Abnormal heart rhythm:
Arrhythmia
slow heart beat:
bradycardia
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Abnormal heart rhythm:
Arrhythmia
slow heart beat:
bradycardia
too fast heart beat:
tachycardia
Signs and symptoms of arrhythmias:
fluttering in chest
skipping a beat
dizziness
shortness of breath
fatigue
lightheadedness
chest pain
What can be used to diagnose arrhythmias?
ECG
Holter monitor:
an ambulatory ECG device that records the electrical activity of the heart continuously for 24-48 hours
What type of arrhythmias can a Holter monitor or continuous ECG?
intermittent
Describe the steps in the cardiac conduction pathway:
electrical impulse begins in the SA node
impulse travels from the SA node to the right and left atria, which causes atria contraction
signals reaches the AV node, electrical conduction slows down
impulse continues through the bundle of His and into the ventricles
the bundle of His divides into the right bundle branch for the right ventricle
left bundle branch for the left ventricle
signal continues to spread through the ventricles via Purkinje fibers, which causes the ventricles to contract.
The heart’s pacemaker:
SA node
Normal HR:
60-100 BPM
Describe the step of electrical signaling ( Cardiac action potential):
Phase 0: heartbeat is initiated when rapid ventricular depolarization occurs in response to an influx of sodium, which causes ventricular contraction ( QRS complex on ECG)
Phase 1: early rapid repolarization( Na channel close)
Phase 2: a plateau in response to an influx of calcium and efflux of potassium
Phase 3: rapid ventricular repolarization occurs in response to an efflux of K; which causes ventricular relaxation ( T wave on ECG)
Phase 4: resting membrane potential is established; atrial depolarization occurs ( P wave on ECG)
What is the most common cause of arrhythmias?
myocardial ischemia infarction
What are some non cardiac conditions that can trigger or predispose a patient arrhythmia?
electrolyte imbalances ( potassium, magnesium, sodium. and calcium)
elevated sympathetic state
drugs ( drugs that prolong QT and illicit drugs)
What is the most common type of arrhythmia?
atrial fibrillation
PVCs
premature ventricular contractions ( also known as skipped heartbeats)
A series of PVCs that result in a HR > 100 BPM:
ventricular tachycardia
If a patient has a pulseless VT:
it is a medical emergency and advanced cardiac life support should be started.
What can happen if you leave and ventricular tachycardia untreated?
it can degenerate into ventricular fibrillation
At what rate is a QTC interval considered to be prolonged?
> 440-460 milliseconds, but it is markedly prolonged > 500 msec.
When a patient has a prolongation of their QT interval it put them at risk for?
torsade de pointes
What medications can increase or prolong QT interval?
antiarrhythmics: class Ia, Ic, and III
anti-infectives: antimalarials, azole antifungals, macrolides, quinolones, lefamulin
antidepressants: SSRIs ( high risk with citalopram and escitalopram)
antiemetics: 5-HT3 receptor antagonists, droperidol, metoclopramide, promethazine
antipsychotics: 1st generation and second generation
onclongy medications: androgen deprivatio therapy, tyrosine kinase inhibitors, arsenic trioxide
cilostazol, donepizil, fingolimod, hydroxyzine, loperamide, methadone, ranolazine, solifenacin
What should be done before starting any drug for a non life threatening arrhythmia?
electrolytes and toxicology screen should be checked to identify any potentially reversible causes
Class I: sodium channel blockers:
Ia: disopyramide, quinidine, procainamide
Ib: lidocaine, mexiletine
Ic: flecainide, propafenone
Vaughan Williams classification Class II:
beta blockers
Vaughan williams classifications class III: potassium channel blockers
dronedarone
dofetilide
sotalol
ibutilide
amiodarone
Vaughan Williams classification class IV: non-DHP CCBs
verapamil
diltiazem
MOA of amiodarone:
class III antiarrythmic that blocks potassium channels and also blocks sodium, calcium, alpha, and beta adrenergic receptors.
