Tachydysrhymias Stefan Da Silva Oct 19 th 2006 Special Guest: Dr. Phil Ukrainetz With a little help...
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Transcript of Tachydysrhymias Stefan Da Silva Oct 19 th 2006 Special Guest: Dr. Phil Ukrainetz With a little help...
TachydysrhymiasTachydysrhymias
Stefan Da SilvaStefan Da SilvaOct 19Oct 19thth 2006 2006
Special Guest: Dr. Phil UkrainetzSpecial Guest: Dr. Phil UkrainetzWith a little help from Drs. R. Hall and With a little help from Drs. R. Hall and
D. PetersonD. Peterson
TachydysrhythmiasTachydysrhythmias
Dysrhythmia: any abnormality in Dysrhythmia: any abnormality in cardiac rhythmcardiac rhythm
AnatomyAnatomy SA nodeSA node AV nodeAV node Bundle BranchesBundle Branches
TachydysrhythmiasTachydysrhythmias
Cardiac Electrophysiology (the very Cardiac Electrophysiology (the very basics!)basics!) Na/K pump Na/K pump
3 Na OUT3 Na OUT 2 K IN2 K IN
This generates approx 10 mV potential across This generates approx 10 mV potential across membranemembrane
The flow of K down the concentration gradient The flow of K down the concentration gradient toward the ECF generates another 80 mVtoward the ECF generates another 80 mV
Ca is also exchanged for Na along membrane via Ca is also exchanged for Na along membrane via osmotic gradientosmotic gradient
= 90 mV membrane resting potential= 90 mV membrane resting potential
TachydysrhythmiasTachydysrhythmias
Mechanisms for DysrhythmiasMechanisms for Dysrhythmias Altered AutomaticityAltered Automaticity Re-entryRe-entry Triggered MechanismsTriggered Mechanisms
TachydysrhythmiasTachydysrhythmias Altered AutomaticityAltered Automaticity
Impulse relatedImpulse related Can occur in multiple settings (ischemia, Can occur in multiple settings (ischemia,
electrolyte abnormalities, drugs…)electrolyte abnormalities, drugs…) Can be a result of spontaneous phase 4 Can be a result of spontaneous phase 4
depolarization in “non-pacemaker” cells (abnormal depolarization in “non-pacemaker” cells (abnormal automaticity)automaticity)
Eg. VT after MI Eg. VT after MI Increase in the slope of depolarization causing it Increase in the slope of depolarization causing it
to be more positive/closer to threshold (enhanced to be more positive/closer to threshold (enhanced automaticity)automaticity)
Eg. Idioventricular rhythm after MIEg. Idioventricular rhythm after MI Enhanced automaticity as a result of catecholamine Enhanced automaticity as a result of catecholamine
increase stimulating non-SA nodal pacemakers.increase stimulating non-SA nodal pacemakers.
TachydysrhythmiasTachydysrhythmias
Re-entryRe-entry Conduction relatedConduction related Most common cause of narrow complex Most common cause of narrow complex
rhythms (50% - 80%)rhythms (50% - 80%) Need 3 conditions for re-entryNeed 3 conditions for re-entry
1) Pathway 1) Pathway 2 paths available 2 paths available 2) Unequal responsiveness between routes2) Unequal responsiveness between routes 3) Decrease in conduction of one route3) Decrease in conduction of one route
TachydysrhythmiasTachydysrhythmias
What happens???What happens??? Dysfunction at the junctionDysfunction at the junction
Impulse finds one route “dysfunctional” (ie. Impulse finds one route “dysfunctional” (ie. in refractory phase) therefore travels down in refractory phase) therefore travels down alternate route and circles back up towards alternate route and circles back up towards initial route (retrograde) since it has initial route (retrograde) since it has recovered from refractory period.recovered from refractory period.
