PANCE Prep- Cardiology COPY Flashcards
In the bradycardia algorithm, if there is a pulse and the pt is unstable (Hypotension, AMS, refractory CP, acute HF, or symptomatic, what do you do?
- Give Atropine (1st line)
- if atropine not effective:
- Epi infusion
- Dopamin infusion
- -Transcutaneous pacing
*there are 3 exceptions to symptomatic/unstable bradycardia
What are the only 2 shockable rhythms using defibrillation (unsynchronized cardioversion)
- Ventricular fibrillation
2. Pulseless VT
In the tachycardia algorithm, what do you do if a person has a pulse but is unstable?
- Unstable tachyarrhythmia
1. Synchronized cardioversion
- if regular, narrow QRS complex, may consider Adenosine
Describe what you check for in the tachycardia algorithm and what you do?
- Check pulse
- if yes, Stable or unstable?
- if unstable–> synchronized cardioversion - if stable, is there a wide QRS 0.12 sec or more?
- If yes (Wide QRS complex tachycardia)–> antiarrhythmic med: amiodarone, lidocaine or procainamide
- If no (narrow QRS complex tachycardia-> vagal maneuvers, adenosine**, BB or CCB
What are the 3 important exceptions to stable tachyarrhythmia rule?
- atrial flutter: BB or CCB 1st line (skip adenosine)
- afib: BB or CCB 1st line (skip adenosine even though Aflutter is often regular and narrow QRS)
- Wolff-Parkinson-White: Procainamide preferred** or amiodarone- avoid use of AV nodal blockers
What med do you usue if you have a regular and narrow QRS tachyarrhythmia?
adenosine
What meds should you avoid in WPW and why?
AV nodal blockers (ABCD)
- Adenosine
- BB
- CCB
- Digoxin
*AV nodal blockade may cause preferential conduction through the fast (preexcitation) pathway–> worsening of the tachyarrhythmia
Describe interpreting an EKG
- Determine rhythm (R-R regular?)
- Rate: (300-150-100-75-60-50) or #r waves in 6 second strip x10
- QRS axis deviation?
- P for every QRS
- PR interval?
- QRS interval?
- LBBB or RBBB?
- RVH or LVH?
- Pathological Q waves: >1 box in depth or height or prolonged QT?
- ST depression or elevation: >1mm
Describe the normal intervals
PR:
QRS:
QT:
Small box:
Big box:
PR: 3-5 small boxes (0.12-0.2sec)
QRS: <3 small boxes (<0.12 sec)
QT: 7.5-11 small boxes (0.3-0.44 sec)
Small box:
Big box:
Describe the sympathetic NS control of the heart
Hormones Epi and NE cause
- increased excitability
- increased force of contraction
- increased SA node discharge rate (increase HR)
*Epi and dobutamine are sympathomimetics (stimulate the SNS)
Describe the parasympathetic NS control of the heart
Hormone acetylcholine (regulated by the vagus nerve) causes:
- decreased excitability
- decreased force of contraction
- decreased SA node discharge rate (decrease HR)
- Vagal stimulation or vagal maneuvers slow down the HR
- Conversely, anticholinergic drugs increase the HR
How do you determine LBBB or RBBB
LBBB:
- Wide QRS >0.12sec
- Broad, slurred/bunny ears bumps R in V5,6
- Deep S wave in V1
- ST elevation in V1-V3
RBBB:
- Wide QRS >0.12sec
- RsR’ in V1, V2
- Wide S wave in V6
Describe the leads involved and artery involved for the area of infarction:
Anterior wall
V1-V4 (V3,4*)–Q waves/ ST elevation
LAD artery or LCA
Describe the leads involved and artery involved for the area of infarction:
Septal
V1 and V2– Q waves/ ST elevation
Proximal LAD
Describe the leads involved and artery involved for the area of infarction:
Lateral wall
I, aVL, V5, V6– Q waves/ ST elevation
Left circumflex artery
Describe the leads involved and artery involved for the area of infarction:
inferior
II, III, aVF– Q waves/ ST elevation
RCA
Describe the leads involved and artery involved for the area of infarction:
Posterior Wall
V1-V2 ST Depression**
RCA or LCX
What is a normal QRS axis
- 30 to +90 degrees
* look at leads I and aVF
Causes of Left axis deviations
- LBBB
- LVH
3 Inferior MI - Elevated diaphragm
- L anterior hemiblock
- WPW
Causes of right axis deviations
- RVH
- Lateral MI
- COPD
- Left posterior hemiblock
in NSR, P waves are positive/upright in leads:___ and neg in leads: ___
Positive P: I, II, aVF
Negative P: aVR
Pathologic causes of bradycardia and what is the 1st line tx
- BB
- CCB
- Digoxin
- carotid massage
- SA node ischemia
- Gram Neg. sepsis
- hypothyroidism
*Anticholinergic Atropine is 1st line (bc excess vagal stimulation is the MC cause of bradycardia)
Heart rate typically ___ during inspiration
Increases in inspiration
decreases in expiration
What is sick sinus syndrome
Brady-tachy syndrome
- Combination of sinus arrest w/ alternating pparoxysms of atrial tachyarrhythmias and bradyarrhythmias
- commonly caused by SA node disease and corrective cardiac surgery