title: Diagnostic Accuracy of Random ECG in Primary Care for Early, Asymptomatic Cardiac Autonomic Neuropathy.
abstract: OBJECTIVE
  Cardiac autonomic reflex tests (CARTs) are time consuming and require patient cooperation for detecting cardiac autonomic neuropathy (CAN). Heart rate variability (HRV) analysis requires less patient cooperation and is quicker to complete. However the reliability of HRV results as a clinical tool, with respect to length of recording and accuracy of diagnosis is inconclusive. The current study investigated the reproducibility associated with varying length of recording for early CAN (eCAN) assessment.
  
  
  METHODS
  Participants were 68 males, 72 females with average age of 55 for controls and 63 for early CAN. Inclusion criteria were that participants were medication free and presented with no comorbidities. ECGs of control and eCAN were recorded and heart rate changes analyzed with the fast Fourier transform (FFT) and Lomb-Scargle periodogram (LSP). Ten-second to 5-minute recordings were extracted from a 15-minute lead-II ECG and accuracy in assessment of eCAN determined.
  
  
  RESULTS
  The eCAN group was older ( P < .001) and systolic blood pressure was higher ( P < .01). HDL-cholesterol was also higher in the eCAN group ( P < .05). HRV analysis showed that both FFT and LSP results were significantly different between eCAN and control down to a 10-second ECG length for low frequency (LSP: P = .013, FFT: P = .024) and high frequency (HF-LSP: P = .002, FFT: P = .002) power. eCAN assessment was optimal down to 90-second recordings with a sensitivity of 100% and specificity of 29.49%.
  
  
  CONCLUSIONS
  HRV is suitable for clinical practice from ECG recordings of more than 90 seconds with high accuracy and repeatability within a session for each participant.
authors.affiliation: 1 Clinical Medicine, Macquarie University, Sydney, Australia.|2 Centre for Research in Complex Systems and School of Community Health, Charles Sturt University, Albury, Australia.
authors.forename: Herbert F
authors.initials: HF
authors.lastname: Jelinek
authors.affiliation: 3 Applied Informatics Research Group, University of Newcastle, Newcastle, Australia.
authors.forename: Marc T P
authors.initials: MTP
authors.lastname: Adam
authors.affiliation: 4 Rural Clinical School, University of Melbourne, Shepparton, Australia.|5 Wangaratta Cardiology and Respiratory Centre, Wangaratta, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Krones
authors.affiliation: 3 Applied Informatics Research Group, University of Newcastle, Newcastle, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Cornforth
mesh_terms: D000328:Adult; D000368:Aged; D058070:Asymptomatic Diseases; D001341:Autonomic Nervous System / Q000503:physiopathology*; D016022:Case-Control Studies; D003929:Diabetic Neuropathies / Q000175:diagnosis* / Q000503:physiopathology; D042241:Early Diagnosis; D004562:Electrocardiography; D005260:Female; D005583:Fourier Analysis; D006321:Heart / Q000294:innervation*; D006331:Heart Diseases / Q000175:diagnosis* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011320:Primary Health Care; D015203:Reproducibility of Results; D013997:Time Factors
keywords: ECG analysis; cardiac autonomic neuropathy; clinical diagnostics; heart rate variability; reliability