1. Introduction
Dachshunds are one of the most recognizable canine breeds, known for their long bodies, short limbs, and bold personalities. From a veterinary cardiology perspective, however, dachshunds also represent a clinically important population due to their predisposition to myxomatous mitral valve disease (MMVD). As a breed, dachshunds fall squarely into the small-breed category most affected by degenerative valvular disease, making early detection and accurate cardiac assessment essential components of routine veterinary care.
The unique body conformation of the dachshund introduces specific challenges when interpreting thoracic radiographs and cardiac measurements. Their elongated thorax, altered rib spacing, and slightly cranial cardiac position can all influence radiographic appearance, potentially leading to over- or underestimation of heart size if breed-specific considerations are not applied. This makes standardized, objective measurement tools such as the vertebral heart score (VHS) and vertebral left atrial size (VLAS) especially valuable in this breed.
Heart disease prevalence in dachshunds increases with age, with MMVD being by far the most common diagnosis. Many dachshunds develop a heart murmur in mid-to-late adulthood, and a significant proportion will eventually progress to clinically relevant cardiac enlargement and congestive heart failure if they live long enough. Because dachshunds are often stoic and may mask early clinical signs, radiographic screening plays a crucial role in identifying disease progression before overt symptoms occur.
This guide provides a comprehensive overview of Dachshund heart health, with a particular focus on VHS and VLAS reference values, interpretation pitfalls, and practical clinical application. In addition to MMVD, other cardiac considerations relevant to the breed—including congenital disease, anesthesia risk, and obesity—are discussed. The goal is to equip veterinarians with breed-specific insights that support accurate diagnosis, appropriate monitoring, and informed client communication.
2. Dachshund VHS Reference Values
Normal VHS for Dachshunds
The vertebral heart score (VHS) is a widely used radiographic method for estimating cardiac size in dogs. In dachshunds, multiple studies have demonstrated that the mean normal VHS is approximately 9.7 ± 0.5 vertebrae, which is remarkably similar to the general canine population.
This finding is clinically useful, as it suggests that dachshunds do not require a dramatically altered VHS reference range compared to other small breeds. However, while the numeric reference interval aligns closely with the standard canine value (typically 8.5–10.5 v), interpretation must always be contextualized to body conformation and serial changes.
Similarity to the General Population
Unlike some brachycephalic or deep-chested breeds that exhibit consistent deviations from standard VHS values, dachshunds tend to cluster tightly around the mean. Most healthy adult dachshunds fall within a VHS range of 9.2–10.2 v, with values above this raising suspicion for cardiomegaly, particularly when supported by clinical findings or auscultation.
That said, reliance on a single measurement can be misleading. A VHS of 10.3 v may be normal for one individual but abnormal for another, especially if prior radiographs demonstrated a stable baseline closer to 9.5 v. For this reason, trend analysis is far more informative than absolute cutoffs.
Body Shape Considerations
Dachshunds present several anatomical features that can influence radiographic interpretation:
- Long body, short legs: This can make positioning challenging and increases the risk of obliquity, which artificially elevates VHS values.
- Elongated thorax: The thoracic cavity is longer than it is tall, which may subtly affect the apparent long-axis measurement.
- Heart position: The heart may appear slightly more cranial and horizontally oriented compared to other breeds.
These factors underscore the importance of meticulous positioning and consistent technique when acquiring thoracic radiographs in dachshunds.
Reference Range Interpretation
When interpreting VHS in dachshunds:
- Values ≤10.0 v are typically considered normal in asymptomatic dogs.
- Values between 10.1–10.5 v warrant closer evaluation and correlation with auscultation and VLAS.
- Values >10.5 v are more suggestive of clinically significant cardiomegaly, particularly if progressive.
Serial measurements taken under similar conditions remain the gold standard for detecting early disease progression in this breed.
3. Dachshund VLAS Reference Values
Normal VLAS Values
The vertebral left atrial size (VLAS) is an increasingly valuable radiographic tool for assessing left atrial enlargement, particularly in dogs with MMVD. In dachshunds, normal VLAS values are generally ≤2.3 vertebrae, consistent with small-breed reference ranges.
VLAS is measured on the right lateral thoracic radiograph, from the ventral aspect of the left mainstem bronchus to the dorsal border of the left atrium, transposed onto the vertebral column beginning at T4. When performed correctly, VLAS provides a sensitive indicator of early left atrial remodeling.
Clinical Cutoffs
In dachshunds:
- VLAS ≤2.3 v is considered normal.
- VLAS 2.4–2.6 v suggests mild left atrial enlargement.
- VLAS ≥2.7 v is strongly associated with clinically relevant MMVD and increased risk of congestive heart failure.
