CFTR and cystic fibrosis: However, the role of dysfunctional CFTR in the pathogenesis of myocardial complications in patients with CF seems unjustified as recent evidence suggests that the quantity of CFTR ion channel expressed in human myocardial tissue (atrial and ventricular) might be physiologically inadequate to activate obvious cyclic adenosine monophosphate (cAMP)-dependent Cl- conductance [17,18].