Anti-arrhythmic drugs: Afib and SVT Flashcards
What is A-fib?
Loss/incoordination of atrial activity
What can A-fib increase the risk of?
-Blood pooling due to inadequate emptying of the ventricle
-Thrombosis
What is SVT?
Tachyarrhythmia originating at the atrial or atrioventricular (AV) nodal tissue
SVT is most commonly due to what?
AV nodal re-entry
Acute SVT can be caused by what?
Alcohol, excessive caffeine, recreational drugs, hyperthyroidism
Vaughan-Williams Classification of Antiarrhythmics for Class Ic?
Na+ channel blockers w/ slow association/dissociation (Flecainide, Propafenone)
Vaughan-Williams Classification of Antiarrhythmics for Class II?
Beta Blockers (Propanolol, Metoprolol)
*Propanolol also shows some class I action
Vaughan-Williams Classification of Antiarrhythmics for Class III?
K+ channel blockers (Amiodarone, Sotalol, Dronedrone, Dofetilide)
*Sotalol is also a BB
*Amiodarone has class I, II, III, and IV activity
Vaughan-Williams Classification of Antiarrhythmics for Class IV?
Ca2+ channel blockers (Verapamil, Diltiazem)
Vaughan-Williams Classification of Antiarrhythmics for Class V?
Work by unknown mechanisms (Adenosine, Digoxin)
Phase 0 of cardiac action potential?
Depolarization (Open Na+ channels)
Phase 1 of cardiac action potential?
Initial Repolarization (K+ leaves)
Phase 2 of cardiac action potential?
Plateau (K+ out, Ca2+ in)
Phase 3 of cardiac action potential?
Rapid Repolarization (K+ rushes out, Ca2+ starts to close)
Phase 4 of cardiac action potential?
Resting potential
MOA of Propafenone?
Blocks fast inward Na+ current, slows increase of action potential, prolongs conduction and refractoriness in all areas of the myocardium, reduced spontaneous automaticity and exhibits some BB activity
Indications for Propafenone?
-A-fib (to prevent recurrence)
-Paroxysmal SVT (to prevent recurrence)
Any change in dosing of Propafenone in geriatric patients?
No, use adult dosing
Renal adjustment for Propafenone?
None (yet use w/ caution as 50% metabolites are excreted through the urine)
Hepatic adjustment for Propafenone?
None (yet consider adjustment if necessary as drug undergoes hepatic metabolism)
ROA for Propafenone?
PO
*swallow whole: do not chew/crush
*with or w/o meals
Side effects of Propafenone?
N/V, loss of strength/energy, constipation, change in taste, headache, anxiety
Frequency of Propafenone?
BID or TID
Seek assistance/report to prescriber for Propafenone when…?
Infection, angina, bradycardia, tachycardia, severe dizziness, passing out, abnormal heartbeat, SOB, excessive wt. gain, swelling in arms/legs, blurred vision
Drug-drug interactions of Propafenone?
-QT prolongation w/ fluoxetine (paroxetine increases serum conc. of Propafenone)
-Apiprazole (increased serum conc. when taken w/ Propafenone)
-May inc. serum conc. levels of BB
Monitoring parameters for Propafenone?
BP, ECG, Pulse
Is Propafenone absorbed well?
Yes
How much of Propafenone is protein bound?
95%
How long does Propafenone take to peak?
3-8 hours
Half life of Propafenone?
2-32 hours
MOA of Flecainide?
Slows conduction in cardiac tissue by altering transport of ions across cell membrane, slight prolongation of refractory periods, decreases rate of rise of action potential w/o affecting its duration
Indications for Flecainide?
-Paroxysmal A-fib
-Paroxysmal SVT (prevention)
Any changes in dosing for Flecainide in geriatric patients?
No, adult dosing used
Renal adjustment for Flecainide?
Decrease dose/interval
Hepatic adjustment for Flecainide?
None (yet use w/ caution, check plasma conc.)
ROA for Flecainide?
