Compositions and methods for identifying altered effectiveness of beta blocker therapy

A method of identifying and treating a subject having an increased risk of an altered effectiveness of beta blocker therapy to prevent/ameliorate postoperative atrial fibrillation during and/or after coronary artery bypass grafting surgery, comprising:

• a) obtaining a nucleic acid sample from a subject undergoing coronary artery bypass grafting surgery;
• b) detecting in the nucleic acid sample of the subject the presence of:
• i) an A allele at single nucleotide polymorphism rs3740563;
• ii) an A allele at single nucleotide polymorphism rs4752292;
• iii) an A allele at single nucleotide polymorphism rs11198893;
• iv) an A allele at single nucleotide polymorphism rs10787959;
• or
• v) any combination of (i) through (iv) above;
• c) identifying the subject as having an increased risk of altered effectiveness of beta blocker therapy;
• and
• d) administering treatment to said subject identified in step c) as having an increased risk of altered effectiveness of beta blocker therapy, wherein the treatment comprises administration of a nondihydropiridine calcium channel blocker and/or amiodarone to prevent/ameliorate postoperative atrial fibrillation, during and/or after coronary artery bypass grafting surgery.