Can result in narrow complex tachycardiaCan result in narrow complex tachycardia
TachydysrhythmiasTachydysrhythmias TriggeredTriggered
Result of “afterdepolarization” Result of “afterdepolarization” fluctuations in fluctuations in membrane potential that occur as the resting membrane potential that occur as the resting potential is approached which may precipitate potential is approached which may precipitate another depolarizationanother depolarization
Dependant on heart rate for propagationDependant on heart rate for propagation Can be either early or late afterdepolarizations.Can be either early or late afterdepolarizations. Late: enhanced by faster heart rates. eg. Late: enhanced by faster heart rates. eg.
Intracellular Ca overload in reperfusion therapy Intracellular Ca overload in reperfusion therapy post MI can cause dysrhythmias such as VT, post MI can cause dysrhythmias such as VT, bigeminy, junctional rhythmsbigeminy, junctional rhythms
Early: enhanced by slower heart rates. eg. Early: enhanced by slower heart rates. eg. Torsades de pointes Torsades de pointes
Triggered ActivityTriggered Activity(early afterdepolarizations)(early afterdepolarizations)
Early afterdepolar-izations occur during either phase 2 or phase 3 of the action potential, and are seen most commonly in QT prolongation.
Triggered ActivityTriggered Activity(late afterdepolarizations)(late afterdepolarizations)
Late afterdepolar-izations occur shortly after completion of repolarization, and are seen most commonly in digitalis intoxication and high catecholamine states.
TachydysrhythmiasTachydysrhythmias
Antidysrhythmic DrugsAntidysrhythmic Drugs Class IClass I
Na (fast) channel blockersNa (fast) channel blockers ““Membrane stabilizing”Membrane stabilizing” Anti-ectopic effectsAnti-ectopic effects
IA: slows deplolarization and conduction. IA: slows deplolarization and conduction. Prolong repolarization and AP duration Prolong repolarization and AP duration
Eg. Procainamide: dosage Eg. Procainamide: dosage 20 – 30 mg/min 20 – 30 mg/min until termination of dysrhythmia, decrease in until termination of dysrhythmia, decrease in BP, widening QRS greater than 50% of initial BP, widening QRS greater than 50% of initial width or total dose of 18 – 20 mg/kg width or total dose of 18 – 20 mg/kg adminstered (can be given up to 50 mg/min in adminstered (can be given up to 50 mg/min in “urgent” situations..)“urgent” situations..)
Maintenance: 1 – 4 mg/minMaintenance: 1 – 4 mg/min Can be given orally as outpt.Can be given orally as outpt.
TachydysrhythmiasTachydysrhythmias
IB: slows depolarization and conduction. IB: slows depolarization and conduction. Shorten repolarization and action potential Shorten repolarization and action potential durationduration
Eg. Lidocaine: DosingEg. Lidocaine: Dosing 1.0 - 1.5mg/kg IV single dose (if refractory can 1.0 - 1.5mg/kg IV single dose (if refractory can
repeat dose 0.5 – 0.75 mg/kg IV q 5 – 10mins…max repeat dose 0.5 – 0.75 mg/kg IV q 5 – 10mins…max dose 3 mg/kg)dose 3 mg/kg)
IC: markedly slows depolarization and IC: markedly slows depolarization and conduction. Prolongs repolarization and conduction. Prolongs repolarization and action potential durationaction potential duration
Eg. PropafenoneEg. Propafenone 1 – 2 mg/kg at 10mg/min….infuse slowly1 – 2 mg/kg at 10mg/min….infuse slowly
TachydysrhythmiasTachydysrhythmias Class IIClass II
B-Blockers (all the “ol’s”…propanolol, esmolol, B-Blockers (all the “ol’s”…propanolol, esmolol, metoprolol)metoprolol)
Slow SA node rate and AV conductionSlow SA node rate and AV conduction Prolong action potentialProlong action potential Depress conduction in ischemic myocardial tissuesDepress conduction in ischemic myocardial tissues
Class IIIClass III Prolong action potential and refractory periodProlong action potential and refractory period Exhibit antifibrillartory effectsExhibit antifibrillartory effects Eg. AmiodaroneEg. Amiodarone
Dosing: Dosing: Arrest: 300mg IV push then 150 mg IV in 3 to 5 mins..max Arrest: 300mg IV push then 150 mg IV in 3 to 5 mins..max
dose in 24 hrs is 2.2g dose in 24 hrs is 2.2g Arrhythmias: 150 mg IV over 1Arrhythmias: 150 mg IV over 1stst 10 minutes can repeat q 10 minutes can repeat q
10 min as needed to max dose.10 min as needed to max dose.
