This 89-year-old female has presented with collapse and facial trauma. She has lived in a care home for the past 5 years. Despite having lived independently up until then, she was incapable of doing so after suffering from a stroke. She has since developed dementia. She can still mobilise short distances with the aid of a walking frame.
Over the last month, she has become increasingly fatigued and short of breath. This was attributed to a recent COVID-19 infection.
This morning, while mobilising to the toilet, she collapsed to the floor. She struck her head against the corner of a wall, resulting in a nasty laceration above her eye.
The care home staff called for an ambulance. When the paramedics arrived, she was still on the floor but conscious. She was very confused. Staff were applying pressure to a 6 cm laceration above her left eye that was bleeding profusely.
Her vital signs were:
She was attached to a 5-lead cardiac monitor and her ECG rhythm is shown in Figure 1.
What does the ECG show?
Interpretation of the ECG rhythm
This rhythm is third-degree atrioventricular block or complete heart block.
Not all P waves are visible. However, P waves will generally appear at regular intervals. So, if you lay a piece of paper across the rhythm and mark off any obvious P waves, you should then be able to identify any that are ‘hidden’ behind QRS complexes.
This lady was admitted to the emergency department. Her head wound required eight stitches. Cardiac monitoring was commenced.
Several hours after admission, she experienced a further unresponsive episode, this time while lying in her bed. Her ECG rhythm at the time is shown in Figure 2.
Initially, the heart rhythm shows second-degree AV block type 2, with two P waves for every QRS complex. However, she quickly deteriorates to an episode of ventricular standstill, with a succession of P waves and no ventricular response.
She was commenced on an intravenous infusion of isoprenaline. This is a non-selective beta adrenergic receptor agonist. Isoprenaline stimulates both β1 and β2 adrenoceptors producing an increase in cardiac output by increasing both myocardial contractility and heart rate. It can provide a useful bridge to maintain a patient's heart rate while they await a permanent cardiac pacemaker implant.
This lady had a permanent pacemaker implanted the next day and was discharged back to her care home 2 days later.