What is the ½ life of amiodarone?
40-60 days
Amiodarone is the most commonly prescribed and is a preferred:
antiartrhythmic in patients with HF
Amiodarone
nexterone
pacerone
Boxed warnings for amiodarone:
pulmonary toxicity
hepatotoxicity
life threatening arrhythmias only
What are some contraindications to taking amiodarone?
iodine hypersensitivity
What things should you look out for in patients taking amiodarone?
hyper and hypothyroidism
optic neuropathy
corneal microdeposits
photosensitivity: blue-gray skin discoloration
peripheral neuropathy
SE of amiodarone:
hypotension
bradycardia ( may decrease infusion rate)
photosensitivity
DILE
SJS/TEN
What do you monitor in patients taking amiodarone?
ECG
HR
BP
Electrolytes
LFTs ( every 6 months)
thyroid function
How do you administer amiodarone IV infusions?
iv infusions > 2 hours require a non-PVC container: polyolefin or glass
preixed IV bags: nextreone comes in non-PVC , non-DHEP galaxy plastic container
use 0.22 micron filter; central line preferred
incompatible with heparin
What is recommended to prevent drug interactions when taking amiodarone with digoxin?
decrease digoxin by 50%
What do you do to prevent drug interactions between amiodarone and warfarin in patients on both medications?
decrease dose of warfarin by 30-50%
If a patient needs to take both amiodarone and simvastatin, what is the maximum dose per day of simvastatin?
20mg/day
If a patient has to take lovastatin and amiodarone together what is the maximum dose of lovastatin?
40 mg/day
What can enhance the bradycardia effects of amiodarone if used with amiodarone?
sofosbuvir when used together with amiodarone
How do you take quinidine?
take with food or milk to help decrease GI upset
What are some warning for disopyramide?
proarrhythmic
anticholinergic effects
What are some warnings for quinidine?
pro arrhythmic
hemolysis risk: avoid in G6PD deficiency
can cause positive coombs test
SE of quinidine:
DILE
diarrhea
stomach cramping
rash
lightheadedness
cinchonism ( toxicity): tinnitus, hearing loss, blurred vision, headache, delirium
SE of disopyramide:
anticholinergic effects: dry mouth, constipation, urinary rentention
Dosage form of procainamide
injection
How is the active metabolite , N-acetyl procainamide is cleared?
renally cleared
What is the therapeutic level of procainamide?
4-10 mcg/mL
Boxed warning for procainamide:
agranulocytosis
long termuse leads to positive antinuclear antibody in 50% of patients which can result in DILE
How does metabolism of procainamide to NAPA occur?
by acetylation: slow acetylators are at risk for drug accumulation and toxicity
Class Ib antiatrhymics are used in the treatment of what type of arrhythmias?
ventricular arrhythmias only
MOA of Class Ib drugs:
block sodium channels
Dosage form of lidocaine for arrhythmias:
injection
IV lidocaine is useful for:
refractory VT/cardiac arrest
MOA of flecanide:
block sodium channels
Boxed warnings for flecanide:
proarrhythmic
Contraindications to using flecanide and propafenone:
heart failure
MI
Side effects of propafenone:
taste disturbance: metallic taste in mouth
Contraindications to dronedarone:
patients with decompensated HF or permanent AF due to increased risk of death, stroke, and HF
CYP3A4 inhibitors and QT prolonging drugs
What are some warnings of dronedarone?
hepatic failure
pulmonary toxicity
SE of dronedarone:
proarrhythmic
diarrhea
bradycardia
asthenia
Tue/False: dronedarone does not contain iodine and has little effect on thyroid function
True
How do you initiate dofetilide?
it has to be started in a setting with continuous ECG monitoring.
assess CrCl for a minimum of 3 days
True/False: Dofetilide is not a preferred antiarrhythmic in HF
False; it is preferred in HF
How do you dose sotalol if a patients CrCl <60 mL/min?
decrease frequency
Side effects of sotaol:
bradycardia
palpitations
chest pain
dizziness
fatiue
dypsnea
Dosage form of ibutilide
Injection
When is adenosine used?
to treat supraventriular re-entrant tachycardias
Dosage form of adenosine:
injection
What is the ½ life of adenosine?