TachydysrhythmiasTachydysrhythmias
Class IVClass IV Slow Ca channel blockersSlow Ca channel blockers Depress anterograde conduction Depress anterograde conduction
through AV node.through AV node. Eg. Diltiazem Eg. Diltiazem
Dosing: 15 – 20 mg IV over 2 minutes, can Dosing: 15 – 20 mg IV over 2 minutes, can repeat at 20 – 25 mg IV after 15 minutesrepeat at 20 – 25 mg IV after 15 minutes
Can give Calcium prior to decrease Can give Calcium prior to decrease hypotensive effectshypotensive effects
TachydysrhythmiasTachydysrhythmias
ApproachApproach ABC’sABC’s Stable vs non-stableStable vs non-stable ECGECG
Wide vs Narrow!!!Wide vs Narrow!!! Regular vs IrregularRegular vs Irregular P waves vs No P wavesP waves vs No P waves
Old Chart (old ECG’s extremely helpful)Old Chart (old ECG’s extremely helpful)
TachydysrhythmiasTachydysrhythmias What do you want to know?What do you want to know?
Stable or not stableStable or not stable Stable…now what?Stable…now what?
Have time to do focussed hx and physicalHave time to do focussed hx and physical Hx: Hx:
timing, palpitations, dizziness, chest pain, SOB, timing, palpitations, dizziness, chest pain, SOB, syncope etcsyncope etc
Previous hx of similarPrevious hx of similar MedicationsMedications
PhysicalPhysical Evidence of end-organ perfusion/alteration in Evidence of end-organ perfusion/alteration in
cognitioncognition Regular cardio-pulmonary exam.Regular cardio-pulmonary exam.
ECGECG InterventionsInterventions
Case #1Case #1 76 yr old male presenting with 1 day hx 76 yr old male presenting with 1 day hx
of heart “racing” and mild breathlessof heart “racing” and mild breathless PMHx: “some heart problems”PMHx: “some heart problems” Meds: “…half a blue pill for BP and Meds: “…half a blue pill for BP and
water pill or something like that…”water pill or something like that…” Vitals: fluctuating HR 120 – 150, BP Vitals: fluctuating HR 120 – 150, BP
160/96, Sat 96% RA, 36.5 temp160/96, Sat 96% RA, 36.5 temp
TachydysrhythmiasTachydysrhythmias
TachydysrhythmiasTachydysrhythmias Atrial FibrillationAtrial Fibrillation
““chaos”chaos” Irregularly irregularIrregularly irregular No distinct “P” wavesNo distinct “P” waves Narrow Complex Narrow Complex
Ashman Phenomenon: isolated/repeated aberrant Ashman Phenomenon: isolated/repeated aberrant ventricular conduction in RBBB patternventricular conduction in RBBB pattern
Atrial rates of ~300 bpmAtrial rates of ~300 bpm Ventricular rates ~ 150 – 200Ventricular rates ~ 150 – 200 Can be dangerous in patients with LV dysfunction as Can be dangerous in patients with LV dysfunction as
high likelihood of going into heart failure if in Afib high likelihood of going into heart failure if in Afib If > 200 bpm beware of accessory pathway and If > 200 bpm beware of accessory pathway and
predisposition to Vfibpredisposition to Vfib
TachydysrhythmiasTachydysrhythmias Causes: IHD, pericarditis, thyroid dysfunction, Causes: IHD, pericarditis, thyroid dysfunction,
cardiomyopathy, PE, CHFcardiomyopathy, PE, CHF Tx: Tx:
Stable vs unstableStable vs unstable Immediate cardioversion if unstableImmediate cardioversion if unstable
Rate controlRate control Preserved vs unpreserved ventricular functionPreserved vs unpreserved ventricular function Ca++/B-blockersCa++/B-blockers If in doubt Diltiazem can be used for both normal and impaired LV If in doubt Diltiazem can be used for both normal and impaired LV
function (ACLS)function (ACLS) Rhythm controlRhythm control
Duration Duration Chemical vs ElectricalChemical vs Electrical
AmiodaroneAmiodarone AnticoagulationAnticoagulation
Anticoag clinicsAnticoag clinics Afib clinic here in CalgaryAfib clinic here in Calgary Don’t forget to think about cause of atrial fib/flutter and treat!Don’t forget to think about cause of atrial fib/flutter and treat!
