Palpitations and Testing: A Lesson About Clinical Decision Rules

Real cases inspired the following story. I changed some of the details for patients’ privacy.

I saw a young lady complaining of palpitations early one morning in the ER. The palpitations started gradually, an hour or two before presentation. 

She denied chest pain, SOB, leg swelling, recent travel, oral contraceptives, and recent surgery. 

She was tachycardic, but otherwise had a normal cardiac exam, normal pulmonary exam, clear speech, and  normal gait. 

Her EKG showed sinus tachycardia with a rate of 103 bpm, normal intervals, no ST segment deviation, and normal T waves. 

I did Wells score for pulmonary embolism, and then talked to the patient and her boyfriend about my plan for testing. 

As I talked to them further, she revealed that earlier this morning she drank several, high-caffeine energy drinks to stay awake after coming back from a nightclub at about 4 AM. About half an hour after the energy drinks she began feeling the palpitations. She was also feeling a little jittery and had fine tremors. All the pieces now fit. She had a mild caffeine overdose. I discharged her home and to the caffeine wear off. I declined her request for a sleep aid.

Clinical decision rules like the Wells score are useful tools. However, we have to recognize their limitations. These rules do not take into account every possible situation. Clinical decision rules are supposed to help your clinical judgement, not supersede it. Think about it this way: 

They are your tools, you are not their tool.

For trainees, I usually advise using clinical decision rules as a starting point to help organize their diagnostic thought process. The rules give some structure tp the often-jumbled data the patients can give. Remember that:

The rules are not necessarily an end, but a beginning.

As usesful as the clinical decision rules are, remember their limitations.

If you are interested in this topic or other topics related to medical decision making, check out my previous post on Clinical Decision Rules and my book A Guide to Clinical Decision Making.