Management of Supraventricular Management of Supraventricular TachycardiasTachycardias

Sandeep K. Jain, M.D.Sandeep K. Jain, M.D.Cardiac ElectrophysiologyCardiac Electrophysiology

May 31, 2008

HistoryHistory

Pattern of symptoms / palpitationsPattern of symptoms / palpitations

TriggersTriggers Caffeine, tobacco, alcoholCaffeine, tobacco, alcohol Nasal decongestantsNasal decongestants Emotional eventsEmotional events

SyncopeSyncope

Physical ExamPhysical Exam

AV dissociationAV dissociation

Split S2Split S2

More than one arrhythmia can yield More than one arrhythmia can yield similar exam findings so not as useful for similar exam findings so not as useful for making a diagnosismaking a diagnosis

SVT mechanismsSVT mechanisms Sinus tachycardiaSinus tachycardia Atrial flutterAtrial flutter Atrial fibrillationAtrial fibrillation Junctional tachycardiaJunctional tachycardia Atrial tachycardiaAtrial tachycardia AV node reentry tachycardia (AVNRT)AV node reentry tachycardia (AVNRT) Accessory pathway mediated tachycardia Accessory pathway mediated tachycardia (AVRT)(AVRT)

ECGECG

Are P-waves present?Are P-waves present?What are atrial and ventricular rates and What are atrial and ventricular rates and are they the same ?are they the same ?Regular or Irregular ?Regular or Irregular ?Is the PR or RP constant ?Is the PR or RP constant ?

Carotid Sinus MassageCarotid Sinus MassageIncreases vagal toneIncreases vagal toneSinus slowing and prolongs AV nodal Sinus slowing and prolongs AV nodal refractorinessrefractoriness

Sinus tach – gradually slows then returns Sinus tach – gradually slows then returns to rate prior to massageto rate prior to massageAVNRT or AVRT can terminateAVNRT or AVRT can terminateAT, AF and AFL ventricular response AT, AF and AFL ventricular response slowsslows

Sinus TachycardiaSinus Tachycardia

Gradual change in heart rateGradual change in heart rateNormal P-wave contourNormal P-wave contourConstant PR interval before each QRS Constant PR interval before each QRS unless there is AV block (long RP)unless there is AV block (long RP)Carotid massage or Valsalva will gradually Carotid massage or Valsalva will gradually slow rate and then resume to original rateslow rate and then resume to original rate

Almost always secondaryAlmost always secondaryManagement is to treat underlying causeManagement is to treat underlying cause

Rarely, inappropriate sinus tachycardia in Rarely, inappropriate sinus tachycardia in which case beta-blockers, Ca-blockers can which case beta-blockers, Ca-blockers can be utilizedbe utilizedSinus node reentry tachycardia is abrupt in Sinus node reentry tachycardia is abrupt in onset, anxiety related and can be treated onset, anxiety related and can be treated with RF ablationwith RF ablation

Atrial FlutterAtrial FlutterMacro-reentrant rhythm in the atriaMacro-reentrant rhythm in the atriaUsually associated with underlying heart Usually associated with underlying heart diseasediseaseTypical flutter is in the right atrium and can Typical flutter is in the right atrium and can travel in counterclockwise and clockwise travel in counterclockwise and clockwise directionsdirectionsIncisional scars from prior cardiac surgery / Incisional scars from prior cardiac surgery / congenital abnormalitiescongenital abnormalitiesAtrial rate is typically 250-350 beats/minAtrial rate is typically 250-350 beats/minVentricular rate of 150 – look out for 2:1 Ventricular rate of 150 – look out for 2:1 flutterflutter

Counterclockwise Clockwise

Diagnostic maneuvers - AdenosineDiagnostic maneuvers - Adenosine

Atrial Flutter - ManagementAtrial Flutter - ManagementRate control / anticoagulationRate control / anticoagulation Beta-blocker, Ca-blocker, DigoxinBeta-blocker, Ca-blocker, Digoxin Stroke risk likely not much different than atrial Stroke risk likely not much different than atrial

fibrillationfibrillationCardioversionCardioversion DCCV with low energies possible (50-100J)DCCV with low energies possible (50-100J) Ibutilide successful in 60-90%Ibutilide successful in 60-90%

Prolongs QT and need to be monitored 4-6 hoursProlongs QT and need to be monitored 4-6 hours post administrationpost administration