TachydysrhythmiasTachydysrhythmias
““Convert or Not to Convert”….Convert or Not to Convert”…. > 48 hrs increased risk of embolic (however > 48 hrs increased risk of embolic (however
Rosen’s mentions can convert up to 72 hrs)Rosen’s mentions can convert up to 72 hrs) Chemical vs ElectricalChemical vs Electrical
Electrical Electrical 50 – 100 J to start50 – 100 J to start No associated risk of malignant ventricular No associated risk of malignant ventricular
dysrhythmias on pts with dig unless evidence of dysrhythmias on pts with dig unless evidence of toxicitytoxicity
Can premedicate with rate slowing agent (Ca++)Can premedicate with rate slowing agent (Ca++) ChemicalChemical
Amiodarone 5mg/kg IV, over 15 – 20 minutesAmiodarone 5mg/kg IV, over 15 – 20 minutes Other options…procainamide, ibutilideOther options…procainamide, ibutilide
Don’t forget about Anticoagulation!Don’t forget about Anticoagulation!
TachydysrhythmiasTachydysrhythmias
Atrial FlutterAtrial Flutter ““sawtooth” pattern best seen in II, III, aVF, sawtooth” pattern best seen in II, III, aVF,
V1, V2V1, V2 Usually 2:1 or 4:1 but any ratio can be seenUsually 2:1 or 4:1 but any ratio can be seen Atrial rates ~300/min (classical)Atrial rates ~300/min (classical) Ventricular rates ~ 150 bpm (classical)Ventricular rates ~ 150 bpm (classical) Narrow ComplexNarrow Complex Causes: CHF, Underlying heart disease, Causes: CHF, Underlying heart disease,
Valve dysfxn, MetabolicValve dysfxn, Metabolic
TachydysrhythmiasTachydysrhythmias Tx: stable vs unstableTx: stable vs unstable
Ca++ (Diltiazem may better b/c of less hypotension Ca++ (Diltiazem may better b/c of less hypotension and inotropic effect)/B-blockerand inotropic effect)/B-blocker
Digitalis (0.5mg IV initial and repeat doses q1-2hrs in Digitalis (0.5mg IV initial and repeat doses q1-2hrs in 0.25mg increments until effect or total dose = 1.5mg)0.25mg increments until effect or total dose = 1.5mg)
Magnesium (2 – 4 g IV)Magnesium (2 – 4 g IV) Cardioversion (unstable or recurrent)Cardioversion (unstable or recurrent)
Low energy cardioversion 25 – 50 JLow energy cardioversion 25 – 50 J Determine cause!! Determine cause!!
PitfallsPitfalls Watch out for possibility of accessory pathway (eg. Watch out for possibility of accessory pathway (eg.
