(1) Background:
Short QT syndrome (SQTS) may result in
sudden cardiac death. So far, no drugs, except
quinidine, have been demonstrated to be effective in some patients with SQTS type 1 (SQTS1). This study was designed to examine the potential effectiveness of
vernakalant for treating SQTS1 patients, using human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with SQTS1. (2) Methods: Patch clamp and
calcium imaging techniques were used to examine the
drug effects. (3) Results:
Vernakalant prolonged the action potential duration (APD) in hiPSC-CMs from a SQTS1-patient (SQTS1-hiPSC-CMs). In spontaneously beating SQTS1-hiPSC-CMs,
vernakalant reduced the
arrhythmia-like events induced by
carbachol plus
epinephrine.
Vernakalant failed to suppress the hERG channel currents but reduced the outward small-conductance
calcium-activated potassium channel current. In addition, it enhanced Na/Ca exchanger currents and late
sodium currents, in agreement with its APD-prolonging effect. (4) Conclusions: The results demonstrated that
vernakalant can prolong APD and reduce
arrhythmia-like events in SQTS1-hiPSC-CMs and may be a candidate
drug for treating arrhythmias in SQTS1-patients.