Basics EPS Flashcards
Formula for Sinoatrial Conduction Time
(Basic Cycle Length - return interval) / 2
Normal sinoatrial conduction time
<120msec
Normal AH interval
55-150
Normal HV interval
35-55
Normal sinus node recovery time (uncorrected)
<1500ms
At what sinus node recovery time should pacing be considered?
> 2500ms
Formula for corrected sinus node recovery time?
SNRT - BCL
What is a normal corrected sinus node recovery time?
350-550ms
What is a normal PA interval?
25-55msec
What does the PA interval measure?
Intra-atrial conduction
At what HV interval is there a significant risk of progression to 2nd or 3rd degree heart block?
HV of >100ms
Normal AV nodal WCL?
350-500
Normal AVN ERP?
250-400
Normal HIS bundle spike duration?
<30msec
What is the rate of PPM requirement over 1 year with a HV interval >100msec?
25%
How do you define the HIS bundle ERP?
Longest h1-h2 not followed by a V2
How do you calculate HIS Bundle ERP?
H1-h2
What’s a normal HIS bundle ERP?
<400
What are the three pathophysiologic mechanisms of arrythmia?
- Automaticity
- Triggered Activity
- Re-Entry
What is the formula for determining you are within the circuit after successful entrainment?
PPI - TCL is <20msec
If SVT is inducible by V pacing what does that suggest?
Less likely atrial tachy, more likely AVNRT/AVRT
If AV nodal block stops tachycardia, what does this indicate?
AV nodal dependent tachycardia (AVNRT or AVRT)
How does assessing retrograde atrial activation assist in determining accessory pathway location?
Can assist in determining left or right sided. Earliest CS1-2 left sided. Earliest HRA, right sided.