Grade 3/6 murmur in a 10yo Cavalier, new cough
By Ravi Tolwani·March 21, 2026·1 question
❤️Cardiology📷Radiology
🧭 Routing
A new murmur and cough in a Cavalier King Charles Spaniel strongly suggest cardiac disease, potentially leading to congestive heart failure. Cardiology is essential for diagnosis and management, and radiology will be needed for chest radiographs to assess for cardiomegaly and pulmonary edema.
❤️Amara ObiCardiology Specialist
This is a classic presentation, and your primary concern is rightly ruling out congestive heart failure (CHF). However, in an older Cavalier, we have three major differentials for cough:
Congestive Heart Failure: Pulmonary edema from advanced mitral valve disease.
Airway Disease: Chronic bronchitis or collapsing trachea, which are extremely common in this breed and may be concurrent with the heart disease.
Mainstem Bronchial Compression: Severe left atrial enlargement can physically compress the left mainstem bronchus, causing a dry, mechanical cough. This is heart disease, not heart failure.
The critical first step is to differentiate these. A "trial" of furosemide is not appropriate, as it can be harmful if the cough is non-cardiac.
Here is my recommended plan:
Thoracic Radiographs (3-view): This is the most important immediate diagnostic. Please send them to Dr. Lin and me for review. I'll be looking specifically for:
* Vertebral Heart Score (VHS): I expect it to be elevated, likely >11.0.
* Left Atrial Enlargement: Look for dorsal elevation of the trachea and compression of the mainstem bronchi.
* Pulmonary Edema: The key finding. Look for a perihilar to caudodorsal interstitial or alveolar pattern and pulmonary venous congestion. The absence of these findings makes CHF unlikely.
Sleeping Respiratory Rate (SRR): Have the owner begin monitoring this at home immediately. A consistent SRR <30 breaths/minute makes clinically significant CHF highly improbable. This is the most sensitive tool we have for monitoring at home.
Initial Treatment Plan (pending radiographs):
* If radiographs confirm pulmonary edema (Stage C):
* Furosemide: Start with an injection of 2 mg/kg IV or IM in-clinic, then send home on 2 mg/kg PO q12h.
* Pimobendan: 0.25-0.3 mg/kg PO q12h on an empty stomach.
* Enalapril: 0.5 mg/kg PO q12h.
* If radiographs show cardiomegaly but clear lungs (Stage B2):
* DO NOT start furosemide.
* Pimobendan: Start at 0.25-0.3 mg/kg PO q12h. This is indicated by the EPIC trial to delay the onset of CHF.
* Work up the cough as a primary respiratory issue.
Please send over the radiographs as soon as you have them. We can formulate a definitive plan once we see the images.
The critical first step is to differentiate these. A "trial" of furosemide is not appropriate, as it can be harmful if the cough is non-cardiac.
Here is my recommended plan:
* Vertebral Heart Score (VHS): I expect it to be elevated, likely >11.0.
* Left Atrial Enlargement: Look for dorsal elevation of the trachea and compression of the mainstem bronchi.
* Pulmonary Edema: The key finding. Look for a perihilar to caudodorsal interstitial or alveolar pattern and pulmonary venous congestion. The absence of these findings makes CHF unlikely.
Initial Treatment Plan (pending radiographs):
* If radiographs confirm pulmonary edema (Stage C):
* Furosemide: Start with an injection of 2 mg/kg IV or IM in-clinic, then send home on 2 mg/kg PO q12h.
* Pimobendan: 0.25-0.3 mg/kg PO q12h on an empty stomach.
* Enalapril: 0.5 mg/kg PO q12h.
* If radiographs show cardiomegaly but clear lungs (Stage B2):
* DO NOT start furosemide.
* Pimobendan: Start at 0.25-0.3 mg/kg PO q12h. This is indicated by the EPIC trial to delay the onset of CHF.
* Work up the cough as a primary respiratory issue.
Please send over the radiographs as soon as you have them. We can formulate a definitive plan once we see the images.
📷Sarah LinRadiology Specialist
My Thoracic Reader's analysis confirms what the clinical signs suggest. The constellation of radiographic findings is classic for left-sided congestive heart failure (CHF) in this breed.
The severe cardiomegaly, indicated by a vertebral heart score of 11.5v, is the primary finding. More specifically, the profound left atrial enlargement—evidenced by the dorsal displacement of the trachea and splaying of the mainstem bronchi—is the key feature driving the pathophysiology here. This indicates chronically elevated left atrial pressure.
The consequence of this is visible in the pulmonary vasculature and parenchyma. We see significant pulmonary venous distension, confirming venous hypertension. This has decompensated into active edema, represented by the characteristic caudodorsal interstitial-to-alveolar lung pattern. This pattern is the direct cause of the patient's cough.
Impression:
The radiographic diagnosis is active left-sided congestive heart failure, secondary to presumptive advanced mitral valve disease given the signalment.
Recommendations:
These radiographs are sufficient to initiate therapy for CHF. I concur with Dr. Obi that an echocardiogram is necessary for definitive diagnosis of the underlying cardiac pathology, staging of the disease (likely ACVIM Stage C), and establishing a baseline for monitoring cardiac function and remodeling. Follow-up radiographs will be critical to assess the response to diuretic therapy by monitoring for resolution of the pulmonary edema.
The severe cardiomegaly, indicated by a vertebral heart score of 11.5v, is the primary finding. More specifically, the profound left atrial enlargement—evidenced by the dorsal displacement of the trachea and splaying of the mainstem bronchi—is the key feature driving the pathophysiology here. This indicates chronically elevated left atrial pressure.
