Before You Begin
Question #46369
The Question
A patient with severe renal failure develops hyperkalemia (elevated extracellular K+). Which of the following accurately describes the primary Electrocardiogram (ECG) abnormality observed in this condition and its underlying cellular mechanism?
Options
- A.
Tall, peaked T-waves caused by a reduced resting membrane potential gradient that alters ventricular repolarization and shortens the calcium plateau phase.
- B.
Enlarged P-waves caused by the hyperpolarization of the SA node, leading to delayed atrial depolarization.
- C.
Narrowed QRS complex resulting from an increased availability of fast voltage-gated Na+ channels during ventricular systole.
- D.
Inverted T-waves due to a prolonged influx of Ca2+ ions, which extends the duration of ventricular systole.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
ECG Wave Interpretation|Calcium Homeostasis|Conducting System Sequence
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that K+ efflux causes repolarization, so they mistakenly assume high extracellular K+ would delay repolarization and prolong the action potential (leading to inverted T-waves).
However, the reduced gradient actually alters channel kinetics, shortening the action potential duration (plateau) and causing peaked T-waves.
This requires synthesizing NCERT's definition of the T-wave (ventricular repolarization) with the principles of resting membrane potentials.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Body Fluids and Circulation - Class 11 |
| Concept | ECG Wave Interpretation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |