Week 7a: Cardiac Arrhythmias Flashcards
P waves in sinus arrythmias
P waves are upright in I, II and aVF
Treatment for sinus bradycardia?
atropine 0.5mg q3-5min or adrenergic infusions such as dopamine or epinephrine IV
causes of sinus tachycardia
exercise, fever, and hyperthyroidism among others
treatment of sinus tachycardia
digoxin, beta blockers, CCBs, BBs, amiodarone
paroxysmal supra ventricular tachycardia
episodes of rapid heart rate that start in a part of the heart above the ventricles
what is the most common arrhythmia?
atrial fibrillation
chaotic and ineffective atrial depolarization
atrial fibrillation
signs and symptoms of atrial fibrillation
fainting, exercise intolerance, palpitations, pulmonary edema, decreased CO
medications for atrial fibrillation
- anticoagulants
- CCBs
- BBs
- cardiac glycosides
what is an intervention for atrial fibrillation?
atrial ablation
ECG of atrial fibrillation
- tracing shows irregularly irregular rhythm with no P waves
which arrhythmia has the following characteristics?
- regular ventricular rate of 150bpm
- varying ratios of F waves to QRS complexes (most common is 4:1)
- Sawtooth pattern
atrial flutter
which ECG will show a constant PR interval, greater than 2 seconds and all impulses conducted?
1st Degree AV block
Which arrhythmia results when each impulse is slower and slower and finally does not conduct an impulse, which results in a PR interval that gets longer and longer until a QRS complex is missing
2nd degree AV block type 1
Which arrhythmia has the following characteristics?
- AV node conducts no impulses
- atria and ventricles beat at an intrinsic rate (80 and 40 respectively)
- no association between P waves and QRS complexes
3rd degree AV block
What are some characteristics of ventricular arrhythmias?
- wide QRS complex
- Variable rate
- No P waves
what arrhythmia occurs earlier than the sinus beat, is wide and has no P wave?
Premature ventricular contraction
idioventricular rhythm
- escape rhythm
- 20-40 bpm
which ventricular arrhythmia has a rate greater than 100 bpm
ventricular tachycardia
which type of ventricular tachycardia occurs secondary to prolonged QT interval?
Torsades des pointes
what type of ventricular arrhythmia includes unorganized activity of the ventricle?
ventricular tachycardia/fibrillation
which type of arrhythmia is life threatening, pulseless, with no CO?
Vfib and Vtach
vtach/vfib algorithm
1) CPR/IV/Access airway
2) Defibrillate 360 J
3) Epinephrine 1mg q3-5min
4) Amiodarone 300mg bolus
asystole algorithm
1) CPR/IV/Airway
2) Epinephrine 1mg q3-5min
3) consider pacing (low effectiveness)
class I drugs
act by blocking the fast sodium channels
class II agents
beta adrenergic blocking drugs that act by blunting the effect of sympathetic nervous system stimulation on the heart
class III agents
act by extending the action potential and refractoriness
class IV agents
act by blocking the slow calcium channels, thereby depressing phase 4 and lengthening phase 1 and 2
procainamide is a?
sodium channel blocker
therapeutic effects and uses for procainamide?
PAT, atrial flutter, atria fibrillation and prophylaxis of PSVT
adverse effects of procainamide?
confusion and psychosis at high doses
what is the primary indication of class IB drugs?
ventricular dysrhythmias
class IB drugs work by?
shortening the refractory period
Lidocaine is a?
Class IB drug
class IC drugs….?
profoundly decrease conduction velocity
what is the prototype drug of beta blockers?
propranolol
beta blockers work by?
decreasing the conduction velocity
what is the prototype drug of potassium channel blockers?
amiodarone
therapeutic effects and uses of amiodarone?
- atrial and ventricular dysrhythmias
- resistant ventricular tachycardias
- recurrent fibrillation
what are some serious adverse effects of amiodarone?
- pneumonia like syndrome
- prodysrhythmic action (arythmias)
what is the prototype drug of calcium channel blockers?
verapamil
which medication is contraindicated in ventricular dysthymias and must be carefully monitored for toxicity, drug interactions, and adverse effects
digoxin
diastolic heart failure
signs and symptoms of heart failure with normal ejection fraction. mainly seen in elderly patients with hypertensive heart disease
what results due to low cardiac output?
hypotension
which condition includes peripheral edema, weight gain, liver congestion dysfunction and failure, renal hypertension, abdominal distension, LOC changes, and fatigue
right sided heart failure
causes of right sided heart failure
- conditions that restrict blood flow to the lungs
- stenosis or regurgitation of the tricuspid or pulmonic valves
- right ventricular infarction
- cardiomyopathy
- persistent life sided failure
- acute or chronic pulmonary disease (for pulmonale)
causes of left sided heart failure?
- acute MI
- cardiomyopathy
manifestations of left sided heart failure
- SOB
- crackles
- pulmonary edema
- exercise intolerance
- cough and pink froth (rare)
what is the result of fluid moving into the alveoli, causing lung stiffness, making lung expansion more difficult and impairs the gas exchange function of the lung
pulmonary edema
How do ACEIs help in HF?
- decrease vascular resistance
- decrease secretion of aldosterone
- decrease secretion of ADH
what are some serious adverse effects of ACEIs?
Angioedema, cough, and hyperkalemia
dobutamine and dopamine are examples of?
beta 1 adrenergic agonists
what do beta1 adrenergic agonists do?
increase contractility of the heart to produce more powerful contractions but also reduce vasoconstriction and can produce dysrhythmias including tachycardia
the effect of increased force of contraction of the heart when digoxin is a result of?
increased calcium in the cell
what are some serious adverse effects of digoxin?
atrial dysrhythmias, sinus bradycardia, ventricular dysrhythmias, AV block
what is often the first sign of digoxin toxicity?
nausea and vomiting
what is the PO onset of digitalization?
30-120 mins
What is the peak of PO digitalization?
2-6 hours
how many days of digitalization until steady state is achieved?
7 days
IV onset of digitalization?
5- 30 mins
peak of IV digitalization
1-4 hours
therapeutic level of digoxin?
0.8-2ng/ml
toxic level of digoxin
> 2.4 ng/ml
contraindications of digoxin
- patients taking calcium channel blockers
- ventricular fibrillation
Milrinone is a?
phosphodiesterase III inhibitor
therapeutic effects and uses of milrinone (primacor)?
Short term treatment of life threatening heart failure
mechanism of action of milrinone (primacor)
the persistence of cGMP results in vasodilation and a positive inotropic effect
adverse effects of milrinone (primacor)
headache, nausea, vomiting, ventricular dysrhythmias