Ventricular rates of > 200 bpm since normal AV nodal Ventricular rates of > 200 bpm since normal AV nodal pathways are unlikely to allow rates that high)pathways are unlikely to allow rates that high)
Avoid primary AV nodal blocking agents in these Avoid primary AV nodal blocking agents in these instances since may precipitate Vfib instances since may precipitate Vfib
Should investigate with EP studies Should investigate with EP studies
TachydysrhythmiasTachydysrhythmias
Case # 2Case # 2 40 yr old male “feeling funny in chest”. 40 yr old male “feeling funny in chest”. PMHx: HealthyPMHx: Healthy Meds: noneMeds: none Vitals: HR 200, BP 130/80, Sats 98% Vitals: HR 200, BP 130/80, Sats 98%
RA, RA,
TachydysrhythmiasTachydysrhythmias
Narrow Complex Tachycardias (that Narrow Complex Tachycardias (that are not Afib/Aflutter)are not Afib/Aflutter) QRS < 0.12 sec and ventricular rate of QRS < 0.12 sec and ventricular rate of
> 100> 100 P waves usually “hidden” due to fast P waves usually “hidden” due to fast
raterate Regular Regular Stable vs UnstableStable vs Unstable
TachydysrhythmiasTachydysrhythmias
Sinus TachycardiaSinus Tachycardia Don’t forget to think about the cause!!!Don’t forget to think about the cause!!! Response to physiological stress due to Response to physiological stress due to
body trying to increase cardiac outputbody trying to increase cardiac output Eg. Sepsis, PE, shock…Eg. Sepsis, PE, shock…
Tx: treat the cause!!Tx: treat the cause!!
TachydysrhythmiasTachydysrhythmias
Atrial TachycardiaAtrial Tachycardia Tachycardia originating above nonsinus Tachycardia originating above nonsinus
focus above the AV nodefocus above the AV node Gradual or abruptGradual or abrupt Hallmark: narrow complex tachycardia Hallmark: narrow complex tachycardia
with each QRS preceded by a P wave with each QRS preceded by a P wave that is morphologically different from that is morphologically different from the sinus P wavethe sinus P wave
TachydysrhythmiasTachydysrhythmias
Case #3Case #3 75 yr old male sent in by GP because of 75 yr old male sent in by GP because of
lightheadedness and dizziness following lightheadedness and dizziness following progressive SOB and productive cough for 2 progressive SOB and productive cough for 2 days.days.
PMHx: COPDPMHx: COPD Meds: “Damm oxygen at home…makes me Meds: “Damm oxygen at home…makes me
feel like a dog on a leash…AND I can’t feel like a dog on a leash…AND I can’t smoke with it on!!”smoke with it on!!”
Vitals: 120 HR irregular, 160/90, O2 88% on Vitals: 120 HR irregular, 160/90, O2 88% on 1 L1 L
TachydysrhythmiasTachydysrhythmias Multifocal Atrial TachycardiaMultifocal Atrial Tachycardia
““wandering atrial pacemaker”wandering atrial pacemaker” ECG findingsECG findings
At least 3 morphologically distinct P wavesAt least 3 morphologically distinct P waves Changing P-P, P-R, and R-R intervalsChanging P-P, P-R, and R-R intervals Atrial rhythm usually b/w 100 – 180 bpmAtrial rhythm usually b/w 100 – 180 bpm
Most commonly in elderly patientsMost commonly in elderly patients Causes: chronic lung problems, pulmonary Causes: chronic lung problems, pulmonary
diseasedisease TX: treat underlying problem (usually resp)TX: treat underlying problem (usually resp)
Mg 2 g IV over 60 secs then 1 – 2 g/h infusionMg 2 g IV over 60 secs then 1 – 2 g/h infusion Verapamil 5 – 10 mg IVVerapamil 5 – 10 mg IV B-blockers (watch out for theroretical risk of B-blockers (watch out for theroretical risk of
increasing pulmonary issues)increasing pulmonary issues)
TachydysrhythmiasTachydysrhythmias
Supraventricular TachycardiaSupraventricular Tachycardia SVT: any tachycardia originating above the SVT: any tachycardia originating above the
ventricles; includes sinus tach, Afib, aflut, PSVT, ventricles; includes sinus tach, Afib, aflut, PSVT, junctional tachjunctional tach
PSVT: a type of SVT; two causes…….PSVT: a type of SVT; two causes……. AVNRT: AV node Re-entrant Tachycardia (also called AVNRT: AV node Re-entrant Tachycardia (also called
