Arrhythmias Flashcards
What is the cardiac conduction system?
- The electrical system that helps the heart pump; starts in the SA node, goes to the AV node, down the bundle of his with the Purkinje Fibers then to the ventricles.
Where at on the ECG does the action potential take place
- Depolarization starts within the P wave
- QRS complex is where the Action potential starts
- Repolarization starts within the T wave
What is the normal value of ECG intervals?
- PR Interval: 0.12 - 0.20 secs
- QRS Duration: 0.08 - 0.12 secs
- QT Interval: 0.38 - 0.46 secs
- QTc Interval: 0.36 - 0.45 secs [MEN]
- QTc Interval: 0.38 - 0.46 secs [WOMEN]
What is known as Torsades de Pointes?
- It is a polymorphic ventricular tachycardia characterized on ECG by oscillatory changes of QRS with a QTc interval of > 500ms [CAN CAUSE SUDDEN DEATH]
What are some of the drugs that may cause Torsades de Pointes?
- Antiarrhythmics: Procainamide, flecainide, Ibutilide, Dofetilide, Sotalol, Amiodarone, Dronedarone
- Antimicrobials, Antidepressants, Antipsychotics, Anticancer, Opioids,…
What does supraventricular arrhythmias mean and are some examples?
- Arrhythmias that are above the ventricles
- Sinus Bradycardia, Atrioventricular [AV] Block, Sinus Tachycardia, Afib, Supraventricular Tachycardia
What is Sinus Bradycardia?
- It is the decrease in automaticity of the SA node, typically a heart rate of about < 60 BPM
What are some of the causes of Sinus Bradycardia?
- MI or Ischemia, Electrolyte inbalence [High K and Mg], Drugs [Digoxin, Beta-Blockers, CCBs,… - anything that will slow down the heart]
What are some of the symptoms related to Sinus Bradycardia?
- Hypotension, Dizziness, Fainting [Syncope]
How do we treat a patient with Sinus Bradycardia?
- ONLY if they are symptomatic
- Atropine 0.5 -1mg IV, repeat every 5 mins until a max does of 3 mg
- Unresponsive toward Atropine; use Dopamine, Epinephrine, Isoproterenol
Since Atropine is the main medication used in the treatment of Sinus Bradycardia, what are some of its side effects?
- Tachycardia, Urinary Retention, Blurred Vision, Dry Mouth, Mydriasis [Anticholinergics]
What is the Treatment of Sinus Bradycardia after heart transplant or spinal cord injury?
- NO Atropine because the nerves are cut
- Aminophylline 6 mg/kg over 30 mins
- OR Theophylline 300mg [Heart]/5-10mg [Spine]
What is a non-pharmacologic treatment for Sinus Bradycardia?
- Pacemaker: will send a shock to the heart to keep it in normal rhythm
What is an important feature to know about Afib?
- 120 to 180 BPM
- Irregularly Irregular
- NO P wave
What are some of the definiations that are related to Afib?
- Paroxysmal, Persistent, Permanent, Long-standing persistent, Nonvalvular
What is Paroxysmal Afib?
- Intermittent Episodes of AFib; episodes start suddenly and spontaneously, last for minutes to hours and terminate suddenly and spontaneously
What is Persistent AFib?
- A continuous episode of AFib that DOES NOT terminate spontaneously [lasts > 7days]
What is Long-Standing Persistent AFib?
- Continuous AFib > 12 months
What is Permanent AFib?
- AFib is ALWAYS present, the patient is never again in sinus rhythm
What is Nonvalvular AFib?
- AFib in the absence of rheumatic mitral valve stenosis, a mechanical or bioprosthetic heart valve, or mitral valve repair
What is some of the causes towards AFib?
- HTN, CAD, HF, Valvular Heart Disease
What are some of the symptoms of AFib?
- Asymptomatic?, Palpitations, Dizziness, Fatigue, Lighthehadedness, SOB, Hypotension,…
What are the treatment goals for AFib?
- Persistent Afib: Ventricular Rate Control, Prevention of Stroke, Conversion SInus Rhythm
- Paroxysmal AFib: Ventricular Rate Control, Prevention of Stroke, Maintenance Sinus Rhythm
- Permanent AFib: Ventricular Rate Control, Prevention of Stroke
What are the drugs that are used in Ventricular Rate Control for AFib?
- Direct AV Node Inhibition
- Diltiazem, Verapamil, Beta-Blockers [Esmolol, Propranolol, Metoprolol], Digoxin, Amiodarone
What is the algoritihm for Ventricular Rest Control for AFib?
