Learning Cardiology

Q. Which of the following represents a normal HV interval during cardiac electrophysiological testing? A. <20 ms B. 35-55 ms C. 100-125 ms D. >200 ms Correct Answer: B. 35-55 ms Explanation:  https://www.learningcardiology.com/2020/07/normal-cardiac-electrophysiology.html

Important intervals in cardiac electrophysiology 1. PA interval: 25-55 ms 2. AH interval: 55-125 ms 3. HBE interval: <30 ms 4. HV interval: 35-55 ms 5. QRS: ≤ 100 ms 6. Corrected QT interval (QTc): ≤ 450 ms (for males); ≤ 470 ms (for females) 7. Sinus node recovery time (SNRT): ≤1500 ms 8. Corrected sinus node recovery time (CSNRT): ≤ 550 ms 9. Sinoatrial conduction time (SACT): 50-115 ms 10. Atrial effective refractory period (ERP): 180-330 ms 11. AV nodal ERP: 250-400 ms 12. Ventricular ERP: 180-290 ms

Q. What will be class of the following LM bifurcation disease as per the newly proposed ABCD classification system? A. ABC B. ABc C. Ab D. BC Correct answer: B. ABc Explanation:  ABCD classification for LM bifurcation

A new classification system for LM bifurcation/ trifurcation lesions has been proposed.  1. Following nomenclature has been suggested:       A/a for LM coronary artery      B/b for LAD artery      C/c for left circumflex coronary artery      D/d for ramus intermedius artery (intermediate branch) Whether a capital or small letter would be used, depends upon the diameter of the vessel as explained below.  2. Each artery is given one of the above-mentioned letters if the stenosis is considered to be significant (i.e., >70% in lumen reduction visually,  or based on FFR or other resting indices, cCT-cFFR, IVUS, OCT). 3. If the stenosis is not considered significant, no letter would be assigned. 4. A capital letter is used if the vessel diameter is ≥3.5 mm, while a small letter is used if the diameter is smaller than 3.5.  5. The image below has significant stenosis in all three vessels i.e LM, LAD and LCx. LM and LAD arteries are more than 3.5 mm in diameter, whereas LCx is smaller than