Ablation Flashcards
attempt to modify, isolate or destroy the automatic foci or reentrant circuit
Ablation
ablation is to create an electrically unexcitable area
scar tissue
risks of ablation (7)
inadvertent complete heart block cardiac perforation cardiac tamponade esophageal fistula stroke phrenic nerve injury at access site
risks of ablation %
2%
produces lesion at site and causes minimal damage to surrounding tissue
radiofrequency (RF) ablation
RF works by uses ___ current delivered between catheter ___ and the ____ _____
alternating
tip
indifferent electrode (skin patch)
current for RF is delivered at a frequency of
300-750 kHz
current is deliverved at a voltage of
40-60 Volts
high frequency, low voltage results in
controlled thermal injury
affects the tissue closest to the electrode tip
Resistive heat
transferred from the electrode-tissue to adjacent tissue
conductive heat
heat responsible for lesion size
conductive heating
conventional RF catheter FR diameter and mm tip
7-8Fr
4mm
power of 30 W delivered to a 4mm tip creates a lesions of depth and diameter
4-5mm
New RF catheters offer tip size
produce lesion X times volume of the 4mm
8mm
4x the volume of the 4mm
newer rf catheters may be used to create full thickness lesions such as
pectinate muscles for atrial flutter
monitors and maintain target tissue temperature and prevents gas formation (steam) or charring at the electrode-tissue interface
RF generator
irreversible thermal injury occurs when the temp of the myocardial tissue
48 to 50 (o) celsius
time it takes to achieve steady state of current delivery and heat dissipation by tissue and blood
5 to 20 seconds
temps >50 can cause a
100
steam pop or charring
RF lesions are usually placed in the superior portions of the crista terminalis to achieve the desired result
SA nodal reentrant tachycardia (SANRT)
typical atrial flutter treated by creating a series of RF lesions across
triscupid isthmus
Atrial flutter creates the line of block across the slow pathway from ___ to ___
triscupid annulus to inferior vena cava
reentrant, chronic or permanent AF needs to electrically divide the atria into smaller sections
maze procedure
