12.3 Permanent, Temporary, Leadless & Biventricular Pacemakers

Permanent, Temporary, Leadless & Biventricular Pacemakers

Pacing is Procedures 1.D hardware: a generator and a lead that can capture ventricle (and often atrium) when the patient's conduction will not. The CI technologist runs venous access under fluoro, proves lead position, builds or avoids a pocket, and knows when the problem is a pneumothorax, twiddler's syndrome, or infection rather than the battery looks fine. Walk indications, contraindications, access, equipment, image use, complications, and closure for each device class.

Quick Answer: Permanent pacing: axillary, subclavian, or cephalic vein, prepectoral pocket, RV ± RA leads, fluoro for apex versus septum. Temporary: balloon-tipped transvenous from IJ or femoral, or transcutaneous pads. Leadless (Micra-class): femoral to RV, no pocket. CRT/BiV: CS lead to an LV epicardial vein after an occlusive CS venogram, watching for phrenic capture. Teaching CRT indication: LBBB plus low EF (guideline-level, not an ARRT cutoff).

Permanent pacemaker: indications through closure

Indications (teaching): symptomatic sinus-node dysfunction, high-grade AV block, and complete heart block — especially an infranodal escape. Asymptomatic isolated first-degree delay is not an implant lecture.

Contraindications / delays: active systemic infection when you can wait, pocket implant during bacteremia (how hardware becomes infected), and a patient who needs temporary pacing now while INR or infection is sorted.

Access. Axillary (often extra-thoracic, ultrasound or contrast-guided), subclavian (higher pneumothorax and subclavian-crush teaching), or cephalic cutdown (no needle in the lung, but a small vein). A contrast venogram through an ipsilateral IV shows the path and stenosis. Equipment: peel-away sheaths, active- or passive-fixation leads, a programmer, fluoro, and a pericardiocentesis tray if a helix goes too far.

Image use is fluoro from needle to helix: RAO for RV apex versus outflow, LAO for septum versus free wall (septal lead points posterior/spinal, free-wall lead points anterior/sternal — teaching geometry). RV apex is the classic stable site; septal / RVOT septum is chosen in many labs to avoid apical dyssynchrony. Know both; do not call a mid-septal lead dislodged because it is not on the diaphragm.

Leads and pocket. Single-chamber VVI: RV only. Dual-chamber DDD: RA + RV. The generator sits in a prepectoral subcutaneous pocket (submuscular in thin patients or when erosion is a concern). Closure is layered pocket closure, hemostasis, a pressure dressing, and arm precautions per lab — not a femoral collagen plug.

Complications you must recognize:

• Pneumothorax (and hemothorax) after subclavian/axillary access — post-implant chest fluoro or film.
• Perforation/tamponade from an RV lead helix.
• Lead dislodgement (high threshold, loss of capture, a lead that no longer is apical or in the appendage).
• Twiddler's syndrome: the patient rotates the generator in the pocket and reels the leads out.
• Infection: pocket erythema, drainage, erosion, bacteremia — later an extraction problem (12.4).
• Subclavian crush, hematoma, and venous stenosis.

Temporary pacing

Transcutaneous pads are the bridge in the room: anterior–posterior or anterior–lateral, capture current as needed, sedation because it hurts. They are not a week-long solution.

Temporary transvenous: a balloon-tipped flow-directed catheter from the internal jugular or femoral vein into the RV, for symptomatic bradycardia or CHB awaiting a permanent system or after inferior MI with nodal block that may recover. Image use: fluoro to prove RV, not PA and not coronary sinus. Never leave a balloon inflated in a wedge — this is a pacing lead, not a forgotten Swan. Complications: perforation, infection if the wire sits for days, and loss of capture when the patient moves. Closure is a temporary suture/sleeve at the neck or groin until the permanent implant or the wire comes out.

Leadless pacemakers (Micra-class)

Leadless devices (Micra-class teaching) are delivered through a large femoral venous sheath and deployed in the RV. There is no pectoral pocket and no transvenous lead in the SVC. That removes pocket infection and subclavian crush from the story and replaces them with femoral vascular injury, RV perforation/tamponade, and retrieval that is not a simple helix unscrew years later.

Indications teaching: patients who need ventricular pacing without a good pocket (anatomy, infection history) or who are VVI-appropriate. Dual-chamber leadless systems exist in evolution; do not claim ARRT tests a specific model year. Image use: fluoro plus contrast to confirm RV septal/apical deployment and to watch for effusion. Closure: femoral venous hemostasis after a large sheath — figure-of-8 or device, not a 5-Fr hold.

Biventricular pacing / CRT

Cardiac resynchronization therapy (CRT) adds a left-ventricular lead through the coronary sinus into a lateral or posterolateral LV epicardial vein so the LV is paced from the outside of the lateral wall, resynchronizing a left bundle-branch block (LBBB) pattern.

Teaching indication (guideline-level, not an unpublished ARRT EF cutoff): HFrEF / low ejection fraction, wide LBBB, and heart-failure symptoms despite medical therapy. Do not implant CRT thinking it is a blood-pressure toy in a narrow-QRS, normal-EF patient.

Unique tech task: occlusive CS venogram — balloon-occlude the CS and inject so the venous tree appears; pick a target vein; avoid phrenic-adjacent laterals if possible. After the lead is in, pace and feel/see the diaphragm: phrenic capture means a lateral vein too close to the nerve — reposition. CS dissection, inability to cannulate, and lead dislodgement from a small vein are everyday CRT complications.

Leads: typically RA + RV + CS/LV. The RV lead still provides backup pacing and ICD function when the generator is a CRT-D (that pairing is the next section's ICD logic).

Device / leads / unique tech task

Worked case

CHB in holding, BP 70, transcutaneous pads capturing painfully. Place a balloon-tipped temporary from the IJ under fluoro into the RV, confirm capture, then implant a permanent dual-chamber system from the left axillary vein. Chest fluoro shows no pneumothorax. If the patient instead has LBBB, low EF, class III HF, plan CRT: CS venogram, LV lead, phrenic test. If the patient has no pocket real estate after prior infection, a leadless femoral RV implant is the conversation — still watch for tamponade.

Exam traps

• Subclavian access without thinking pneumothorax.
• Calling CRT an extra RV lead.
• Skipping the occlusive CS venogram.
• Ignoring phrenic capture on the LV lead.
• Treating leadless as a pocket device.
• Shocking CHB instead of pacing.
• Leaving a temporary balloon wedged in a PA.