title: aVR, an index of all ECG limb leads, with clinical utility for monitoring of patients with edematous states, including heart failure.
abstract: BACKGROUND
  Nonreproducibility of precordial electrocardiogram (ECG) leads in serial ECGs has led to emphasis on the limb leads for some applications. Since modern electrocardiographs measure leads I and II and calculate on line the other four limb leads, the former can substitute for the set of six limb leads. Furthermore, based on the mathematical relationship of lead aVR and leads I and II, it was hypothesized that aVR could be used as a representative index of the set of the six limb leads. The aim of this study was to evaluate whether ECG lead aVR could function as an index of all limb leads, in clinical electrocardiography.
  
  
  METHODS
  Automation-derived and manually derived QRS voltage amplitude measurements of all limb leads in ECGs of a series of 100 randomly selected consecutive patients, and ECGs of 36 patients with various edematous states (EDST), congestive heart failure (CHF), or undergoing hemodialysis (HD), and aVR were inter-correlated with the sums of leads I and II (SigmaI&II), and the entire set of the six limb leads (Sigma6LbLds).
  
  
  RESULTS
  Correlation of aVR with SigmaI&II and Sigma6LbLds was excellent (P < 0.00005); also, aVR was found to be a reliable index of the six limb leads in repeat ECGs in the patients with various EDST, CHF, or undergoing HD, in whom changes in aVR correlated with changes in patients' body weight.
  
  
  CONCLUSIONS
  aVR could be taken as an index of all ECG limb leads in analysis in general, and in monitoring patients with EDST, CHF, and HD in particular.
authors.affiliation: Mount Sinai School of Medicine of the New York University, Elmhurst Hospital Center, New York, USA. madiasj@nychhc.org
authors.forename: John E
authors.initials: JE
authors.lastname: Madias
mesh_terms: D004487:Edema / Q000175:diagnosis*; D004562:Electrocardiography / Q000379:methods; D004594:Electrophysiology; D006333:Heart Failure / Q000175:diagnosis*; D006801:Humans; D008991:Monitoring, Physiologic / Q000379:methods*; D006435:Renal Dialysis