- No Other CV: Used Beta-Blockers, Diltiazem or Verapamil
- Hypertension: Used Beta-Blockers, Diltiazem or Verapamil
- HFrEF: Used Digoxin
[When all else fails use Aminodarone] - COPD: Used Beta-Blockers, Diltiazem or Verapamil [NO Amiodarone]
What are the medications that are used for Conversion to sinus rhythm for AFib?
- DCC, Aminodarone, Dofetilide, Ibutilide, Propafenone, Flecaintide
When is conversion safe in AFib and when is it not safe?
- It is safe < 48 hours
- It is NOT safe > 48 hours; there might be a clot
When is a patient classified as hemodynamically UNSTABLE?
- SBP < 90, HR > 150, Current Chest Pain, Unconscious
What is some side effects for Amiodarone within AFib?
- Hypotension, Bradycardia, Blue-Grey Skin Color, Photosensitivity, PULMONARY FIBROSIS, Hypo/Hyperthyroidism
What is important to know about Propafenone and Flecainide within AFib?
- Should NOT be used in patient that have HFrEF; will exacerbate the symptoms
What is the dosing for Propafenone and Felcainide within AFib?
- Propafenone: 450 - 600 mg once
- Flecainide: 200 - 300 mg once
- “Pill in the Pocket”: keep on body and take when having symptoms
What is the Dosing for Dofetilide within AFib?
- CrCL > 60 = 500 mcg BID
- CrCl 40 - 59 = 250 mcg BID
- CrCl 20 -39 = 125 mcg BID
- CrCl < 20 = CONTRAINDICATED
What is the Pathway for Conversion to sinus rhythm during AFib < 48 hours?
- DCC? then Either HFrEF or NO HFrEF
- NO EFrEF: Amiodarone, Dofetilide, Flecainide, Propafenone, Ibutilide
- HFrEF: Amiodarone, Dofetilide, Ibutilide [NOT is EF < 30%]
What is the pathway for Conversion to sinus rhythem during AFib > 48 hours?
- DELAY CONVERSION: anticoag for 3 weeks then DCC
- EARLY CONVERSION: TEE [checking for thrombi]
- NO Thrombus: Go to other pathway [DCC]
- Thrombus: Anticoag > 4 weeks then TEE again
What medications are used in the maintenance of sinus rhythm for AFib?
- Amiodarone, Sotalol, Propafenone, Flecainide, Dofetilide, Dronedarone
What are some of side effects for Aminodarone for AFib?
- Blue-grey color skin, Pulmonary Fibrosis, Hyper/Hypothyroidism, Bradycardia, Photosensitivity
How is Aminodarone different than Dronedarone within AFib?
- Dronedarone DOES NOT have as many severe side effects like Aminodarone does
What is important to know about Sotalol’s dosing for maintenance of sinus rhythm in AFib?
- QTc < 450ms?
- CrCl >60 = 80 mg BID OR CrCL 40-60 = 80 mg qd
- NO sotalol CrCl < 40
- QTc < 500ms = discharge or increase dose
- QTc > 500ms = D/C sotalol
For AFib and NO heart disease, what medication do you use for maintenance?
- Dofetilide, Propafenone, flecainide, Sotalol, Dronedarone [Amiodarone for last last line]
- Catheter Ablation
For AFib WITH heart disease, what medication do you use for maintenance?
- CAD: Dofetilide, Dronedarone, Sotalol [Catheter Ablation]
- HFrEF: Amiodarone, Dofetilide [Catheter Ablation]
- Amiodarone last line
What is important to know about Dofetilide’s dosing for maintenance of sinus rhythm during AFib?
- QTc < 440 ms
- The same as other one 500 to 250 to 125
- <15% QTc Increase = good; >15% QTc increase = 1/2 the dose
What are the following factors for the CHADsVASc score?
- CHF = 1pt
- HTN = 1pt
- Age > 75 = 2pt
- DM = 1pt
- Stroke = 2pt
- Vascular Disease = 1pt
- Age 65-74 = 1pt
- Sex [F] = 1pt
When should patients get an anticoag based on their CHADsVASc score for prevention of stroke during AFIb?
- RECOMMENDED: > 2 in men & > 3 in women
- CONSIDERED: 1 in men & > 2 in women
- NO: 0 in men & 0 - 1 in women
When is Warfarin perferred over NOACs in AFib stroke prevention?
- Warfarin > NOAC: patients that have Mechanical Heart Valves and Valvular AFib
- NOAC > Warfarin: use in general?
What are the NOACs used in AFib stroke prevention?
- Dabigatran, Rivaroxaban, Apixaban, Endoxaban
What is the doing for Dabigatran for Stroke Prevention during AFib?
- CrCl > 30 = 150 mg BID
- CrCL 15 - 30 = 75 mg BID
- CrCl < 15 = NONE
What is the dosing for Rivaroxaban for Stroke Prevention during AFib?
