title: Variable interatrial conduction illustrated in a hypertrophic cardiomyopathy population.
abstract: BACKGROUND
  Patients with hypertrophic cardiomyopathy (HCM) have a high incidence of atrial fibrillation. They also have a longer P-wave duration than healthy controls, indicating conduction alterations. Previous studies have demonstrated orthogonal P-wave morphology alterations in patients with paroxysmal atrial fibrillation. In the present study, the P-wave morphology of patients with HCM was compared with that of matched controls in order to explore the nature of the atrial conduction alterations.
  
  
  RESULTS
  A total of 65 patients (45 men, mean age 49 +/- 15) with HCM were included. The control population (n = 65) was age and gender matched (45 men, mean age 49 +/- 15). Five minutes of 12-lead ECG was recorded. The data were subsequently transformed to orthogonal lead data, and unfiltered signal-averaged P-wave analysis was performed. The P-wave duration was longer in the HCM patients compared to the controls (149 +/- 22 vs 130 +/- 16 ms, P < 0.0001). Examination of the P-wave morphology demonstrated changes in conduction patterns compatible with interatrial conduction block of varying severity in both groups, but a higher degree of interatrial block seen in the HCM population. These changes were most prominent in the Leads Y and Z.
  
  
  CONCLUSIONS
  The present study suggests that the longer P-wave duration observed in HCM patients may be explained by a higher prevalence of block in one or more of the interatrial conduction routes.
authors.affiliation: Department of Cardiology, Lund University Hospital, Lund, Sweden. fredrik.holmqvist@med.lu.se
authors.forename: Fredrik
authors.initials: F
authors.lastname: Holmqvist
authors.forename: Pyotr G
authors.initials: PG
authors.lastname: Platonov
authors.forename: Jonas
authors.initials: J
authors.lastname: Carlson
authors.forename: Rasmus
authors.initials: R
authors.lastname: Havmöller
authors.forename: Johan E P
authors.initials: JE
authors.lastname: Waktare
authors.forename: William J
authors.initials: WJ
authors.lastname: McKenna
authors.forename: S Bertil
authors.initials: SB
authors.lastname: Olsson
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Meurling
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D004452:Echocardiography; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted