Question

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

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

2. What specifically, about atrial fibrillation makes the patient feel very weak and tired?

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

3. What is meant by “sinus rhythm”? Any cardiac rhythm in which depolarization of the cardiac muscle begins at the sinus node. Characterized by the presence of correctly oriented P waves on an ECG.

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

The physician is unsuccessful at converting  GB back to sinus rhythm with the drug so he his placed on chronic therapy of metoprolol and warfarin.

5. What types of drugs are metoprolol and warfarin and what is the specific mechanism of action used to help treat patients with atrial fibrillation?

6. What are specific things to keep in mind when safely prescribing and monitoring exercise for GB?

Answer 1