PO
*may need to watch dietary changes of milk intake
Side effects of Flecainide?
Headache, dizziness, visual disturbances, dyspnea, nausea, fatigue, tremor
Seek assistance/report to prescriber for Flecainide when…?
Hepatic impairment, angina, severe dizziness, syncope, arrhythmia, bradycardia, tachycardia, dyspnea, excessive wt. gain, edema in extremities, tremors, vision changes, ecchymosis (bleeding under skin), hemorrhage
Disease related concerns for Flecainide?
Contraindicated in those w/ structural heart disease
Drug-drug interactions of Flecainide?
Watch meds w/ QT prolongation effects
Monitoring for Flecainide?
ECG, BP, Pulse, Periodic serum trough concentrations
When does Flecainide peak?
3 hours
Half life of Flecainide?
8-20 hours depending upon age
Selectivity of Metoprolol?
B-1 selective
MOA of Metoprolol?
Select inhibitor of B-1-adrenergic receptors, competitively blocks B-1 R’s w/ little to no efffect on B-2 R’s at oral doses <100mg in adults
Indications for Metoprolol?
-A-fib: acute & maintenance
-SVT: off label use for acute & maintenance
Any dose changes for Metoprolol in geriatric patients?
No, use adult dosing
Renal or Hepatic adjustments for Metoprolol?
None
ROA of Metoprolol?
IV bolus or PO (with food)
Side effects of Metoprolol?
Diarrhea, loss of strength/energy, vomiting, hypotension, dizziness, fatigue
Dose frequency of Metoprolol?
QD or BID
Seek assistance/report to prescriber for Metoprolol when…?
Depression, illogical thinking, memory impairment, severe dizziness, passing out, skin discoloration, sensation of cold, angina, arrhythmias, bradycardia, SOB, excessive wt. gain, swelling of extremities, vision changes
Disease related concerns with Metoprolol?
DM, bradycardia, peripheral vascular disease/Raynaud’s, thyroid disease, depression
Can you withdraw Metoprolol abruptly?
NO, slow taper over 1-2 weeks to avoid rebound tachycardia
Drug-drug interactions with Metoprolol?
NSAIDs, Sulfonylureas, Theophylline
Monitoring with Metoprolol?
IV: ECG, HR, BP
PO: HR, Rhythm, BP
Onset of action for PO Metoprolol?
3-6 hours
Onset of action for IV Metoprolol?
20 min
Half life of Metoprolol?
3-9 hours depending on Hepatic function
MOA of Amiodarone?
Adrenergic stimulation (alpha & beta blocking properties), affects sodium, potassium, and calcium channels, prolongs action potential and refractory period in myocardial tissue, decreases AV conduction and sinus node function
Indications for Amiodarone?
-A-fib: acute, maintenance, off-label
-SVT: not first line, acute
Changes for Amiodarone dosing in geriatric patients?
Adult doses but typically on the lower end of dosing, slow taper
Renal adjustment for Amiodarone?
None
Hepatic adjustment for Amiodarone?
In more severe impairment, dose reduce or avoid
ROA of Amiodarone?
-IV over 1 or more hours
-PO (with food, divide dose if GI upset, avoid grapefruit juice**)
Black box warning/side effects for Amiodarone?
Arrhythmia, pulmonary toxicity
Constipation, N/V, loss of strength/energy, lack of appetite
Seek assistance with Amiodarone if…?
Liver problems, signs of severe pulmonary disorder, signs of thyroid problems, signs of SJS-TEN, bradycardia, vision changes, eye pain, severe eye irritation, sensitivity to light, SOB, bruising/bleeding, joint/muscle pain
Drug-drug interactions of Amiodarone?
-Numerous due to extensive metabolism (CYP3A4, 2C8, 2C9, 2D6, 1A2)
-MAJOR INTERACTION: Sofosbuvir (severe bradycardia)
-Watch w/ meds that have QT prolongation effects
Monitoring for Amiodarone?
