The physician asks to repeat the pacing protocol that induced tachycardia… and you give them a blank stare. After the procedure, the dictating physician asks what the HV interval was… and you have no clue. This has most likely happened to all of us at one point in time in which we were put on the spot, but due to lack of documentation, we’re unable to respond. As common as this problem is, it is ridiculous that the solution is so easy. All that is needed is proper documentation.
Having a routine is very helpful, especially to those newer to EP. So, start a good documentation habit now so you don’t get caught like a deer in the headlights. As soon as the patient is connected to the 12-lead ECG, I recommend taking a recording. This baseline ECG may need to be referred to during the procedure for comparison of P waves or QRS complexes in tachycardia. It may also be compared to during or after the case to be sure there was no harm caused to the patient such as ST elevation or a long PR interval. This is also a good time to start the auto-record feature. Once, I was halfway through the EP study when I realized that I did not turn on auto-record and none of the information thus far had been saved…Grr – learn from my mistakes.
If the patient is in the lab for a PVC or VT procedure, begin the Holter monitor recording function if available or at least mark any spontaneous PVCs. This may be very beneficial as many times when the patient has sedation the PVCs may be suppressed making it impossible for activation mapping. In this case, the recorded PVC template may still be utilized for pace mapping.
The next step in documentation is as soon as the catheters are inserted. Once a His signal is observed, note or save the recorded electrogram. A better His recording may be acquired later; however, the His signal is sometimes challenging to find, so I don’t want to lose the opportunity when it is presented. When all of the catheters are in the correct position, save a baseline electrogram. This is a good time to measure and document the baseline intervals.
During the EP study, you will document AV/VA block and tissue ERPs. Document the pacing protocol used when jumps, echo beats, or activation changes are observed. You can always go back into the case log or scroll through the recording if a measurement is missed, but this may be very time-consuming. The pacing protocol that was used to induce the tachycardia should be documented as well as whether or not the patient was on Isoproterenol. The tachycardia cycle length will be needed to know the proper pacing rate for various differential pacing maneuvers and to notice any changes in the rate. If in doubt – document.
Documentation may be performed in the EP recording system itself, and in many systems, a report may be printed off for the physician. However, I still like to have a physical worksheet to write on. We (EP Essentials) created a documentation sheet for this purpose. This is very beneficial for a quick recall of information as well as for the physician to use for dictation. It is not only for the recorded measurements but also for any other procedural information that they may need. This particular worksheet also has additional information on how to make measurements and normal values. Feel free to print this off to utilize in your lab and begin a good documentation routine so you don’t have to worry about being caught off guard.
This week’s EP question:
This sweep speed works best for intracardiac measurements.
- 25 mm/sec
- 100 mm/sec
- 200 mm/sec
- 400 mm/sec
Answer
200 mm/sec
A sweep speed (screen recording speed) of 25 ms is utilized in recording a standard ECG. However, in electrophysiology, a sweep speed of 100 to 200 is more appropriate. For detailed measurements of the intracardiac intervals such as the AH and HV intervals, 200 ms is the best choice. This will help separate the waveforms for clear measurements. During decremental pacing, a sweep speed of 100 ms may be helpful to observe block; however, it may be challenging to accurately measure.
Notice the different sweep speeds in the following example.
