title: Electrocardiogram voltage discordance: interpretation of low QRS voltage only in the limb leads.
abstract: BACKGROUND
  Low voltage on the surface electrocardiogram (ECG) is defined as QRS voltage less than 5 mm in all limb leads and less than 10 mm in all precordial leads. The clinical correlate of an ECG with low voltage in the limb leads but normal precordial QRS amplitudes is unclear.
  
  
  METHODS
  Twelve-lead ECGs with QRS voltage less than 5 mm in all limb leads and more than 10 mm in at least 2 contiguous precordial leads were collected. Presence of clinical conditions associated with low voltage was determined from clinical data and chest imaging.
  
  
  RESULTS
  Fifty-one of 100 patients had voltage discordant ECGs that correlated with conditions known to cause diffuse low voltage. Among those without associated conditions, 63% had dilated ventricles, with an average ejection fraction of 33%.
  
  
  CONCLUSIONS
  Low voltage isolated to the limb leads is associated with the same conditions that cause diffuse low voltage in only half of patients. In the remainder, more than 60% have dilated cardiomyopathies.
authors: University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
authors: Jason S
authors: JS
authors: Chinitz
authors: Joshua M
authors: JM
authors: Cooper
authors: Ralph J
authors: RJ
authors: Verdino
mesh_terms: D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000295:instrumentation* / Q000379:methods*; D004566:Electrodes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*; D018497:Ventricular Dysfunction, Right / Q000175:diagnosis*