Key result
Action potential triangulation accelerates L-type calcium channel recovery from inactivation (normalized reactivation currents 0.21 vs 0.14), leading to membrane potential instability capable of initiating torsade de pointes.
Population
Guinea pig and rabbit left ventricular single myocytes
Comparison
Action potential triangulation and dofetilide vs Square-like AP
Design
Preclinical
Authors
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Triangulation may promote TdP via faster calcium recovery in animals; leaves open relevance to human proarrhythmia risk assessment.
Absolute Event Rate: 0.21% vs 0.14%
Action potential triangulation accelerates L-type calcium channel recovery from inactivation, leading to repolarization instability and potential initiation of torsade de pointes.
Guo et al. (2007) studied Arrhythmogenesis / Torsade de pointes. Action potential triangulation (triangular waveform clamping) vs. Square waveform clamping was evaluated on Normalized I(Ca-L) instant reactivation currents at -40 mV. Action potential triangulation accelerates L-type calcium channel recovery from inactivation (normalized reactivation currents 0.21 vs 0.14), leading to membrane potential instability capable of initiating torsade de pointes.
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