Cards Test 1 Combo Flashcards
Arrhythmia commonly found in COPD/lung disease patients
Multifocal Atrial Tachycardia
continuous rapid-firing of multiple atrial automaticity foci
atrial fibrillation
What should you think if you have a ventricular rate of exactly 150bpm?
atrial flutter
Which BBB can be fairly common in healthy hearts?
Right BBB
Which leads are useful in assessing atrial enlargement?
V1 and II
Why is V1 useful in assessing atrial enlargement?
it’s perpendicular to the flow of electricity through the atria, and thus produces a nice biphasic P wave that’s useful to look at when left atrial enlargement is suspected
Why is lead II useful in assessing atrial enlargement?
Lead II is parallel to the flow of electricity in the atria, and will thus be enlarged if atria are enlarged
Evidence of RAE on EKG?
-P wave > 2.5mm in leads II or the first part of the diphasic P wave in V1
Evidence of LAE on EKG?
- terminal portion of the diphasic P wave in V1 should drop at least 1 mm below the isoelectric line
- or the terminal portion should be at least 0.04sec in width
Why is LAE sometimes called P mitrale?
-because mitral valve disease is the most common cause
Why is RAE sometimes called P pulmonale?
-because it’s often caused by severe lung disease
Evidence of right ventricular hypertrophy on EKG?
-large R wave in V1 (normally the S wave is larger)
Evidence of left ventricular hypertrophy on EKG?
-S wave in V1 + R wave in V5 > 35mm
Only in what type of patient is it safe to diagnose RVH? Why?
- patient with lung disease
- because lung disease with it’s associated RV afterload increase should be the only real reason for RVH
Triad of myocardial infarction
- ischemia
- injury
- necrosis
Evidence of ischemia on EKG
- ST depression
- T wave inversion
What is ST elevation on EKG?
infarction
Evidence of infarction on EKG?
-ST elevation
What is ST depression on EKG?
ischemia
What are the three stages through which an EKG evolves during an acute myocardial infarction?
- T wave peaking followed by T wave inversion
- ST segment elevation
- Appearance of new Q waves
In what lead(s) is T wave inversion normal
-V1
In which leads would T wave inversion be present in a patient with Wellens Syndrome?
V2 and V3
What is the worst “kind” of ST depression?
- downsloping
- horizontal is also bad
What makes a Q wave significant?
- at least 0.04 seconds (1 small square) wide
- or 1/4 of the entire QRS amplitude
What do significant Q waves indicate?
irreversible myocardial cell death
How does hypocalcemia manifest on EKG? Why?
- prolonged QT interval
- because this is where ventricular contraction occurs, and not enough calcium prolongs ventricular contraction
What arrhythmia may be triggered by hypocalcemia?
-Torsades de pointes
possible causes of hypocalcemia
- primary/secondary hypoparathyroidism
- vitamin D deficiency
- chronic kidney disease
How does hypercalcemia manifest on EKG? Why?
- shortened QT interval
- b/c a lot of calcium allows for very quick ventricular contraction
Possible causes of hypercalcemia
- malignancy
- chronic kidney disease
- adrenal insuffiency
How does hypokalemia manifest on EKG? Why?
- Early: T wave flattening
- ST segment starts to depress and can invert the T wave
- U wave in severe cases
- Remember that K+ is involved in phase 3 repolarization, which manifests on the T wave of EKG
causes of hypokalemia
- diuretics
- vomiting/diarrhea
How does hyperkalemia manifest on EKG? Why?
- peaked T waves
- P waves may be flattened or absent
- Severe: QRS widens and fuses with T wave
- remember that K+ is involved in phase 3 repolarization, which manifests on the T wave of EKG
Causes of hyperkalemia
- ACE inhibitors
- K+ sparing diuretics
- renal failure
- hypoaldosteronism
Normal PR interval
0.12-0.20
what should you think if there’s a lengthened PR interval?
AV block
what should you think if there’s a shortened PR interval?
accessory pathway
What is the normal duration of the QRS complex?
- Less than or equal to 0.12 seconds
What should you think if the QRS complex is widened?
-BBB
Where would you see an R, R’ if there’s a RBBB?
