title: Exploratory insights from the right-sided electrocardiogram following prolonged endurance exercise.
abstract: BACKGROUND
  Prolonged strenuous exercise has a profound effect on cardiac function. The right heart may be more susceptible to this imposition; yet, right-sided chest leads have not been utilised in this setting.
  
  
  METHODS
  Thirty highly trained athletes at the 2014 Western States 100-mile Endurance Run from Squaw Valley to Auburn, California (body mass 68 ± 12 kg, age 45 ± 10 years, 57 ± 15 miles per week) were recruited for the study. Pre- and post-race, a right-sided 12-lead ECG was obtained and data were extracted for P, R and S waves, J point, ST segment and T wave amplitude. Data were compared using Students T-test and statistical significance set as P < .05.
  
  
  RESULTS
  There was a significant increase in P wave amplitude (29%) and QTc interval (4%) pre- to post-race from standard 12-lead ECG. From the right-sided12-lead ECG, a 23% (P = .01) and 38% (P = .03) increase in J point amplitude in V1R and V2R and a 22% (P = .05) increase in ST segment integral in V2R and V3R were evident. T wave inversion was evident in leads V2R-V6R in 50-90% of athletes, respectively. Close examination revealed marked heterogeneity in individual ECGs.
  
  
  CONCLUSIONS
  Completion of a 100-mile ultra-marathon resulted in significant changes in the right-sided ECG alongside more marked responses in specific individuals. P wave, ST segment and T wave changes post-race are indicative of acute exercise-induced right heart electrical adaptation.
authors.affiliation: a Research Institute for Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Lord
authors.affiliation: a Research Institute for Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , UK.
authors.forename: Keith
authors.initials: K
authors.lastname: George
authors.affiliation: a Research Institute for Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , UK.|b Countess of Chester Hospital, NHS Trust , Chester , UK.
authors.forename: John
authors.initials: J
authors.lastname: Somauroo
authors.affiliation: c Falk Cardiovascular Research Center , Stanford University School of Medicine , Stanford , CA , USA.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Jain
authors.affiliation: c Falk Cardiovascular Research Center , Stanford University School of Medicine , Stanford , CA , USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Reese
authors.affiliation: d Department of Physical Medicine & Rehabilitatiion , University of California Davis Medical Center , Sacramento , CA , USA.
authors.forename: Martin D
authors.initials: MD
authors.lastname: Hoffman
authors.affiliation: c Falk Cardiovascular Research Center , Stanford University School of Medicine , Stanford , CA , USA.
authors.forename: Francois
authors.initials: F
authors.lastname: Haddad
authors.affiliation: c Falk Cardiovascular Research Center , Stanford University School of Medicine , Stanford , CA , USA.
authors.forename: Euan
authors.initials: E
authors.lastname: Ashley
authors.affiliation: a Research Institute for Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Jones
authors.affiliation: a Research Institute for Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , UK.
authors.forename: David
authors.initials: D
authors.lastname: Oxborough
mesh_terms: D000328:Adult; D056352:Athletes; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology*
keywords: Electrocardiogram; prolonged endurance exercise; right-sided ECG