Overdrive atrial pacing if availableOverdrive atrial pacing if available

Atrial Flutter - ManagementAtrial Flutter - Management

AntiarrhythmicsAntiarrhythmics Class Ia and Ic agents – convert and maintain Class Ia and Ic agents – convert and maintain

sinus rhythmsinus rhythm Class III – amiodarone, sotalol, dofetilideClass III – amiodarone, sotalol, dofetilide

Need to have AV nodal agent on board to Need to have AV nodal agent on board to prevent 1:1 flutter prevent 1:1 flutter Flutter rate slows and allows 1:1 conductionFlutter rate slows and allows 1:1 conduction Class IA agents also have a vagolytic effectClass IA agents also have a vagolytic effect

Flecainide administrationFlecainide administration

Atrial Flutter - ManagementAtrial Flutter - Management

Radiofrequency AblationRadiofrequency Ablation High success rates for typical flutterHigh success rates for typical flutter Atypical circuits can be approached Atypical circuits can be approached

percutaneously with advanced mapping percutaneously with advanced mapping systemssystems

Significant proportion of patients eventually Significant proportion of patients eventually develop atrial fibrillation indicating develop atrial fibrillation indicating underlying substrate is the issueunderlying substrate is the issue

Atrial FibrillationAtrial Fibrillation

Multiple wavelets propagating in different Multiple wavelets propagating in different directions directions No effective atrial contractionNo effective atrial contractionMost common arrhythmiaMost common arrhythmia 1% of those older than 601% of those older than 60 5% of those older than 695% of those older than 69

Mutliple causes – consider mechanical such Mutliple causes – consider mechanical such as from an RA catheteras from an RA catheter

Atrial FibrillationAtrial FibrillationRate vs Rhythm ControlRate vs Rhythm Control No benefit of either if asymptomaticNo benefit of either if asymptomatic

AnticoagulationAnticoagulation Congestive Heart FailureCongestive Heart Failure HypertensionHypertension Age > 65Age > 65 DiabetesDiabetes StrokeStroke

Maintenance of sinus rhythm does not necessarily Maintenance of sinus rhythm does not necessarily eliminate stroke riskeliminate stroke risk

Atrial FibrillationAtrial FibrillationRate ControlRate Control Ca-blocker, Beta-blocker, digoxinCa-blocker, Beta-blocker, digoxin

ConversionConversion DCCVDCCV Class I : Procainamide, Flecainide, PropafenoneClass I : Procainamide, Flecainide, Propafenone Class III: Amiodarone, Sotalol (both poor as converting Class III: Amiodarone, Sotalol (both poor as converting

agents), ibutilideagents), ibutilide

Maintenance of sinus rhythmMaintenance of sinus rhythm Same as above + dofetilideSame as above + dofetilide 50-70% efficacy at 1 year50-70% efficacy at 1 year RF ablation is an emerging toolRF ablation is an emerging tool

Atrial TachycardiaAtrial Tachycardia

Rapid, focal discharge in the atriumRapid, focal discharge in the atriumRate generally 150-200 bpm Rate generally 150-200 bpm P-wave contour different from sinusP-wave contour different from sinusP-waves generally found in second half of P-waves generally found in second half of tachycardia cycle (long RP / short PR)tachycardia cycle (long RP / short PR)

Most commonly in those with structural Most commonly in those with structural heart disease but also seen in those without heart disease but also seen in those without any cardiac abnormalityany cardiac abnormality

Atrial TachycardiaAtrial Tachycardia

Adenosine ResponseAdenosine Response

Terminates tachycardia with an ‘R’ waveTerminates tachycardia with an ‘R’ wave

OROR

Tachycardia persists with AV BlockTachycardia persists with AV Block

Atrial Tachycardia - ManagementAtrial Tachycardia - Management

Beta- and Ca- blockersBeta- and Ca- blockersClass I antiarrhythmics in normal heartsClass I antiarrhythmics in normal heartsClass III antiarrhythmics in abnormal heartsClass III antiarrhythmics in abnormal hearts

Radiofrequency ablation for those who are Radiofrequency ablation for those who are refractory / intolerant to medicationsrefractory / intolerant to medications

AV Node Reentry TachycardiaAV Node Reentry TachycardiaRegular, sudden onset and termination at Regular, sudden onset and termination at rates between 150-250 bpm rates between 150-250 bpm QRS usually normal unless aberrancy is QRS usually normal unless aberrancy is presentpresentReentry within the AV nodeReentry within the AV nodeP-wave seen just prior to or just after the P-wave seen just prior to or just after the QRS complex (Short RP tachycardia)QRS complex (Short RP tachycardia)Usually occurs without any structural heart Usually occurs without any structural heart diseasedisease

