title: Patients with persistent atrial fibrillation taking oral verapamil exhibit a lower atrial frequency on the ECG.
abstract: BACKGROUND
  While there is agreement that verapamil attenuates the AF- induced refractory period shortening when given before AF induction, controversy exists regarding its effects when given after the onset of persistent AF. This study aimed to compare atrial fibrillatory frequency obtained from the surface ECG in patients with persistent atrial fibrillation (AF) with oral verapamil treatment to those without this treatment.
  
  
  RESULTS
  Surface ECG recordings were performed in 57 patients (34 male, 23 female, mean age 59 +/- 11 years) with persistent AF (> 7 days). The frequency content of the fibrillatory baseline was quantified using digital signal processing (filtering, QRST complex averaging and subtraction, Fourier transformation). In 27 patients with verapamil treatment (120 or 240 mg/day for at least 7 days) mean fibrillatory frequency measured 6.4 +/- 0.2 Hz, compared to 7.0 +/- 0.4 Hz (P = 0.012) in 30 patients without verapamil. In a subset of 20 randomly selected patients (10 with, 10 without verapamil treatment) a 24-hour Holter ECG recording was performed and fibrillatory frequency determined at 4 PM, 10 PM, 4 AM, and 10 AM. While there was a significant frequency reduction in the verapamil treated patients at night (P = 0.011), it remained constant over time in the other patients.
  
  
  CONCLUSIONS
  In patients with persistent AF, fibrillatory frequency assessed by spectral analysis of the surface ECG is lower in patients taking verapamil.
authors.affiliation: Department of Cardiology, University Hospital Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany. andreas.bollmann@medizin.uni-magdeburg.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Bollmann
authors.forename: Kai
authors.initials: K
authors.lastname: Sonne
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Esperer
authors.forename: Ines
authors.initials: I
authors.lastname: Toepffer
authors.forename: Helmut U
authors.initials: HU
authors.lastname: Klein
mesh_terms: D000284:Administration, Oral; D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology*; D002940:Circadian Rhythm; D015716:Electrocardiography, Ambulatory; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D014700:Verapamil / Q000627:therapeutic use*
chemical_list: D000889:Anti-Arrhythmia Agents; D014700:Verapamil