The present invention relates to methods for the treatment of conditions characterised by abnormalities of myocardial cell ion levels, such as Na<;SUP>;+<;/SUP>;, K<;SUP>;+<;/SUP>; and Ca<;SUP>;2+<;/SUP>; ions. The present invention also relates to methods of treatment of heart failure and myocardial hypertrophy. The invention also relates to compounds and compositions, such as beta<;SUB>;3 <;/SUB>;adrenoceptor agonists, useful in the treatment of mammals, particularly humans, having a condition characterised by abnormalities of myocardial cell ion levels, such as Na<;SUP>;+<;/SUP>;, K<;SUP>;+<;/SUP>; and Ca<;SUP>;2+<;/SUP>; ions, including heart failure and myocardial hypertrophy.