12.2 Ablation for AF, Atrial Flutter & VT

Ablation for AF, Atrial Flutter & VT

Procedures 1.D continues into ablation. The R.T.(CI) is not the electrophysiologist, but you will set up transseptal, run ICE, manage ACT on a left-sided case, watch an esophageal temperature probe, and recognize the complication that is missed too late: atrioesophageal fistula after AF ablation, phrenic palsy at the right pulmonary veins, stroke, and tamponade. Typical cavotricuspid isthmus (CTI) flutter is a different, usually right-sided operation. Scar VT can go epicardial and can need hemodynamic support.

Quick Answer: AF ablation is pulmonary-vein isolation (PVI) via transseptal puncture into the LA, with ICE, heparin/ACT, and an esophageal temp probe. Typical AFL is a CTI line in the right atrium. VT ablation targets infarct scar and may need epicardial access. Energy is RF, cryo, or emerging pulsed field ablation (PFA) — know the concept; do not invent ARRT-specific PFA facts.

Focus of Questions on every ablation

For each target, walk the same list: indications, contraindications, access, equipment, image use, complications, closure.

Indications (teaching). AF: symptomatic AF, especially when drugs fail or are declined, and selected first-line cases. Typical AFL: a well-defined right-atrial circuit with high acute success after a CTI line. VT: scar-related reentry, PVC burden, ICD storms, or VT that needs to be uninducible. Contraindications: LA thrombus for left-sided AF work, inability to anticoagulate, active infection, and a patient who cannot lie for a long mapping case without a better airway plan. Unstable VT that will not tolerate mapping needs support or a different strategy, not stubborn endocardial tourism.

Equipment common to the room: irrigated RF generator or cryo console or a PFA system if the lab has one, diagnostic and ablation catheters, ICE, 3-D mapping, a stimulator, defibrillator on the pads, arterial monitoring as needed, and a pericardiocentesis tray you can reach without a scavenger hunt.

Closure: venous hemostasis after large sheaths (figure-of-8, device, or manual), reversal or continuation of anticoagulation per the operator (left-sided AF patients usually stay anticoagulated), and a neuro check because stroke is a left-atrial disease.

AF: pulmonary-vein isolation, transseptal, ICE, ACT

The pulmonary veins are the classic triggers of AF. PVI electrically isolates the PV antra from the LA so those triggers cannot drive the atrium. That work happens in the left atrium.

Access starts femoral venous. Transseptal puncture then crosses the fossa ovalis from RA to LA. The technologist's image job is ICE in the RA: show the septum, show tenting of the needle/dilator, show the LA and LAA (look for thrombus before you burn), and keep a view that can prove a pericardial effusion the moment the pressure drops. Fluoro (typically LAO/RAO) is the second pair of eyes, not the only pair.

Once you are left-sided, heparin is not optional. Typical lab teaching (not an unpublished ARRT second): keep activated clotting time (ACT) in a high therapeutic band often discussed around ≥300 seconds (many labs 300–350) while catheters are in the LA. Check ACT on a schedule. A clot on a transseptal sheath is a stroke.

Esophagus, phrenic nerve, stroke

The posterior LA wall sits on the esophagus. Labs place an esophageal temperature probe and avoid letting posterior RF or cryo run while the probe is climbing. Atrioesophageal fistula (AEF) is rare and delayed (often days to weeks later): fever, chest pain, neurologic events, GI bleeding — and it is often fatal. It is not an immediate post-pull hematoma. Delayed fever after AF ablation is an emergency workup, not a UTI until proven otherwise.

The right phrenic nerve runs near the right pulmonary veins (especially the right superior PV). Cryoballoon PVI is the classic phrenic story: pace the phrenic from the SVC and watch the diaphragm; stop if capture weakens. RF at the right PVs can also injure it. Left PVs are not the usual phrenic lecture.

Stroke (and TIA) is the left-atrial thromboembolic complication: thrombus, char, or air through a transseptal sheath. Bubble-free exchanges, ACT discipline, and ICE for LAA thrombus before ablation are the technologist's stroke prevention.

Typical AFL: CTI line, often right-sided only

Typical atrial flutter is cavotricuspid isthmus-dependent: the circuit uses the isthmus of tissue between the tricuspid annulus and the inferior vena cava. Ablation draws a line of block across that isthmus. Access is right heart — femoral venous catheters in RA, His, CS, and a tricuspid-annulus ablation catheter. Transseptal is not required for typical CTI flutter. That is the exam fork versus AF.

Image use: fluoro RAO often shows the isthmus well; the CS catheter is a left-atrial timing reference still reached from the RA ostium. Endpoint teaching is bidirectional block across the CTI, not the sawtooth looked smaller.

Hallmark complication is lower left-sided stroke risk than AF PVI, but AV block if energy wanders too septal toward the His/AV node, plus the usual tamponade and vascular issues. Typical flutter is not a no-complications case.

VT: infarct scar, epicardial access, support

Scar-related VT in ischemic cardiomyopathy is reentry around infarct substrate. Mapping may be substrate (voltage) or activation during VT if the patient will tolerate it. Many will not.

Access: femoral venous plus retrograde aortic or transseptal into the LV for endocardial mapping. Epicardial access (subxiphoid pericardial puncture) is used when the circuit is epicardial — more often discussed in nonischemic VT or after failed endocardial ablation. Epicardial work can injure coronary arteries and the phrenic nerve on the LV lateral wall.

Hemodynamic support (IABP, catheter LVAD, ECMO in extremes) is in the room when VT is poorly tolerated. The CI technologist already knows these devices from the interventional chapters; here they exist so mapping can continue without collapse.

Complications: tamponade (endocardial steam pop or epicardial access), hemodynamic collapse, coronary injury, AV block if the circuit is near the conduction system, and stroke if LV thrombus was ignored.

Energy: RF versus cryo versus PFA conceptually

Radiofrequency (RF) heats. Irrigated RF is standard in the LA to reduce char. Steam pop is sudden intramural vapor — a perforation/tamponade risk. Cryoenergy freezes. Cryoballoon PVI is common; cryo can be reversible if you stop early, which is why it is attractive near the phrenic — if you are watching the diaphragm. Cryo does not make phrenic injury impossible.

Pulsed field ablation (PFA) is a newer, nonthermal energy using electroporation. Early teaching points are tissue selectivity and theoretically less thermal esophageal injury — emerging, lab-dependent, and not a place to invent ARRT-specific settings, pass scores, or a claim that ARRT has retired RF. If a stem says PFA, treat it as another energy source with the same transseptal, ACT, and tamponade rules.

Ablation / access / hallmark complication

Worked case

Planned PVI. ICE shows LAA thrombus. Stop. Do not puncture. Do not ablate. Anticoagulate and reschedule. If ICE is clean, transseptal, heparin to a therapeutic ACT, esophageal probe in, watch the right diaphragm during right-PV energy. Two weeks later the patient has fever and a stroke: AEF is on the list until a capable center says it is not.

Exam traps

• Transseptal for typical CTI flutter.
• Calling AEF an immediate sheath-pull bleed.
• Ignoring ACT once the catheter is in the LA.
• Assuming cryo cannot injure the phrenic nerve.
• Inventing ARRT-only PFA numbers.
• Treating wide-complex storm as just map faster with no support.