevalence of SDB (46.2vs.31.2%, p=0.013); the increased prevalence of SDB was only involved central sleep apnea (CSA)(31.1vs.14.1%, p=0.001). Patients with objective sleep apnea (OSA) or CSA were older and had a shorter6MWT distance, lower left ventricle ejection fraction and PaO2, a longer lung-to-finger circulation time and a higher prevalence of atrial fibrillation (AF) and hypertension (all p<0.05) as compared with patients without SDB. Multinomial logistic regression analysis showed that PaO2≤85mmHg was the only risk factors for OSA. Male gender, AF, a6MWT distance≤300m, a PaO2≤85mmHg, and a PaCO2≤40mmHg were risk factors for CSA.Conclusions:Patients with RVHD had a high prevalence of SDB (predominantly CSA). RVHD patients with SDB, particularly those who had CSA, manifested more severe symptoms and greater cardiac functions impairment. Assessments of the clinical manifestations and cardiac functions may be important for predicting the risk factors for SDB. Background:Cheyne-Stokes respiration (CSR), which often occurs in patients with congestive heart failure (CHF), may be a predictor for poor outcome. Interruption of CSR can improve the prognosis of patients with CHF. Phrenic nerve stimulation (PNS) may interrupt CSR in patients with CHF. We report the clinical use of transvenous PNS by intervention in patients with CHF and CSR.Methods:Nineteen patients with CHF and CSR were enrolled. A single stimulation lead was placed at the junction between the superior vena cava and brachiocephalic vein or in the left-side pericardiophrenic vein. PNS stimulation was performed using Eupnea System device (RespiCardia Inc). Respiratory properties, electrocardiogram and electroencephalogram were assessed before and during PNS. PNS was assessed at a maximum of10mA.Results:Successful stimulation capture was achieved in16patients. Failure to capture occurred in three patients because of dislocation of leads. No adverse events were seen under maximum normal stimulation parameters for an overnight study. When PNS was applied following a series of central sleep apneic events, a trend toward stabilization of breathing and heart rate as well as improvement in oxygen saturation was seen. Compared with pre-PNS, during PNS there was a significant decrease in apnea-hypopnea index (33.8±9.3vs8.1±2.3, p=0.00), an increase in mean and minimal oxygen saturation as measured by pulse oximetry (89.7%±1.6%vs94.3%±0.9%and80.3%±3.7%vs88.5%±3.3%, respectively, all p=0.00) and end-tidal CO2(38.0±4.3mmHg vs40.3±3.1mmHg, p=0.02), but no significant difference in sleep efficiency (74.6%±4.1%vs73.7%±5.4%, p=0.36). Conclusions:The preliminary results showed that in a small group of patients with CHF and CSR,1night of unilateral transvenous PNS improved indices of CSR and was not associated with adverse events. Background:Central sleep apnea (CSA) with Cheyne-Stokes respiration is common in patients with heart failure (HF) and is associated with poor quality of life and prognosis. In early period, an acute study of small sample using transvenous stimulation of the phrenic nerve to treat CSA in HF have shown that it significantly reduced episodes of CSA and improved key polysomnographic parameters. In this study, we evaluated the safety of chronic PNS with implantable phrenic nerve stimulator (IPNS) in HF patients with CSA.Methods:The study was a prospective, non-randomized evaluation of IPNS in eight HF patients with CSA. The IPNS lead was positioned in either the left pericardiophrenic or right brachiocephalic vein. Leads were connected to a proprietary pulse generator implanted in the right pectoral area. Continuous monitoring at least48hours during implantation and6months’ follow-up were performed for all patients and at the end the IPNS setting and and function was re-interrogated to check for any changes.Results:Six of the eight patients completed the study (one lost to follow-up; one death from severe pneumonia). No side effects or adverse events related to PNS occurred.Conclusions:Use of chronic PNS with IPNS appears to be a safe and feasible in HF patients with CSA. Large multi-center studies are needed to prove the final safety in patients with HF..