Cardiovascular screening models: antihypertensive, antiarrhythmic and antianginal assays MCQs With Answer

Cardiovascular screening models: antihypertensive, antiarrhythmic and antianginal assays MCQs With Answer

Introduction: This quiz set focuses on practical and mechanistic cardiovascular screening models used in preclinical pharmacology for antihypertensive, antiarrhythmic and antianginal drug discovery. It covers in vivo rodent models (genetic and renovascular hypertension, DOCA‑salt, coronary ligation), ex vivo preparations (Langendorff heart, isolated atria), common arrhythmia induction methods (aconitine, ouabain, electrical pacing), endpoints (blood pressure, ECG intervals, infarct size, coronary flow) and drug mechanisms (ACE inhibitors, beta‑blockers, nitrates, late INa inhibitors). Designed for M.Pharm students, these MCQs reinforce experimental design, interpretation of results and safety considerations essential for translational cardiovascular screening.

Q1. Which animal model is commonly used to evaluate chronic genetic hypertension and long‑term antihypertensive effects?

• Wistar rats fed high‑fat diet
• Spontaneously hypertensive rat (SHR)
• DOCA‑salt mouse
• Two‑kidney one‑clip (2K1C) rabbit

Correct Answer: Spontaneously hypertensive rat (SHR)

Q2. Tail‑cuff plethysmography in conscious rodents primarily measures which parameter?

• Central venous pressure
• Systolic arterial pressure
• Mean arterial pressure using arterial catheter
• Pulmonary arterial pressure

Correct Answer: Systolic arterial pressure

Q3. What is the gold‑standard technique for continuous, high‑fidelity arterial pressure and heart rate recording in freely moving rodents?

• Oscillometric tail device
• Noninvasive cuff plethysmography
• Radiotelemetry (implantable telemetry)
• Surface ECG with adhesive electrodes

Correct Answer: Radiotelemetry (implantable telemetry)

Q4. The primary pathophysiological mechanism underlying the two‑kidney one‑clip (2K1C) model of hypertension is:

• Mineralocorticoid excess with suppressed renin
• Volume overload due to sodium retention only
• Renin release from the clipped kidney causing increased angiotensin II
• Primary endothelial dysfunction without RAAS activation

Correct Answer: Renin release from the clipped kidney causing increased angiotensin II

Q5. The DOCA‑salt model of hypertension is best characterized by which of the following?

• High renin, angiotensin II‑dependent hypertension
• Mineralocorticoid‑induced, salt‑sensitive hypertension with suppressed renin
• Autoimmune vasculitis causing secondary hypertension
• Neurogenic hypertension from chronic stress

Correct Answer: Mineralocorticoid‑induced, salt‑sensitive hypertension with suppressed renin

Q6. The Langendorff isolated heart preparation is primarily used to assess which of the following?

• Whole‑animal systemic blood pressure responses
• Ex vivo cardiac contractile function, coronary flow and arrhythmogenesis
• Renal renin secretion under neurohumoral control
• In vivo endothelial function in conscious animals

Correct Answer: Ex vivo cardiac contractile function, coronary flow and arrhythmogenesis

Q7. Which isolated tissue preparation is commonly used to evaluate atrial contractility and chronotropic drug effects in preclinical screening?

• Isolated guinea‑pig right atrium
• Whole Langendorff mouse heart only
• Isolated rat soleus muscle
• Isolated rabbit aorta ring

Correct Answer: Isolated guinea‑pig right atrium

Q8. Aconitine is used to induce arrhythmias in screening studies by which mechanism?

• Blockade of L‑type calcium channels
• Persistent activation of voltage‑gated sodium channels causing sustained Na+ influx
• Inhibition of Na+/K+‑ATPase with secondary Ca2+ overload
• Direct potassium channel opening leading to hyperpolarization

Correct Answer: Persistent activation of voltage‑gated sodium channels causing sustained Na+ influx

Q9. Ouabain‑induced arrhythmia in isolated heart models results mainly from:

• Enhanced outward K+ currents and shortened APD
• Blockade of gap junctions between myocytes
• Inhibition of Na+/K+‑ATPase causing intracellular Na+ and secondary Ca2+ accumulation
• Activation of β‑adrenergic receptors causing tachyarrhythmia

Correct Answer: Inhibition of Na+/K+‑ATPase causing intracellular Na+ and secondary Ca2+ accumulation

Q10. Which ECG change is the most sensitive indicator of delayed ventricular repolarization and proarrhythmic risk in preclinical studies?

