Arrhythmias Flashcards
What is an Arrhythmia?
- Abnormal heart rhythem; too fast [tachycardia] & too slow [bradycardia]
What is the Cardiac Conduction Pathway?
- Impluse starts at SA Node
- Travels to Right/Left Atria [Contracts]
- Passes through AV Node
- Into bundle of His
5 & 6. Bundle of His splits into Right and Left - Lastly going through Purkinje Fibers [Contracts]
What is the Cardiac Action Potential?
- Movement on ions through Myocytes that cause electrical impluses [powering cardiac system]
- SN Node can start it on its own [only one too do this]
What are the 4 phases of the Cardiac Action Potential?
Phase 0: Rapid Depolarization due to influx of Na = contractions (QRS Wave)
Phase 1: Early Repolarizaton [Na channel closed]
Phase 2: Influx of Ca & Efflux of K
Phase 3: Ventricular Repolarization [Efflux of K] (T Wave)
Phase 4: Rest (P Wave)
What are some of the common causes of Arrhythmias?
- Myocardial Ischemia OR
- INfarctions
What are some of the non-cardiac conditions that can cause Arrhythmias?
- Electrolye Imbances [K, Mg, Ca, Na]
- Elevated Sympathetic States [Hyperthyroidism, Infections]
- Drugs [legal or those that prolong QT]
What are the 2 types of Arrhythmias?
- Supraventricular [Sinus Tachy, A. Fib, A. Flutter, A. Tachy, PSVT]
- Ventricular [Premature Ventricular Contractions (PVC), V. Tachy, V. FIb]
What is important to know about the Premature Ventricular Contractions [PVCs]?
-
- “Skipped Heartbeats”
- A series with HR > 100 is V. Tach [Pulseless V. Tach is a medical emergency]
- V. Tach –> V. Fib = medical emergency
When is it considered that your QT Interval is Prolonged?
- > 440 - 460 milliseconds
- > 500 is very bad
What are some of the risk factors that may increase QT interval?
- Higher Doses
- On mulitple QT proloning drug
- Reduce drug Clearance [do to renal clearance]
- Low K or Mg
- Female
What are some of the drugs that could increase or prolong the QT Interval?
- Class Ia, Ic, III antiarrhythmics
- Antimalarials, Macrolides, Quinolones
- SSRIs [Citalopram/Escitalopram], TCAs, Mirtazipine, Trazodone, Velafazine
- Ondansetron, Droperidol, Metoclopramide, Promethazine
- Haloperidol, Chlorproazine, Ziprasidone
- TKIs, Leuprolide
- ETC
What is one thing that needs to be done before starting on an antiarrhythmic drug?
- Eletrolyte and toxicology screening
- all antiarrhythmics can cause new or worse the ones already present
What are the Class Ia Antiarrhythmic Drugs?
Sodium Channel Blockers?
- Disopyramide
- Quinidine
- Procainamide
What are the Class Ib Antiarrhythmic Drugs?
- Lidocaine
- Mexiletine
What are the Class Ic Antiarrhythmic Drugs?
- Flecainide
- Propafenone
What are the Class II Antiarrhythmic Drugs?
- Beta-Blockers
What are the Class III Antiarrhythmic Drugs?
Potassium Channel Blockers?
- Dronedatone
- Dofetilide
- Sotalol
- Ibutilide
- Amiodarone
What are the Class IV Antiarrhythmic Drugs?
Non-DHP CCBs?
- Verapimil
- Diltiazem
What is the way to remember all the Vaughan Williams Classificaitons?
- Double Quarter Pounder, Lettuce, Mayo, Fries Please! Because Dieting During Stress Is Always Very Difficult
What is the way that Amiodarone works in the body?
- K Channel Blocker but it also blocks Na and Ca channels
Half Life of 40 - 60 days
What is the BOXED WARNING for Amiodarone?
- Pulmonary Toxicity
- Heptatotoxicity
- For Life-Threatening Arrhythmias ONLY [Proarrhythmic]
What is the contraindicatoins for Amiodarone?
-
- Iodine Hypersensitivity
What is the Warnings for Amiodarone?
- Hyper- and Hypothyroidism [Hypo more common]
- Optic Neuropathy
- Corneal Micodeposits
- Photosensitivity [Blue-Gray Skin Coloration]
What is the side effects for Amiodarone?
- Hypotension
- Bradycardia [may need to lower infusion rate]
- Photosensitivity
What are some things to Monitor for Amiodarone?