AV Node Reentry TachycardiaAV Node Reentry Tachycardia

Antegrade limb is the slow pathwayRetrograde limb is the fast pathway

BaselineBaseline

AV Node Reentry TachycardiaAV Node Reentry Tachycardia

AVNRT 2:1AVNRT 2:1

AV Node Reentry - ManagementAV Node Reentry - Management

IV adenosine, vagal maneuvers, carotid massageIV adenosine, vagal maneuvers, carotid massageCa, Beta-blockers, rarely antiarrhythmicsCa, Beta-blockers, rarely antiarrhythmicsOverdrive atrial or ventricular pacingOverdrive atrial or ventricular pacing

RF ablation is usually treatment of choice for chronic RF ablation is usually treatment of choice for chronic management – cost-effective and high success management – cost-effective and high success rate (~1% incidence of AV block requiring rate (~1% incidence of AV block requiring permanent pacemaker)permanent pacemaker)

Accessory PathwaysAccessory PathwaysMuscular connections outside of the specialized Muscular connections outside of the specialized conduction system connecting the atrium and conduction system connecting the atrium and ventricle while bypassing the AV nodeventricle while bypassing the AV node

Can be manifest (WPW) or concealed (retrograde Can be manifest (WPW) or concealed (retrograde only conduction)only conduction)

Concealed pathways not apparent on ECGConcealed pathways not apparent on ECG

Manifest pathways have a delta wave representing Manifest pathways have a delta wave representing pre-excitation of ventricular tissue prior to pre-excitation of ventricular tissue prior to activation via the His-purkinje systemactivation via the His-purkinje system

Concealed Accessory PathwaysConcealed Accessory Pathways30% of people with SVT referred for EP evaluation30% of people with SVT referred for EP evaluationCan present with syncopeCan present with syncope

Normal baseline 12-lead ECGNormal baseline 12-lead ECG

Orthodromic atrioventricular reentry tachycardia is the Orthodromic atrioventricular reentry tachycardia is the mechanism of SVT (down the AV node and up the mechanism of SVT (down the AV node and up the accessory pathway)accessory pathway)

Will often see a retrograde P-wave during SVT – short Will often see a retrograde P-wave during SVT – short RP unless slowly conducting pathwayRP unless slowly conducting pathway

Orthodromic AV reentry tachycardiaOrthodromic AV reentry tachycardia

Most common arrhythmia with presence of an accessory pathway

Macro-reentrant circuit in which the impulse travels down the AV node andup the accessory pathway

Narrow QRS interval

Accessory PathwaysAccessory Pathways

Accessory PathwaysAccessory Pathways

Response to BBB AberrationResponse to BBB Aberration

Does VA interval increase with development of BBB?Does VA interval increase with development of BBB?

An increase in VA interval indicates the presence and An increase in VA interval indicates the presence and participation of a bypass tract on the side of the blocked participation of a bypass tract on the side of the blocked bundlebundle

Concealed Accessory PathwaysConcealed Accessory Pathways

Same management as for AV node reentrySame management as for AV node reentry

RF ablation should be considered early in RF ablation should be considered early in symptomatic patientssymptomatic patients

Atrial fibrillation in conjunction with a concealed Atrial fibrillation in conjunction with a concealed pathway does not pose a risk of sudden death pathway does not pose a risk of sudden death and IV Ca-blocker not contraindicated as the and IV Ca-blocker not contraindicated as the pathway does not conduct antegradepathway does not conduct antegrade

Pre-excitation syndrome - WPWPre-excitation syndrome - WPWWPW syndrome is when tachycardia is WPW syndrome is when tachycardia is associated with the finding of a delta wave on the associated with the finding of a delta wave on the ECGECGIncidence is 1.5 per thousandIncidence is 1.5 per thousandEbstein’s anomaly associated with multiple Ebstein’s anomaly associated with multiple bypass tractsbypass tractsBaseline ECG findingsBaseline ECG findings PR interval < 120msPR interval < 120ms QRS > 120ms with a slurred, slowly rising onset (delta QRS > 120ms with a slurred, slowly rising onset (delta

wave) and usually normal terminal portion of QRSwave) and usually normal terminal portion of QRS Secondary ST-T changes in opposite direction of delta Secondary ST-T changes in opposite direction of delta

wavewave

Accessory pathwaysAccessory pathways

Left free wall most common, then posteroseptal, right free wall and anteroseptal

Pre-excitation syndromesPre-excitation syndromes

Pre-excitation syndrome - WPWPre-excitation syndrome - WPW

Most common tachycardia is Orthodromic AVRT Most common tachycardia is Orthodromic AVRT as seen in concealed bypass tractsas seen in concealed bypass tracts

