Objective Unfavourable effects of sleep-disordered breathing (SDB) in heart failure (HF) are mainly mediated by impaired sympathetic activity. Few data are available on SDB and cardiac adrenergic impairment evaluated at myocardial level. The aim of the study was to assess the relationship between SDB, cardiac sympathetic innervation assessed by 123I-metaiodobenzylguanidine (123I-MIBG) imaging and prognosis in HF.
Methods Observational, prospective study enrolling patients with HF and reduced systolic function. Patients underwent nocturnal cardiorespiratory monitoring to assess SDB presence by apnoea/hypopnoea index (AHI), and 123I-MIBG imaging to calculate heart-to-mediastinum (H/M) ratios and washout rate. Patients were prospectively followed for 29±18 months for the combined endpoint of cardiovascular death and HF hospitalisation.
Results Ninety-four patients (66.1±9.8 years; left ventricular ejection fraction 32±7%) were enrolled; 72 (77%) showed SDB and, compared with non-SDB, significantly reduced early (1.67±0.22 vs 1.77±0.13; p=0.019) and late H/M ratios (1.50±0.22 vs 1.61±0.23; p=0.038). Dividing patients into two groups according to SDB severity, patients with a moderate–severe disturbance (AHI >15; n=43) showed significantly worse survival for the composite study outcome (log-rank test, p=0.001) with respect to patients with mild or no disorder (AHI ≤15; n=51). Adding SDB variables to the already known prognostic role of 123I-MIBG imaging, we observed a worse survival in patients with both SDB and H/M impairment.
Conclusions Patients with systolic HF and SDB show more impaired cardiac adrenergic innervation assessed by 123I-MIBG imaging, and more adverse prognosis compared with HF patients without SDB.
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OS and SP contributed equally to this study.
Contributors OS: conception, design, analysis of nocturnal cardiorespiratory monitoring and writing of the first draft. SP: conception, design and execution of research project and writing of the first draft. RF: execution of research project, analysis and interpretation of data. TP and VP: design and execution of research project, acquiring scintigraphy data. GR, AR, VP, FDM and AS: design, execution of research project, analysis and interpretation of data. PG, SD, FDM and AP: execution of research project, interpretation of data. DB: statistical analysis. DL and BT: review and critique of manuscript. AC: review and critique of manuscript. Final approval of the manuscript submitted. PP-F: conception, design. Review and approval of the final content of the manuscript.
Competing interests None declared.
Ethics approval Comitato Etico “Carlo Romano” Federico II University of Naples.
Provenance and peer review Not commissioned; externally peer reviewed.