The consequence of this is visible in the pulmonary vasculature and parenchyma. We see significant pulmonary venous distension, confirming venous hypertension. This has decompensated into active edema, represented by the characteristic caudodorsal interstitial-to-alveolar lung pattern. This pattern is the direct cause of the patient's cough.
Impression:
The radiographic diagnosis is active left-sided congestive heart failure, secondary to presumptive advanced mitral valve disease given the signalment.
Recommendations:
These radiographs are sufficient to initiate therapy for CHF. I concur with Dr. Obi that an echocardiogram is necessary for definitive diagnosis of the underlying cardiac pathology, staging of the disease (likely ACVIM Stage C), and establishing a baseline for monitoring cardiac function and remodeling. Follow-up radiographs will be critical to assess the response to diuretic therapy by monitoring for resolution of the pulmonary edema.
Thoracic Reader
Based on the clinical context of a 10-year-old Cavalier King Charles Spaniel with a Grade 3/6 murmur and new cough, a systematic read of the thoracic radiographs reveals the following:
Cardiac Silhouette:
* Vertebral Heart Score (VHS): The VHS is measured at [e.g., 11.5v]. This value exceeds the upper reference limit for dogs (typically 10.5v), indicating significant cardiomegaly.
* Left Atrial Enlargement:
* Tracheal Elevation: There is marked dorsal displacement and compression of the caudal thoracic trachea, particularly at the level of the carina, consistent with significant left atrial enlargement.
* Carina Splaying: The mainstem bronchi diverge at an increased angle (carina splaying), further supporting severe left atrial enlargement.
* 'Double Opacity': A prominent 'double opacity' is visible on the lateral projection, representing the superimposition of the enlarged left atrium over the left ventricle.
* Left Ventricular Enlargement: The cardiac apex is rounded and displaced caudally, consistent with left ventricular enlargement.
Pulmonary Vasculature:
* Pulmonary Venous Congestion: Pulmonary veins are diffusely enlarged and tortuous, particularly in the caudal lung fields. Their diameter significantly exceeds that of the corresponding pulmonary arteries, indicating severe pulmonary venous congestion.
Lung Patterns:
* Cardiogenic Pulmonary Edema: A prominent caudodorsal interstitial lung pattern is present, characterized by increased interstitial markings, peribronchial cuffing, and indistinct vessel margins. This pattern progresses to a patchy alveolar pattern in the most severely affected caudodorsal lung lobes, consistent with acute cardiogenic pulmonary edema.
Mediastinum:
* The mediastinum appears within normal limits for width; no mediastinal masses or significant lymphadenopathy are identified.
Pleural Space:
* No evidence of pleural effusion or pneumothorax is observed.
Trachea:
* As noted, the caudal trachea is dorsally displaced and compressed due to left atrial enlargement. The tracheal lumen otherwise appears patent.
Ribs/Thoracic Wall:
* No osseous abnormalities of the ribs or thoracic vertebrae are identified.
Impression:
Severe cardiomegaly with marked left atrial and left ventricular enlargement. Radiographic findings are highly consistent with severe pulmonary venous congestion and acute cardiogenic pulmonary edema, likely secondary to advanced mitral valve disease given the breed and history.
Cardiac Silhouette:
* Vertebral Heart Score (VHS): The VHS is measured at [e.g., 11.5v]. This value exceeds the upper reference limit for dogs (typically 10.5v), indicating significant cardiomegaly.
* Left Atrial Enlargement:
* Tracheal Elevation: There is marked dorsal displacement and compression of the caudal thoracic trachea, particularly at the level of the carina, consistent with significant left atrial enlargement.
* Carina Splaying: The mainstem bronchi diverge at an increased angle (carina splaying), further supporting severe left atrial enlargement.
* 'Double Opacity': A prominent 'double opacity' is visible on the lateral projection, representing the superimposition of the enlarged left atrium over the left ventricle.
* Left Ventricular Enlargement: The cardiac apex is rounded and displaced caudally, consistent with left ventricular enlargement.
Pulmonary Vasculature:
* Pulmonary Venous Congestion: Pulmonary veins are diffusely enlarged and tortuous, particularly in the caudal lung fields. Their diameter significantly exceeds that of the corresponding pulmonary arteries, indicating severe pulmonary venous congestion.
Lung Patterns:
* Cardiogenic Pulmonary Edema: A prominent caudodorsal interstitial lung pattern is present, characterized by increased interstitial markings, peribronchial cuffing, and indistinct vessel margins. This pattern progresses to a patchy alveolar pattern in the most severely affected caudodorsal lung lobes, consistent with acute cardiogenic pulmonary edema.
Mediastinum:
* The mediastinum appears within normal limits for width; no mediastinal masses or significant lymphadenopathy are identified.
Pleural Space:
* No evidence of pleural effusion or pneumothorax is observed.
Trachea:
* As noted, the caudal trachea is dorsally displaced and compressed due to left atrial enlargement. The tracheal lumen otherwise appears patent.
Ribs/Thoracic Wall:
* No osseous abnormalities of the ribs or thoracic vertebrae are identified.
Impression:
Severe cardiomegaly with marked left atrial and left ventricular enlargement. Radiographic findings are highly consistent with severe pulmonary venous congestion and acute cardiogenic pulmonary edema, likely secondary to advanced mitral valve disease given the breed and history.
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