1/🏥It's Your First Night...
Highlights
- 1/🏥It's your first night alone in the CCU
😵💫You admit a patient with syncope due to complete heart block
🕡HR is 30 bpm with a wide ventricular escape rhythm
You wonder if it's time for your first #TVP, but
🔆is it indicated?
🔆& how are you going to set it up for success? https://t.co/QsFjhqeSSZ (View Tweet)
- 2/ Learning Objectives:
🔆Recognize indications for pacing
🔆How to manage TVP/adjust settings (View Tweet)
- 3/ But first let’s start with a huge thank you to @AmitGoyalMG @A_h_ghoneem and @RichardAFerraro for their never-ending guidance and help making this happen! 👏🏼
@CardioNerds 🫀 (View Tweet)
- 4/ The author has no conflicts of interest.
There is no commercial support for this content. (View Tweet)
- 5/ Let's first take a vote 🗳️
I feel comfortable identifying patients who may require a TVP and troubleshooting common TVP problems (View Tweet)
- 6/ What are the most common indications for TVP? 🤔
🔆Bradyarrhythmia à symptoms😵💫or hemodynamic compromise 🏥(eg. sinus bradycardia, 2nd or 3rd degree AV block)
🔆Overdrive pacing (eg. VT, TdP)
🔆Digoxin toxicity💊
🔆PPM Failure
https://t.co/yAEUYzDhAw (View Tweet)
- 7/ So let’s get to know our TVP settings better🤓
For our case, our TVP mode will be VVI
V=Ventricle sensed
V=Ventricle paced
I=pacing Inhibited if native beat is sensed
Vs the other common mode of VOO
V=Ventricle paced
O=not sensed
O=no inhibition of pacing (View Tweet)
- 8/ Although there are different types of generators, they all have the same 3 variables that you can control:
🕑Rate
⚡️Output
⚠️Sensitivity
Let’s start with Rate🕑meaning the number of impulses generated by your TVP/minute
(View Tweet)
- 9/ Next, let’s look at the Output ⚡️which is the current🔌produced by the generator during every beat (measured in milliAmpers, mA)
The⬆️the mA, the⬆️the output
(obvious right? wait until you see what's coming next though😉)
(View Tweet)
- 10/ Finally, let’s talk about Sensitivity ⚠️which is the minimum current 🔌needed to detect native cardiac activity and inhibit pacing 🫀(measured in millivolts, mV)
🚨Don’t be fooled!
The⬇️the mV, the ⬇️ current is needed to be detected by the TVP so the⬆️the sensitivity!
(View Tweet)
- 11/ To make sure we really understand the concept of sensitivity ⚠️
Let’s look at our favorite sensitivity analogy where you’re the pacer trying to see the QRS complex from behind a fence 👇🏻
Fence = mV
(View Tweet)
- 12/ 🚨So let’s go back to the CCU!
Your patient now has a TVP, rate is set at 60 bpm, output 10, sensitivity 8, but you see this on tele 👇🏻
So,
What is the problem?🤔
What are potential causes? 📋
How can you troubleshoot it? 🔧
(View Tweet)
- 13/ 🚨Prob = undersensing ⚠️
Pacer doesn’t detect intracardiac signal🫀(native QRS) ➡️asynchronous pacing
Possible causes➡️low sensitivity (fence too high), electrolyte abnormality, lead failure (View Tweet)
- 14/ ✅ How to correct?
⬆️sensitivity by ⬇️mV, this allows pacer to detect more cardiac signals🫀
Review reversible causes such as electrolytes🩸
Check hardware (lead placement)🛠️
(View Tweet)
- 15/ You ⬆️sensitivity from 8 mV to 7 mV ➡️you are no longer seeing asynchronous pacing (no inappropriate pacing spikes after native QRS)
You cut down mV to roughly half (7 mV ➡️4 mV) and perfecto!👌🏼
Your patient is being paced at a rate of 60 bpm and feels great!👏🏼 (View Tweet)
- 16/ Congratulations! First curveball dodged!
But now, your patient’s tele shows this 👇🏻
So, let’s try this again
What is the problem?🤔
What are potential causes? 📋
How can you troubleshoot it? 🔧
(View Tweet)
- 17/ 🚨Prob = capture 🥅 failure
An impulse is generated by pacer but it does not cause myocardial depolarization🫀
(pacing spikes not followed by QRS complexes)
Possible causes➡️lead dislodgment, low output (View Tweet)
- 18/ ✅ How to correct?
Increase output⚡️by increasing mA
Check lead positioning (View Tweet)
- 19/You ⬆️ output from 10 mA to 12 mA ➡️ each pacing spike is now followed by a QRS complex (capture achieved! 👏🏼)
You double your output to 24 mA, and the patient feels great! 🥳
But why do you need such a high output? 🤔
Check your lead position, it probably moved! (View Tweet)
- 20/ Amazing job so far! But wait, you now look at tele and you see this 👇🏻
Your patient is in complete heart block again! And there are no pacing spikes at all! 💔
So, one last time folks 🦾
What is the problem?🤔
What are potential causes? 📋
How can you troubleshoot it? 🔧
(View Tweet)
- 21/ it could be one of two problems:
DDx 1: Oversensing ⚠️
Pacer senses signals it shouldn’t (eg. T waves or P waves) thinking they are QRS complexes ➡️ inappropriate inhibition of pacing
Possible causes➡️ high sensitivity (fence too low), lead failure (View Tweet)
- 22/ 🚨DDx 2: output⚡️failure
Native HR < set rate🕑, but still no pacing
(no pacing spikes when there should be pacing spikes)
Possible causes ➡️lead failure, generator failure, battery failure, oversensing (View Tweet)
- 23/ So how can you trouble shoot? 🔧
⬇️ sensitivity by ⬆️ mV (bring the fence up), will overcome both DDx!
Check hardware (as below) 🛠️
(View Tweet)
- 24/ General check list 📜to go through when troubleshooting🧑🏻🔧
-generator on? 🔛
-Battery low? 🪫
-Wires attached well?
-Leads connected?🔌
-Could the TVP wire have been displaced? (View Tweet)
- 25/ So lets ask again now 👀
I feel comfortable identifying patients who may require a TVP and troubleshooting common TVP problems🦸🏾♀️ (View Tweet)
- 26/ I learned something in this Tweetorial that may change my clinical practice🤓 (View Tweet)
- 27/ Congratulations on making it to the end of this thread and for keeping your patient alive in the CCU! 🥳
Thank you so much for listening and hope you learned something new from this little tweetorial 📚
#Cardiotwitter #TVP https://t.co/uyerJsYqjl (View Tweet)