Arrhythmias Ochs p1

What is the normal sinus rhythm

60-100 BPM

Where does the normal sinus rythum originate from?

SA node.

What is a disruption in the normal sequence of cardiac conduction?

arrhythmia (abnormal heart rhythm)

What can cause an arrhythmia?

Change in sequence or electrical impulses

Bradyarrhythmia or tachyarrhythmia

Inefficient pumping of blood

What is the order of normal cardiac conduction?

SA → Atriums → AV → Bundle of His → Bundle Branches → Purkinje FIbers

Explain the phases of Normal Cardiac Conductances?

Phase 0: Rapid upstroke of (Na+)

Phase 1: (Na+) turns off and (K+) turns on

Phase 2: (Ca2+) turns on

Phase 3: (Ca2+) turns off, and (K+) stays on

Phase 4: Gradual sodium influx

Automatic Tachycardias have an abnormality in…

impulse generation

What causes an Automatic Tachycardia?

Drugs

Hypoxia

Electrolyte abnormalities (Hypokalemia)

Reentry Tachycardias have an abnormality in…

impulse conduction

Are arrhythmia asymptomatic or symptomatic?

Both

What are symptoms of arrhythmia’s?

Shortness of breath

Fatigue

Dizziness

What are causes of Arrhythmias?

M E D S

(1) Metabolic Dearrangements

-Hyperthyroidism

(2) Electrolyte Disturbances

-K,Na,Ca,Mg

(3) Drug Toxicity

-Antiarrhythmics

(4) Structural abnormalities

-Left Ventricular dysfunction

-Coronary artery disease

-Heart Valve disorders

-Hypertension

-Heart Failure

-Myocardial Infarction / Ischemia

What is the cornerstone tool to diagnose arrhythmias?

Electrocardiogram (ECG)

What are the three tools to diagnose arrhythmias?

-ECG

-Holter Monitor

-Electrophysiologic studies

What is the potential risk when taking an anti-arrhythmic?

It can worsen the arrhythmia or even cause another arrhythmia.

aka: Proarrhythmic.

What should be done before taking an anti arrhythmic?

Correct electrolyte abnormalities

What are the Class 1a drugs?

DOUBLE QUARTER POUNDER

1.) Disopyramide

2.) Quinidine

3.) Procainamide

Whar are the Class 1b drugs?

LETTUCE MAYO PICKLES

1.) Lidocaine

2.) Mexiletene

3.) Phenytoin

What are Class 1c

FRIES PLEASE

1.) Flecainide

2.) Propafenone

What does Class 1 agents block?

Na+ Conductance

Which phase do Class 1 agents work?

Phase 0

What is the boxed warning for all Class 1 agents?

Pro-arrhythmic potential

-QTc Prolongation

Class 1a agents are effective to treat…

Supraventricular and Ventricular Arrhythmias

What are the ADE’s of of Class 1a agents?

Proarrhythmic, worsening HF

What is the Black Boxed Warning for Procainamide?

Drug induced lupus erythematosus

Class 1b agents are effective to treat…

Ventricular arrhythmias only

What are the ADE’s of Class 1b agents?

CNS effects

Class 1c agents are effective to treat…

Supraventricular and Ventricular Arrhythmias

What is contraindicated in Class 1c agents?

HF, recent MI, Ventricular hypertrophy

What is the BBW for Class 1c agents?

DEATH

Which Class 1 agents can be used as “pill-in-the-pocket” for acute cardioversion?

Class 1c

What type of drugs are used in class ll?

Beta Blockers

What does beta blockade decrease?

adrenergic innervation

Class __ agents are most effective for tachycardias in which nodal tissues are abnormally automatic, or part of a reentrant loop.

ll

Class ll agents may also be useful for…

Exercise related tachycardias, or tachycardias precipitated by high sympathetic tone.

Afib and heart failure can be treated with what agents?

3 main beta blockers

What phase do Class ll agents primarily work?