VLAS is particularly useful when VHS is borderline, as left atrial enlargement often precedes generalized cardiomegaly.
Monitoring Recommendations
For dachshunds with a known heart murmur:
- Establish a baseline VLAS at diagnosis.
- Repeat measurements every 6–12 months, depending on murmur grade and age.
- Use VLAS trends to guide decisions regarding echocardiography and medical intervention.
4. MMVD in Dachshunds
Prevalence and Onset Age
Myxomatous mitral valve disease is the most common cardiac condition affecting dachshunds. Prevalence increases sharply with age, with many dogs developing a murmur by 7–9 years. By 10 years of age, a substantial proportion of dachshunds will have echocardiographic evidence of mitral valve degeneration.
Disease Progression
MMVD in dachshunds typically follows the classic progression:
- Stage B1 – Murmur present, no cardiac enlargement.
- Stage B2 – Murmur with radiographic or echocardiographic enlargement.
- Stage C – Past or current congestive heart failure.
- Stage D – Refractory heart failure.
Radiographic markers such as rising VHS and VLAS are critical for identifying the transition from B1 to B2, which has direct therapeutic implications.
Comparison to Other Breeds
Compared to Cavalier King Charles Spaniels, dachshunds often develop MMVD slightly later and may progress more slowly. However, once cardiac enlargement occurs, progression to clinical signs can be relatively rapid if not monitored closely.
Prognosis
With appropriate monitoring and timely initiation of therapy, many dachshunds with MMVD maintain good quality of life for years. Early detection of cardiac enlargement using VHS and VLAS significantly improves long-term outcomes.
5. Other Cardiac Considerations
Patent Ductus Arteriosus
Although uncommon, patent ductus arteriosus (PDA) has been reported in dachshunds. Early detection is essential, as untreated PDA can lead to volume overload and heart failure. Radiographs may show left-sided enlargement and pulmonary overcirculation.
Intervertebral Disc Disease and Cardiac Effects
Dachshunds are famously predisposed to intervertebral disc disease (IVDD). While not a cardiac condition, IVDD has important cardiovascular implications:
- Stress and pain can elevate heart rate and blood pressure.
- Anesthesia for spinal surgery requires careful cardiac assessment, especially in older dogs with murmurs.
- Pre-anesthetic thoracic radiographs can identify occult cardiomegaly.
Obesity Impact on Cardiac Assessment
Obesity is common in dachshunds and complicates cardiac evaluation by:
- Reducing radiographic contrast.
- Increasing apparent cardiac silhouette size.
- Masking clinical signs of heart disease.
Weight management is therefore an essential component of heart health in this breed.
6. Radiographic Technique
Positioning the Long Body
Proper positioning is critical in dachshunds:
- Ensure true right lateral recumbency with the sternum elevated.
- Avoid spinal curvature, which can distort vertebral landmarks.
- Extend forelimbs cranially to prevent superimposition.
Measurement Landmarks
- Long axis: from carina to cardiac apex.
- Short axis: perpendicular at the widest point.
- Begin vertebral transposition at T4 for consistency.
Tips for Accuracy
- Use the same positioning and exposure settings for follow-up studies.
- Measure during peak inspiration.
- Combine VHS with VLAS for improved sensitivity.
7. Monitoring Recommendations
Screening Schedule
- Baseline thoracic radiographs at first detection of a murmur.
- Repeat imaging every 12 months for Stage B1.
- Every 6 months for dogs approaching Stage B2.
Owner Education
Educate owners on early signs of heart disease, including cough, exercise intolerance, and increased resting respiratory rate.
8. Clinical Case
A 9-year-old neutered male dachshund presented for annual wellness examination. A grade II/VI left apical systolic murmur was noted. Thoracic radiographs revealed a VHS of 10.1 v and VLAS of 2.5 v, compared to previous values of 9.6 v and 2.2 v one year prior. Although asymptomatic, the increase prompted echocardiography, confirming Stage B2 MMVD. Pimobendan therapy was initiated, and the dog remained clinically stable 18 months later.
9. Key Takeaways
- Dachshunds are predisposed to MMVD and benefit from proactive cardiac screening.
- Normal VHS is ~9.7 ± 0.5 v, similar to the general population.
- VLAS is a sensitive marker for early left atrial enlargement.
- Consistent radiographic technique and serial measurements are essential.
- Early detection improves prognosis and quality of life.
Related Resources
- Breed-Specific VHS Comparison Chart - Compare VHS and VLAS values across multiple breeds
- VHS (Vertebral Heart Score) Complete Guide - Learn the fundamentals of VHS measurement
- VLAS (Vertebral Left Atrial Size) Guide - Understanding left atrial measurements