This document outlines the key components of a basic electrophysiology (EP) study, including measuring basic intervals like PA, AH, and HV; testing sinus node function with measurements like sinus node recovery time; performing atrial and ventricular extra-stimulus testing to determine refractory periods; and conducting a minimum protocol involving basic interval measurements, sinus node assessment, ventricular and atrial extra-stimulus testing, and incremental pacing. The purpose is to provide diagnostic information about cardiac conduction and rhythm.

1. BASIC EP STUDY
PART 2
SAKHAN SOLIDA, MD
Cardiologist
ESC, EHRA and ESH member
Preah Kossamak Hospital

2. • Basic intervals
• Test of SN function
• Atrial extra-stimulus testing
• Ventricular extra-stimulus testing
• Measurement of the refractory period
• A minimum protocol for diagnostic EP studies

3. • PA interval 25-55ms
• AH intervals 55-125ms
• HBE < 30ms
• HV 35-55ms

5. Test of SN function
• SN recovery time (SNRT) : Interval from last paced complex to spontaneous complex.
• The corrected SNRT (CSNRT) = SNRT – Sinus CL
• Used to detect intrinsic function of the sinus node

7. • Sino-atrial conduction time (SACT) : Detect delayed conduction between SN and adjacent atrial
tissue.

8. • Sino-atrial conduction time (SACT) : (A2A3 –A1A1)/ 2

10. Atrial extra-stimulus

12. Atrial refractoriness

14. Ventricular extra-stimulus testing

18. Ventricular refractoriness

20. Measurement of Refractory Period
• ERP : The longest coupling interval that failing to capture the tissue or the conducted over the
structure.
• FRP : The shortest coupling interval that can be elicited from a tissue or structure any “input”
interval.
• RRP : The ” input” interval to a tissue or structure at which the “output” interval just begins to differ
from
the “input” interval
Ex.
- AVNERP is the longest A1A2 interval that fails to be conducted to the His bundle.
- AVNFRP is the shortest H1H2 interval that can be elicited by any A1A2 interval.
- AVNRRP is the longest A1A2 interval at which A2H2 exceeds A1H1 (or H1H2 exceeds A1A2)

22. A minimum protocol for diagnostic EP studies
• Measurement of the basic intervals : rhythm, CL, PA, AH, HV,QRS, QRS morpholoy, QT, QTc
• Assessment of SNRT
• Ventricular extra-stimulus testing down to ventricular refractoriness at the basic CL of 600 and
400ms
• Incremental ventricular pacing from slightly faster the sinus rhythm down to VA Wenckebach
point or minimum CL of 300ms.
• Atrial extra-stimulus testing down to refractoriness at the basic CL of 600 and 400ms
• Incremental arial pacing from slightly faster the sinus rhythm down to VA Wenckebach point or
minimum CL of 300ms.

23. THANKS