Congestive Heart Failure and MVD (Canine) — NAVLE Prep

Quick anchor

Trigger

Old small dog + left apical murmur

CHF proof

Cardiomegaly + pulmonary edema

First step

Oxygen, calm handling, diuresis

Trap

Cough alone is not CHF

High-yield takeaways

Start with the safest next step, then narrow the case using signalment, timeline, exam findings, diagnostics, and response to treatment.
Use the traps, differentials, and practice questions to rehearse NAVLE-style reasoning instead of memorizing isolated facts.
This educational study page is not a clinical protocol; confirm patient-specific decisions with current references and clinician judgment.

30-second revision

MVD clueOld small dog + left apical systolic murmur

CHF proofCardiomegaly + pulmonary venous congestion + edema

Left-sided signsTachypnea, dyspnea, crackles, pulmonary edema

Emergency moveOxygen, calm handling, diuresis

Chronic rolesPimobendan, diuretics, ACE inhibitor support

Critical trapCough or murmur alone does not prove CHF

Exam core — read this first

MVD pattern → older small-breed dog with left apical systolic murmur

Left-sided CHF → tachypnea/dyspnea with cardiomegaly, enlarged pulmonary veins, and interstitial/alveolar pulmonary edema

Emergency branch → reduce respiratory distress before a complete cardiac workup

Do not overcall CHF → cough or murmur alone can be airway disease, early MVD, pneumonia, or pulmonary hypertension

Emergency Triage Alert

Respiratory Distress Comes First

A dyspneic dog with suspected cardiogenic pulmonary edema needs oxygen, minimal stress handling, and diuretic therapy. Do not delay stabilization for a complete echo or prolonged radiograph session.

Pattern recognition

CHF pattern

Tachypnea / dyspneaLeft apical systolic murmurPulmonary edema on rads

Radiograph clues

CardiomegalyLeft atrial enlargementPulmonary venous congestionInterstitial-to-alveolar edemaOften perihilar/caudodorsal in dogs

NAVLE trigger: Murmur + pulmonary venous congestion + edema is CHF. Murmur + cough with clear lungs is not automatically CHF.

Decision core — what NAVLE actually asks

Dyspneic dog with cardiogenic edema pattern

→ Oxygen, minimize stress, begin diuresis, then complete cardiac staging once safer

Murmur but no cardiomegaly or pulmonary edema

→ Do not diagnose CHF; stage MVD and investigate airway/respiratory causes of cough

Chronic MVD/CHF plan

→ Pimobendan supports cardiac performance; diuretics control congestion; ACE inhibitors are chronic support, not acute rescue

Key interpretation

Murmur

Left apical systolic

Classic MVD clue

Heart size

Cardiomegaly

Supports clinically important disease

Pulmonary veins

Enlarged

Pulmonary venous congestion

Lung pattern

Interstitial / alveolar

Cardiogenic edema when paired with heart disease

Airway cough

Clear lungs possible

Do not overdiagnose CHF

Pneumonia

Inflammatory pattern

Often fever, leukogram, cranioventral emphasis

⚠ A dog can have MVD and cough without being in CHF. The NAVLE answer needs respiratory distress plus congestion evidence, especially pulmonary venous congestion and edema.

Treatment

Acute

Oxygen, minimal stress handling, and loop diuretic therapy

This is the stabilization branch for left-sided CHF with pulmonary edema.

Chronic

Pimobendan + diuretic-based congestion control

Pimobendan is a high-yield MVD/CHF medication concept; diuretics address fluid congestion.

Support

ACE inhibitor as chronic support when appropriate

High-level board role: chronic neurohormonal/afterload support, not the immediate rescue answer for pulmonary edema.

NAVLE traps — where students lose marks

Cough alone does not prove CHF

Small dogs commonly have airway disease, tracheal collapse, chronic bronchitis, or left atrial bronchial compression without pulmonary edema.

Do not treat cardiogenic edema as pneumonia when the heart pattern is obvious

Cardiomegaly plus big pulmonary veins plus edema points to diuresis and oxygen first.

Do not give aggressive fluids reflexively to a dyspneic CHF dog

Extra volume can worsen pulmonary congestion.

ACE inhibitor is not the acute pulmonary edema rescue answer

The immediate emergency priorities are oxygen, stress reduction, and diuresis.

Differentials — how to separate these on NAVLE

Fast separator: CHF needs a heart-disease congestion pattern. Airway disease coughs without edema, pneumonia has inflammatory lung clues, and pulmonary hypertension can cause respiratory signs without classic left-sided edema.

Problem	Typical clue	Radiograph clue	Board separator
Left-sided CHF from MVD	Old small dog, left apical murmur, dyspnea	Cardiomegaly + pulmonary veins + edema	Oxygen + diuresis first
Airway disease / tracheal collapse	Honking cough, excitement trigger, small breed	No pulmonary edema	Cough without venous congestion
Chronic bronchitis	Chronic cough, often stable breathing at rest	Bronchial pattern	No classic cardiogenic edema
Pneumonia	Fever, lethargy, leukogram, productive cough possible	Often cranioventral alveolar pattern	Infectious/inflammatory context
Pulmonary hypertension	Syncope, loud P2, right-sided strain signs	Pulmonary artery/right heart changes	Not left atrial edema pattern
DCM-related CHF	Large breed, weak pulses, arrhythmia/syncope	Cardiomegaly with congestion	Underlying myocardial disease, not MVD signalment

Practice questions

Pre-built NAVLE-style · CHF / myxomatous mitral valve disease

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Q1Recognition

A 12yr Cavalier King Charles Spaniel has a loud left apical systolic murmur, tachypnea, dyspnea, cardiomegaly, enlarged pulmonary veins, and an interstitial-to-alveolar lung pattern. Which diagnosis best fits?

Q2Emergency stabilization

A dog with suspected cardiogenic pulmonary edema is anxious and dyspneic. Which immediate plan best matches the NAVLE priority?

Q3Overdiagnosis trap

An older small-breed dog has a chronic cough and a soft left apical murmur. Resting respiratory rate is normal, lungs are clear, and thoracic radiographs show no cardiomegaly or pulmonary edema. Which interpretation is most appropriate?

Q4NAVLE case drill

A coughing dog is febrile and lethargic with a neutrophilic leukogram. Thoracic radiographs show a cranioventral alveolar pattern, normal heart size, and no pulmonary venous congestion. Which differential best fits this pattern?

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