Phase 4

What are the names of the Class lll agents?

Amiodarone, Dronedarone, Soltalol, Ibutilide, Dofetilide

What type of channel blockade is Class lll agents?

Potassium channels (phase 3)

Which two class lll agents are effective for ventricular and supraventricular arrhythmias?

Amiodarone and Soltalol

Which Class lll agents are effective for only supraventricular?

Ibutilide, Dofetilide, and Dronedarone

What is the half life of Amiodarone?

>50 days

How is Amiodarone metabolized?

CYP 3A4

(inhibitors of CYP- 2C9, 2D6, 3A4, PgP)

What should be done with digoxin before taking Amiodarone?

Decrease dose by 50%

What should be done with warfarin when before starting Amiodarone?

Decrease by 30% or monitor closely.

What are the Warnings of Amiodarone?

Pulmonary toxicity

Thyroid abnormalities

Liver injury

Arrhythmia

Optic Neuritus and corneal microdeposits

Neuropathy

Dermatologic

Why would one take Dronedarone over Amiodarone?

Less effect on thyroid.

Dronedarone is less ____ and has a small Vd (___L/kg)

Lipophilic, 20

What should be done with Digoxin before starting Dronedarone?

Decrease dose by 50%

What can be elevated if taking warfarin and dronedarone?

INR

What are the contraindications of Dronedarone?

Permanent AF → Increase risk of death

QTc >500

Pregnancy (category x)

Use with QTc prolonging agents

When taking Soltalol, when should dose adjustment be made?

Renal impairment

Soltalol is contraindicated in….

CrCl <40, and Hypokalemia

When taking Soltalol, patient must be in hospital for atleast ___ days

3 days on maintenance dose to monitor QTc

What is the baseline QTc for soltalol?

How often should it be monitored after dose?

When should it be discontinued?

1) <450

2) Q2-4H

3) QTc >500

What is the ROA for Ibutilide?

Intravenous, has to be inpatient

Why is Ibutilide used?

Converts afib to sinus rhythm

What is the warning for Ibutilide?

Proarrythmic

-(EKG monitoring for 4 hours after infusion or until QTc returns to baseline)

When is Dofetilide indicated?

Conversion of Afib AND maintenance of NSR

Is Dofetilide effective for conversion of Paroxysmal atrial fibrillation?

No

How long should EKG be monitored for Dofetilide?

3 days

What should be done if QTc reaches >500 for Dofetilide? What if unchanged after second dose?

Reduce. Discontinue

What drugs are contraindicated with Dofetilide?

Cimetidine, trimethoprim, ketoconazole, prochlorperazine, dolutegravir, megestrol, use of HCTZ

What agents belong to class IV?

Non DHP’s: Veramapil and Diltiazem

When are Class IV agents preffered over beta blockers?

If co-existing COPD/asthma

Can Non-DHP’s be used if Heart failure and Afib overlap and LVEF <40%

No

What are warnings of Diltiazem and Veramapil?

-Heart failure

-LVEF <40%

What are the side effects of Diltiazem and Veramapil?

Edema

What drugs have an additive effect with Non-DHPs?

Amiodarone, Digoxin, Beta blockers, Clonidine

What is the MOA of Digoxin?

Blocks Na-K-ATPase pump

Typical dose of Digoxin?

0.125-0.25mg

AFib therapeutic range for Digoxin?

0.8-2

When should digoxin dose be decreased?

-CrCl <50

-PO to IV: reduce by 20-25%

What are ADR’s of Digoxin?

-GI (Naseau, Vomitting)

-CNS

-Visual (Green/yellow Halos)

Bradycardia

What is the MOA, ROA, ADR of Adenosine?

MOA- Slow conduction through AV node and restore normal sinus

-Used in Paroxysmal supraventricular tachycardia, including Wolf-Parkinson-White syndrome)

ROA- IV bolus/infusion

ADR: Facial Flushing