Disclosures Research Support: NIH, PCORI, TRDRP, Medtronic, - - PDF document

10/12/2018 1

Common Rhythm Problems in Hospital Medicine

Gregory M Marcus, MD, MAS Professor of Medicine Division of Cardiology University of California, San Francisc

Disclosures

• Research Support: NIH, PCORI, TRDRP,

Medtronic, Jawbone, Eight Sleep

• Consulting: InCarda
• Equity: InCarda

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Goals of the Talk

• What to do when encountering an

arrhythmia

• Leveraging the encounter to maximize

benefit to the patient long-term

Tachyarrhythmias- Unstable

SVT Atrial fibrillation AF with WPW VT/ VF

• Unconscious, altered mental status,
• ngoing chest pain
• “Hypotension” is a clinical judgment

SHOCK THE PATIENT

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Anything other than VF MAKE SURE IT IS ON “SYNCH”

SHOCK THE PATIENT

Unstable SVT, AF, VT “Is the defibrillator

• n synch?”

SHOCK THE PATIENT STILL in unstable SVT, AF, VT SHOCK THE PATIENT “Is the defibrillator

• n synch?”

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Tachyarrhythmias-quasi-stable

Atrial fibrillation SVT AF with WPW VT

Tachyarrhythmias-quasi-stable

Atrial Fibrillation

Nondihydropyrdine Calcium channel blockers Diltiazem Verapamil Beta-blockers Metoprolol Atenolol Carvedilol Labetolol Propanolol

Blood Pressure

• 1. Address underlying condition
• 2. Esmolol
• 3. Digoxin
• 4. Amiodarone
• 5. ?Dronaderone?

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How about cardioversion?

• DC cardioversion is the most efficacious but requires sedation
• If the patient has no structural heart disease (no CAD, normal

EF, not severe LVH) 200-300 mg of flecainide or 600 mg of propafenone (MUST BE GIVEN WITH AV NODAL BLOCKER DUE RISK OF 1:1 ATRIAL FLUTTER)

• Ibutilide IV- Torsades risk, requires 4 hours of monitoring
• Tikosyn (dofetilide) can work, but usually in 1-2 days and

generally in setting of careful QT monitoring over 3 days Elective Cardioversion

46 year old man without cardiovascular risk factors and symptomatic AF on propafenone

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46 year old man without cardiovascular risk factors and symptomatic AF on propafenone

• A SLOWER FLUTTER PARADOXICALLY

CAN RESULT IN A FASTER RHYTHM BECAUSE THE AV NODE CAN ACCOMMODATE A GREATER PROPORTION OF DEPOLARIZATIONS

• PATIENTS ON FLECAINIDE OR

PROPAFENONE REALLY SHOULD BE ON AN AV NODAL BLOCKER

How about cardioversion?

• Most thrombi in atrial fibrillation arise from the left atrial

appendage

• Cardioversion can reduce left atrial appendage function

– Even from AF to sinus

• The pericardioversion period is a particularly pro-

thrombotic time

– Regardless of mode: DC/ electrical, pharmacologic, spontaneous Elective Cardioversion

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I decide to go with

• Prior to cardioversion:1, 2

– Can exclude preexisitng

thrombus by TEE – Can anticoagulate (therapeutic/ for at least 3 weeks) prior to cardioversion

1. JACC 2006;48:e149-246 2. Chest 2004;126:429S-456

Elective Cardioversion

I decide to go with

• During and after cardioversion:1, 2

– Anticoagulation for at least 4 weeks

– Applies even to those who would otherwise not require anticoagulation

• Generally does not make sense to cardiovert

AF in order to avoid anticoagulation

1. JACC 2006;48:e149-246 2. Chest 2004;126:429S-456

Elective Cardioversion

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I decide to go with

• The magic 48 hours

– Must be documented! – Reason to consider starting anticoagulation NOW in the hospital as it may “stop the clock” – There are cases of stroke even within this time window, so

• nly do this if you need to and start anticoagulation if you can

Elective Cardioversion

Primary goal in treating atrial fibrillation: to prevent THROMBOEMBOLISM

• 1. Atrial fibrillation increases the risk of stroke

5 times

• 2. 23.5% of all strokes in those age 80-89 are

attributed to AF

Wolf et al. Stroke 1991

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ATRIAL FIBRILLATION IS OFTEN ASYMPTOMAIC

Page et al. Circulation 1994

Audience Response Question Among Cryptogenic Stroke Patients, AF can be found in:

• 0-3%
• 3-10%
• 10-20%
• 20-30%

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AF is common if you look hard enough among cryptogenic stroke patients

Brachman et al. Circ A&E 2016

We want to prevent THROMBOEMBOLISM

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How is This Relevant to Hospital Medicine?

• That patient who develops atrial fibrillation in

the setting of cellulitis or pneumonia

• ASSUME YOU WERE LUCKY TO CATCH IT

BECAUSE THE PATIENT WAS BEING MONITORED

• ANTICOAGULTE UNLESS THERE IS A

COMPELLING REASON NOT TO

–Examples: »CHADSVASC of 0 or perhaps 1 »History of hemorrhagic stroke

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Gialdini et al. JAMA 2014

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“A patient never calls you in the middle of the night to thank you for not having a stroke.”

