Pick Up the Pace: TVP for the Emergency Physician
April 2024
Author: Dr. Maria Mosley-Colón, MD PGY3
Peer Reviewers: Dr. Reena Sheth MD PGY3, Dr. Charles Pan MD PGY4
Faculty Editor: Dr. Adam Blumenberg, Assistant Professor of Emergency Medicine at Columbia University Medical Center
The authors of this article have no financial or industry relationships to disclose.
Case 1: An 80-year-old male with a past medical history of anemia and BPH is brought in by EMS following a fall. The patient’s wife reports he was walking to the bathroom when he suddenly fell to the ground. The patient endorses loss of consciousness and denies any prodromal symptoms prior to the fall, stating “I wouldn’t have even known that I passed out except that I woke up on the floor.” His wife also notes that for the past three days, he has had intermittent episodes of an uncomfortable sensation in his chest. During these seconds-long episodes, he makes a gasping noise, stops speaking, and sometimes exhibits shaking movements of the upper extremities. She is concerned that he may be having seizures.
While in the ED, the patient is noted to have a sinus pause on telemetry lasting up to 13 seconds, with associated myoclonic jerking. He immediately returns to a normal mental status following this pause.
————
Case 2: A 75-year-old male with a past medical history of HTN, HLD, and right bundle branch block is brought in by EMS after they were called for two days of fatigue, lightheadedness, and decreased alertness. Upon EMS arrival, the patient was found to be bradycardic to a rate of 32 bpm. External pacing pads were placed and transcutaneous pacing was initiated. En route, mechanical capture was noted to be inconsistent and intermittent. On arrival to the ED, a 12-lead EKG is obtained and shows complete heart block.
————
In both these cases, the ED team decided to proceed with transvenous pacer (TVP) insertion.
I. Background
Transvenous pacer (TVP) insertion is an important but infrequently utilized skill for emergency physicians. Lack of familiarity with the procedure and necessary equipment are sometimes perceived as obstacles. Despite these perceived obstacles, emergency physicians have high (> 95%) success rates with transvenous pacer insertion.[6]
II. Indications
The most common indications for transvenous pacing include:
Unstable bradycardia (typically second-degree Mobitz II AV block or complete heart block)
Sick sinus syndrome with sinus pauses
Unstable tachydysrhythmias requiring overdrive pacing
Failure of transcutaneous pacing
TVP insertion should generally be performed in conjunction with cardiology consultation when available.
III. Equipment
1. Pacing Generator (The “Box”)
Tranvenous pacing requires the use of a pacing generator which delivers electrical current to the heart. These generators come with a long, non-sterile wire to connect the generator box itself to wires from the pacing catheter (more on this later). The possible settings on the “box” are a frequent source of intimidation for the uninitiated, so let’s go over them here.
MODES: Pacing generators have numerous “modes” of pacing. The most commonly utilized and relevant options for the emergency physician are asynchronous pacing (such as DOO) and VVI. The “code” representing a pacer mode can have up to five characters, but for our purposes, only the first three need be considered.
DOO is typically the default setting when the pacing box first starts up. Many generators also have a red “emergency” button that converts the generator to DOO mode. But what is DOO? The three letters in the name indicate that either the atria or ventricles may be paced (“dual”) and that there is no sensing occurring. Thus, while in DOO mode the generator will deliver electrical signals regardless of any intrinsic signals generated by the myocardium. “Dual” is a bit of a misnomer given that most ED pacers have only a single lead and will end up pacing the right ventricle once inserted. When in doubt, asynchronous pacing with DOO is a perfectly acceptable mode of pacing for emergent situations and is the simplest option.
VVI is a slightly more sophisticated option and is preferred by some practitioners due to the theoretical risk of R-on-T phenomenon that is inherent to asynchronous pacing. The three letters in “VVI” indicate that the ventricle is being paced, the ventricle is being sensed, and the generator output is inhibited when an intrinsic beat is sensed from the ventricle. Some physicians may prefer to establish initial capture with DOO and then transition to VVI. This article will not delve into the specifics of VVI pacing, but we wanted to mention it to establish at least some familiarity.