BP, HR (ECG) & rhythm throughout therapy, lethargy, edema of hands/feet, weight loss, pulm. toxicity (Baseline PFTs & CXR, continue monitoring CXR annually w therapy), LFTs (semiannually), serum electrolytes (esp. K+ and Mg), thyroid function tests
Onset of Amiodarone?
2 days-3 weeks
Half life of Amiodarone?
40-55 days
How much of Amiodarone is protein bound?
96%
MOA of Dronedarone?
Structurally related to amiodarone.
Inhibits sodium and potassium channels prolonging AP and refractory period in myocardial tissue w/o reverse-use dependent effects, decreases AV conduction & sinus node function through inhibition of calcium channels, Beta-1 R blocking activity
Indications for Dronedarone?
Paroxysmal or persistent A-fib
Any changes in dosing of Dronedarone in geriatric patients?
No, use adult dosing
Renal adjustments for Dronedarone?
None
Hepatic adjustments for Dronedarone?
Contraindicated in severe impairment
ROA for Dronedarone?
PO (w/ morning & evening meal, avoid grapefruit**)
Side effects of Dronedarone?
Diarrhea, N/V, loss of strength/energy, abdominal pain
Frequency of dosing for Dronedarone?
BID
Seek assistance with Dronedarone if…?
Signs of kidney problems, signs of heart problems, signs of liver problems, signs of severe pulmonary disorder, dizziness, bradycardia, abnormal heartbeat, QT prolongation
Drug-Drug interactions of Dronedarone?
-Increases conc. of Atorvastatin
-BB: bradycardia
-CCB
-Avoid cyclosporine
-Reduce Digoxin by 50%
-Avoid propafenone (QT-prolongation)
-Increases conc. of Fentanyl
Monitoring for Dronedarone?
ECG (at least q3months), BP, HR & rhythm throughout, signs of lethargy, edema of hands/feet, serum electrolytes (esp. K+ & Mg), serum liver enzymes & bilirubin (periodically, esp. in first 6 months)
Peak for Dronedarone?
3-6 hours
Half life of Dronedarone?
13-19 hours
How much of Dronedarone is protein bound?
> 98%
Sotalol has what kind of slectivity?
Non-selective BB
MOA of Sotalol?
Increased sinus cycle length, slowed HR, decreased AV nodal conduction, increased AV nodal refractoriness, has both Beta-1 & Beta-2 R blocking activity
Seek assistance with Sotalol if..?
Dizziness, passing out, angina, bradycardia, tachycardia, abnormal heartbeat, severe loss of strength/energy, vision changes, SOB, excessive wt. gain, swelling of extremities, *injection site pain/irritation/edema, *excessive sweating
Warnings for Sotalol?
Proarrhythmia, QT-prolongation, do not stop abruptly, avoid if asthma, use w/ caution in DM
Drug-drug interactions with Sotalol?
Watch for additive effects (esp. meds that may cause bradycardia or QT prolongation)
Monitoring for Sotalol?
Serum creatinine, magnesium, & potassium
HR, BP, ECG
Onset of IV Sotalol?
5-10 min
Onset of PO Sotalol?
1-2 hrs
Half life of Sotalol?
12 hrs (up to 69 hrs in renal impairment)
Labelling of Sotalol (Betapace brand)?
“AF” - drug more expensive but is the same drug w/ the same efficacy
Frequency of dosing for Sotalol?
BID
Indications for Sotalol?
-Symptomatic A-fib
-SVT (off label)
Any dose changes for Sotalol in geriatric patients?
No, use adult dosing
Renal adjustment for Sotalol?
Extend interval if CrCl <60 mL
Hepatic adjustment for Sotalol?
None
ROA for Sotalol?
IV over 5 hours
PO (without regards to meals)
Side effects of Sotalol?
Headache, diarrhea, N/V, fatigue, weakness, sleep disorders
MOA of Dofetilide?
Blockade of cardiac K+ ion chqannel using delay of repolarization
Indications for Dofetilide?
