TACHYARRHYTHMIA TACHYARRHYTHMIA

Dr Syed RazaDr Syed Raza

Initial EvaluationInitial Evaluation

Hemodynamic stabilityHemodynamic stability History of CAD or previous MIHistory of CAD or previous MI History of syncopeHistory of syncope Depressed LV functionDepressed LV function Baseline ECGBaseline ECG Characteristics of the tachycardiaCharacteristics of the tachycardia

– Narrow complexNarrow complex– Wide complexWide complex– Other morphologic cluesOther morphologic clues

Should you use electrical Should you use electrical therapy?therapy?

Acute hemodynamic collapseAcute hemodynamic collapse Acute cardiac ischemia or infarctionAcute cardiac ischemia or infarction Tachycardia induced congestive Tachycardia induced congestive

heart failureheart failure Follow ACLS protocols in most casesFollow ACLS protocols in most cases

What’s the rhythm?What’s the rhythm?

To treat effectively means knowing the To treat effectively means knowing the differential diagnosesdifferential diagnoses

Use patient cluesUse patient clues ALWAYS obtain a proper 12-lead ECGALWAYS obtain a proper 12-lead ECG ECG “quick look”ECG “quick look”

– Narrow or wide complex?Narrow or wide complex?– Regularity?Regularity?– Possible preexcitation?Possible preexcitation?– Ischemic changes?Ischemic changes?

Narrow Complex Narrow Complex TachycardiaTachycardia

Differential diagnosesDifferential diagnoses– Sinus tachycardiaSinus tachycardia– Atrial tachycardiaAtrial tachycardia– Atrial fibrillation/flutterAtrial fibrillation/flutter– AV nodal reentrant tachycardiaAV nodal reentrant tachycardia– AV reentrant tachycardia AV reentrant tachycardia – Unusual VTsUnusual VTs

RP

PR

Looking at the PR-RP Looking at the PR-RP intervalsintervals

Long RP tachycardiaLong RP tachycardia– Sinus tachycardiaSinus tachycardia– Atrial tachycardiaAtrial tachycardia– Aytypical AVNRTAytypical AVNRT– Some AVRTsSome AVRTs

Short RP tachycardiaShort RP tachycardia– Typical AVNRTTypical AVNRT– Most AVRTsMost AVRTs

RP

PR

RP<PR (Short RP)

RP>PR (Long RP)

Atrial tachycardiaAtrial tachycardia

Can be an incessant rhythmCan be an incessant rhythm Rate: usually <220 bpmRate: usually <220 bpm Does not need the AV node for perpetuationDoes not need the AV node for perpetuation Adenosine response:Adenosine response:

– Transient AV block WITHOUT terminationTransient AV block WITHOUT termination– Transient AV block WITH termination Transient AV block WITH termination

(40%)(40%) Use your knowledge of the AV node to make Use your knowledge of the AV node to make

the diagnosisthe diagnosis

ATRIAL FLUTTER ATRIAL FLUTTER

ATRIAL FIBRILLATION WITH ATRIAL FIBRILLATION WITH RAPID VENTRICULAR RAPID VENTRICULAR RESPONSERESPONSE

ATRIO-VENTRICULAR ATRIO-VENTRICULAR NODAL RE ENTERANT NODAL RE ENTERANT TACHYCARDIA TACHYCARDIA ( AVNRT) ( AVNRT)

AV Nodal Reentrant AV Nodal Reentrant Tachycardia (AVNRT)Tachycardia (AVNRT)

Most common Most common reentrant SVTreentrant SVT

May achieve rates May achieve rates >200 bpm>200 bpm

Look for the psuedo-Look for the psuedo-R’ in V1 or NO P wave R’ in V1 or NO P wave AT ALL!AT ALL!

