PSVT - AVNRT ABLATION
ELECTROPHYSIOLOGY PROCEDURE NOTE
ELECTROPHYSIOLOGY: Michael Bui, MD
ASSISTANT:
INDICATIONS FOR PROCEDURE (PREOPERATIVE DIAGNOSIS):
1. Paroxysmal SVT
POSTOPERATIVE DIAGNOSIS:
1. Typical Slow-Fast AVNRT
PROCEDURES PERFOMRED:
1. SVT Ablation
2. Comprehensive EP Study with Induction:
3. Left Atrial Pacing/Recording
4. 3D Mapping
ESTIMATED BLOOD LOSS: 10 cc
COMPLICATIONS: None
FLUOROSCOPY TIME: 0.0 minutes (Fluoroless)
DAP = 0.0 Gycm2
AIR KERMA = 0.0 mGy
CLINICAL PROFILE:
SUMMARY OF PROCEDURE:
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The risks and benefits of the procedure were explained to the patient in full,
and in simple terms. The risks of the procedure include, but are not limited
to: pain, bleeding, infection, perforation of vessels or heart, pericardial
effusion, tamponade requiring intervention or surgery, damage to existing native
conduction system requiring need for permanent pacemaker, unstable heart rhythm,
stroke, myocardial infarction, and death. The risks of blood transfusion were
discussed, and include fever, transfusion reaction, and infection. All questions
were answered, and the patient voices understanding. The patient acknowledged
the risks of the procedure, and still wanted to proceed.
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SHEATHS AND CATHETERS:
Access the femoral veins were obtained using the seldinger technique: The right
femoral vein was successfully cannulated with the needle. A guide wire was then
passed through the needle easily. A blade was used to make a nick at the entry
site to widen the entry point. The needle was then retracted. A sheath was
then placed over the guidewire and then flushed. This was repeated in a similar
fashion for the following access points:
Right Femoral Vein:
7Fr Sheath: A deflectable decapolar catheter was placed through
the sheath and positioned into the coronary sinus.
8Fr Sheath: A Biosense Webster Pentaray Catheter was placed through this to
map the Right Atrium. Then a Biosense Webster irrigated tip
mapping and ablation DF curve catheter was placed through this
sheath into the right atrium and right ventricle.
***To enhance stability, we switched out the 8Fr sheath for a
Biosense Webster Vizigo sheath and then placed the ablation
catheter through this***
Left Femoral Vein:
6Fr Sheath: A non-deflectable quadripolar catheter was positioned
into the High right atrium.
6Fr Sheath: A Deflectable quadripolar catheter was positioned
into the Right Ventricle.
RESULTS:
I. Basic Intervals
Examination of the patient's 12 lead ECG revealed no evidence of manifest pre-
excitation. The baseline PR interval was not markedly prolonged.
Prior to the ablation, the following measurements were obtained:
PR = msec
QRS = msec
QT = msec
AH = msec
HV = msec
AA = msec
After ablation, the following measurements were obtained:
PR = msec
QRS = msec
QT = msec
AH = msec
HV = msec
AA = msec
DETAILS OF PROCEDURE:
I. DIAGNOSTIC PORTION OF PROCEDURE:
The patient was brought to the EP lab in a fasting and hemodynamically stable
condition. The patient was prepped and draped in a sterile fashion. The Right
and Left groin areas was anesthetized with lidocaine solution. Sheaths and
multipolar electrode catheters were placed and positioned as described in the
above section labeled, "Sheaths and Catheters." Fluoroscopy was used to help
guide and position the catheters.
After the above catheters were in position, we proceeded with pacing from the
high right atrium. Electrical signals were recorded from the right atrium, His
bundle, coronary sinus, and right ventricle.
We then sought to induce the tachyarrhythmia. Burst pacing as well as
introducing S1 extra-stimuli were performed.
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While we were unable to induce
sustained PSVT, while introducing extra-stimuli at a coupling interval of
_____ msec, we observed two consecutive echo beats with a VA interval ~ __
msec, consistent with Dual Nodal AV physiology.
Thus, we felt given the consectuive echo beats as well as documented PSVT (with
ECG suggestive of AVNRT), we felt that this represented AVNRT and proceeded with
a slow pathway modification.
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II. Intervention Portion of Procedure
Using the _______ catheter, we made geometry of the right atrium, coronary
sinus and also did voltage mapping.
A Biosense webster 4 mm tip DF curve catheter was advanced into the right
atrium. Usung the Carto-3 system, we first marked the His bundle, making a "His
cloud."
We were able to use Koch's triangle to approximate the area of the slow pathway.
Then, using the voltage map we made a "Bridge Map" and found the area where the
voltage abruptly changed from high voltage to lower voltage. A propagation map
in sinus rhythm also identified this area. This area fit within Koch's triangle. This technique of Bridge mapping has been described in the literature (Bailin, Steven et al. "Direct visualization of the slow pathway using voltage gradient mapping: a novel approach for successful ablation of the atrioventricular nodal reentry tachycarida. Europace (2011) 13, 1188 - 1194).
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The high voltage slider was adjusted to ___ mV, and the low voltage slider was adjusted ynamically to reveal low voltage bridges wtihin the atrial septum.
We observed a single low voltage bridge
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We next positioned the ablation catheter using the traditional anatomic approach. In the RAO projection, the catheter was positioned into the right
ventricle, towards the posteroseptum, and advanced to approximately 1/3 of the
distance between the coronary sinus ostium and the right ventricular apex. The catheter was repositioned and withdrawn until there was an atrial to ventricular (A:V) ratio of approximately 1:5. In the LAO projection, the catheter was positioned just outside of the coronary sinus ostium, at approximately between 5 and 6 O'clock position. The ablation catheter was inferior to the His bundle, and no His signals were detected on the ablation catheter.
The area of interest as mapped out by the traditional anatomical approach (guided by Koch's Triangle) also corresponded with the area identified by bridge mapping. Several radiofrequency lesions were applied to this region, which resulted in several junctional beats. No lingering AV block was seen.
We then performed a remap of the area, and verified that we no longer had low voltage bridges post ablation.
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Re-testing was then performed with burst pacing and extra-stimuli pacing, and no induction of any sustained tachyarrhythmias was observed, nor any consistent echo beats.
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The procedure was then terminated. The procedure was then terminated. Figure of eight stitches were applied to the bilateral groins, and then the catheters were removed along with the sheaths. The patient was then transported back to a monitored bed.
The patient was then transported back to a monitored bed.
IMPRESSION AND RECOMMENDATIONS:
1. SVT
-EP Study consistent with Dual Nodal AV Physiology
-S/p Successful AVNRT ablation with modification of the slow
pathway.
PLAN:
1. No lifting any object greater than 5 lbs for 1 week.
2. Follow up in EP clinic in ~ 4-6 months
-If no recurrences of symptoms / AVNRT, can DC from EP clinic