A-fib
SVT (ongoing managment, off label use)
Dose changes for Dofetilide in geriatric patients?
Adult dosing, but be cautious with renal dysfunction
Renal adjustment for Dofetilide?
Dose reduction necessary
Hepatic adjustment for Dofetilide?
None, but use w/ caution
ROA for Dofetilide?
PO (with or w/o food)
Side effects of Dofetilide?
Headache, common cold/flu-like sx, nausea, dizziness
Frequency of dosing for Dofetilide?
BID
Seek assistance with Dofetilide if…?
Angina, dizziness, passing out, bradycardia, tachycardia, abnormal heartbeat, SOB, *Torsades de pointes
Drug-drug interactions with Dofetilide?
-Cimetidine: increases serum conc. of Dofetilide (avoid)
-Antifungals: decrease metabolism of Dofetilide (avoid)
-QT prolongation meds (avoid)
-Verapamil: increases serum conc. of Dofetilide
Monitoring for Dofetilide?
ECG (w/ attention to QT), serum creatinine (baseline and changes), K+ and Mg levels
Peak of Dofetilide?
Fasting: 2-3 hours
Half life of Dofetilide?
10 hours (prolonged w/ renal impairment)
What kind of CCBs are Verapamil and Diltiazem?
Non-dihydropyridine
MOA of Diltiazem?
Inhibits Ca2+ from entering slow channels during depolarization, produces relaxation of coronary vascular smooth muscle/coronary vasodilation
Indications for Diltiazem?
A-fib (acute) (rate control -off label)
SVT (ongoing management, off label)
Changes in dosing of Diltiazem in geriatric patients?
None, adult dosing used
Renal and Hepatic adjustment for Diltiazem?
None, but use w/ caution
ROA for Diltiazem?
IV bolus over 2 min, then continuous infusion
PO (depends on formulation-> w/ meals, empty stomach, or before bedtime)
Side effects of Diltiazem?
Edema, *flushing, headache, nausea, loss of strength/energy, *rhinorrhea, *pharyngitis, *infection site irritation
Frequency of dosing for Diltiazem?
QD or QID
Seek assistance with Diltiazem if….?
Liver problems, severe dizziness, passing out, bradycardia, abnormal heartbeat, SOB, excessive wt. gain, swelling of extremities, signs of *SJS-TEN
Drug-drug interactions of Diltiazem?
-Atorvastatin: each can inc. serum concentration of other
-Cimetidine: increases serum conc. of CCB
-Increases serum conc. of Fentanyl
Monitoring for Diltiazem?
LFTs, kidney function, BP, ECG, HR
Onset for Diltiazem?
IV: 1-3 min
PO: 30-60 min
Half life of Diltiazem?
IV: 3.5-4 hrs
PO: 3-9.5 hrs (depending on formulation)
Changes in Verapamil for geriatric patients?
None, use adult dosing
MOA for Verapamil?
Inhibits calcium from entering slow channels during depolarization, relaxation of coronary vascular smooth muscle/coronary vasodilation, slows automaticity and conduction of AV node
Indications for Verapamil?
-A-fib (rate control)
-SVT (acute treatment, off label)
Renal adjustment for Verapamil?
None unless Verelan PM (initial 100mg QD at bedtime), otherwise just use w/ caution
Hepatic adjustment for Verapamil?
Reduce dose, % reduction dependent on formulation
ROA of Verapamil?
IV over 2-3 min
PO dependent upon formulation (w/ food, watch splitting, no crushing!)
Side effects of Verapamil?
Constipation, headache, gingival hyperplasia, edemae
Frequency of dosing for Verapamil?
QD or QID
Monitoring for Verapamil?
BP, HR, periodic LFTs, ECG
Onset of Verapamil?
IV 3-5 min
PO 1-2 hrs
Half life of Verapamil?
4-12 hours
How much of Verapamil is protein bound?
90%
Drug-drug interactions of Verapamil?
