Cardiac Electrophysiology and the ECG
- Previous year questions on Cardiac Electrophysiology and the ECG for NEET PG (National Eligibility cum Entrance Test - Postgraduate), from the Physiology section of the exam.
- Most questions here come from previous-year papers of Indian postgraduate medical entrance and licensing exams; where a paper and year are recorded the question carries them. The image-based questions are original vignettes written around an openly licensed figure, and were never asked in any exam.
- 68 live questions in Cardiac Electrophysiology and the ECG.
- 4 of 68 questions carry a verified exam year: 2017, 2018, 2019.
- Physiology is worth about 17 of 300 questions on the exam. See every subject’s weightage.
- Question set last updated 6 Sept 2026.
Q1.The pacemaker potential is due to
- AFast Na+ channel
- BDecrease in K+ permeability✓ Correct answer
- CSlow Ca++ channel
- DRapid repolarization
Q2.Phase of cardiac action potential, where calcium channels close & slow potassium channels open :
- APhase I
- BPhase II
- CPhase III✓ Correct answer
- DPhase IV
Q3.PR interval in ECG shows?
- AVentricular depolarization
- BVentricular Repolarization
- CConduction through AV node.✓ Correct answer
- DAtrial Repolarization
Q4.In an ECG the cardiac event corresponding to the ST segment is:
- AAtrial depolarisation
- BVentricular depolarisation
- CAtrial repolarisation
- DVentricular repolarisation✓ Correct answer
Q5.Sinus arrhythmia occurs:-
- ADue to sympathetic overstimulation
- BDue to change in respiration✓ Correct answer
- CDue to change in body temperature
Q6.The PR interval in ECG denotes?
- AAtrial depolarization only
- BAtrial depolarization with A - V conduction✓ Correct answer
- CVentricular depolarization and ventricular repolarization
- DAtrial depolarization with atrial repolarization
Q7.Which of the following is the function of Hyperpolarizing Cyclic Nucleotide (HCN) gated channels?
- ACardiac rhythm generation✓ Correct answer
- BGeneration of mitochondrial action potential
- CMyocardial muscle contraction
- DMemory formation
Q8.During inhibition of SA node by vagal stimulation, which of the following occurs:
- AActing on K+ channels resulting in ↑ efflux✓ Correct answer
- BActing on K+ channels resulting in ↑ influx
- CActing on Ca2+ channels resulting in ↑ efflux
- DActing on Ca2+ channels resulting in ↑ influx
Q9.Which of the following phase is absent in action potential of pacemaker cells?
- APhase 0
- BPhase 1✓ Correct answer
- CPhase 3
- DPhase 4
Q10.PR interval corresponds to ECG changes as
- AVentricular depolarization
- BVentricular depolarization and atrial repolarization
- CAtrial depolarization and conduction through AV node✓ Correct answer
- DVentricular repolarization
Answer key
Q1: B. Decrease in K+ permeability; Q2: C. Phase III; Q3: C. Conduction through AV node; Q4: D. Ventricular repolarisation; Q5: B. Due to change in respiration; Q6: B. Atrial depolarization with A - V conduction; Q7: A. Cardiac rhythm generation; Q8: A. Acting on K+ channels resulting in ↑ efflux; Q9: B. Phase 1; Q10: C. Atrial depolarization and conduction through AV node.
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