Samir Rafla technique of ablation of AVNRT and case presentation
Technique of Ablation ofAVNRTAnd case presentationProf. Samir Rafla, FACC, FESCAlexandria Univ.
Catheter position for radiofrequency slow pathway ablation. Thetip of the ablation catheter is between the coronary sinus (CS) osand the tricuspid valve in the right anterior oblique (RAO) view. Inthe left anterior oblique (LAO) view, the tip of the ablation catheteris just posterior (septal) to the His catheter at the level of thecoronary sinus os. Note the angled sheath supporting the ablationcatheter.
A, Right anterior oblique (RAO) view of the cardiac anatomysurrounding the triangle of Koch (upper left) and catheter positionsfor ablation of the slow pathway as shown in (upper right).
Annotated versions of the upper figures. In the lower right, the catheterpositions are superimposed on the cardiac anatomy, showing theablation catheter tip for slow pathway ablation in the area between thecoronary sinus (CS) os and the tricuspid valve (TV).
The areas for slow and fast pathway ablation are shaded inred. In the lower right panel, the salient cardiac anatomicfeatures are superimposed on the RAO fluoroscopic view ofthe catheter positions.
Progression of ablation sites (shaded yellow areas) for slow pathway ablation.Left panels show RAO views, right panels show LAO views. 1. The first ablationattempts are directed at the area between the coronary sinus (CS) os (dashedcircle) and the tricuspid valve no more superiorly than the roof of the CS. 2. Thesecond area for ablation is between the CS and tricuspid valve (TV) but inferiorto the CS os. 3. The third area is the proximal CS. 4. The last area for ablationis more superiorly on the septum above the level of the CS os. The risk foratrioventricular block is increased with ablation superior to the CS os.
Limits of anatomic sites for slow pathway ablation. A, In the left anterior oblique (LAO)view, acceptable areas for ablation are slightly septal to the His catheter and generallybetween 3 and 6 oclock, with the His catheter representing 12 oclock and the roof of theCS 6 oclock. B, Right anterior oblique view of ablation catheter (AB) at the level of thecoronary sinus (CS) os near the tricuspid annulus. The estimated boundaries of thetriangle of Koch are delineated by the broken lines. The green marker indicates thecaudal to cranial limits with the lowest incidence of heart block. This area corresponds tosites inferior to the CS os to the superior margin (roof ) of the CS os. The area in red,beginning near the mid-point between the CS os and the His recording, represents ahigh risk for atrioventricular block. The area in yellow, beginning at the roof of the CS, isintermediate risk for heart block.
Case : Case SummaryThe patient is a 73-year-old female witha long history of palpitations andhypertension. Echo reveals normalLVEF with an LA diameter of 38 mm.The transesophageal EPstudy revealed SVT, which was inducedwith minimum effort .
Fig. 1.1 The 12-lead resting ECG (paper speed 25 mm/s)showed sinus rhythm with a ventricular rate of 80 bpm ashort PR interval (102 ms) and a QRS width of 80 ms
Case DiscussionAlthough the patient is elderly, the ECGshows a regular narrow complextachycardia. Atrial tachycardia, AVNRT,and AVRT should all be considered. Inthis case, no visible P waves are seenduring the SVT. This suggests eitherAVNRT or AT with a long PR interval. Inthis case, AVNRT was induced in the EPlab and successfully ablated (Figs. 1.3–1.16).
Fig. 1.3 Intracardiac recordings taken at baseline during theelectrophysiology study (paper speed 200 mm/s). Four surface ECG leads (I,aVF, V1, V6), one bipolar recording from the high right atrium (HRA), threebipolar recordings from the His bundle region (distal = HIS D, intermediate =HIS I and proximal = HIS P), two bipolar recordings from the coronary sinus(CS prox =proximal coronary sinus and CS dist = distal coronary sinus), andthe distal bipolar recording of the mapping catheter (MC D). A atrium, Vventricle, H His bundle
Fig. 1.4 (a, b). Intracardiac recordings taken during programmed atrial stimulation(paper speed 200 mm/s). Same display that is shown in Fig. 1.3. (a) With a couplinginterval of 410 ms the AH interval is 188 ms and (b) with a coupling interval of 280ms it suddenly increased to 307 ms (ERP of the fast pathway with a jump of 120 ms)a
Fig. 1.5 Intracardiac recordings taken during programmed atrial stimulationwith two beats with retrograde conduction through the fast pathway (S slowpathway and F fast pathway) (paper speed 100 mm/s). Same display as thatshown in Fig. 1.3
Fig. 1.8 Intracardiac recordings taken during programmed atrial stimulation with aninfusion of isoproterenol IV (paper speed 100 mm/s) showing induction of AVNRT (cyclelength 300 ms).
Fig. 1.9 Intracardiac recordings (paper speed 200 mm/s). Same display as shown inFig. 1.3. Pace mapping of the anteroseptal region of Koch’s triangle with a stim-Hinterval of 78 ms. St pacing, A atrium, V ventricle, H His bundle
Fig. 18.10 Intracardiac recordings (paper speed 200 mm/s). Same display asFig. 1.19-3. Pace mapping of the midseptal region of Koch’s triangle with a stim-Hinterval of 81 ms. St pacing, A atrium, V ventricle, H His bundle
Fig. 1.11 Intracardiac recordings (paper speed 200 mm/s). Same display as shown inFig. 1.3. Pace mapping of the posteroseptal region of Koch’s triangle with a stim-Hinterval of 106 ms. St pacing, A atrium, V ventricle, H His bundle
Fig. 1.12 Intracardiac recordings (paper speed 200 mm/s). Same display asshown in Fig. 1.3. Ablation site slow pathway potential
Fig. 1.16 RAO and LAO of mapping catheter at theablation site in the posteroseptal part of Koch’s triangleDelise P, Sitta N, Bonso A, et al. Pace mapping of Koch’s triangle reduces risk ofatrioventricular block during ablation of atrioventricular nodal reentrant tachycardia. JCardiovasc Electrophysiol. 2005;16:30-35.