-Antifungals
-May increase conc. of Dofetilide and Fentanyl
-Simvistatin: limit adult max of Simv. to 10mg/day
-Ethanol: may increase blood ethanol levels, prolong effects
-Grapefruit juice may increase serum conc. of Verapamil
Seek assistance with Verapamil if…?
Liber problems, bradycardia, arrhythmia, severe dizziness, passing out, SOB, excessive wt. gain, swelling of extremities
MOA of Digoxin?
Direct suppression of AV nodal conduction increasing effective refractory period and decreasing conduction velocity, positive inotropic effect, enhanced vagal tone, dec. ventricular rate to fast atrial arrhythmias
Indications for Digoxin?
A-fib (rate control) (off label dose)
SVT (rate control, off label use)
Adjustment of Digoxin for geriatric patients?
Do not exceed 0.125 mg/day in pts 65+y/o
Renal adjustment for Digoxin?
Reduce by 50% or avoid (may need to alter dose interval to q48hrs)
Hepatic adjustment for Digoxin?
None
ROA of Digoxin?
Total digitalizing dose (TDD)-
-IV: 8-12 mcg/kg (administer half of TDD over 5 min w/ remaining as 25% fractions at 4-8 hr intervals) OR (may administer 0.25mg w/ repeat dosing to max of 1.5 mg over 24 hrs followed by oral maintenance regimen)
-IV over 5 min
-IM (not preferred)
-PO (maintain adequate amounts of K+)
Side effects of Digoxin?
Headache, dizziness
Dosing frequency of Digoxin?
QD
Seek assistance with Digoxin if…?
N/V, severe diarrhea, vision changes, visual halos o bright colors around lights, weight loss, lack of appetite, black/tarry/bloody stools, confusion, brady/tachycardia, hallucinations, irregular heartbeat, mood changes, severe abdominal pain, enlarged breasts
Condition interacting with Digoxin?
Hypothyroidism may cause increased digoxin levels (due to decreased clearance)
Drug-drug interactions with Digoxin?
Amiodarone: increases digoxin levels
Monitoring with Digoxin?
-Digoxin toxicity levels over 2ng/mL
-Electrolytes (hypercalcemia can cause toxicity despite digoxin levels)
-HR, rhythm, periodic ECGs to assess effects/signs of toxicity
Onset of Digoxin?
IV 50-60 min
PO 1-2 hrs
Half life of Digoxin?
36-48 hours
MOA of Adenosine?
Slows conduction time through AV node, interrupting re-entry pathways through AV node, restoring NSR
Indications for Adenosine?
Paroxysmal SVT
Adjustment of Adenosine for geriatric patients?
None, use adult dosing
Renal & Hepatic adjustment with Adenosine?
None
ROA for Adenosine?
IV push
Side effects of Adenosine?
Abdominal pain, flushing
Seek assistance with Adenosine if….?
*Severe cerebrovascular disease (change in strength, one side > other, difficulty speaking/thinking, change in balance or vision), SOB, angina, severe dizziness, passing out, brady/tachycardia, abnormal heartbeat, seizures, severe headache, *neck pain, *jaw pain, *throat pain
Interactions with Adenosine?
-Caffeine: diminishes effects of adenosine
-Nicotine: enhances effect of AV blocking, may inc. HR, inc. severity of chest pain
Monitoring for Adenosine?
ECG, HR, BP
Onset on Adenosine?
Rapid
Half life of Adenosine?
<10 seconds
What is the “pill-in-the-pocket” approach for single-dose outpatient tx of select patients?
Single PO dose of meds can be given to terminate SVT outside of hospital in selected patients once safety is established
Who is the “pill-in-the-pocket” approach an option for?
-Infrequent (<few/yr) but prolonged (>1-2hrs) SVT episodes which are hemodynamically tolerated
-Only one episode of SVT
Drug options for “pill-in-the-pocket” approach?
CCBs, BBs, Flecainide 100-300mg, Propafenone 150-450mg
“ABC” treatment method for A-fib?
