Attenuation of electrical remodelling in chronic atrial fibrillation following oral treatment with verapamil.
OBJECTIVE
Electrical remodelling with shortening of the atrial refractory period and increased fibrillatory rate occurs after onset of atrial fibrillation and can be attenuated by pre-treatment with intravenous verapamil. The aim of the present study was to investigate whether already established fibrillatory-induced shortening of atrial fibrillatory cycle length could be reversed with oral verapamil.


RESULTS
Thirteen patients (nine men; mean age 67 years) with chronic atrial fibrillation (CAF) were studied. The dominant atrial cycle length (DACL) was estimated non-invasively using the frequency analysis of fibrillatory ECG (FAF-ECG) method. Measurements were repeated following treatment with slow release oral verapamil. DACL increased from 147 +/- 13 ms to 156 +/- 21 ms after 1 day (P=0.02), to 164 +/- 18 ms after 5 days (P=0.005) and finally to 160 +/- 16 ms after 6 weeks (P=0.008).


CONCLUSIONS
Long-term oral treatment with verapamil increases the DACL significantly in patients with CAF. The prolongation is evident after 1 day and is further developed during the first 5 days of treatment. Since DACL is believed to be an index of refractoriness, the findings of the present study suggest that this treatment increases the atrial refractory period in patients with CAF.
Meurling
C J
CJ
Department of Cardiology, Lund University, Sweden.
Ingemansson
M P
MP
Roijer
A
A
Carlson
J
J
Lindholm
C J
CJ
Smideberg
B
B
Sornmo
L
L
Stridh
M
M
Olsson
S B
SB
D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000503:physiopathology*; D001794:Blood Pressure / Q000187:drug effects; D002908:Chronic Disease; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D014700:Verapamil / Q000494:pharmacology* / Q000627:therapeutic use
D000889:Anti-Arrhythmia Agents; D014700:Verapamil