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Supraventricular Arrhythmias

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Supraventricular Arrhythmias. Ira R. Friedlander, M.D. 8/26/14. Definition. Rapid heart rhythm during which the electrical impulse propagates down the normal His Purkinje system similar to normal sinus rhythm Distinct from ventricular tachycardia which only originates in the ventricles. - PowerPoint PPT Presentation

Text of Supraventricular Arrhythmias

  • Supraventricular ArrhythmiasIra R. Friedlander, M.D.8/26/14

  • DefinitionRapid heart rhythm during which the electrical impulse propagates down the normal His Purkinje system similar to normal sinus rhythm Distinct from ventricular tachycardia which only originates in the ventricles

  • Mechanisms of ArrhythmiaAutomaticityEnhanced automaticity Abnormal automaticity

  • Mechanisms of ArrhythmiaTriggered ActivitySmall depolarizations during or just after repolarization (phases 3 or 4) which can trigger a new depolarization.

  • Mechanisms of ArrhythmiaReentry-most common mechanismShort circuit that forms between two pathways that are either anatomically or functionally distinctTypically:Path 1: Slow conduction, short refractory periodPath 2: Rapid conduction, long refractory period

  • ReentryPanel A: Most impulses conduct down both pathways.Panel B: Unidirectional block, due to longer refractoriness in one pathway.Panel C: Potential to have reentry back up the previously refractory pathwayPanel D: Reentry then can persist.

  • Supraventricular ArrhythmiasAtrial arrhythmias (AT, AFL and AF)Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET)Atrioventricular reentrant tachycardia (AVRT)Wolf-Parkinson-White SyndromeOrthodromic AVRTAntidromic AVRT

  • SVT: Symptoms May be variablePalpitations, chest pounding, neck poundingWeakness/malaiseDyspneaChest painLightheadednessNear syncope/syncopeSymptoms usually abrupt in onset and terminationMay have history of symptoms since childhood or have a positive FHx

  • SVT: Physical ExamIn absence of tachycardia, usually normalRapid heart rate (150-250)May be irregular or regular (mechanism)BP may be low or with narrow pulse pressureNeck veins may reveal cannon waves.

  • Sinus RhythmOriginates in sinus node (automaticity)50-100 bpm restingUp to 200 bpmConduction through normal AV axisP wave morphology reflects site of onset

  • Atrial TachycardiaEctopic atrial focusReentrant, automatic or triggered150-250 bpm1:1 AV conductionParoxysmal or warm upP wave morphology variable

  • 20 yr woman with post-partum congestive heart failure

  • Adenosine Injection

  • Post- Adenosine Injection

  • Catheter location : Right atrial appendageRAOLAO

  • Earliest Atrial Activation : Right Atrial Appendage- 23 msec

  • Sinus RhythmAtrial TachycardiaRF on1.9 sec

  • Atrial FlutterReentrant circuit localized to the RA 250-350 bpm2:1 or variable AV blockClassic saw-tooth P waves

  • IIaVFV1CS OsTA 1,2TA 3,4TA 5,6TA 7,8TA 9,10TA 11,12TA 13,14TA 17,18TA 19,20Typical = CounterclockwiseTA 19,20CS OsTA 9,10TA 1,2

  • Atypical = ClockwiseTA 19,20CS OsTA 9,10TA 1,2

  • Atrial FibrillationChaotic atrial rhythm due to multiple reentrant wavelets350-500 bpmVentricular rate irregular and rapid due to variable AV blockHTN, valvular dz., metabolic dz., CMP, EtOH

  • Atrial FibrillationThe rapid atrial activity results in: Increased risk of thrombus formation and strokeRapid and irregular ventricular rate

    The treatment is aimed at:Decreasing the risk of stroke (coumadin, ASA)Decreasing the ventricular rate (beta-blockers, calcium channel blockers, digoxin)Restoring the rhythm to sinus (drug therapy, catheter ablation, surgical Maze)

  • Atrial FibrillationAdvantages of rhythm control: Abolition of symptomsHalting atrial enlargementImprovement in left ventricular function and exercise capacityDisadvantages of rhythm control:Subjecting patients to drug therapy and/or procedure that might be associated with complications

  • Atrial FibrillationTreatmentIn patients with minimal symptoms and normal left ventricular function: Coumadin/ASARate control (drugs, AVJ ablation + BV pacing)

    In patients with significant symptoms and/or left ventricular dysfunction:Coumadin/ASARate control (drugs, AVJ ablation + BV pacing)Rhythm control (anti-arrhytmic drugs, catheter ablation)

  • Drug Therapy to Maintain Sinus Rhythm in Patients with Recurrent Paroxysmal or Persistent Atrial Fibrillation ACC/AHA/ESC Guidelines

  • Atrial FibrillationCatheter AblationAblate PV potentials PV Isolation Pappone (circumferential LA ablation)

  • AV Nodal Reentrant TachycardiaMorphology and location of P wave relative to QRS distinct

  • 27 y.o with palpitations

  • Pseudo R in V1 during tachycardiaNSRAVNRT

  • Junctional Ectopic Tachycardia

  • Normal sinus rhythmJunctional tachycardia

  • Wolff-Parkinson-White SyndromeSecond electrical connection exists between the atria and ventricles (accessory pathway)Resemble atrial tissueResults in a short PR andDelta wave (pre-excitation)Some AP conducts only retrograde (concealed)

  • Arrythmias in WPWThe most common arrhythmia is orthodromic AV reentrant tachycardia (narrow QRS)Less common are pre-excited tachcyardias (wide QRS)Antidromic AV reentrant tachycardia Atrial tachycardia/flutter with pre-excitationAVNRT with pre-excitationAtrial fibrillation with pre-excitation (most life threatening due to rapid ventricular response)

  • Orthodromic AVRTConduction down AV axis during tachycardia gives NARROW QRS complex

  • Pre-excited Tachycardia MechanismsAVRTATAVNRTConduction down AP during tachycardia gives WIDE QRS complex

  • Atrial Fibrillation

  • RF Ablation in WPW

  • SUMMARYMechanisms of SVTAtrial TachycardiaAVNRTAVRTFPSP

  • Differential Diagnosis of NCTShort RPAVRTATSlow-Slow AVNRT

    Long RPATAtypical AVNRTPJRT

    P buried in QRSTypical AVNRTATJET

  • SUMMARYObtain a 12 lead ECG. The location of the P wave will dictate the differential diagnosisIf hemodynamically unstable (chest pain, heart failure, hypotension) CARDIOVERSIONIf hemodynamically stable AV NODAL AGENTLong 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

    Does seeing the next ECG help youPredictions about V:A time for DDXCircuits require two pathways with different conduction vel and different refractory periods