Differentiation between AVNRT and AVRT_advanced lecture
Advanced AVNRT and AVRT With differentiation Advanced EP Training (中華民國心律醫學會) 謝敏雄 醫師 台北醫學大學醫學系副教授 萬芳醫院心臟內科主任 April 24, 2011 於台北國際飯店
Supraventricular tachycardia (SVT) • Etiology: (臺北榮總十三年經驗) 1. AVNRT (n=1452): 50% Typical (slow-fast) 90% Atypical (fast-slow) 7% Variant (intermediate) 9% 2. AVRT (n=1221): 42% orthodromic (fast AP 90% or slow AP 10%) 3. AT (n=245): 8%
12-lead ECG fordifferential diagnosis of SVTs (important!)
Retrograde P wave in SVT (Tai CT et al. JACC 1997)
Short RP SVT1. Slow-Fast AVNRT: No apparent retrograde P wave: 50% Pseudo R’ in V1 or pseudo-S in inferior leads: 50%2. Orthodromic AVRT: 70 ms<RP<PR The presence of delta wave in NSR.3. AT with PR prolongation: the presence of AV block favors AT.
Favors AVNRT1. The presence of dual AVN physiology: upper or lower common pathway.2. The critical prolongation (jump) of AH interval during the initiation of SVT.3. The concentric atrial activation: especially a straight line from ECG-A-V or A before V (SF AVNRT)
AVNRT• Antegrade SAVN: AH jump > 50 ms• Continuous curve AVNRT• Retrograde SAVN:1.Long VA interval2.CSO-A earliest.• Retrograde intermediate AVN:1.Intermediate VA interval2.His-A and CSO-A both earlier• AVNRT with retrograde eccentric activation
Continuous curve AVNRT (Tai CT et al. Circulation 1997)
Initiation of S-F AVNRT Progressive AH prolongation with jump
Lower common of VA interval Progressive prolongation pathway V A V AV AV A
AVNRT with eccentric A activation (Ong M. et al. IJC 2007)
Favors AVRT1. No decremental conduction during pacing (except slow AP).2. The eccentric atrial activation with short VA interval (>70 ms)3. VA interval increases >30 ms with functional BBB.
His refractory VPC• 35-55 ms before the His deflection.• Advance the following A: AVRT• VPC without conducting to atrium but terminate the SVT: rule out AT.• VPC from the sites other than RVA: LV: for left side APs RVOT: for septal APs
Ventricular Overdrive Pacing (VOP) (10-40 msshorter than tachycardia) during SVT
VOP entrains the SVT• VOP could not entrain SVT: AT• The same atrial activation sequence: AVNRT or AVRT The different atrial activation sequence: AT• The presence of lower common pathway: AVNRT is more likely.• The presence of V-A-A-V response: AT• The presence of V-A-V response: favors AVNRT or AVRT.
VOP during SVT A A V V AT1. The retrograde A sequence is different during tachycardia and VOP2. The presence of V-A-A-V response during VOP (Veenhuyzen G. et al. PACE 2011)
Para-Hisian pacingHirao, K. et al. Circulation 1996;94:1027-1035
Ablation Strategy of AVNRT• Make a correct diagnosis!!!• Ablation of slow or intermediate AVN1. Anatomic approach: P M A2. Electrogram approach: small A, large V3. JT during RF• How to avoid AV block?1. ablation during A pacing2. avoid ablation during SVT or V pacing.3. You have only one second to stop RF!!!
Flat and horizontal Koch’s Triangle RAO LAO (Lee PC et al. Curr Opin Cardiol. 2009)
Ablation Strategy of AVRT• Make a correct diagnosis!!!• Localization of the APs: 12-lead ECG algorithm and intracardiac recordings.• Antegrade approach: for RT AP• Retrograde approach: for LT AP1. V site (subvalvular): small A, large V, stable ablation catheter2. A site (ante- or retro-grade): larger A, unstable ablation catheter