H. Barakpour,MD.,Electrophysiologist November 2014,Javad-Alaeme Heart Hospital

Originates in sinus node (automaticity) bpm resting Up to 200 bpm Conduction through normal AV axis P wave morphology reflects site of onset

Atrial arrhythmias (AT, AFL and AF) Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET) Atrioventricular reentrant tachycardia (AVRT) Wolf-Parkinson-White Syndrome Orthodromic AVRT Antidromic AVRT

May be variable Palpitations, chest pounding, neck pounding Weakness/malaise Dyspnea Chest pain Lightheadedness Near syncope/syncope Symptoms usually abrupt in onset and termination May have history of symptoms since childhood or have a positive FHx

In absence of tachycardia, usually normal Rapid heart rate ( ) May be irregular or regular BP may be low or with narrow pulse pressure Neck veins may reveal cannon waves

AV nodal dependent arrhythmias AVNRT (micro-reentrant circuit) AVRT (macro-reentrant circuit): anti/orthodromic JET (junctional ectopic tachycardia) - childhood and associated with congenital heart disease AV nodal independent arrhythmias Atrial tachycardia Inappropriate Sinus Tachycardia Sinus Node Reentrant Tachycardia Atrial flutter Atrial fibrillation

AVRT FP SP

Short “RP” Tachycardias: Typical AVNRT AVRT Long “RP” Tachycardias: Atrial Tachycardia Atypical AVNRT AVRT with long retrograde conduction PJRT

Short RP AVRT AT Slow-Slow AVNRT Long RP AT Atypical AVNRT PJRT P buried in QRS Typical AVNRT AT JET

Valsalva maneuvers Carotid sinus massage Slows SA nodal and/or AV nodal conduction Adenosine Slows sinus rate Increases AV nodal conduction delay 6 or 12 mg bolus Effect blocked by theophylline, methylxanthines (caffeine); and potentiated by dipyridamole

Most SVTs triggered by a PAC If the PAC conducts with a long PR, dual AV 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

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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 (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)

Adenosine Injection I II III aVR aVL aVF V1 V2 V3 V4 V5 V6

AV block Wenckebach Variable block (e.g. atrial tachycardias) 2:1 with typical flutter; odd multiples with atypical flutter Multifocal atrial tachycardia (MAT) Atrial Fibrillation (with or w/o pre-excitation)

Ectopic atrial focus Reentrant, automatic or triggered bpm 1:1 AV conduction Paroxysmal or “warm up” P wave morphology variable

Usually 1:1 AVN conduction and persistence despite AV block Usually from right atria (Ring of Fire) Can be seen as an incisional tachycardia from previous surgery..i.e. ASD repair May see remission in children so do not attempt ablation until adulthood

Focal Atrial Tachycardia CSO IVC RAFW RAA LAA LAFW PV SN IASIASIASIAS CT * * * SVC

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II III aVL I MAP dist MAP prox CT 1,2 CT 5,6 CT 9,10 CT 15,16 CT 3,4 CT 7,8 CT 13,14 CS dist CS prox CT 11,12 Earliest Atrial Activation : Right Atrial Appendage - 23 msec

Catheter location : Right atrial appendage RAO LAO CT MAP CS His CT MAP CS His

II III aVL I MAP dist MAP prox CT 1,2 CT 5,6 CT 9,10 CT 15,16 CT 3,4 CT 7,8 CT 13,14 CS dist CS prox CT 11,12 CT 17,18 CT 19,20 Sinus Rhythm Atrial Tachycardia RF on 1.9 sec

Reentrant circuit localized to the RA bpm 2:1 or variable AV block Classic “saw-tooth” P waves

Activation on Halo Catheter II aVF V1 CS Os TA 1,2 TA 3,4 TA 5,6 TA 7,8 TA 9,10 TA 11,12 TA 13,14 TA 17,18 TA 19,20 Typical = Counterclockwise TA 19,20 CS Os TA 9,10 TA 1,2

Activation on Halo Catheter Atypical = Clockwise II aVF V1 CS Os TA 1,2 TA 3,4 TA 5,6 TA 7,8 TA 9,10 TA 11,12 TA 13,14 TA 17,18 19,20 TA 19,20 CS Os TA 9,10 TA 1,2

