Effect of adaptive servo-ventilation for central sleep apnoea in systolic heart failure on muscle sympathetic nerve activity: a SERVE-HF randomised ancillary study

Figures

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  FIGURE 1. Study flowchart. MSNA: muscle sympathetic nerve activity; 6MWT: 6-min walk test; MLHFQ: Minnesota Living with Heart Failure Questionnaire; EQ5D: EuroQol-5D; ASV: adaptive servo-ventilation. Control group 3-month follow-up visit results are for 20 patients because one patient died at 67 days.

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  FIGURE 2. a, b) Change in sympathetic tone measured using muscle sympathetic nerve activity (MSNA) expressed both in a) bursts per minute (bursts·min−1) and b) bursts per 100 heart beats (bursts·100 hb−1). c, d) Sample MSNA and blood pressure raw signals from two patients: c) control and d) adaptive servo-ventilation (ASV). AUI: arbitrary integration units.

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  FIGURE 3. Relationship between sympathetic tone measured using muscle sympathetic nerve activity (MSNA) in the control and adaptive servo-ventilation (ASV) groups and risk of: a) primary end-point (all-cause death, or life-saving cardiovascular intervention or unplanned hospitalisation for worsening chronic heart failure): events in seven (33.3%) and seven (36.8%) patients in the control and ASV groups, respectively; b) all-cause death: events in six (28.6%) and five (26.3%) patients in the control and ASV groups, respectively; and c) cardiovascular death: events in five (23.8%) and three (15.8%) patients in the control and ASV groups, respectively. Bursts·min−1: bursts per minute; bursts·100 hb−1: bursts per 100 heart beats. Cox regression with Firth's penalised maximum likelihood bias reduction method was applied. For continuous independent variables, results are presented as hazard ratio (HR) values for a 1-unit increase in the independent variable within the randomisation group. Statistical significance of a difference in those HR values is given as “p-value for interaction”.

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  FIGURE 4. Summary figure. In chronic heart failure patients, the suppression of central sleep apnoea (CSA) by adaptive servo-ventilation (ASV) does not have a significant effect on chronic heart failure-related sympathetic activation and leads to increased cardiovascular mortality.