• Michael Ezekowitz, M.B., Ch.B., D.Phil

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What if I have a suspicion for AF but we don’t catch it?

• Can order a Zio patch (monitors for 1-2

weeks)

Injectable Loop Recorder

• In-person validation

(n=51): c-statistic=0.97 (95% CI 0.94-1).

• Ambulatory validation

(n=617): c- statistic=0.72 (95% CI 0.64-0.78) %)

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Atrial fibrillation ablation

• Elective, generally takes time to schedule
• For SYMPTOMATIC AF- not stroke prevention
• Empiric (target PV isolation)
• Efficacy ~70% in PAF and ~50% in persistent AF at 1

year, attrition in many over time

• Can have early recurrence with long-term success

Audience Response Question The success of a typical atrial flutter ablation is:

• 40-50%
• 50-70%
• 70-95%
• 95-100%

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Atrial FLUTTER ablation

• Quicker procedure, easier to schedule
• We have a very clear target
• Flutter tends to be more difficult to rate control
• Antiarrhythmic drugs do not work so well for flutter
• Ablation of atrial flutter is FIRST LINE
• Success rate is ~97%

Tachyarrhythmias-quasi-stable

SVT

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Tachyarrhythmias-quasi-stable

SVT

Vagal Manuevers

WA WAIT! GET A 12 LEAD ECG! GET A 12 LEAD ECG!

Tachyarrhythmias-quasi-stable

SVT

Vagal Manuevers

• Carotid sinus massage
• Valsava
• Will terminate ~20%1
• 1. Lim SH et al. Ann Emerg Med 1998;31:30-35

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Tachyarrhythmias-quasi-stable

SVT

Adenosine

• Metabolized by red blood

cells and endothelium

• Give 6 mg IV with 20 cc flush
• Repeat with 12 mg IV X 2
• How do I know if I’ve given

enough?

75% reduction in ED visits among those undergoing catheter ablation (p=0.003).

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Tachyarrhythmias-quasi-stable The most likely diagnosis is:

• 1. Ventricular Tachycardia
• 2. Atrial fibrillation with WPW
• 3. SVT with aberrancy

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Tachyarrhythmias-quasi-stable Tachyarrhythmias-quasi-stable

Atrial Fibrillation with preexcitation

AV nodal blockers

Give:

Procainamide Ibutilide Then refer to EP for ablation

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Tachyarrhythmias-quasi-stable

Ventricular Tachycardia

• Scarcity of data
• Amiodarone probably the most

effective1,2

• - Can cause bradycardia
• - Can hinder EP studies/ ablation

Extrapolate from cardiac pulseless VT/ VF versus placebo:

• 1. Kudenchuck PJ et al. N Engl

J Med 1999;341:871-878 versus lidocaine:

• 2. Dorian P et al. N Engl J Med

2002;346:884-890

Tachyarrhythmias-quasi-stable

Ventricular Tachycardia

• Scarcity of data
• Consider
• - Lidocaine gtt
• - Procainamide
• watch for hypotension and

prolonged QT

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Tachyarrhythmias-quasi-stable

Ventricular Tachycardia

• Get EP involved
• May respond to beta-blockers or

calcium channel blockers

• May be amenable to ablation

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Tachyarrhythmias- a long QT

1.Electrolytes

Hypokalemia Hypo-Mg2+ Hypo-Ca2+

• 2. DRUGS
• 3. Congenital

Tachyarrhythmias

• 1. IV magnesium
• 2. Isoproterenol
• 3. Transvenous pacing
• 4. Unstable DC shock

THINK ABOUT TORSADES IF AMIODARONE ISN’T WORKING FOR “VF” OR PERHAPS MAKING THINGS WORSE

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Bradyarrhythmias

• Important questions:

– Is this dynamic/ reversible/ vagal?

• IE, more likely benign
• IE, less likely respond to pacing
• IE, more likely transient

– Or is this structural

• IE, more likely dangerous
• IE, more likely needs pacing
• In the absence of SYMPTOMS, type II second

degree AV block or third degree AV block pacemaker

Short term:

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Pacemakers

• Should be interrogated/ checked every 6

months

– Eg, doesn’t necessarily need to be checked while in the hospital

• Generally CAN now do MRIs with certain

restrictions regarding machine and personnel available

• We want to avoid RV pacing

– It’s an EP sin to RV pace frequently in anyone with a depressed EF

Biventricular Pacemaker

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His Bundle Pacing Implantable Cardioverter- Defibrillators

• Generally interrogated/ checked every 3 months
• All ICDs can also pace
• Anti-tachycardia pacing (ATP) is one way to

break a VT circuit without pain – But can always accelerate VT or lead to VF

• Generally ALSO CAN now do MRIs with certain

restrictions regarding machine and personnel available

• Trend towards longer delays in detection,

allowing faster rates with reduction in inappropriate shocks and DECREASE mortality

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• Pt. comes in with multiple,

recurrent shocks from his ICD

1.PUTS DEVICE IN “MAGNET MODE” 2.FOR AN ICD: INHIBITS THERAPY DETECTION 3.FOR A PACEMAKER: INHIBITS SENSING

• 1. Place external pads
• 2. Place magnet on chest

Thank You