• Shortened PR interval
• Prolonged QT interval (QTc prolongation)
• Low QRS amplitude only
• ST segment elevation alone

Correct Answer: Prolonged QT interval (QTc prolongation)

Q11. Organic nitrates (e.g., nitroglycerin) relieve angina primarily through which mechanism?

• Direct blockade of sodium channels in myocardium
• Activation of nitric oxide–cGMP pathway producing venodilation and reduced preload
• Inhibition of ACE reducing afterload acutely
• Selective blocking of myocardial beta‑1 receptors

Correct Answer: Activation of nitric oxide–cGMP pathway producing venodilation and reduced preload

Q12. Ranolazine reduces myocardial ischemia and angina predominantly by:

• Increasing heart rate via chronotropic stimulation
• Inhibiting the late inward sodium current (late INa) to reduce diastolic wall tension
• Potent activation of beta‑2 receptors on coronary vessels
• Blocking ACE to reduce remodeling

Correct Answer: Inhibiting the late inward sodium current (late INa) to reduce diastolic wall tension

Q13. Coronary artery ligation (left anterior descending artery ligation) in rodents is primarily used to model which condition for antianginal and cardioprotective screening?

• Systemic hypertension without ischemia
• Myocardial infarction and regional ischemia
• Cardiac hypertrophy due to pressure overload
• Arrhythmia due to metabolic toxin only

Correct Answer: Myocardial infarction and regional ischemia

Q14. In ischemia‑reperfusion studies, which endpoint is commonly used to quantify myocardial injury and therapeutic protection?

• Heart weight alone
• Infarct size measurement using TTC (triphenyl tetrazolium chloride) staining
• Pulmonary wedge pressure only
• Renal plasma flow measurement

Correct Answer: Infarct size measurement using TTC (triphenyl tetrazolium chloride) staining

Q15. Pacing‑induced arrhythmia models using programmed electrical stimulation are useful to evaluate an antiarrhythmic drug’s ability to:

• Reduce systolic blood pressure exclusively
• Suppress electrically induced ventricular tachycardia/fibrillation susceptibility
• Increase renal renin secretion in vivo
• Measure coronary artery endothelial function noninvasively

Correct Answer: Suppress electrically induced ventricular tachycardia/fibrillation susceptibility

Q16. Which Vaughan‑Williams class of antiarrhythmic drugs primarily blocks potassium channels and prolongs repolarization (action potential duration)?

• Class I
• Class II
• Class III
• Class IV

Correct Answer: Class III

Q17. Administration of an effective β‑blocker in an ECG‑monitored animal model typically produces which of the following changes?

• Shortening of the QT interval
• Increase in PR interval due to slowed AV nodal conduction
• Marked widening of the QRS complex without rate change
• Immediate ST segment elevation only

Correct Answer: Increase in PR interval due to slowed AV nodal conduction

Q18. Dihydropyridine calcium channel blockers (e.g., nifedipine) exert antianginal effects mainly by:

• Blocking late sodium current in myocytes
• Inhibiting L‑type calcium channels causing coronary and peripheral vasodilation and reduced afterload
• Stimulating α1 adrenergic receptors causing vasoconstriction
• Direct inhibition of Na+/K+‑ATPase

Correct Answer: Inhibiting L‑type calcium channels causing coronary and peripheral vasodilation and reduced afterload

Q19. In the Langendorff perfused heart, coronary flow rate is most practically measured by:

• Noninvasive Doppler placed over the epicardium
• Collecting and measuring effluent perfusate volume per unit time from the coronary sinus outflow
• Estimating from heart weight and contractility indices only
• Measuring arterial blood gases of the perfusate exclusively

Correct Answer: Collecting and measuring effluent perfusate volume per unit time from the coronary sinus outflow

Q20. In preclinical safety pharmacology for antiarrhythmic screening, which parameter is most directly associated with proarrhythmic risk such as torsades de pointes?

• Decrease in heart weight
• Prolongation of QTc interval and occurrence of early afterdepolarizations (EADs)
• Elevation of serum creatinine alone
• Transient drop in body temperature

Correct Answer: Prolongation of QTc interval and occurrence of early afterdepolarizations (EADs)

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