First Aid for the USMLE Step 2 CK: Cardiovascular Flashcards
What is considered normal HR for an adult?
60 - 100
- Below 60: bradycardia
- Above 100: tachycardia
The technical definition of sinus rhythm is _____________.
a P wave before every QRS complex
A normal PR interval is between ____________.
120 and 200 milliseconds
List two things that can cause a widened QRS complex.
- PVC
* Bundle-branch block
The QRS complex should be no longer than ___________.
120 msec (three small boxes)
How does left bundle-branch block present on an EKG?
- QRS greater than 120 msec
- Deep S and no R on lead V1
- Tall R in I, V5, and V6
In addition to the rabbit ears, list two signs of right bundle-branch block.
- Wide R in V1
* Wide S in V6
What does it mean if QRS is positive in I and aVF?
Normal axis
What does it mean if QRS is positive in I and negative in aVF?
Left axis deviation
What does it mean if QRS is negative in I and positive in aVF?
Right axis deviation
The QTc should be no longer than _____________.
440 msec
Q waves should not be longer than ____________.
1/3 of the QRS amplitude
Go through the progression of ischemia.
- T wave inversion
- ST depression or elevation
- Q waves
What is poor R wave progression?
Normally, the R wave amplitude should increase from V1 to V5. If this doesn’t happen, it can be a sign of ischemia.
Go through the formula for determining left- and right-ventricular hypertrophy.
• LVH: amplitude of S in V1 + R in V5 or V6 is > 35 mm
•RVH: right-axis deviation and an R wave
in V1 > 7 mm
Go through the cardiac physical exam.
- Heart auscultation: murmurs, rubs, gallops, rate, rhythm
- Point of maximum impulse
- Jugular venous distension
- Kussmaul sign (inspiring worsens JVD)
- Hepatojugular distension
- Edema
- Pulses
An early decrescendo diastolic murmur is a sign of ____________.
aortic regurgitation
What is pulsus parvus et tardus?
A late and slow pulse that can be a sign of aortic stenosis
List four treatment pillars of atrial fibrillation.
- Anticoagulants
- Beta-blockers (rate control)
- Cardioversion / CCBs (for beta-blocker intolerance)
- Digoxin (for refractory atrial fibrillation)
Explain how the CHADVAS system is used to determine when anticoagulation is needed.
CHA(2)DS(2)VAS
- CHF (1 point)
- HTN (1 point)
- Age greater than 75 (2 points)
- Diabetes (1 point)
- Stroke history 2 points)
- Vascular disease (1 point)
- Age 65 - 74 (1 point)
- Sex (1 point)
Anti-coagulate for score two or more.
What drug treats WPW?
Procainamide
First-degree AV block is defined as _______________.
a PR interval greater than 200 msec
What’s the difference between Mobitz I (Wenckebach) and Mobitz II heart block?
- I is progressive PR lengthening until a QRS is missed.
- II is static PR with occasional QRS missed.
(“ONE by ONE, the PR intervals lengthen in Mobitz ONE.”)
What is sick sinus syndrome?
A heterogeneous syndrome in which people develop sporadic bradycardia and tachycardia
This is the most common indication for pacemaker placement!
Go through the causes of acute and chronic atrial fibrillation.
•Acute: PIRATES
- Pulmonary disease
- Ischemia
- Rheumatic heart disease (mitral stenosis - > left atrial enlargement)
- Anemia
- Thyrotoxicosis
- Ethanol
- Sepsis
•Chronic:
- HTN
- CHF
Those with atrial fibrillation typically have no _____________ on ECG.
P waves
What should you do in new-onset atrial fibrillation?
- If it’s unstable and been less than 2 days, then cardiovert.
- If it’s been longer than 2 days or unclear, then must get echo to rule out atrial clot.
What is atrial flutter?
A circular pattern of electrical activity in the atria that does not involve rapid ventricular response
Treat the same as atrial fibrillation.
Differentiate AV-nodal reentrant tachycardia (AVNRT) and AV-reentrant tachycardia (AVRT).
- Both involve electrical depolarization passing back into the atria from the ventricles.
- AVNRT depolarizes the atria and the ventricles at the same time THROUGH the node.
- AVRT depolarizes the atria through a pathway outside the node. This is the pathology of WPW tachycardia.
Describe paroxysmal atrial tachycardia.
In PAT, there is an ectopic atrial pacemaker site with a rate of greater than 100 BPM. It can be diagnosed with an EKG showing a P wave before every QRS but with an atypical axis.
What is the classic caveat of diuretics and digoxin use in CHF?
They improve symptoms but confer no mortality benefit.
Review CHF.
- There is no one test for CHF. It is a clinical syndrome.
- History:
- Dyspnea (initially exertional and finally at rest)
- Chronic cough
- Fatigue
• Exam:
- S3/S4
- Elevated parasternal lift
- Pedal edema
- Pulmonary edema (if left-sided), JVD/hepatomegaly (if right-sided)
•Tests:
- Echo: dilated or thickened ventricles
- Elevated BNP
These things can precipitate PVCs: ________________.
- Hyperthyroidism
- Electrolyte abnormalities
- Hypoxia
If someone has ventricular tachycardia, what is the “big” question you need to ask to know how serious it is?
“Is it sustained (greater than 30 seconds) or non-sustained (less than 30 seconds)?”
Non-sustained ventricular tachycardia is often asymptomatic. Sustained ventricular tachycardia can lead to hypotensive shock.
List two treatments for ventricular tachycardia.
- If unstable: cardioversion
* If stable but symptomatic: amiodarone, lidocaine, procainamide
What is a key difference between ventricular fibrillation and torsades on an EKG?
Torsades will have narrow QRS complexes, while ventricular fibrillation will have wide QRS complexes.
What is the difference between cardioversion and defibrillation?
- Defibrillation is a non-synchronous shocking of ventricular fibrillation. It is non-synchronous because there is no rhythm in ventricular fibrillation, so it doesn’t matter when in the electrical activity of the heart you defibrillate.
- Cardioversion is a synchronous shocking of the heart, used in unstable atrial fibrillation or ventricular tachycardia. The “synchronous” part means that it shocks during the R wave to reset unstable tachycardias.
List two electrolyte abnormalities that predispose to torsades.
- Hypokalemia
* Hypomagnesemia