Bệnh viện trung ương Quân đội 108 Viện tim mạch Triệt phá đường dẫn truyền phụ vùng dưới vách bằng sóng RF (Ablation of Posteroseptal AP)

Transcription

1 Bệnh viện trung ương Quân đội 108 Viện tim mạch Triệt phá đường dẫn truyền phụ vùng dưới vách bằng sóng RF (Ablation of Posteroseptal AP) Bs. Phạm Trường Sơn

2 Posteroseptal AP :Inferoseptal AP (inferior to the true septal)

3 The most complex: Pyramid space, confluence of 4 chamber - Superior: Central fibrous - Anterior:Ventricular septum - Posterior: left and Right Atria - TV is 5 mm to MV: + right atrium- left Ventricle space (thin tissue: AP inside) + CS os: at the superior (ablation site) 4 courses: Right to right, Right to left (common) Left to left, CS to left, CS to Diverticulum Ablated at: the MV ring, TV ring, inside CS

4 ECG characteristic 1/ Negative delta waves in leads III, avf (less common) positive delta waves in I and avl

5 2/Retrograde P waves : - Negative in the leads II, III, avf - Positive in AVR,AVL 3/ Slow and decremental retrograde conduction: incessant tachycardia. - Permanent junctional reciprocating tachycardia(pjrt)

6 EP Studying: 1. During AV reentrant tachycardia, the earliest atrial activation usually is recorded from + The ostium of the coronary sinus + The proximal coronary sinus within 2 cm (those beyond 1 2 cm are considered as left free-wall pathways: leftsided endocardial approach) 2. Functional left bundle branch block during tachycardia results in either no change or only a nominal prolongation of the VA interval (10 to 30 msec) - Functional right bundle branch block usually does not affect the VA interval.

7 Differentiation with SS-AVNRT (long VA time) - Advanced A during His refractoriness - Terminate tachy by PVC not conduct to A - Parahisian pacing: No change Stim to A - VA (V pacing and Tachy)< 85ms - VOD (PPI CL) <115 ms - VA pacing(at V base)<(at V apex)

8 Left sided aproach ECG 1/ Positive delta wave at V1, some study show no role 2/ R/S ratio 1 in lead V1 is the most predictive location 3/ If QRS transition between V1 and V2, the R-wave ( lead I) < S- wave mv is indicative of left-sided AP.

9 The 12-lead electrocardiogram of a patient with manifest right posteroseptal accessory pathway. R/S ratio < 1 in lead V1

10 The 12-lead electrocardiogram of a patient with manifest left posteroseptal. R/S ratio 1 in lead V1

11 EPS 1. Earliest atrial activation during AVRT was in the middle CS:

12 2. The prolongation (10 30ms increase) of the VA interval in response to the development of left bundle-branch block during orthodromic AVRT : 3. Long-RP AVRT defining a right endocardial AP.

13 4. The difference of VA intervals during AVRT, measured at the His catheter and the site of earliest atrial activation in the CS: -If 25 ms: a left endocardial AP in 89% of patients -If <25 ms in 95% of patients with a right endocardial or epicardial AP.

14 - These mapping criteria above are not necessarily predictive of where the effective ablation site is located. - Dhala et al: Overall success rate for the right-sided approach alone was 94% regardless of the above-mentioned electrophysiologic criteria + The right posteroseptum or the proximal coronary sinus: 50 % + The posteroseptal region of the tricuspid valve : 30% + Within the terminal 1 cm of the coronary sinus including its ostium: 16 % - Explained : many posteroseptal APs are right atrio-left ventricular fibers : right atrial approach

15 The most common reasons for prolonged or failed attempts at ablation: -Difficulties with catheter manipulation :48% +Inability to reach the appropriate AP site +Catheter instability + Inadequate tissue contact -Inaccurate mapping: 26% +AP at a site away from the mapped Area -The presence of epicardial APs

16 -40% of all patients referred after an unsuccessful ablation procedure - The CS method used as a primary method had an efficacy rate of 56% -The prevalence of an epicardial AP was 4%-25%. The largest series by Sun et al.: + CS-associated AP in 171 pt (36%) - Arruda et al :24% of the patients with posteroseptal APs required RF application in a venous branch or anomaly of the CS +(22%) in CS diverticulum and (70%) in the middle cardiac vein - Require: longer procedure times, longer radiation exposure, more RF, complication