-lead V1
Where should you see an R,R’ if there’s an LBBB?
-Lead V5
What would you think if there was an R, R’ in lead V1?
RBBB
What should you think if there’s an R,R’ in lead V5?
LBBB
What is the normal QTc (QT interval) for males?
<450
What is the normal QTc (QT interval) for females?
<460
What are the three mechanisms of tachyarrhythmias?
- Enhanced automaticity
- Reentry
- Triggered Activity
What will be the response of a ventricular tachyarrhythmia to a vagal maneuver? Why?
- little to no effect at all
- because there’s little to no parasympathetic innervation in ventricular cells
On what ion does nodal tissue primarily rely for initiating depolarization?
calcium
For a reentry to exist, what must be true about the Purkinge fiber with two conduction pathways to ventricular muscle?
- there must be a limb with slow conduction
- each limb must have a different refractory period
spontaneous depolarizations requiring a preceding impulse (a triggering beat)
after-depolarizations
After-depolarization that occurs before membrane repolarization is complete
early after-depolarization
Which after-depolarization may be the mechanism responsible for arrhythmogenesis related to the prolonged QT syndrome?
early after-depolarizations
Which type of after-depolarization is often triggered by electrolyte disturbances?
early after-depolarizations
After-depolarization that occurs after membrane repolarization is complete
delayed after-depolarization
what can cause delayed after-depolarizations?
an abnormal intracellular calcium load high enough to cause spontaneous depolarization
During what phase of repolarization do early after-depolarizations “strike”?
Phase 2 or 3
During what phase of the myocardial action potential do delayed after-depolarizations arise?
Phase 4
How can you calculate the upper rate range for sinus tachycardia?
220 - patient’s age
What do we call it when patients have a rapid rise in HR with mild exertion?
-Inappropriate chronotropic response (part of inappropriate sinus tachycardia)
What would the resting HR be of a patient with inappropriate sinus tachycardia?
> 100bpm
What is the most common mechanism of PSVT?
-reentry involving AV node, atrium, or an accessory pathway
Will junctional tachycardias terminate with vagal maneuvers?
no
Accessory pathway between the atria and ventricles?
Bundle of Kent
In what instances is WPW especially dangerous?
If patient has A fib or flutter
DOC for WPW
IV procainamide
What type of drug is best for treating WPW?
Na+ blocker
What drug do we need to make sure patients with WPW syndrome don’t take?? Why?
- Digoxin
- because it shortens the refractory period and may accelerate ventricular response in a setting of Afib
Most common cardiac arrhythmia necessitating hospitalization in the US
Afib
Which arrhythmia is associated with post-op status? On what post-op day does it most often occur?
- Afib
- POD #3
What signs of Afib might you witness as a result of the loss of atrial contractile force (and therefore decreased cardiac output)?
- pulmonary rales
- S3
- peripheral edema (pitting)
- JVD
What is the focus of Afib treatment?
- rate control
- anticoagulation
- restoration of sinus rhythm
What drugs are good for the initial rate control of Afib an a hemodynamically stable patient?
- IV diltiazem
- IV metoprolol
What drug is commonly used for long-term anticoagulation?
Warfarin
What INR do we want to achieve in our Afib patients before cardioverting?
2.0-3.0
What is the most commonly used drug for Afib cardioversion?
IV Ibutilide
How long must you maintain target INR before cardioverting Afib?
3-4 weeks
Where is the reentry circuit that’s commonly associated with Aflutter located?
usually along the tricuspid valve annulus
What kind of medical therapy is often implemented in a patient with Aflutter?
- slow ventricular rate by drugs that increase AV block
- restore sinus rhythm (slow conduction or prolong refractory period of the atria - Class IA, IC, or III)
- DCCV if above fails
Which ventricular arrhythmia is more common among young, healthy individuals?
PVCs
What do we call it when there are more than three PVCs in a row?
ventricular tachycardia
If a patient says they feel a “flip-flop” of their heart, what are they more than likely describing?
The onset of a normal beat after the compensatory pause that follows a PVC
What is the most common cause of ventricular tachycardia?
