Where it fits
Affera is Medtronic’s all-in-one platform: high-density mapping, pulsed field ablation (PFA), and radiofrequency ablation on a single catheter — the Sphere-9 — driven by Prism mapping software. Compared with Carto and EnSite X, the distinguishing move is the elimination of the map-then-swap-to-ablate step. Compared with dedicated PFA systems like Farapulse (Boston Scientific) that pair with a separate mapping platform, Affera collapses both functions onto one workstation.
For the lab, this changes the rhythm of the case more than any single feature: fewer catheter exchanges, fewer transseptal passes, and a tighter integration between the map and the energy delivery.
Localization technology
Affera uses impedance-based localization through body-surface patches.
- A set of skin electrodes drives low-amplitude currents across the thorax along three orthogonal axes.
- Every electrode on every catheter in the field measures voltage in each axis, which the system translates into 3D position.
- There is no magnetic location pad — the platform is entirely electric-field-based, which means simpler under-table setup but also that map stability depends heavily on patch quality and patient stillness.
Prism software builds anatomy from impedance points and continuously refines geometry as the Sphere-9 expands and sweeps the chamber.
Compatible catheters & accessories
- Sphere-9 catheter — the centerpiece. A 9 mm expandable lattice tip with nine electrodes that:
- Maps in high density when deployed against tissue.
- Delivers PFA (pulsed-field ablation) in one energy mode.
- Delivers RF in another energy mode, with temperature feedback through the lattice.
- Standard diagnostic catheters (decapolar CS, His) visualize via impedance.
- Body-surface electrode set provided with the system.
- ICE catheter (any compatible platform) used alongside for transseptal and chamber confirmation — ICE imaging is not natively fused into Prism the way CARTOSOUND fuses into Carto.
Lab setup
Pre-case prep:
- Boot the Prism workstation and the Affera generator early; both need warm-up and self-test time.
- Patch placement with patient supine, arms in final position:
- Anterior chest, posterior back, and lateral patches per the system diagram.
- Dispersive / return patches for RF energy.
- Standard surface ECG patches for recording integration.
- Skin prep matters more here than on a magnetic system — clip, alcohol, dry. Bad patches = bad geometry, with no magnetic backup to rescue it.
- Confirm patch impedance in range and stable.
- Connect Sphere-9 to the catheter interface; confirm the catheter shows on screen and electrode signals are clean.
- Verify the generator is in the correct energy mode (PFA vs. RF) for the planned start of the case; mis-set energy at first application is a known near-miss.
Workflow during the case
Typical PFA-based PVI flow:
- Femoral access, CS catheter placement, transseptal under ICE.
- Sphere-9 advanced into the LA, deployed, and used to map PV ostia and posterior wall. Mapping mode streams points from the lattice; the team sweeps each PV antrum.
- Tag landmarks (PV ostia, LAA ridge, esophagus position on ICE).
- Switch the generator to PFA mode. Confirm energy parameters, patient grounding, and that anesthesia has paralyzed the patient (PFA causes brisk diaphragmatic and skeletal muscle stimulation).
- Position Sphere-9 at each ablation site, deploy against tissue, deliver the PFA train; reposition and repeat around the antrum.
- If a non-PV target needs focal RF — CTI line, focal lesion — switch the same catheter to RF mode without exchanging.
- Re-map after ablation to confirm isolation; tag any reconnection sites.
- Final geometry and lesion set saved to the case archive.
What’s distinctive
- One catheter for map and ablate. No exchange, no re-registration, no lost time.
- Two energy modes on the same catheter — PFA for antral PVI, RF for focal touch-ups or linear lesions where tissue selectivity is preferred.
- Lattice expandable tip contacts a broader footprint than a focal-tip catheter; lesions are wider and shallower in PFA mode.
- Integrated console means lesion data, map data, and energy data live in the same record.
- Trade-off: pure impedance localization, so the platform is more sensitive to patch quality and patient movement than magnetic systems.
Common pitfalls
- PFA muscle stimulation surprise. PFA delivery causes immediate diaphragm and skeletal muscle contraction. If paralysis is incomplete, the patient jumps, geometry shifts, and the team is rattled. Always confirm full neuromuscular blockade with anesthesia before the first PFA application.
- Energy mode mismatch. Generator left in RF when the operator calls for PFA, or vice versa. Read back the mode every time the energy type changes.
- Patch impedance drift through the case — sweating, repositioning, long fluid loads. Watch the impedance display; replace patches if values move out of range.
- Sphere-9 deployment in small chambers. The 9 mm lattice does not fit cleanly into every PV ostium or small atrium. Recognize that some anatomy is suboptimal and have a fallback plan (smaller, focal catheter on a different platform).
- Loss of impedance reference. A patch peel mid-case can shift the whole map; the platform has no magnetic backup to anchor against.
- Anticoagulation discipline. PFA does not change the heparin requirement — ACT goals are the same as RF AF cases; do not let the “different energy” framing slip the team off protocol.
Staff role
- Before the case — patch placement, system and generator boot, Sphere-9 connected and confirmed, ICE catheter ready, anesthesia briefed on paralysis requirement for PFA.
- During the case — mapping tech drives Prism, calls out lesion location and energy parameters, confirms each mode switch with the operator. Nurses confirm paralysis status with anesthesia before each PFA train.
- Energy delivery — repeat-back protocol: operator calls “PFA on,” tech confirms mode, generator confirms armed, anesthesia confirms paralysis, then deliver.
- End of case — save maps, export lesion record, document energy mode for each lesion in the case log.