9. V Wave = CS (LBB)V Wave = CS (LBB)
& RVa (RBB)& RVa (RBB)
His potential = HisHis potential = His
A-Wave = HRAA-Wave = HRA
Relationship of the Intracardiac Electrogram to the Activation
Sequence
15. Koch’s Triangle
An imaginary area called Koch’s triangle extends from the tricuspid annulus to the tendon of
Todaro to the CS ostium. Two tracts of atrial fibers within Koch’s triangle form anatomically
distinct conduction pathways to the compact AV node.
• His bundle and compact AV node are at the apex of Koch’s triangle (thus must be avoided
during ablation) and define the anterior aspect of the atrial septum.
•CS ostium is at the base and forms the posterior portion of the atrial septum.
• Tricuspid annulus defines the third face of Koch’s triangle.
• The anterior/superior tract, which lies along the tendon of Tadaro near the compact AV node,
is the fast pathway. The posterior/inferior tract, which lies along the tricuspid valve annulus
near the CS ostium, is the slow pathway of the AV node. The slow pathway is farther away
from the AV node and can usually be safely ablated.
1515
16. Right Atrial Anatomy
The triangle in the picture is called the “Triangle of Koch” and has one face made
up of the tricuspid annulus, another the “Tendon of Todaro” and the last the base
of the CSos. At the tip of the triangle is the AV node. Thus EP doctors have this
in mind when they ablate in the RA in order to avoid ablating the AV node and
causing complete heart block requiring a pacemaker implantation.
Nakagawa et al., Circulation, 1996;94
At the base of the CSos is theAt the base of the CSos is the
Thesbian Valve (ThV). This canThesbian Valve (ThV). This can
be quite large and completelybe quite large and completely
cover the CSos making it verycover the CSos making it very
difficult to insert a CS catheter.difficult to insert a CS catheter.
Some patients also have aSome patients also have a
diverticulum, which is a hugediverticulum, which is a huge
pouch just inside the CSos. Thispouch just inside the CSos. This
too makes advancing the CStoo makes advancing the CS
catheter difficult after accessingcatheter difficult after accessing
the CSos.the CSos.
The heart lies in the mediastinum with its own long axis tilted relative to the long axis of the body. Appreciation of this discrepancy is important in the setting of cross-sectional echocardiography.
Relationship of the intracardiac electrogram to the activation sequence: Intracardiac recordings record only the activation in the small area in the local proximity of the electrode on the catheter that is being used for the recording. This is unlike the 12 lead recordings which represent the entire activation of the heart. Thus the following potentials or waves are recorded: A wave – the A wave represents the atrial activation at the site the catheter is located in right or left atrium. In a standard EP study the HRA catheter is used to record the A wave from the high right atrium near the sinus node. His potential – the His potential is recorded by the His (HBE) catheter which is straddling the tricuspid valve. It represents the activation as it leaves the AV node and rapidly travels past the electrode on the His bundle. V wave – the V wave is recorded usually by the RVA catheter located in the apex of the right ventricle (RV) and the His catheter located on the His with its tip in the (RV) complex is the activation of the right and left ventricles. If an ablation catheter is placed in the RV it too will record a V wave.
所以 , 心臟構造相關位置是很重要的 所以 , 心臟構造相關位置是很重要的 A. Superior Vena Cava B. Right Atrium C. Coronary Sinus D. Inferior Vena Cava E. Pulmonary Veins F. Left Atrium G. Left Ventricle H. Right Ventricle
Intracardiac EGM recordings – Catheter Placement : In the standard electrophysiology study (EPS) procedure, 4 catheters are generally inserted and placed in the high right atrium (HRA), coronary sinus (CS), His region (HIS) and right ventricular apex (RVA). If an ablation procedure is to be performed, one more catheter called the ablation catheter is inserted. Below are the locations where the 4 catheters used in the EPS are placed. High right atrium (HRA): positioned in the right atrial appendage His bundle electrogram (HBE or HIS): positioned with the tip electrodes crossing the tricuspid annulus and a few millimeters on the ventricular side of the tricuspid annulus, and the proximal electrodes on the atrial side of the tricuspid annulus. The best His potential recording is a few millimeters into the ventricular side of the tricuspid annulus. Coronary Sinus (CS): positioned in the coronary sinus between the left atrium and left ventricular and covers anywhere from the left posteroseptal region to the left anterior region depending on how deep it is placed in the CS. Right ventricular apex (RVA): positioned in the right ventricular apex. An alternative location can be the right ventricular outflow tract (RVOT) Characteristic recordings will be made as the wavefront propagates across the recording pairs or unipolar recording electrodes. Those recordings are then compared in terms of relative timing of those various catheters around the heart.