AV node dependent!AV node dependent! Most common type Most common type

(>90%) is the slow-(>90%) is the slow-fast variety (typical)fast variety (typical)

“pseudo-R’”

ATRIOVENTRICULAR RE ATRIOVENTRICULAR RE ENTERANT TACHYCARDIA ENTERANT TACHYCARDIA (AVRT)(AVRT)

Atrioventricular Atrioventricular Reciprocating Tachycardia Reciprocating Tachycardia (AVRT)(AVRT)

Can be orthodromic Can be orthodromic (most common) or (most common) or antidromic (very antidromic (very uncommon)uncommon)

Needs AV node to Needs AV node to perpetuate rhythmperpetuate rhythm

Always associated with Always associated with an AV bypass tractan AV bypass tract

May mimic AVNRT and May mimic AVNRT and atrial tachycardiaatrial tachycardia

Can be short or long RPCan be short or long RP

Therapies Therapies

Some atrial tachycardias (about 40%) Some atrial tachycardias (about 40%) can be terminated with adenosinecan be terminated with adenosine

Atrial flutter and fibrillation are not Atrial flutter and fibrillation are not terminated by changing AV nodal terminated by changing AV nodal conductionconduction– Consider rate controlConsider rate control– Electrical or chemical cardioverisionElectrical or chemical cardioverision– RF ablationRF ablation

Acute therapies for SVTAcute therapies for SVT

Many SVTs depend on the AV node for Many SVTs depend on the AV node for conduction (e.g. AVNRT, AVRT, etc)conduction (e.g. AVNRT, AVRT, etc)

Try affecting AV nodal conduction to Try affecting AV nodal conduction to terminate the tachycardiaterminate the tachycardia– ValsalvaValsalva– CSMCSM– AdenosineAdenosine– Beta-blockers, Ca channel antagonistsBeta-blockers, Ca channel antagonists– ELECTRO-PHYSIOLOGY AND RADIO ELECTRO-PHYSIOLOGY AND RADIO

FREQUENCY ABLATIONFREQUENCY ABLATION

WIDE COMLEX WIDE COMLEX TACHYCARDIATACHYCARDIA

DefinitionDefinition

Wide QRS complex tachycardia is a rhythm with a rate of Wide QRS complex tachycardia is a rhythm with a rate of

more than 100 b/m and QRS duration of more than 120 msmore than 100 b/m and QRS duration of more than 120 ms

VT (80%)

SVT (20%)

Stewart RB. Ann Intern Med 1986

DefinitionsDefinitions --WCTWCT :Rate equal or more than 100 and QRS :Rate equal or more than 100 and QRS

duration of at least 120 msec.duration of at least 120 msec. --VTVT :a WCT originating below the level of His :a WCT originating below the level of His

bundle.bundle. --LBBB morphologyLBBB morphology: QRS duration more than : QRS duration more than

120 with predominantly negative terminal 120 with predominantly negative terminal deflection in V1.deflection in V1.

--RBBB morphologyRBBB morphology : QRS duration more than : QRS duration more than 120 and a terminal positive deflection in V1.120 and a terminal positive deflection in V1.

Importance of diagnosis of Importance of diagnosis of WCTWCT

Correct diagnosis is important both for Correct diagnosis is important both for acute management and also acute management and also subsequent management.subsequent management.

-If we inject verapamil to a patient with -If we inject verapamil to a patient with VT and low EF , prolonged hypotension VT and low EF , prolonged hypotension and hemodynamic deterioration and hemodynamic deterioration happens.happens.

-Non of the criteria is perfect but they -Non of the criteria is perfect but they can be helpful.can be helpful.

Differential Diagnosis of Differential Diagnosis of WCTWCT

--Ventricular tachycardia (about 80% of cases ).Ventricular tachycardia (about 80% of cases ). -SVT with abnormal interventricular conduction (15-30 -SVT with abnormal interventricular conduction (15-30

%):%): **SVT with BBB aberration (fixed or functional).SVT with BBB aberration (fixed or functional). **Pre-excited SVT (SVT with ventricular activation Pre-excited SVT (SVT with ventricular activation

occurring over an anomalous AV connection ).Their occurring over an anomalous AV connection ).Their ECG can be indistinguishable from VT originating at ECG can be indistinguishable from VT originating at the base of ventricle.(1-5 % of all)the base of ventricle.(1-5 % of all)

**SVT with wide QRS due to abnormal muscle-SVT with wide QRS due to abnormal muscle-muscle spread of impulse.( surgery, DCM)muscle spread of impulse.( surgery, DCM)

**SVT with wide complex due to drug or electrolyte-SVT with wide complex due to drug or electrolyte-induced changes. (hyperkalemia. Class Ia ,Ic drugs or induced changes. (hyperkalemia. Class Ia ,Ic drugs or Amiodarone)Amiodarone)

-Ventricular paced rhythms .(small but growing -Ventricular paced rhythms .(small but growing percentage )percentage )