17 - Embryologically, the CS develops: + As a remnant of sinus venosus musculature and as a continuation of RA + 40 mm of the CS is surrounded: striated muscle, with connections to LA - When connected with the epicardial surface of the ventricle: epicardial AP -Multiple left atrial myocardium connections to V: +Ablation at the Atrial site often produces : change in the activation sequence, should target at single V insertion. - Extensions of the CS myocardial coat to the : 5-20 mm deep into the vein +The middle cardiac vein (MCV): 82% + Posterior coronary vein (PCV):11% +Both vein: 5% -Requires ablation of the ventricular end at the insertion of the MCV or PCV into the CS

18 Diagnosis -Negative delta wave in lead II : highly specific finding for epicardial +Highest sensitivity (87%) +Low specificity (20-70%) -Positive delta in avr + Highest specificity (99%) + Moderate sensitivity (70%) -Deep S in V6 + Se: 70% + Sp:87% - Combination of 2 mentioned criteria: Highly accurate predictor -The differentiation between epicardial and left endocardial Ap: difficult.

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20 -The delta wave is negative in III, and AVF: posteroseptal region. - Delta wave is negative in lead II and positive in AVR. -AP can be localized to CS

21 The 12-lead electrocardiogram of a patient with manifest epicardial posteroseptal accessory pathway. Positive delta wave in lead avr, and deep S-wave in V6.

22 Target 1. Earliest ventricular activation during atrial pacing or earliest atrial activation during ventricular pacing/orthodromic reciprocating tachycardia. -Not ideal. For example, downward slanted posteroseptal pathway, the earliest atrial activation may be close to the compact AV node. 2. Fragmented or double potentials at the site of earliest atrial activation in the CS: during retrograde conduction -While further away from this site the potentials frequently fused producing a single patter - Antz clarify the double potential at CS. +One is sharp potential representing CS musculature +The other is rouded, recorded along the floor of the CS and usually ( leftward activation of the CS musculature).

23 3. The ideal site for successful ablation: at a site where the accessory pathway courses epicardially (accessory pathway potentials) -A strong relation between AP potential amplitude and success +The large amplitude of AP potential indicates close proximity to the AP -Differentiate with the other signal from: the atrial electrogram, ventricular electrogram, His bundle electrogram.

24 - Pacing at a more rapid rate causes block in the accessory pathway and subsequently block in the AV node, as well. -The A and V electrogram is seen to be easily dissociated from the accessory pathway potential (Ap)

25 - Power <30 W, irrigated <15 w RF delivery inside CS -Avoided in distal small branches of CS: -Slow flow Lack of cooling high temperature low power delivery, venous occlusion. -Intramural thrombosis of the CS has been reported. - Solution : + Larger catheter electrodes or fluid irrigation can be used

26 Outcomes of posteroseptal ablation - Successful rate: 93%-98% - Complication: +CS branch: venous perforation, tamponade, venous occlusion -Damage to the RCA - Heart block: rare, AV nodal artery -Recurrence: 6-50%.

27 Coronary Artery Injury - Extremely low (0.06% - 0.1% ) - Within 2 mm of the ablation site - Acutely or several weeks after ablation - The acute injury due to : + Vasospasm from thermal energy: reversible ST segment elevation, normal angiography + RF energy directly on a coronary artery: acute edema with wall thickening and luminal narrowing, thrombosis with complete obstruction -Delayed coronary injury: Intimal hyperplasia, damages to the arterial wall and endothelium, which provides a nidus for progressive thrombus formation weeks later

28 LAO: + Ablation catheter placed near the ostium of the middle cardiac vein. + A guiding sheath has engaged the right coronary artery

29 Ng.Th.T I II III AVR AVL AVF V1 V2 V3 V4 V5

30 Erliest at CS 9-10 during SVT

31 Intermitent AP after Abl

32 AP gone

33 Tr.Q.H

34 VA during tachy

35 AP potential

36 VA block after ablation

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44 CS aneurysm - The prevalence of CS aneurysms in patients with left posteroseptal AP: 2% to 26%. -If presented in postero AP, usually as connection.

45 - The majority of CS aneurysms are located along the inferoseptal aspect of the CS (usually within1.5 cm of the CS ostium) - 25% of the cases, aneurysm extends from the medial cardiac vein rather than from the CS itself -It Result from incomplete regression of the sinus venosus -Postmortem: muscular bundle within the wall of diverticulum, a continuation of the usual fibers found in the proximal coronary sinus. - When these fibers connect the atrial myocardium to ventricular myocardium, a complex epicardial accessory pathway is created.

