Review Note
Last Update: 02/24/2025 05:56 AM
Current Deck: ACG Part 2::Cardiac SSU
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Commit #289340
Discuss anaesthesia for cardiac ablations
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Commit #289340Issues with care :
- Remote location unfamiliar staff and equipment
- Major complications include cardiac tamponade and esophageal damage
Used for the treatment of atrial fluuter, atrial fibrillation, and atrio-ventricular nodal re-entry tachycardias.
Intracardiac electrograms :
- Electrophysiology catheter placed to measure electrical activity of the heart to establish diagnosis and understand arrhythmia , and check success of ablation
- Intracardiac recorded from high right atrium, coronary sinus, His Bundle and right ventricular apex, supplemented by ECG I, II, III, aVl V1 and V6
Origins of arrhythmias :
- Right sided atrial ablation
- Atrial flutter arrises from R atria, in 90% it is in anti-clockwise circle
- Single ablation ling created between IVC and tricuspid valve to interrupt circuit (cavotricuspid isthmus CTI)
- AVNRT ablation
- Due to slow pathway of the AV node, lying between the CS and His Bundle
- Slow pathway amenable to ablation by single burn.
- Usually carried out under LA and sedation to prevent suppression of the arrhythmia
- AV re-entry tachycardia
- Accessory pathway on the av ring, tricuspid or mitral valve annulus.
- Identify with targeted pacing
- Tricuspid accessory pathways ablated with right sided catheters
- Mitral require transseptal or retrograde trans-aortic approach
- Left sided atrial ablation
- Atrial fibrillation
- Arrises from the four pulmonary vein scotia
- Paroxysmal and persistent AF amendable, not usually persistent
- TOE performed prior to exclude Left atrial appendage thrombus
- Ablation catheter passed to R heart from femoral vein and IVC or subclavian vein, passed across foramen ovale in atrial septum to LA
- Fluoroscopy and/or TOE used to guide transeptal puncture
- Comlications include atrial perforation, aortic perforation and cardiac tamponade
Ablation energies :
- Radiofrequency : reduces energy delivered to te endocardium
- Radiofrequency with irrigation : saline infused over the tip, allows more energy to be delivered and concentrated.
- Can use 500-1000ml fluid which can lead to fluid overload.
- Cryoablation :: freezing used when there are concerns about heart block. (adjacent to AV node for example AVNRT )
- Low energy direct current useful for very deep ie epicardial accessory pathways
- Cryo-balloon
- Laser balloon : catheter balloon inflated in pulmonary vein ostia and laser energy delivered
Anaesthesia :
- Sedation +LA eg SVT where more successful if arrhythmia not suppressed vs GA for children, anxious, unable to lie flat, heart disease, long operations.
- Can last 1-6hrs
- Little post-operative pain
- May be degree of pericardial irritation
Anaesthetic challenges:
- Positioning :
- Often foriegn narrow tables, care for pressure sores.
- Remote location :
- Unfamiliar equipment,
- non-tipping tables
- Heparin use :
- Heparin given aiming 250-300 once transseptal puncture.
- Imaging :
- TOE may be needed to guide LA ablation, necessitating GA
- Immobility
- NMB or remifentanil to prevent coughing and movement.
- Adequate recovery for a remote area
- Trained staff with appropriate monitors
No significant difference between propofol or volatile. Exception AVNRTs which are probably suppressed by GA
Complications :
- Vascular of arterial and venous puncture
- Complications of transseptal puncture
- Atrial or aortic perforation, cardiac tamponade, shunt
- Complciations of LA ablation
- Mitral damage, pulmonary vein stenosis. Coronary obstruction
- Arrhythmias
- Oesophageal damage due to thermal injury
- Thoracic n injury
- L recurrent laryngeal n palsy, vagal n injury
- Embolic complications
- Stroke TIA,
- Atrial stuntting
- Infection
- Burns
https://academic.oup.com/bjaed/article/12/5/230/289246