Distinguishing VT from Distinguishing VT from SVT with aberrancy SVT with aberrancy

SVT can occasionally present as an unknown SVT can occasionally present as an unknown wide-complex tachycardia if if occurs in the wide-complex tachycardia if if occurs in the presence of:presence of:– Preexisting bundle branch blockPreexisting bundle branch block– Rate related bundle branch blockRate related bundle branch block– An accessory pathwayAn accessory pathway

Distinguishing VT from Distinguishing VT from SVT with aberrancySVT with aberrancy

VT accounts for ~80% of all cases of regular VT accounts for ~80% of all cases of regular wide-complex tachycardias, and ~95% of all wide-complex tachycardias, and ~95% of all cases of regular wide-complex tachycardias cases of regular wide-complex tachycardias which occur in patients with a history of MI.which occur in patients with a history of MI.

One of the most common lethal errors made One of the most common lethal errors made in arrhythmia diagnosis is to mistake VT for in arrhythmia diagnosis is to mistake VT for SVT and treat with verapamil, diltiazem, and SVT and treat with verapamil, diltiazem, and adenosine, all of which can precipitate adenosine, all of which can precipitate ventricular fibrillation in patients in VT, even ventricular fibrillation in patients in VT, even if initially stable.if initially stable.

Distinguishing VT from Distinguishing VT from SVT with aberrancySVT with aberrancy

Therefore, all wide-complex Therefore, all wide-complex tachycardias should be assumed tachycardias should be assumed to be VT until proven otherwise.to be VT until proven otherwise.

EKG features highly EKG features highly suggestive suggestive of VT:of VT:

Fusion beatsFusion beats

Capture beats Capture beats

Dissociated P waves (AV dissociation)Dissociated P waves (AV dissociation)

EKG features moderately EKG features moderately suggestive of VT:suggestive of VT:

QRS duration > 160msQRS duration > 160ms

An extreme QRS axis (-90 to -180 degrees)An extreme QRS axis (-90 to -180 degrees)

Precordial QRS concordancePrecordial QRS concordance

Variations in the QRS and ST-T morphologiesVariations in the QRS and ST-T morphologies

Slight irregularity at the onset of the Slight irregularity at the onset of the arrhythmia arrhythmia

Physical findings highly Physical findings highly suggestive of VT:suggestive of VT:

Signs of AV dissociation, including:Signs of AV dissociation, including:– Canon A waves in the jugular venous Canon A waves in the jugular venous

pulsationspulsations– Varying BP measurement from beat to beatVarying BP measurement from beat to beat

– Varying intensity of SVarying intensity of S11

SVT vs VT Clinical history

Medication Drug-induced tachycardia → Torsade de pointes

Diuretics

Digoxin-induced arrhythmia → [digoxin] ≥2ng/l or normal if hypokalemia

Age - ≥ 35 ys → VT (positive predictive value of 85%)

Underlying heart disease Previous MI → 98% VT

Pacemakers or ICD Increased risk of ventricular tachyarrhythmia

WIDE QRS

Step 4: LBBB - type wide QRS complex

SVT VT

small R wave notching of S waveR wave >40ms

fast downslopeof S wave

no Q wave

Q wave

> 70ms

V1

V6

Fusion beat and capture beat

Concordance and Northwest Axis

MIMICS OF VTMIMICS OF VT

Tachycardia with previous Q wave MITachycardia with previous Q wave MI Tachycardia with previous BBBTachycardia with previous BBB SVT with aberrant conductionSVT with aberrant conduction

Previous MI

Previous RBBB

Wide complex SVT from bypass Wide complex SVT from bypass tracttract

Torsade de PointesTorsade de Pointes

Torsade de pointes means “twisting of the points”

It is most commonly seen in the setting of a prolonged QT interval (either congenital or acquired), and is caused by early after depolarizations.

This rhythm is usually short lived, and resolves spontaneously within seconds, but can progress to ventricular fibrillation if prolonged.

Torsade de PointesTorsade de Pointes

EKG Characteristics: Irregular wide-complex tachycardia

The morphology, amplitude, and axis of the QRS

complexes cycle through a sinusoidal pattern

No discernable P waves

Tachycardia algorithmTachycardia algorithm

AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Ciurculation 2005

Tachycardia algorithmTachycardia algorithm