One day GB reports to you for exercise and when taking hisresting blood pressure and pulse note his blood pressure is 118/64,his pulse rate is 150 and highly irregular.  GB indicateshe has felt very weak and tired lately almost didn’t show up toexercise.   You refer him to his physician whoobtains an ECG and determines he has atrial fibrillation.

1. What physiological mechanisms caused GB’s pulse rate to be highand irregular and his blood pressure low?

1. What specifically, about atrial fibrillation makes the patientfeel very weak and tired?

The physician prescribes dofetilide to try to convert GB back tosinus rhythm.  

1. What is meant by “sinus rhythm”? Any cardiac rhythm in whichdepolarization of the cardiac muscle begins at the sinus node.Characterized by the presence of correctly oriented P waves on anECG.

1. What type of drug is dofetilide and what is the mechanism ofaction to convert atrial fibrillation to sinus rhythm.

The physician is unsuccessful at converting  GB backto sinus rhythm with the drug so he his placed on chronic therapyof metoprolol and warfarin.

1. What types of drugs are metoprolol and warfarin and what is thespecific mechanism of action used to help treat patients withatrial fibrillation?

1. What are specific things to keep in mind when safelyprescribing and monitoring exercise for GB?