RF Ablation of Atrial Flutter Atrial flutter involves a macro-reentry circuit within the right atrium. Critical areas of conduction within the right atrium are necessary to sustain atrial flutter. RF ablation of conduction within such critical sites (most commonly the inferior vena cava-tricuspid valve isthmus) abolishes atrial flutter in 85% of cases. Cosio FG. Am J Cardiol. 1993;71:

Chaotic atrial rhythm due to multiple reentrant wavelets bpm Ventricular rate irregular and rapid due to variable AV block

Morphology and location of P wave relative to QRS distinct

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 bpm but may exceed 200 bpm

 AVNRT is typically paroxysmal and may occur spontaneously in patients or upon provocation with exertion, coffee, tea or alcohol. It is more common in women than men (~75% of cases occurring in women) and may occur in young and healthy patients as well as those suffering chronic heart disease.

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 wave absence help distinguish AVNRT from AVRT and atrial tachycardia

Initiation and termination by PACs, PVCs or atrial pacing during AVW Dual AVN physiology Initiation depends on critical A-H delay Concentric retrograde atrial activation(V-A -42 to 70 msec) Retrograde P wave within QRS with distortion of terminal portion of the QRS Atrium, His bundle and ventricle not required vagal maneuvers slow and then terminate SVT

Initiation and termination by PACs, PVCs, or ventricular pacing during VAW Dual retrograde AVN physiology Initiation depends 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 vagal maneuvers slow and then terminate SVT, always in the retrograde slow pathway

NSRAVNRT

Normal sinus rhythm Junctional tachycardia

Second electrical connection exists between the atria and ventricles (accessory pathway) Resemble atrial tissue Results in a short PR and Delta wave (pre-excitation) Some AP conducts only retrograde (concealed)

Pre-excitation affects 3/1000 patients on routine screening….not all develop PSVT Antegrade (delta wave) and retrograde conduction More common in men Most present in young adulthood 15% incidence of AFIB Multiple pathways in 10%

165 children (5-12 years) screened 60 randomized, 13 withdrew: 20 ablation and 27 no ablation 1 child in ablation group had arrhythmia (5%) and 12 of 27 in control group ( 44% ) 2 children in control group had VF and one died Pappone et al; NEJM 2004;351:

The most common arrhythmia is orthodromic AV reentrant tachycardia (narrow QRS) Less common are pre-excited tachycardias (wide QRS)

Activation sequence is ventricle via atria; therefore P wave often in the ST or T. Left lateral AP: (+) Delta V1; (-) Delta I Right sided AP: (-) Delta V1 {QS pattern}; (+) Delta I Concealed AP :implies only retrograde conduction; i.e. no pre-excitation and only orthodromic AVRT.

Conduction down AV axis during tachycardia gives NARROW QRS complex

Pre-excited Tachycardia Mechanisms AVRT AT AVNRT Conduction down AP during tachycardia gives WIDE QRS complex

Chronic tachycardia in otherwise structurally normal heart as the sole cause of developing ventricular dysfunction Can follow any chronic cardiac tachyarrhythmia

50% have SV ectopics Sustained arrhythmia rare (2-3/1000) Symptomatic increase in 20% Risk to mother and fetus AA drugs toxic and should be reserved for only highly symptomatic patients Role of RF ablation

Obtain a 12 lead ECG. The location of the P wave will dictate the differential diagnosis. If hemodynamically unstable (chest pain, heart failure, hypotension) CARDIOVERSION If hemodynamically stable AV NODAL AGENT Long term therapy depends on mechanism and can be conservative, pharmacologic or invasive EP study often needed for definitive characterization of mechanism and can cure most SVTs with 90% success rate

:Symptomatic patients AVNRT (>90% succes rate) WPW and symptomatic AVRT (>90%) A.Flutter (>90%) A.Fib (40-70%) High risk for sudden death: AFib with WPW and cycle length <250 ms Not amenable to catheter ablation: MAT Reversible causes (thryotoxicosis; post-op,…)