< 10 seconds
Intermittent Afib that terminates within 7 days of onset:
paroxysmal Afib
Continuous Afib sustained for > 7 days:
persistent Afib
What is used to reduce the risk of clots/stroke in Afib patients?
anticoagulation
What are the two ain strategies in the treatment of AFib?
rate and rhythm control
What is the goal resting HR in patients with symptomatic AFib?
< 80 BPM
What is the goal resting HR in patients who are asymptomatic and have preserved left ventricular function?
< 110 BPM
What are the recommended medications for controlling ventriular rate in patients with AFib?
beta blockers and non-DHP CCBs
If a patient has AFib and HFrEF they should not recieve:
non-DHP CCBs
What is the goal of rhythm control in AFib patients?
restore and maintain normal sinus rhythm
What antiarrythmics are used for rhythm control in AFib patients?
Class Ia, Ic, or III anti-arrhythmic drugs or electrical cardioversion
What should be avoided in permanent AFib?
a rhythm control strategy with antiarryhtmic drugs
Therapeutic range of digoxin for AFib:
0.8-2 ng/mL
Dose of digoxin for AFib:
0.125-0.25 mg`
A patient taking digoxin and have a CrCl <60 mL/min:
decreased dose or frequency and hold in acute renal failure
How do you stwitch from oral to IV dose?
decrease dose by 20-25%
What are signs and symptoms of digoxin toxicity?
Nausea and vomiting
loss appetite
blurred/double vision
greenish-yellow halos
bradycardia
life threathening arrhythmias
increase risk of toxicity with: hypokalemia, hypomagnesemia, hypercalcemia
When is digoxin used in Afib patients?
used in combination with beta blocker or non-DHP CCBs for rate control
What causes an acute ischemic stroke?
thrombus that forms during cerebral atherosclerotic infarction ( non-cardioembolic stroke)
embolus that forms in the heart and travels to the brain ( cardioembolic stroke)
TIA:
a mini stroke caused by temporary clot in the brain
Modifiable risk factors of stroke:
hypertension
atrial fibrilation
dyslipidemia
diabetes
physical inactivity
smoking
Non-modifiable risk factors:
prior stroke or TIA
advanced age > 80 years old
race: higher risk in African American Patients
genetic diseases
Signs and symptoms of stroke:
F: face dropping
A: arm weakness
S: speech difficulty
T: time to call 911
What imaging is preformed within 20 minutes of arrival to the ER to quickly identify if a stroke symptoms are due to hemorrhage?
brain imaging using CT
What is the goal of managing an ischemic stroke?
restore blood flow
MOA of alteplase (tPA or rtPA):
tissue plasminogen activator that binds to fibrin in a thrombus and converts plasminogen to plasmin, which results in fribrinolysis
True/False; alteplase is the only fibrinolytic FDA approved for ischemic strokes
True
When is a patient a candidate for alteplase administration?
when their is no bleeding seen on the imaging
Criteria that must be met to start alteplase:
no bleeding is seen on the brain imaging
stroke symptom onset is < 4.5 hours
alteplase can be administered within 60 minutes of hospital arrival
no contraindications to alteplase
What are the contraindications to alteplase?
active internal bleed: ICH
risk of internal bleed due to;
severe hypertension: BP >185/110 mmHg ( lower BP to <185/110 mmHg with IV labetalol and nicardipine before alteplase administration)
head trauma
labs: elevated INR ( >1.7) , low platelet counts
drug interactions: anticoagulants usage ( treatment doe of LMWH within previous 24 hours, use of direct thrombin inhibitor or direct factor Xa inhibitor within previous 48 hours or taking warfarin)
history of recent stroke( within past 3 months)
blood glucose < 50 mg/dL