Atrial fibrillation (Afib) is a new onset of irregular heart beat. It can occur with either a normal heart rate or with an increase heart rate known as rapid ventricular response (RVR). From my experience this most commonly occurs post op from a post anesthesia hyper-sympathetic surge following anesthesia. Other causes include but are not limited to thyroxocosis, enlarged atrium, infection, heart failure and chronic pulmonary diseases such as COPD. In this case, since this post op patient was stable, I slowed the heart with medicine and moved the patient to telemetry. The patient’s irregular heart rate broke by the morning. Classic.
Remember the first question to ask is, “is the patient stable?” In this case, the patient was stable and I used meds. However, if you feel the patient is going to die in the next 5 minutes, they are UNSTABLE and need immediate cardioversion. If they are alive and unstable meaning they have a pulse but low blood pressure, diaphoresis and have altered mental status and you’re going to shock them but be sure to use a synchronized shock to avoid an R on T phenomenon. not common.
When the patient is stable with a RVR, we need a negative chronotrope or something to slow the heart rate down. Diltiazem is most commonly used as a 0.25 mg/kg bolus, then either a drip or given orally. We also have to address the possibility that the patient may develop blood clots. Not all patients who develop atrial fibrillation convert spontaneously back to sinus rhythm. To evaluate the risk of blood clots, and whether we should put a patient on blood thinners, we would use the CHADS2 score.
S=Stroke – which gives you 2 points.
If your CHADS2 is equal or greater than 2, you earned yourself anticoagulation.
If your CHADS2 score is under 2….use aspirin.
It also needs to be questioned if the patient can be converted back to sinus rhythm. Here, we ask how long they have been in Afib. If greater than 48 hours, we take pause. If less than 48 hours, we can consider cardioversion electively.
Summary with Afib:
1) Keep heart rate slow
2) Prevent clots – ? anticoagulation
3) Sinus rhythm? – can or should we cardiovert?