AMPERAGE: Another generator setting that can be modified is the level of amperage (also referred to as the output), which can range from 0.1 mA to 25 mA. The default setting upon startup is typically 20 or 25 mA. A higher level of current/amperage results in a higher probability of capture. Start high (e.g. 20 mA); this can be weaned down later once capture is confirmed.
SENSITIVITY: The sensitivity setting determines the voltage at which the native rhythm can be detected. In an asynchronous mode (such as DOO), this setting is turned all the way down so that generator pacing will occur asynchronously regardless of the endogenous rhythm. In VVI, a native R wave with an amplitude that exceeds the sensitivity threshold will inhibit the pacemaker. A higher-sensitivity setting will be denoted by a lower number, as this indicates that less voltage is required to register as a native rhythm.
RATE: Finally, the pacing generator box will include a dial to set the pacing rate. Common strategies for initial rate determination include setting the rate to double the intrinsic rate, setting the pacer rate to 20 bpm above the intrinsic rate, or just setting the pacer rate to 80 bpm.
‼️ In an emergent situation, feel free to use DOO mode with a 20 mA output and an 80 bpm rate.
An example of a pacer generator “box.” Note the red DOO button which converts the pacer to asynchronous mode for easy use in emergencies. [original image]
An example of a non-sterile pacer generator wire. The black end connects to the generator box itself. The blue end contains ports (not visible in the photo) that connect to wires from the pacing catheter. One port is marked as positive, the other negative. [image source]
2. Pacing wire and electrodes
These will often be available in a “TVP kit.” The pacing wire itself is a small catheter (often 5 Fr diameter) with a balloon and electrodes at the distal tip. The balloon is small but mighty and holds 1.5 mL of air. On the other end of the pacing catheter, there are two short wires (to connect to the generator) and a separate port through which air will be injected into the balloon. The air-entry port has a locking lever/ stopcock to keep the balloon inflated and prevent air from flowing backwards out of the balloon. Marks along the pacing catheter allow you to keep track of depth as you advance.
An example of a temporary transvenous pacing catheter, shown with the balloon inflated. The black and red tips connect to the ports of the generator wire. The other opening connects to a syringe in order to inflate the balloon. [image source]
3. Introducer / central access kit
The “introducer” is the CVC through which the pacing wire will be inserted. You want a 6Fr single-lumen CVC so that the pacing wire itself can comfortably fit inside. Cordis brand percutaneous sheath introducers are a common choice.
4. Pulse oximetry and cardiac monitor
These tools will help indicate that capture has been obtained. POCUS can also be used to visualize wire location (more on this below). 12-lead electrocardiography can also be used to confirm pacer location, but this practice has become less common and will not be discussed in detail here.
IV. Procedure
If possible, two individuals should be involved in TVP placement. One person will “gown up” to sterilely float the catheter, and the other will remain non-sterile to set up and adjust the generator.
1. Obtain central access with your introducer sheath. This process is identical to typical central line insertion and will not be reviewed in detail here. Right IJ access is the best choice, but a left subclavian approach can also work.
2. Connect the generator box wire (ending in positive and negative ports) to the sterile pacing catheter wires. The sterile pacing catheter wires may require adapters to fit into the aforementioned ports; if so, these will be included in your TVP kit. The adaptors simply slide on the tips of the pacing catheter wires. The wire labeled “proximal” needs to be inserted into the positive port of the generator. The wire labeled “distal” connects to the negative port of the generator. We recommend draping the non-sterile generator wires over an IV pole so that it can float above the sterile field while reaching your pacer wire tips more easily.
3. Check that the balloon on the pacing catheter inflates by connecting a small syringe (included in your TVP kit) to the air-entry port of the pacing wire and injecting 1.5 mL of air. Deflate the balloon before proceeding.
4. Place the sterile plastic sleeve over your pacer wire and connect it to your central line. This is an easy step to forget and doing so will require you to restart the entire procedure later. Please note that the sterile sleeve is directional and needs to be oriented correctly; the proximal and distal ends are not interchangeable.