Major difference is the capacity for anterograde Major difference is the capacity for anterograde conduction over the pathway during atrial conduction over the pathway during atrial fibrillation (15-30%) or atrial flutter (5%) and thus fibrillation (15-30%) or atrial flutter (5%) and thus the rare incidence of sudden cardiac deaththe rare incidence of sudden cardiac death

Some children lose conduction in the pathway Some children lose conduction in the pathway but usually persists if present at age 5but usually persists if present at age 5

Pre-excitation syndromesPre-excitation syndromes

Pre-excitation syndromesPre-excitation syndromes

WPW - TreatmentWPW - Treatment

ECG abnormality only without arrhythmias ECG abnormality only without arrhythmias may may notnot require EP evaluation require EP evaluation

Symptomatic patients should receive treatmentSymptomatic patients should receive treatment Ablation – Electrical or SurgicalAblation – Electrical or Surgical

Good success rates but with procedural risksGood success rates but with procedural risks PharmacologicPharmacologic

Drugs prolong conduction and/or refractoriness in the AV Drugs prolong conduction and/or refractoriness in the AV node, accessory pathway, or bothnode, accessory pathway, or bothSome agents can suppress premature atrial contractions Some agents can suppress premature atrial contractions which can induce arrhythmiaswhich can induce arrhythmias

WPW - TreatmentWPW - Treatment

Prolong conduction time and refractoriness in AV Prolong conduction time and refractoriness in AV node: node: Adenosine, verapamil, beta-blockers, digoxinAdenosine, verapamil, beta-blockers, digoxin

Prolong refractory period in accessory pathway:Prolong refractory period in accessory pathway: Class IA and IC drugsClass IA and IC drugs

Affect both AP and AV node:Affect both AP and AV node: Class IC drugs, amiodarone, and sotalolClass IC drugs, amiodarone, and sotalol

WPW – Acute EpisodeWPW – Acute EpisodeNormal QRS, regular R-R intervals, retrograde p-Normal QRS, regular R-R intervals, retrograde p-waveswaves Approach same as AVNRT – vagal maneuvers, Approach same as AVNRT – vagal maneuvers,

adenosine, IV Ca-blockeradenosine, IV Ca-blocker Note, atrial fibrillation can occur after drug Note, atrial fibrillation can occur after drug

administration, so external defibrillator back-up should administration, so external defibrillator back-up should be ready be ready

Atrial Fibrillation or Flutter with irregular R-R Atrial Fibrillation or Flutter with irregular R-R intervals and abnormal QRS complexesintervals and abnormal QRS complexes Agents which affect AV node and pathway Agents which affect AV node and pathway

(procainamide with beta blocker)(procainamide with beta blocker) Any signs of hemodynamic impairment – electrical Any signs of hemodynamic impairment – electrical

cardioversion is initial treatment of choicecardioversion is initial treatment of choice

WPW - TreatmentWPW - Treatment

DRUGS NOT TO USE in AF/AFL with WPWDRUGS NOT TO USE in AF/AFL with WPW:: DigoxinDigoxin has varying effects on the accessory pathway has varying effects on the accessory pathway

and can shorten refractoriness and speed ventricular and can shorten refractoriness and speed ventricular response to atrial fibrillationresponse to atrial fibrillation

IV IV LidocaineLidocaine can also increase ventricular response can also increase ventricular response raterate

IV IV VerapamilVerapamil can precipitate ventricular fibrillation in can precipitate ventricular fibrillation in this circumstance (may not happen with oral)this circumstance (may not happen with oral)

CatecholaminesCatecholamines

Supraventricular TachycardiasSupraventricular Tachycardias

Short RP / Long PRShort RP / Long PR

AV node reentryAV node reentryAV reentryAV reentry

Long RP / Short PRLong RP / Short PR

Atrial tachycardiaAtrial tachycardiaSinus node reentrySinus node reentryAtypical AV node Atypical AV node

reentryreentryAV reentry with a slowly AV reentry with a slowly

conducting pathwayconducting pathway