Avoid stroke, Better symptoms, Comorbidity management
How to avoid stroke in A-fib patients?
Anticoagulants (VKAs-Warfarin, NOACS-dabigatran, rivaroxaban, apixaban)
LA Appendage exclusion (surgery, precutaneous)
How to better symptoms in a-fib patients?
HR control (BB, CCB, Digoxin)
Rhythm control (Cardioversion, Antiarrhythmetics- Amiodarone, etc., Ablation/Surgery)
Comorbidity management with A-fib?
Obesity, BP, DM, CAD, CPAP if sleep apnea, Avoid excessive ETOH (abstinence ideal), Moderate physical activity, HF control
What is the best option for anticoagulation in poor renal function?
Warfarin
What is the best option for anticoagulation in mechanical heart valves?
Warfarin
What is the best option for anticoagulation in rheumatic mitral stenosis?
Warfarin
What is the best option for anticoagulation in those who may easily miss doses?
Warfarin
Warfarin frequency of dosing?
Once daily
INR target w/ Warfarin?
2-3
Good option for anticoagulation for reducing stroke risk/major bleed?
Apixaban
Apixaban frequency of dosing?
BID
Which anticoagulant has an increased risk for GI bleed or MI?
Dabigitran
Dabigitran frequency of dosing?
BID
Which anticoagulant requires close monitoring of renal function?
Edoxaban
Edoxaban frequency of dosing?
Once daily
Which anticoagulant should be used in caution with Diltiazem, Dronedarone, and Verapamil, and also has an increased risk of GI bleed?
Rivaroxaban
Rivaroxaban frequency of dosing?
Once daily
Drugs for rate control in A-fib?
BB, Non-DHP CCBs, Digoxin, Amiodarone
Which medications should be used in A-fib with COPD?
BB, Diltiazem, Verapamil
Which medications should be used in A-fib with LV dysfunction or HF?
BB, Digoxin
Amiodarone
Which medications should be used in A-fib with HTN or HFpEF?
BB, Diltiazem, Verapamil
Amiodarone
Which medications should be used in A-fib with no other CV disease?
BB, Diltiazem, Verapamil
Amiodarone
Antiarrhythmic drugs for A-fib?
Flecainide, Propafenone, Amiodarone, Varnakalant, Ibutilide
Antiarrhythmic drugs for maintenance doses in A-fib?
Amiodarone, Flecainide, Propafenone, Disopyramide, Sotalol
Strategies for rhythm control in patients with paroxysmal and persistent A-Fib with no structural heart disease?
Dofetilide, Dronedarone, Flecainide, Propafenone, Sotalol
Amiodarone
+/- Catheter ablation
Strategies for rhythm control in patients with paroxysmal and persistent A-Fib with structural heart disease (CAD)?
Dofetilide, Dronedarone, Sotalol
Amiodarone
+/- Catheter ablation
Strategies for rhythm control in patients with paroxysmal and persistent A-Fib with structural heart disease (HF)?
Dofetilide, Amiodarone
+/- Catheter ablation
Acute tx of SVT of unknown mechanism?
Vagal maneuvers and/or IV adenosine (Class I)
–> if ineffective or not feasbile:
-Hemodynamically stable pts: IV BB, IV diltiazem or IV verapamil (Class IIa), if still ineffective: synchronized cardioversion
-Non-stable pts: Synchronized cardioversion
Tx of ongoing SVT of unknown mechanism?
Ablation candidate?
Yes- EP study/catheter ablation (if pre-excitation and a candidate, or if no pre-excitation and prefers ablation)
No- med therapy (if ineffective, catheter ablation)
Drug options for ongoing SVT of unknown mechanism?
-Recommended: BB, diltiazem or verapamil (in absence of pre-excitation)
-Flecainide or Propafenone (in absence of SHD)
-Amiodarone, Dofetilide, or Sotalol
-Digoxin (in absence of pre-excitation)