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His catheter specifications: Since the true His is a little higher than a normal Josephson or Cournand catheter reaches, often the His recording may be problematic. The His catheter is often very unstable requiring the doctor to reposition it several times during the procedure. Therefore catheters with multiple electrodes (6-10) with close spacing (2mm) help obtain better recordings. Also using catheters with a longer reach and/or larger curve can help. Curves such as the CRD-2 and IBI His curve are extremely helpful with stability and reach up to the true site of the His potential. Catheters with a longer reach and multiple electrodes tend to give better stability and better His recordings. The His catheter is usually only used for recording, but occasionally can be used for Parahisan pacing. Narrower spacing is desirable to be able to record a sharper His potential. Also by having an octapolar or decapolar catheter, it will have more electrodes back further on the shaft to help record the atrial potential which is often lost more distally. Most Common Curves If fixed curve, CRD-2, CRD, JSN or IBI His Curve, Josephson or Cournand If a big heart, CRD-1 or JSN-1 If steerable, a medium sweep or IBI Medium Usually is only used for recording, but the distal pair of electrodes may be used for Parahisian pacing Most Common Access Femoral access Most Common Electrode Number Quadripolar, but Hexapolar, Octapolar or Decapolar are common Most Common Electrode Spacing Usually 2mm or 5mm, but 10mm (rare) or 2-5-2mm (rare) can also be used
An imaginary area called Koch’s triangle extends from the tricuspid annulus to the tendon of Todaro to the CS ostium. Two tracts of atrial fibers within Koch’s triangle form anatomically distinct conduction pathways to the compact AV node. The His bundle and compact AV node are at the apex of Koch’s triangle, and thus must be avoided during ablation. These structures define the anterior aspect of the atrial septum. The CS ostium is at the base and forms the posterior portion of the atrial septum. The anterior/superior tract, which lies along the tendon of Tadaro near the compact AV node, is the fast pathway. The posterior/inferior tract, which lies along the tricuspid valve annulus near the CS ostium, is the slow pathway of the AV node. Tricuspid annulus defines the third face of Koch’s triangle. The slow pathway is farther away from the AV node and can usually be ablated (isolated without causing complete AV block.
At the base of the CSos is the Thesbian Valve (ThV). This can be quite large and completely cover the CSos making it very difficult to insert a CS catheter. Some patients also have a “Diverticulum”, which is a huge pouch just inside the CSos. This too makes advancing the CS catheter difficult after accessing the CSos. Again as in the previous slide, the “Triangle of Koch” has one face of the triangle made up of the tricuspid annulus, another the “Tendon of Todaro” and the last the base of the CSos. At the tip of the triangle is the AV node. Thus EP doctors have this in mind when they ablate in the RA in order to avoid ablating the AV node and causing complete heart block requiring a pacemaker implantation.
