AVNRT
• Most common cause of a regular narrow complex tachycardia
• Involves a slow and a fast pathway in the region of the AV node
• Turn around point appears above the bundle of His
arrhythmias? • Which patients should be offered catheter ablation? • Atrial Fibrillation and Atrial Flutter • What are the incidence and prevalence of atrial fibrillation? • What are the major sequelae of atrial fibrillation? • What are the risk factors for stroke in atrial fibrillation? • What are the treatment options for patients with atrial
RP relationship
• Short “RP” Tachycardias: Typical AVNRT AVRT
• Long “RP” Tachycardias: Atrial Tachycardia Atypical AVNRT AVRT with long retrograde conduction PJRT
vagal , maneuvers slow and then terminate SVT, always in the retrograde slow pathway
AVNRT Treatment
• Low threshold for catheter ablation given long term success rate > 90% and low risk of complications
2) (-) or biphasic in V1
• Left atrial focus:
1) (-) or isoelectric in aVL 2) (+) V1 suggests back to front
Tachycardia onset
• Most SVTs triggered by a PAC • If the PAC conducts with a long PR, dual AV
Supraventricular arrhythmias
Jerry John July 29, 2009
Objectives
• Supraventricular Arrhythmias • How do supraventricular arrhythmias manifest? • What are the common supraventricular arrhythmias? • What is the mechanism of atrioventricular arrhythmias? • Which drugs are used in the management of supraventricular
• AVNRT p waves however can be buried in the QRS if VA conduction is very short
• Ends with a QRS : almost always atrial tachycardia (some rare AV node dependent tachycardias can terminate in this manner)
wave absence help distinguish AVNRT from AVRT and atrial tachycardia
AVNRT
• Initiation and termination by APDs, VPDs or atrial pacing during AVW
• Dual AVN physiology • Initiation depends on critical A-H delay • Concentric retrograde atrial activation(V-A -42 to 70
nodal physiology is suggested with the conduction being through the slow pathway • If a PVC initiates SVT, it is likely to be AV node dependent
Tachycardia termination
(short/long)
P waves
• (-) Inferior leads atrial activation from low to high: AVNRT, atypical AVNRT; AVRT
• Right atrial focus:
1) (-/+) in aVL right atrium activated first and then left atrium)
(caffeine); and potentiated by dipyridamole
P waves
• Rate • Morphology (Sinus/Retrograde/abnormal) • Conduction (2:1; 3:1, etc.) • Response to AV Block • VA conduction (i.e. R-P relationship):
• P wave
– Rate – Morphology (Sinus/Retrograde/abnormal): look at the T waves and
the psuedo R (V1) and psedo S (inferior leads) – Conduction (2:1; 3:1, etc.) – Response to AV Block – VA conduction (i.e. R-P relationship): (short/long)
JACC 2009; 53:2353-58
EKG
• AV node dependent (Y/N) • Re-entrant circuit (Y/N)
– Circuit (Macro/Micro) – Anatomic (e.g. previous ASD repair, CVTI) – Accessory pathway ( WPW, Mahaim, etc. )
Where’s the P wave
• Valsalva • Carotid sinus massage
– Slows SA nodal; and/or AV nodal conduction
• Adenosine
– Slows sinus rate – Increases AV nodal conduction delay – T ½ 5 seconds – 6 or 12 mg bolus – Effect blocked by theophylline, methylxanthines
• Ends with a P wave: suggests an AV nodal dependent arrhythmia because the generation of the P wave without a QRS suggests block in the AV node… this is more likely to be AVNRT or AVRT
AV Node Depdendence (Y/N)
AV nodal dependent arrhythmias • AVNRT (micro-reentrant circuit) • AVRT (macro-reentrant circuit): anti/orthodromic • JET (junctional ectopic tachycardia) - childhood and
• AV nodal blocking agents (diagnosis/treatment)
– Adenosine – BB/CCB – Digoxin
Atypical AVNRT
• Initiation and termination by APDs, VPDs, or ventricular pacing during retrograde AVW
• Dual retrograde AVN physiology • Initiation dependent on critical H-A delay • Earliest retrograde activation at CS os • Retrograde P wave with long R-P interval • Atrium, His bundle, and ventricle not required,
• 160-190 bpm but may exceed 200 bpm • Slow-fast form accounts for 90% of AVNRT • Fast-slow or slow-slow AVNRT accounts for 10% • Pseudo r’ in V1, pseudo S wave in 2,3,avf, and p
msec) • Retrograde P wave within QRS with distortion of
terminal portion of the QRS • Atrium, His bundle and ventricle not required , vagal