TRPM4 and chronic obstructive pulmonary disease: TRPM4 inhibition with 9-phenanthrol also mimicked the reduction of action potential duration evoked by TRPM4 deletion in atrial cells (Simard et al., 2013) and reverted the early after-depolarization involved in cardiac arrhythmias observed after a process of hypoxia and re-oxygenation (Simard et al., 2012).