March 15, 1995Circulation
Ibutilide, a Methanesulfonanilide Antiarrhythmic, Is a Potent Blocker of the Rapidly Activating Delayed Rectifier K+Current (IKr) in AT-1 Cells
Key result
Ibutilide and dofetilide were both potent IKr blockers in mouse atrial tumor myocytes, with EC50 values of 20 nmol/L and 12 nmol/L, respectively.
Authors
Discussion
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Implication
These EC50 values in murine AT-1 cells warrant no clinical change; leaves open translation to human IKr and arrhythmia risk.
PICO
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Population
In vitro study on 20 mouse atrial tumor myocytes (AT-1 cells) comparing the IKr blocking effects of ibutilide and dofetilide.
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Intervention / Comparator
Ibutilide vs Dofetilide
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Primary Outcome
EC50 for IKr block at +20 mV (nmol/L)
Main Result
Absolute Event Rate: 20% vs 12%
Limitations
- An effect on inward currents is not excluded.
Cite This Study
Yang et al. (1995) studied this question. Ibutilide vs. Dofetilide was evaluated on EC50 for IKr block at +20 mV (nmol/L). Ibutilide and dofetilide were both potent IKr blockers in mouse atrial tumor myocytes, with EC50 values of 20 nmol/L and 12 nmol/L, respectively.