Conventional wisdom in feline medicine is that a ‘valentine’-shaped heart noted on thoracic radiography is a feature of hypertrophic cardiomyopathy (HCM). A ‘valentine’ heart shape is the terminology used to describe a cardiac silhouette with focal enlargement at the level of the base of the heart in patients.
The authors have not found any prior study that assesses the relationship between cardiac chamber enlargement and cardiac disease with the ‘valentine’-shaped heart. With this study, their goal was to evaluate by echocardiography the association between a ‘valentine’ heart shape on ventrodorsal thoracic radiographs and single or multiple chamber enlargement(s) with the presence and type of cardiomyopathy (CM) in cats. Their hypothesis was that the ‘valentine’ heart shape is not specifically associated with feline HCM or with specific chamber enlargement.
Forty-one cats met the inclusion criteria for the study and the median age of the cats in the study was 11 years. It was noted that the median age of cats (12 years) affected with cardiomyopathies was significantly higher compared to cats without cardiomyopathies (6 years). In this population of cats with a ‘valentine’-shaped heart noted, 83% (34/41) were diagnosed with some form of CM. Therefore, this specific cardiac silhouette is strongly associated with cardiac disease. Where the ‘valentine’ heart shape was most commonly seen was in diseases causing LA (left atrium) enlargement or a combination of LA and LV (left ventricle) enlargement (20/41). While biatrial enlargement alone numbers were low, the combination of with LV or RV (right ventricle) enlargement occurred in 34 % of the study population. Unclassified hypertrophic cardiomyopathy (UCM) and HCM were the most common types of cardiomyopathy found in this group of cats.
The study’s findings indicate that recognition of a ‘valentine’ heart shape should not lead directly to a specific diagnosis of HCM or to the assumption of biatrial enlargement. Yet, a large majority of the cats in this study did have some form of cardiomyopathy, just not specifically HCM. It should be noted that a ‘valentine’ –shaped heart could be viewed occasionally in cats without true cardiac enlargement and even more rarely seen in cats without atriomegaly.
Gretchen Singletary, DVM, DACVIM (Cardiology) presented on this topic - it's approved for 1 hour of CE credit and is available for viewing on demand: Feline Heart Disease - Tips for Maximizing Your Diagnostic Capability.
