Premium
Effect of Atrial Electrical Remodeling on the Efficacy of Antiarrhythmic Drugs: Comparison of Amiodarone with I Kr ‐ and I to /IKur‐Blockade In Vivo
Author(s) -
LINZ DOMINIK K.,
AFKHAM FRENI,
ITTER GABI,
RÜTTEN HARTMUT,
WIRTH KLAUS J.
Publication year - 2007
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2007.00962.x
Subject(s) - amiodarone , medicine , dofetilide , atrial fibrillation , cardiology , ventricle , sinus rhythm , blockade , antiarrhythmic agent , refractory (planetary science) , refractory period , anesthesia , heart disease , receptor , physics , astrobiology
Amiodarone is the gold standard in the prevention of recurrence of atrial fibrillation (AF), but the causes for its superior clinical efficacy are not understood. We hypothesized that atrial electrical remodeling increases the atrial efficacy of amiodarone. Methods and Results: We investigated the effect of an acute intravenous dose of amiodarone on atrial refractory periods (AERP) in sinus rhythm (SR) and after 5, 24, and 72 hours of atrial tachypacing in comparison with the I Kr blocker dofetilide and the I to /IKur blockers AVE1231 and AVE0118 in five instrumented goats. Electrical remodeling progressively increased the AERP‐prolonging effect of 3 mg/kg of AVE1231 and AVE0118 (2‐fold increase in AERP at 72 hours vs SR, P < 0.01), but strongly decreased that of 10 μg/kg dofetilide (<0.5‐fold, P < 0.05, at 300 and 400 ms basic cycle length). After 5 and 24 hours of tachypacing, the effect of 3 mg/kg amiodarone strongly increased (2‐fold, P < 0.01 after 24 hours vs SR). This early gain in AERP prolongation was confirmed in anesthetized pigs with 3.5 hours of atrial tachypacing (2.4‐fold increase, P < 0.01). At 72 hours of atrial tachypacing in the goat, however, the early gain was lost and the effect of amiodarone was similar again to that in SR. Conclusion: Atrial electrical remodeling changed the efficacy of the antiarrhythmic agents in a different way. The favorable efficacy profile of amiodarone during electrical remodeling, particularly the marked increase in AERP prolongation in early electrical remodeling, may explain its superior clinical efficacy over existing antiarrhythmic drugs.