CARDIAC BOOTCAMP CASE
A 78 year old man is brought to your emergency department after collapsing at the local shopping centre that morning. He is now alert with no memory of the event. His observations are normal.
What does the ECG show?
( This case is taken from an old Fellowship Exam paper)
What does the ECG show?
( This case is taken from an old Fellowship Exam paper)
The obvious things to pick up here are (a more detailed approach would use the ECG in 20 Seconds Method):
The underlying rhythm is a MOBITZ II with a variable block. In the first part of the ecg, (after the first 3 QRS complexes) there are 2 P waves for one QRS, so this is a 2:1 block. Following complex number 6, there are 3 P waves for one QRS, so this is a 3:1 block.
PACING SPIKES
It's important to remember that we are not always be able to see pacing spikes. They may also not be visible in all leads. In this ecg, pacing spikes seen in lead V6 are not seen in lead II. Always look at all leads in an ecg for evidence of pacing spikes(the last step in the ECG in 20 seconds Approach). There are no pacing spikes in this ECG until we get to the last third of the tracing. See below.
A pacemaker really only does a few things. It may sense and inhibit complexes etc., but the basics are:
- The dropped QRS Complexes and the
- Pacemaker spikes
The underlying rhythm is a MOBITZ II with a variable block. In the first part of the ecg, (after the first 3 QRS complexes) there are 2 P waves for one QRS, so this is a 2:1 block. Following complex number 6, there are 3 P waves for one QRS, so this is a 3:1 block.
PACING SPIKES
It's important to remember that we are not always be able to see pacing spikes. They may also not be visible in all leads. In this ecg, pacing spikes seen in lead V6 are not seen in lead II. Always look at all leads in an ecg for evidence of pacing spikes(the last step in the ECG in 20 seconds Approach). There are no pacing spikes in this ECG until we get to the last third of the tracing. See below.
A pacemaker really only does a few things. It may sense and inhibit complexes etc., but the basics are:
- It delivers a pacing spike
- The pacing spike(energy) is captured by the cardiac chamber and an impulse is generated
Review of the pacemaker behaviour in this ECG
The main issues with pacemakers are:
In this case we see that following the patients native rhythm, in the first few complexes, the pacemaker senses that there are less than the required cardiac contractions, so delivers pacing impulses. Those impulses or pacing spikes are conducted. However there is no capture in some cases ie., no response to the pacing spike, so this is a Failure to Capture.
This is a lead issue. The main lead issues that occur are:
- Failure to PACE
- Failure to CAPTURE
- Failure to SENSE
In this case we see that following the patients native rhythm, in the first few complexes, the pacemaker senses that there are less than the required cardiac contractions, so delivers pacing impulses. Those impulses or pacing spikes are conducted. However there is no capture in some cases ie., no response to the pacing spike, so this is a Failure to Capture.
This is a lead issue. The main lead issues that occur are:
- Lead fracture
- Insulation breach
- Lead dislodgement
Where to from here?
- It's important to understand the nomenclature of pacemakers.
- What is a VVI pacemaker or an AAI or a VVIRP. It's confusing, but important.
- You must know about
- pacemaker syndrome and
- pacemaker-induced tachycardia and the
- Runaway pacemaker.
- How do you use a magnet?
Cardiac Bootcamp Self Study Course Members, go to the pacemaker section for some quick case studies.