- 20 mg once with evening meal
- CrCl 30 - 50 = 15 mg once with evening meals
- CrCl 15 - 30 = 15 mg once with evening meals
What is the dosing for Apixaban for Stroke Prevention during AFib?
- 5 or 2.5 mg BID
- CAN be used during ESKD
What is the dosing for Endoxaban for Stroke Prevention during AFib?
- CrCl > 95 = NONE
- CrCl 50 - 95 = 60 mg qd
- CrCl 15 - 50 = 30 mg qd
- CrCl < 15 = NONE
What are the antidotes for each of the Anticoag medications?
- Dabigatran: Idarucizumab
- “-Xaban”: Andexanet Alfa
What is Supraventricular Tachycardia?
- Regular Rhythms with narrow QRS complexes
- HR 110 - 250 BPM
- Mostly takes place in the AV node
What is the mechanism of SVT?
- Normally the impulse will around the AV node and down the Bundle of His; in SVT the impulse will travel around the AV node depolarizing the atrium
What are some of the symptoms of SVT?
- “Neck Pounding”, Palpitations, Dizziness, Weakness, Lightheadedness, Increase Urination
What is important to note about SVT?
- Its not necessarily life threatening but it can lead to VT which is VERY life threatening
What are some of the medications used in terminating SVT?
- Adeonsine, Beta-Blockers, Verapamil, Diltiazem
What is important to know about Adeonsine for termination of SVT?
- May cause chest pain, flushing, SOB, Sinus Pause, Bronchospasm
- These should only last about 30 secs
What is the dosing for Adeosine?
- Start with 6 mg IV rapidly
- Flush with saline
- Wait 2 mins
- 12 mg IV rapidly
- Flush
- Wait 2 mins
- 12mg IV rapidly
- Flush
What is the way we terminate SVT?
- Try Vagal Manuevers and/or Adenosine
- Work?
- Try Beta-Blockers, Verapamil, Diltiazem
- Work?
- DCC [Last line]
What is the way that we prevent the recurrence of SVT?
- Symptomatic?
- Catheter Ablation?
- No: then NO HFrEF or HFrEF
- NO HFrEF: Beta-blocker, Diltiazem, Verapamil, Propafenone, Flecainide
- HFrEF: Digoxin, Amiodarone, Dofetilide
What are Premature ventricular complexes?
- Wide QRS Complexes
- Electrical fibers that are activated within the ventricular muscle instead of the Bundle of His
What are the types of PVCs?
- Simple: Single PVC
- Couplets: Pair of PVC
- Every 2nd Beat: Bigeminy
- Every 3rd Beat: Trigeminy
- Every 4th Beat: Quadrigeminy
Should Asymptomatic PVCs be treated?
NO!
- no known treatment
What is the treatment strategy for symptomatic PVCs?
- NO CAD or HF: beta-blocker, diltiazem, verapamil [Catheter Ablation if drug no do goo]
- CAD: beta-blockers, diltiazem, verapamil
- HF: beta-blockers
What is Ventricular Tachycardia?
- Regular Rhythm; back to back PVC
- Wide QRS complexes
What are the main risk factors that cause VT?
- CAD
- MI
- HFrEF
What are some drugs that may cause VT?
- Flecainide, Propafenone, Digoxin [High Dose]
What are some of the drug use in the termination of VT?
- Procainamide, Amiodarone, Sotalol, Verapamil [Only for Verapamil-VT], Beta-Blockers [Only for Outflow-VT]
What are some of the adverse affects with Procainamide for VT?
- Hypotension, QT interval prolongation, Torsades de Pointes
What is the treatment plan for termination of VT?
- Heart Disease?
- DCC [haven’t eaten in 8 hours] or Procainamide [DoC] or Amiodarone/Sotalol
- VT?
- Yes: DCC; NO: prevetn recurrence
What are some fo the medication used to prevent recurrence and sudden cardiac death in VT?
- Implantable Cardioverter defibrillator [ICD], Amiodarone, Sotalol, Catheter Ablation
Where is the ICD implanted and where does it go to in the body?
- It is implanted right below the collar bone and goes down the vein into the the heart; connects to the AV Node and into the ventricle muscle
- Doesn’t prevent the arrhythmia it just prevent death
What is Ventricular Fibrillation?
- It irregular, disorganized, chaotic electrical activity
- No P wave or QRS wave
- No Pulse and No Blood Pressure
What are some of the risk factors that cause VFib?
- MI
- HFrEF
- CAD
What is the only really effective treatment for terminating VFib?
- Electric Shock via defib
What are some of the medications that are used in VFib?
- Epinephrine, Amiodarone, Lidocaine
