PANCE Prep- Cardiology Flashcards
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 the normal intervals
PR:
QRS:
QT:
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)
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
in NSR, P waves are positive/upright in leads:___ and neg in leads: ___
Positive P: I, II, aVF
Negative P: aVR
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
Management of Sick Sinus Syndrome
- Permanent pacemaker if symptomatic (dual chamber pacing usually preferred over ventricular pacing).
- *if brady alternating with ventricular tachycardia–> permanent pacemaker w/ automatic implantable cardioverter-defibrillator (AICD)
___ is the most helpful in determining the presence of AV conduction blocks
PR interval
Describe 1st, 2nd type 1 and 2, and 3rd degree AV blocks
1st: Fixed, prolonged PRI (>0.2sec) and QRS followed by every P
2nd Type I (Wenckebach): Progressive PRI lengthening then DROPPED QRS
2nd Type II (Mobitz II): Fixed prolonged PRI then DROPPED QRS
3rd: AV dissociation: P waves NOT related to QRS, all P waves NOT followed by QRS = decreased Cardiac output
What is the management of 1st, 2nd type 1 and 2, and 3rd degree AV blocks
1st: none, observe (may progress)
2nd type I (Wenckebach):
- Symptomatic: ATROPINE, epi +/- pacemaker
- Asymptomatic: observe +/- cardiac consult
2nd type II: ATROPINE OR TEMP. PACING, (progression to 3rd degree is common so PPM is definitive tx)
3rd:
- Acute/symptomatic: temporary pacing–> PPM
- Definitive tx: PPM
Describe the appearance of Aflutter and rate
- “saw tooth” waves
2. Rate: 250-350bpm (no P waves but is usually REGULAR)
Management of Atrial flutter
- Stable: Vagal, BB, or CCB
- Unstable: Direct current synchronized cardioversion
- Definitive tx: Radiofrequency ablation
*Anticoagulation use is similar to afib
___ is the most common chronic arrhythmia
atrial fibrillation
*most patients are asymptomatic
Why are people with atrial fibrillation at increase risk for stroke?
The ineffective quivering of the atria may cause thrombi (clots) to form, which can embolize and cause ischemic strokes
Describe the 4 different types of Afib
- Paroxysmal: self terminating w/in 7 days (usually <24hrs) +/- recurrent
- Persistent: fails to self terminate, lasts >7 days (requires termination via medical or electrical)
- Permanent: persistent AF >1yr (refractory to cardioversion or cardioversion never tried)
- Lone: paroxysmal, persistent or permanent w/o evidence of heart disease
Management of Stable AFib
- Rate control (usually preferred as initial management of symptomatic AF over rhythm control)
- BB: Metoprolol (cautious use in those w/ reactive airway dz**)
- CCB: Diltiazem*, verapamil (non-dihydropyridines)
- Digoxin: +/- use in elderly, **Preferred for rate control in pts w/ hypotension or CHF (not generally used in active patients) - Rhythm control
- Direct current synchronized cardioversion (DCC):
- Pharmacologic: Ibutilide, Flecainide, Sotalol, Amiodarone
- Radiofrequency ablation: PPM, cath-based ablation or surgical MAZE procedure