5. Insert the pacer wire (balloon deflated!) into the introducer sheath. You should angle the pacing wire in the intended course of travel as you advance (e.g. for right IJ access, the pacing wire should be gently angled to the patient’s left as it’s inserted).
6. Steadily advance the pacing wire until 15 cm is reached. This distance ensures that the distal end of the pacing wire is no longer within the lumen of the CVC.
7. Now it’s time to float! The balloon helps the pacer reach the RV. Gently inflate the balloon with 1.5 mL of air.
8. Turn your generator box on and adjust the settings as desired. This should be done by the non-sterile team member.
9. Gradually advance the pacing wire (with balloon inflated) until capture is achieved. The non-sterile team member should continuously watch the cardiac monitor and pulse oximetry for evidence of capture. A pacer spike followed by a QRS complex on the monitor confirms electrical capture. A pacer spike followed by myocardial contraction (with a palpable pulse or correlating waveform/rate on pulse oximetry) confirms mechanical capture.
10. Deflate the balloon by opening the air entry stopcock to allow air to passively flow out of the balloon and back into the syringe.
11. Extend the sherile plastic sleeve to cover the wire and ensure that it is locked in place.
12. POCUS can be used to visualize wire location after placement. A subxiphoid view (or, alternatively, apical four-chamber) can show the pacing wire abutting the RV wall. If desired, ultrasound visualization can also be used during the entire procedure to dynamically track the pacing wire as it’s advanced toward the ventricle. It should be noted that confirmation of electrical and mechanical capture (see step 9 above) -- NOT ultrasound visualization of the wires – indicate a successful procedure.
13. Now it’s time to wean the amperage as tolerated. Once you identify the lowest electrical signal needed to maintain electrical/mechanical capture, set the pacing generator to deliver double that minimum amperage.
Voila! Your patient is now being successfully transvenously paced. Get a chest x-ray to triple check placement, celebrate momentarily, and get them to the CCU ASAP.
V. Troubleshooting
Generally, capture should be obtained by a depth of ~40 cm. If you’ve advanced the pacing wire to 50 cm and have no capture, you may need to troubleshoot and/or re-attempt the procedure.
Double check that your generator is turned on with appropriate amperage and rate settings. Also check that the generator is connected properly to the pacing catheter and that no connections are loose.
If improper placement is suspected, use POCUS to look for pacer presence in the IVC.
If you decide to re-attempt, deflate the balloon before slowly retracting the pacing wire and trying again with advancement.
————
Case Resolutions: Following stabilization and admission to the CCU, each patient received a permanent pacemaker. They have both had an uncomplicated course and are alive and well.
————
References
Birkhahn RH, Gaeta TJ, Tloczkowski J, et al. Emergency medicine-trained physicians are proficient in the insertion of transvenous pacemakers. Ann Emerg Med. 2004;43(4):469-474. https://pubmed.ncbi.nlm.nih.gov/15039689/
Cousar J, Bohanske M, Hill J. Transvenous Cardiac Pacemaker Educational Resource. MedEdPORTAL. 2015;11:10107. https://doi.org/10.15766/mep_2374-8265.10107
Hallagan A, Kasianko C, Vempati A. et al. “Critical Care Device Series: Transvenous Pacemaker”. EMRA, EM Resident. 2023. https://www.emra.org/emresident/article/device-series-tvp
Long B, Bridwell RE, DeVivo A, Gottlieb M. Transvenous Pacemaker Placement: A Review for Emergency Clinicians. J Emerg Med. 2024;66(4):e492-e502. https://pubmed.ncbi.nlm.nih.gov/38453595/
Morgenstern, Justin. “Emergent Cardiac Pacing”. First 10 EM. 2019. https://first10em.com/pacing/
Piela et al. Outcome of Emergency Department Placement of Transvenous Pacemakers. Ann Emerg Med. 2014;(64)4:S110. https://www.annemergmed.com/article/S0196-0644(14)00945-7/fulltext
Weingart, Scott. “EMCrit 310 – Transvenous Pacemakers”. EMCrit Blog. 2021. https://emcrit.org/emcrit/transvenous-pacemakers/