- ECG, HR, BP, Electrolytes
- LFTs, Thyroid Functions
What is the Warnings for Disopyramide?
- Proarrhythmic, Hypotension, Exacerbate HF
- Myasthenia Gravis [Anticholinergic Effects]
What is the side effects for Disopyramide?
- Anticholinergic Effects [Dry Mouth, Dry Eyes, Constipation, Urinary Retention]
What is the side effects for Quinidine?
- Drug-Induced Lupus, Diarrhea, Stomach Cramping
- Cinchonism [toxicity] = Tinnitus, Hearing Loss, Blurred Vision, Headache, Delirium
What is the BOXED WARnING for Procainamide?
- Agranulocytosis [potentially fatal]
- Long term use leads to Antinuclear antibody [ANA] = DILE
What is the Warnings for Procainamide?
- Proarrhythmic
What are some additional notes for procainamide?
- NAPA is the active metabolite –> so slow acetylators have increase toxicity risk
What are some additional notes for Lidocaine & Mexiletine?
- Lidocaine is an injection used for refractory VT/Cardiac arrest
- Mexiletine: Life-threatening Arrhythmias only
What is the BOXED WARNING for Flecainide?
- Proarrhythmic [do NOT use in A. Fib]
What is the contraindications for Flecainide?
- Structural Heart Disease [Heart Failure, MI]
What is the Contraindications for Propafenone?
- Structural Heart Disease [Heart Failure, MI]
What is the warnings for Propafenone?
- Proarrhythmic
What is the side effects for Propafenone?
- Metallic Taste
What is the BOXED WARNINGS for Dronedarone?
- contraindicated in decompensated HF or permanent AFib due to increased risk of death, stroke, and HF
What is the Contraindications for Dronedarone?
- 3A4 inhibitors
- QT Prolonging Agents
What is the Warnings for Dronedarone?
- Hepatic Failure
- Pulmonary
What is the side effects for Dronedarone?
- Proarrhythmic
What are some additional notes for Dronedarone?
- DOES NOT contain iodine = no effect on thyroid [opposite of Amio]
- AVOID: strong inhibitors/inducers of 3A4 and QT prolonging agetns
What is the BOXED WARNING for Dofetilide?
- Initiated with continuous ECG
- Having ability to assess CrCl for a minimum 3 days
- Proarrhythmic
What are some additional notes for Dofetilide?
- Preferred in HF
What is the BOXED WARNING for Sotalol?
- Adjust dosing interval based on CrCl to decrease proarrhythmic risk
- QTc Prolongation is related to the Concentration
What is the warning for sotalol?
- Proarrhythmic
- Can worse HF & cause Bronchodilation
What are some additional notes for Adenosine?
- Half-Life < 10 secs
- Only for supraventricular re-entrant tachycardia
What is A. Fib
- Mulitple wave of electrial impluses that are an irregular ventricular response = decreased cardiac output [heart cant fill up]
What are the four stages of A. Fib?
- Stage 1 [At risk of A. Fib]
- Stage 2 [Pre-A. Fib]
- Stage 3 [A. Fib]
- Stage 4 [Premanent A. Fib]
What is Stage 1 A. Fib [At risk of A. Fib]
- Presence of modifiable [obesity] and non-modifiable [Male sex] risk factors
What is Stage 2 [Pre-A. Fib]
- Evidence of structural or electrical finding of A. Fib
What are the four parts of Stage 3 [A. Fib]
- Paroxysmal [terminates within 7 days]
- Persistent [sustained for > 7 day]
- Long-standing Persistant [susntained for > 12 day]
- Successful Ablation [NO A. Fib b/c surgery]
What is Stage 4 [Permanent A. Fib]?
-
- NO more rhythm control attmepts
What is the Resting Rate Control Goal for someone with A. Fib
- < 80 BPM (< 110 BPM might be more lenient]
What Medications are best to help with Rate Control in A. Fib
- Beta Blockers & Non-DHP CCBs
Patients with HFrEF and A. Fib should NOT get a non-DHP CCB
What is the Stroke prophylaxis for someone with A. Fib
- Clots can form easily with A. Fib
- DOACs or Warfarin [based on CHA2DS2-VASc]
What is the monitoring for Digoxin?
- Electrolytes
- Renal Function
- HR
What is the toxicity for Digoxin?
- N/V; Decreased Appetite
- Blurred/Double Vision; Greenish-Yellow Halos
- Increased risk of Hyopkalemia, Hypomagnesemia, Hypercalcemia
