Impairment of autonomic reactivity is a feature of heart failure whether or not the left ventricular ejection fraction is normal.
BACKGROUND
Autonomic dysfunction (AD) is associated with morbidity and mortality in patients with systolic heart failure (SHF). The extent of AD when LV ejection fraction is preserved (HF-NEF), is unclear. Our objectives were: 1) quantitative assessment of autonomic function in SHF and HF-NEF; and 2) exploration of relationships among AD, symptoms and cardiac function.


METHODS
This was an observational study of patients newly referred from primary care with a heart failure diagnosis; 21 SHF, 20 HF-NEF patients and 21 normal subjects were recruited. All subjects underwent clinical evaluation, 6-minute walk test (6 MWT), Minnesota Questionnaire (MLWHFQ) and echocardiography. Autonomic assessment included haemodynamic responses to standing, deep breathing and handgrip. Concomitant blood pressure variability (BPV) and heart rate variability (HRV) parameters were also derived.


RESULTS
There were significant differences in all haemodynamic responses between SHF, HF-NEF and normal. Log transformed (ln) low frequency spectral component of BPV was lower in SHF (4.1 ± 0.3) than HF-NEF (4.2 ± 0.4) and normal (4.4 ± 0.1; p=0.001 SHF vs HF-NEF and vs normal). Ln LF/HF was greater in normal than HF-NEF and SHF (1.5 ± 0.7 vs 0.9 ± 1.0 vs 0.6 ± 0.6; p=0.003). Autonomic modulations correlated negatively with severity of heart failure.


CONCLUSIONS
Autonomic responses in heart failure were blunted and the attenuation of responses correlated strongly with symptomatic and functional markers of disease severity. Autonomic dysfunction is a feature of the heart failure syndrome but is not dependent on ejection fraction.
Patel
Hitesh
H
Royal Surrey County Hospital, Surrey, UK.
Ozdemir
Baris A
BA
Patel
Mitesh
M
Xiao
Han B
HB
Poole-Wilson
Philip A
PA
Rosen
Stuart D
SD
D000328:Adult; D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000503:physiopathology*; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D018737:Hand Strength / Q000502:physiology; D054143:Heart Failure, Systolic / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D056152:Respiratory Rate / Q000502:physiology; D012720:Severity of Illness Index; D012791:Shy-Drager Syndrome / Q000150:complications / Q000503:physiopathology; D013318:Stroke Volume / Q000502:physiology*; D014463:Ultrasonography; D014636:Valsalva Maneuver / Q000502:physiology