Is there a functional correlate of Kv1.5 in the ventricle of canine heart and what would it mean for the use of I Kur blockers?

The cardiac ultrarapid outward current I Kur , encoded by KCNA5, is of special pharmacological interest, because it is considered to be atrium‐specific. I Kur has therefore become a target in the therapy of atrial tachyarrhythmias. However, the concept of atrium specificity is only valid if a functional I Kur current is in fact absent from the ventricle. However, new work has detected a I Kur ‐like current in canine ventricular myocytes, sensitive to 4‐aminopyridine and suppressed by the I Kur blocker DPO‐1, findings that support the existence of a functional ventricular I Kur . These indications are, however, indirect and more effort is needed to clarify unequivocally the putative role of an expectedly small I Kur component in the ventricle. British Journal of Pharmacology (2007) 152 , 835–837; doi: 10.1038/sj.bjp.0707463 ; published online 17 September 2007