Paroxysmal Junctional Tach) - AV node reentryParoxysmal Junctional Tach) - AV node reentry HR usually less than 200HR usually less than 200 P wave usually buriedP wave usually buried
AVRT: AV Re-entrant Tachycardia - re-entry b/w atria AVRT: AV Re-entrant Tachycardia - re-entry b/w atria and ventricle due to accessory pathwayand ventricle due to accessory pathway
Suspect if HR > 200Suspect if HR > 200 WPW most commonWPW most common
TachydysrhythmiasTachydysrhythmias
Tx:Tx: Stable vs UnstableStable vs Unstable Vagal maneuversVagal maneuvers AdenosineAdenosine CardioversionCardioversion Other options: Amio, CCB, Other options: Amio, CCB,
procainamide…procainamide…
TachydysrhythmiasTachydysrhythmias
Case # 3Case # 3 17 yr old male with episodic “racing 17 yr old male with episodic “racing
heart” for years. No parents with him. heart” for years. No parents with him. States he has had this before and sees a States he has had this before and sees a cardiologist but can’t remember who.cardiologist but can’t remember who.
Vitals: HR 60, BP 110/60, Sats 98% RAVitals: HR 60, BP 110/60, Sats 98% RA
TachydysrhythmiasTachydysrhythmias
WPWWPW Most common accessory pathway syndromeMost common accessory pathway syndrome Hallmark: PSVT at 150 – 300 bpmHallmark: PSVT at 150 – 300 bpm Loss of normal AV conduction restraintLoss of normal AV conduction restraint 70 % of pts have no underlying heart disease70 % of pts have no underlying heart disease Classic 3 featuresClassic 3 features
Short PR interval ( < 0.12 sec)Short PR interval ( < 0.12 sec) QRS > 0.10QRS > 0.10 ““Delta” wave (early activation of myocardium)Delta” wave (early activation of myocardium)
TachydysrhythmiasTachydysrhythmias
OrthodromicOrthodromic Narrow QRSNarrow QRS Delta wave absentDelta wave absent Down through AV Down through AV
nodenode Up through Up through
accessory pathwayaccessory pathway
AntidromicAntidromic Wide QRSWide QRS Delta wave presentDelta wave present Down through Down through
accessory pathwayaccessory pathway Up through AV Up through AV
nodenode
TachydysrhythmiasTachydysrhythmias WPWWPW
TreatmentTreatment Stable vs UnstableStable vs Unstable Depends on 3 observations:Depends on 3 observations:
Symptoms of instabilitySymptoms of instability QRS duration or Delta wave presenceQRS duration or Delta wave presence QRS regularity or irregularityQRS regularity or irregularity
Regular OrthodromicRegular Orthodromic Most commonMost common Treat same as SVTTreat same as SVT
Regular Antidromic or any irregular rhythmRegular Antidromic or any irregular rhythm High risk of Vfib (esp when RR interval < 0.20)High risk of Vfib (esp when RR interval < 0.20) Avoid AV nodal blocking drugs (CCB, BB, dig, adenosine)Avoid AV nodal blocking drugs (CCB, BB, dig, adenosine) Procainamide is drug of choice or cardioversion if > 250 Procainamide is drug of choice or cardioversion if > 250
bpmbpm Amiodarone can also be consideredAmiodarone can also be considered
TachydysrhythmiasTachydysrhythmias
Wide Complex TachycardiasWide Complex Tachycardias > 100 bpm and QRS > 0.12 sec> 100 bpm and QRS > 0.12 sec 2 groups2 groups
VentricularVentricular SVT with aberrancySVT with aberrancy
Must determine difference in order to Must determine difference in order to treat properlytreat properly
Use focused hx, physical exam, and Use focused hx, physical exam, and ECG tracingECG tracing
Distinguishing VT from SVT Distinguishing VT from SVT with aberrancy with aberrancy
SVT can occasionally present as an SVT can occasionally present as an unknown wide-complex tachycardia unknown wide-complex tachycardia if if occurs in the presence of:if if occurs in the presence of: Preexisting bundle branch blockPreexisting bundle branch block Rate related bundle branch blockRate related bundle branch block An accessory pathwayAn accessory pathway Treatment with class IA or IC Treatment with class IA or IC
antiarrhythmicsantiarrhythmics
Distinguishing VT from SVT Distinguishing VT from SVT with aberrancywith 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, ventricular fibrillation in patients in VT, even if initially stable.even if initially stable.