46 -The aneurysm connects with the CS by either a narrow, intermediate, or broad neck. -These diverticulum all occurred in manifest AP due to bidirectional conduction. +A case reported by kivotaka (jpn circ J 2000) one pt with concealed AP successfully ablated at the neck of diverticulum. -The effective ablation was at the neck. At this site, a relative longer retrograde conduction, a larger potential AP - One approach to ablation: Circumferential ablation at the mouth of the diverticulum

47 -Extensive mapping in the right atrium, the coronary sinus (CS) and its branches, and the left atrium: was performed. No result - A CS: angiogram showed the presence of a diverticulum. The earliest ventricular activation was localized to the posteroregion -RF in this area failed to eliminate. -Subxiphoid percutaneous epicardial access, extensive endocardial and epicardial mapping was performed. - The earliest ventricular activation was mapped to the epicardial surface in the posteroseptal region).

48 - A coronary angiogram was performed to ensure that the ablation catheter was not in close proximity to one of the epicardial coronary arteries -The accessory pathway was eliminated after 6.5 seconds - Because of the thickness of the myocardium in this area, energy delivered from endocardial ablation often may not reach the epicardial location of the accessory pathway. - The epicardial ablation lesions were clearly at a distance away from the sites of attempted endocardial ablation. - Epicardial approach should be considered when repeated attempts of endocardial ablation fail

49 Cleveland, Ohio (PACE 2002; SAAD, E.B., ET AL.) -Three previous unsuccessful ablations -Large coronary sinus diverticulum: no electrogram recorded endocardially or within the CS diverticulum preceded the delta wave -Epicardial mapping through the pericardial approach: the earliest recorded activation, indicating an epicardial location. -However, RF at this site was not possible due to high impedances. +Reason: the presence of a relatively thick overlying epicardial fat pad located above the AP that impeded the delivery of energy -Intravascular linear lesions transecting the neck of the large coronary sinus diverticulum using the pericardial catheter: successful ablation

50 Monther Boulos report a case: -Two previous attempts had failed to ablate the posteroseptal AP - The presence of a large bilobar CS aneurysm with a relatively narrow connection between the two lobes AP (left panel), and left anterior oblique (right panel) views.

51 Use the antegrade approach for ablation because + The previous failed attempts +The possible presence of multiple connection sites between the CS musculature and the left atrium - This very low ventricular insertion site may also be one of the reasons for the absence of a deep S wave in lead V6 during sinus rhythm in this patient.

52 Carto was used: - Mapping within the CS aneurysm: delineated its geometry + The earliest ventricular site at the lowest portion (4-5 cm beneath the CS ostium) of the aneurysm. +Preceded the delta wave by 51 ms -A single RF application delivered at this site was sufficient to terminate conduction via this accessory pathway.

53 -The fusion of the local CS aneurysm-related potential with the earliest ventricular electrogram prior to RF ablation. - The dissociation between the two potentials following successful ablation

54 Neil C. Davidson, (Circulation. 2001;104: ) 39-year-old woman presented with atrial fibrillation, -Accessory pathway conduction was abolished surgically - Follow-up electrophysiological study demonstrated a residual accessory ventriculoatria connection. coronary sinus angiography was performed. Large saccular diverticulum at the coronary sinus os in the posterior septum and a smaller diverticulum next to the posterior cardiac vein which are labeled D1 and D2. PCV indicates posterior cardiac vein.

55 - Orthodromic tachycardia was easily inducible, with the accessory pathway as the retrograde limb. - During ventricular pacing, the earliest atrial activation was in the smaller diverticulum -Radiofrequency ablation resulted in loss of retrograde conduction after 3 seconds

56 Practical Approach -Begin at right sided, except strongly suggest left-sided ( R/S ratio in lead V1 1) -CS and its branches is recommended: after a brief mapping of the right posteroseptal area - CS venography done if no site found (esp: AVR (+), deep S at V6): The presence of venous anomaly identify the site of AP - If no, left sided tried, Epicardial approach - Electroanatomical mapping: more complex CS anomalies, multiple accessory pathway

57 XIN CHÂN THÀNH CẢM ƠN