Click on ECG to enlarge
An 80 year old presented with mild nausea and shortness of breath. His vital signs were normal other than the tachycardia.
He had a history of chronic atrial fibrillation, moderate chronic kidney disease and type 2 diabetes.
This ECG was given to a doctor to interpret
The doctor correctly identified that there were no signs of an MI, signed off the ECG and left the patient in the queue to be seen.
An hour later the patient was seen by another doctor. By this time the patient’s heart rate was still 170, his blood pressure was sagging and the was febrile.
10 minutes later the patient’s blood pressure was 80/60.
His lactate was 6.0
No septic source was found but the patient had a history of multiple abdominal surgeries and a colostomy and similar episodes which grew enteric bacteria. It is presumed that he has episodic bacteraemia from his gut. The surgeons understandably were not keen to go hunting for a surgical remedy.
He was started on broad spectrum antibiotics to cover gut flora (cefuroxime and metronidazole), given IV fluids and started immediately on a vasopressor.
We chose to use phenylephrine in the hope that it’s alpha receptor agonism would cause vasoconstriction and cause a reflex drop in heart rate (rather than using a mixed alpha and beta agonist such as noradrenaline). You could equally argue that noradrenaline would give some Beta 1 mediated inotropy which may have increased cardiac output and thus led to a decreased heart rate. Often it is trail and error to see what works for a particular patient.
A vasporessor was used straight away as it was thought an 80 year old heart would not tolerate sepsis and a HR of 170 for long.
This patient’s heart rate and BP improved fairly quickly but if they hadn’t we get into the tricky situation of needing a negative chronotrope (to reduce the rate) but most negative chronotropes also drop the blood pressure. In this setting most clinicians will use diltiazem, though a beta blocker has as much evidence for it. Some will use IV digoxin, though most argue this takes too long to work.
Moral of the story
Engage your brain when reading ECGs.
You are not only looking for myocardial ischaemia – ECGs can tell us a lot about other badness.
This ECG was screaming “This patient is sick, or is going to become sick very soon”
Old hearts can not tolerate going at 170/min for long. This is an old cardiovascular system attempting to compensate for badness, maxed out and about to decompensate.
For someone in fast AF always looks for a driver eg sepsis, congestive heart failure, thyrotoxicosis (rare and it is debated whether we should look for it).
This ECG should have led to a fairly immediate bedside review of the patient.
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