CAD
Why is it important to distinguish monomorphic VT from SVT with aberrant ventricular conduction?
They each require different immediate and long-term treatments
When in doubt as to whether an arrhythmia is SVT with aberrant conduction or VT, which should you assume until proven otherwise?
VT
prior structural heart disease - more likely VT or SVT?
VT
vagal maneuvers affect the rhythm - SVT or VT?
SVT
No relationship of the QRS to P wave - more likely SVT or VT?
VT
QRS complexes in V1-V6 all have similar appearance - more likely SVT or VT?
VT
When trying to determine if an arrhythmia is SVT with aberrant conduction or VT, in what circumstances is VT more likely?
-prior structural heart disease
What is the most common cause of polymorphic VT?
-Acute MI
What is the ultimate cause of Long QT Syndrome?
- sodium and potassium chanelopathies
- this causes a prolongation of ventricular repolarizationd
What’s the primary symptoms of Long QT Syndrome?
syncope
What’s the hallmark arrhythmia of Long QT syndrome?
Torsades de Pointes
What ion imbalances may be associated with Torsades?
- hypokalemia
- hypomagnesemia
What is the most common type of congenital Long QT syndrome?
LQT1
What are common initiators of arrhythmias in LQT2 patients?
- auditory stimuli
- emotional stress
What factors can precipitate syncope and sudden death in LQT1 patients?
- Physical exertion
- sympathetic stimulation
What type of drug would you give to a patient with LQTS patient with a history of syncope or one with a definite prolonged QT interval?
Beta blocker
What would you do with a LQTS patient already on a beta blocker who experiences recurrent syncope?
prophylactic implant of an ICD
What diagnosis should you think of if a patient presents with a history of:
- Unexplained syncope
- Unexplained cardiac death of a family member <30
- Congenital deafness
Long QT Syndrome
What is the only effective therapy for ventricular fibrillation?
non-synchronized electrical defibrillation
What are the two mechanisms of bradycardias?
- disorders of impulse formation
- conduction blocks
What are the most common extrinsic causes of sinus bradycardia?
medications
What is the most common indication for a pacemaker?
Sick Sinus Syndrome
What’s a good drug to give in a patient with severely depressed heart rate?
-IV atropine (anticholinergic)
What type of pacing would you use in a patient when the AV node and vetnricular conduction systems function normally?
Atrial pacing (atria are paced)
What type of pacing would you use in a patient with complete AV block?
P wave-triggered pacing (ventricles paced)
What type of pacing would you use in a patient with SA node dysfunction combined with AV node dysfunction?
A-V sequential pacing (atria and ventricles are paced)
If a junction escape rhythm did produce a P wave, in what leads would be inverted?
II, III, AVF (the inferior leads)
What is the most common cause of 1’ AV block?
Drugs that slow conduction through the AV node (Beta blocker and calcium channel blockers)
Which type of 2’ block is more serious?
Mobitz Type II
Does a patient with a Wenckebach block need a pacemaker?
no
Does a patient with a Mobitz block need a pacemaker?
Yes
How are patients with Mobitz II block likely to present?
dizziness, lightneadedness, or syncope
What is the most common cause of Mobitz II block?
Acute MI (anterior or inferior)
Describe bradycardia management if perfusion is poor
- Prepare for transcutaneous pacing
- Administer IV Atropine
- Begin pacing if Atropine ineffective
- Consider epi or dopamine while waiting for pacer or if pacing is ineffective
What are the two types of temporary pacing?
- Transcutaneous
- Transvenous
What should be included in your differential diagnosis for bradycardia?
- SSS
- Escape Rhythm
- Afib/flutter
- AV blocks
What should be included in your differential diagnosis for tachycardia?
- Sinus tach
- SVT
- Afib/flutter
- MAT
- Vtach
- Vfib
What should be included in your differential diagnosis for an irregular rhythm?
- sinus arrhythmia if all P waves are the same
- Wandering pacemaker if P waves are different
- MAT if P waves are different
- Atrial fibrillation if no P waves
- Atrial flutter if there are flutter waves
- AV blocks
What should you think if you don’t see proper R wave progression?
-Something has happened to the anterior and/or lateral wall of the LV