TachydysrhythmiasTachydysrhythmias Ventricular TachycardiaVentricular Tachycardia
> 50 yrs> 50 yrs Hx of MI, CHF, CABG, Hx of MI, CHF, CABG,
ASHDASHD Mitral Valve ProlapseMitral Valve Prolapse Prev hx of VTPrev hx of VT Cannon “A” wavesCannon “A” waves Variation in arterial pulseVariation in arterial pulse Variable first heart soundVariable first heart sound Fusion beatsFusion beats AV dissociationAV dissociation QRS > 0.14 secQRS > 0.14 sec Extreme LAD Extreme LAD No response to vagal No response to vagal
maneuversmaneuvers V1: R, qR or RSV1: R, qR or RS V6: S, rS, or qRV6: S, rS, or qR
SVT with AberrancySVT with Aberrancy < 36 yrs< 36 yrs No hx of heart diseaseNo hx of heart disease Mitral valve prolapseMitral valve prolapse Prev hx of SVTPrev hx of SVT No cannon “A” wavesNo cannon “A” waves Absence of variabilityAbsence of variability No variable first heart No variable first heart
soundsound No fusion beatsNo fusion beats No AV dissociationNo AV dissociation QRS < 0.14 (usually)QRS < 0.14 (usually) Normal Axis Normal Axis Vagal maneuversVagal maneuvers V1: rsR’V1: rsR’ V6: qRsV6: qRs
A-V Dissociation, Fusion, A-V Dissociation, Fusion, and and
Capture Beats in VTCapture Beats in VT
Fisch C. Electrocardiography of Arrhythmias. 1990;134.
ECTOPY FUSION CAPTURE
V1 E F C
TachydysrhythmiasTachydysrhythmias
Morphology Criteria in leads V1 and Morphology Criteria in leads V1 and V6V6
The Brugada CriteriaThe Brugada Criteria
Table I.
Diagnosis Of Wide QRS Complex Tachycardia With A Regular Rhythm
Step 1. Is there absence of an RS complex in all precordial leads V1 – V6?
If yes, then the rhythm is VT. Sens 0.21 Spec 1.0
Step 2. Is the interval from the onset of the R wave to the nadir of the Swave greater than 100 msec in any precordial leads?
If yes, then the rhythm is VT. Sens 0.66 Spec 0.98
Step 3. Is there AV dissociation?
If yes, then the rhythm is VT.
Sens 0.82 Spec 0.98
Step 4. Are morphology criteria for VT present? See Table II.
If yes, then the rhythm is VT. Sens 0.99 Spec 0.97
Morphology Criteria for Morphology Criteria for VTVT
Table II.
Morphology Criteria for VT
Right bundle type requires waveform from both V1 and V6.
V1 V6
Monophasic R wave QS or QR
QR or RS R/S <1
Left bundle type requires any of the below morphologies.
V1or V2 V6
R wave > 30 msec
Notched downstroke S wave.
Greater than 60msec nadir S wave.
QR or QS
Adapted from Brugada et al. A new approach to the differential diagnosis of regular tachycardia with a wide QRS complex.Circulation 1991; 83:1649-59.
