NAVLE Final Study Guide 2026: 200+ Q&A with Rationales (Cardiology, Neuro, GI, Endocrine, Infectious Disease)

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**NAVLE FINAL STUDY GUIDE 2026 – 200+
TESTED QUESTIONS WITH CORRECT
ANSWERS AND RATIONALES**



# SECTION 1: CARDIOLOGY (Questions 1–20)


**1.** A 6-year-old Dachshund presents with a honking cough and
exercise intolerance. Thoracic radiographs reveal a leftward heart base
silhouette and tracheal elevation. What is the most common underlying
cardiac disease?
A) Dilated cardiomyopathy
B) Mitral valve disease
C) Aortic stenosis
D) Pericardial effusion


**Correct Answer:** B – Mitral valve disease
**Rationale:** Myxomatous mitral valve degeneration (MMVD) is the
most common acquired heart disease in dogs, particularly small breeds.
Enlargement of the left atrium can cause tracheal elevation (visible on
radiographs) and lead to compression of the left mainstem bronchus,
producing a cough.

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**2.** A 4-year-old Maine Coon cat is presented for acute hindlimb
paralysis. The hindlimbs are cold, and there is no femoral pulse. What is
the most likely diagnosis?
A) Aortic thromboembolism (saddle thrombus)
B) Hypertrophic cardiomyopathy
C) Pulmonary edema
D) Spinal cord trauma


**Correct Answer:** A – Aortic thromboembolism (saddle thrombus)
**Rationale:** Aortic thromboembolism is a common complication of
feline hypertrophic cardiomyopathy. It presents with acute, painful
hindlimb paralysis, absent pulses, and cold extremities. Prognosis is
guarded.


**3.** A 10-year-old Boxer is presented with syncope. An ECG shows a
wide QRS complex and a ventricular rate of 200 bpm. The rhythm is
regular. What is the most likely arrhythmia?
A) Supraventricular tachycardia
B) Atrial fibrillation
C) Ventricular tachycardia
D) Sinus tachycardia


**Correct Answer:** C – Ventricular tachycardia

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**Rationale:** Ventricular tachycardia (VT) in Boxers is often
associated with arrhythmogenic right ventricular cardiomyopathy
(ARVC). Wide QRS complexes, rate >150-200 bpm, and lack of P
waves suggest VT.


**4.** A 12-year-old Cavalier King Charles Spaniel has a grade VI/VI
left apical systolic murmur with a palpable thrill. The ECG shows large
P waves (P mitrale). What is the most appropriate next diagnostic test?
A) Echocardiography
B) Serum cardiac troponin
C) Thoracic radiographs
D) Pro-BNP


**Correct Answer:** A – Echocardiography
**Rationale:** An advanced murmur (grade V-VI) with thrill indicates
significant mitral valve disease. Echocardiography assesses severity of
regurgitation, chamber enlargement, and pulmonary pressure.


**5.** A horse has a grade IV/VI hologystolic murmur on the left side, a
bounding pulse, and hyperdynamic apex beat. What is the most likely
lesion?
A) Mitral regurgitation
B) Aortic regurgitation
C) Tricuspid regurgitation

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D) Ventricular septal defect


**Correct Answer:** A – Mitral regurgitation
**Rationale:** Mitral regurgitation in horses produces a hologystolic
murmur with point of maximal intensity (PMI) at the left apex (5th
intercostal space). Bounding pulses and hyperdynamic apex indicate
volume overload.


**6.** An ECG shows atrial fibrillation in a 500-kg Quarter Horse.
What is the most common underlying condition?
A) Idiopathic
B) Bacterial endocarditis
C) Mitral valve disease
D) Atrial enlargement from myopathy


**Correct Answer:** D – Atrial enlargement from myopathy
**Rationale:** In horses, atrial fibrillation is often associated with atrial
enlargement secondary to myopathy or valvular disease. Affected horses
are often large breeds (e.g., Quarter Horses, Thoroughbreds) >15 years.


**7.** A 5-year-old Golden Retriever has a heart rate of 220 bpm at rest,
bounding pulses, and a jugular venous hum. ECG shows narrow QRS
complexes and a rate >200 bpm. Carotid sinus massage slows the heart
rate. What is the arrhythmia?