1. Ouyang F, Fotuhi P, Ho SY, Hebe J, Volkmer M, Goya M, Burns M, Antz M, Ernst S, Cappato R, Kuck KH: Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation. J Am Coll Cardiol 2002;39:500-508 2. Ito S, Tada H, Naito S, Kurosaki K, Ueda M, Hoshizaki H, Miyamori I, Oshima S, Taniguchi K, Nogami A: Development and validation of an ECG algorithm for identifying the optimal ablation site for idiopathic ventricular outflow tract tachycardia. J Cardiovasc Electrophysiol 2003;14:1280-1286 3. Yamauchi Y, Aonuma K, Takahashi A, Sekiguchi Y, Hachiya H, Yokoyama Y, Kumagai K, Nogami A, Iesaka Y, Isobe M: Electrocardiographic characteristics of repetitive monomorphic right ventricular tachycardia originating near the His-bundle. J Cardiovasc Electrophysiol 2005;16:1041-1048 4. Ouyang F, Ma J, Ho SY, Bansch D, Schmidt B, Ernst S, Kuck KH, Liu S, Huang H, Chen M, Chun J, Xia Y, Satomi K, Chu H, Zhang S, Antz M: Focal atrial tachycardia originating from the non-coronary aortic sinus: electrophysiological characteristics and catheter ablation. J Am Coll Cardiol 2006;48:122-131
CS catheter specifications: The CS catheter can be placed from the superior or inferior approaches. If placed by the superior approach, a fixed curve catheter is more often used, but if placed from the inferior approach it is almost always a steerable catheter. Since the CS is a long structure, wider spaced pairs with a tight spacing between the pairs is desirable. Thus, 2-8-2mm spacing is the most common. The CS catheter is mainly used for recording, but is often used for pacing as well. Most Common Curves If fixed curve from the superior access, CSL, DAO-1, DAO, CRD or IBI Special Curve If fixed curve from the inferior access, JSN, JSN-1 or IBI Josephson If steerable, an Extra Large Curl or Medium Sweep or IBI Medium or Large Usually is used mainly for recording, but any pair of electrodes may be used for pacing (especially the distal and proximal pairs). Most Common Access Femoral access – mostly steerable Superior – mostly fixed curve, but steerable as well Most Common Electrode Number Decapolar, but Hexapolar and Octapolar are occasionally used Most Common Electrode Spacing Usually 2-8-2mm or 5mm, but 2-5-2mm, 2mm or 2-10-2mm can also be used for more detail
The RVA catheter is placed in the right ventricular apex. Since that area is highly trabeculated the stability is good. Because it is only used as a reference to see the atrial timing and for pacing, the spacing and number of electrodes are not important. Most Common Curves JSN, CRD, CRD-1, DAO or DAO-1, or IBI Josephson, Cournand, Damoto if steerable, a medium sweep or IBI Medium Pace from the distal pair of electrodes and record from the proximal pair Most Common Access Femoral access (on extremely rare occasions a straight curved catheter from the Superior approach is used ) Most Common Electrode Number Quadripolar Most Common Electrode Spacing 5mm, but 10mm and 2-5-2mm can also be used
This slide shows a fluoroscopy image of the pulmonary veins and am MRI image of the same veins. None the close resemblance of the two pictures. The picture on the upper right shows the sheath that was used to inject the contrast dye through.
The CS drains into the base of the RA and is used to insert a catheter to evaluate conduction between the LA and LV. The CS is actually the part from the CSos to the branching of the vein of Marshall. From there on it is called the Great Cardiac Vein. The Vein of Marshall travels next to the left superior and inferior pulmonary veins (PVs), superior vena cava (SVC) travels next to the right superior and inferior PVs, and pulmonary arteries (PAs) (especially the left PA) travel within close proximity to the left and right superior PVs. Thus by placing catheters in those structures, far-field signals can be recorded from the PVs, helping to distinguish whether ectopy occurs from right or left PVs. The posterior vein of the left ventricle is often targeted for placement of a bi-ventricular pacing lead. The RCA courses between the RA and RV, and the conduction between those 2 structures can be evaluated by a mapping wire in the RCA. The middle cardiac vein (MCV) courses between the RV and LV on the inferior aspect of the heart. When the patient has an epicardial pathway located in the posteroseptal region, the pathway can be accessed to ablate through this vessel. However, due to its close proximity to the posterior descending artery, it can be dangerous.