TachydysrhythmiasTachydysrhythmias Brugada P, et al: A new approach to the Brugada P, et al: A new approach to the
differential diagnosis of regular tachycardia differential diagnosis of regular tachycardia with wide QRS complex. Circulation with wide QRS complex. Circulation 83:1649. 199183:1649. 1991
Any “yes” is VTAny “yes” is VT Can only be used with regular tachycardiasCan only be used with regular tachycardias Later studies showed poor sensitivity and Later studies showed poor sensitivity and
specificity (Isenhour et al, Academic Emerg specificity (Isenhour et al, Academic Emerg Med 2000: 7 (7): 769 – 773)Med 2000: 7 (7): 769 – 773)
Best to think if new onest wide complex Best to think if new onest wide complex tachycardia is VT until proven otherwise.tachycardia is VT until proven otherwise.
TachydysrhythmiasTachydysrhythmias
Case # 4Case # 4 60 yr old male farmer with SOB and 60 yr old male farmer with SOB and
chest pain brought by wifechest pain brought by wife PMx: “sugar diabetes” and “problems PMx: “sugar diabetes” and “problems
with the ticker”with the ticker” Meds: “All I know is what the druggist Meds: “All I know is what the druggist
gives me once a month is what I take…”gives me once a month is what I take…” Has a pulseHas a pulse
TachydysrhythmiasTachydysrhythmias
Ventricular TachycardiasVentricular Tachycardias VTachVTach
MonomorphicMonomorphic PolymorphicPolymorphic
Vfib/flutterVfib/flutter
TachydysrhythmiasTachydysrhythmias
Monomorphic VTachMonomorphic VTach Consistent QRS complexesConsistent QRS complexes Seen in CAD/IHD, lytes abnormalities, Seen in CAD/IHD, lytes abnormalities,
hypoxemiahypoxemia Tx: stableTx: stable
LidocaineLidocaine CardioversionCardioversion Procainamide, Amio, MagnesiumProcainamide, Amio, Magnesium
TachydysrhythmiasTachydysrhythmias
Case # 5Case # 5 80 yr old female feeling weak and dizzy, 80 yr old female feeling weak and dizzy,
EMS patch in rhythm strip because EMS patch in rhythm strip because unsure……unsure……
TachydysrhythmiasTachydysrhythmias Polymorphic VtachPolymorphic Vtach
QRS of varying morphologyQRS of varying morphology More severe diseaseMore severe disease Torsades de PointesTorsades de Pointes
Clinical CriteriaClinical Criteria Ventricular rate > 200 bpmVentricular rate > 200 bpm QRS axis undulatingQRS axis undulating ParoxysmalParoxysmal
Often in setting of prolonged QT intervalOften in setting of prolonged QT interval Hypokalemia, hypomagnesemiaHypokalemia, hypomagnesemia Tx: based on correcting underlying abnormalities Tx: based on correcting underlying abnormalities
and increasing HRand increasing HR MagnesiumMagnesium Overdrive pacingOverdrive pacing IsoproterenolIsoproterenol
TachydysrhythmiasTachydysrhythmias
Wide Complex Tachycardia of Wide Complex Tachycardia of Unknown OriginUnknown Origin Assume VT until proven otherwiseAssume VT until proven otherwise Management same as for monomorphic Management same as for monomorphic
VTVT
TachydysrhythmiasTachydysrhythmias
Take home points:Take home points: Stable vs UnstableStable vs Unstable
Remember this is patient specific.Remember this is patient specific. Eg. Elderly pt in afib with bp of 110/60 could Eg. Elderly pt in afib with bp of 110/60 could
be unstable if they are regularly 160/90.be unstable if they are regularly 160/90.
Review common ED presentations of Review common ED presentations of tachydysrhythmiastachydysrhythmias
Understand the basic concepts behind Understand the basic concepts behind the drugs we choosethe drugs we choose
Review, Review, Review……Review, Review, Review……