Heart Shape & Heart Disease in Cats
In cats, valentine-shaped hearts—those with focal enlargement of the heart base—are commonly attributed to biatrial enlargement and/or hypertrophic cardiomyopathy (HCM). This study sought to establish an association between a valentine heart shape observed in a ventrodorsal thoracic radiograph with the presence of singular or combined cardiac chamber enlargement as well as presence and type of cardiomyopathy in cats. The records of 41 cats with either a valentine-shaped heart or biatrial enlargement described on radiographs were reviewed, with the confirmation of chamber enlargement or specific cardiac disease determined by echocardiogram within 7 days of thoracic radiography. A valentine-shaped heart was strongly associated with cardiac disease (38/41). Of cats with a valentine-shaped heart, 83% (34/41) had some type of cardiomyopathy. However, there was a low association with a specific cardiomyopathy such as hypertrophic (13/34), restrictive (7/34), or unclassified (14/34).
The valentine heart shape was commonly seen in diseases causing left atrial enlargement or a combination of left atrial and left ventricular enlargement (20/41). The frequency of biatrial enlargement alone in cats with a valentine heart shape was low (2/41); however, the combination of biatrial enlargement with left and/or right ventricular enlargement occurred in 34% of cats. A valentine heart shape may not be specific for HCM or biatrial enlargement but is a strong predictor for feline cardiomyopathy in general.
Global Commentary
Diagnosing heart disease in cats can be difficult without echocardiography, but perhaps a more important priority is to identify cats at increased risk for congestive heart failure or aortic thromboembolism. Both this study and an additional study1 report a strong association between a valentine heart shape and a key predictor of cardiac death—left atrial enlargement suggesting that radiography could be used to identify high-risk cats.2 A valentine-shaped heart was not specific for cardiomyopathy with left atrial enlargement, so additional tests (eg, measuring plasma biomarker NT-proBNP) should be considered in suspected high-risk cats.3 Echocardiographic assessment of left atrial size remains the gold standard test for evaluating prognosis in cats with heart disease.—Virginia Luis Fuentes, MA, VetMB, PhD, CertVR, DVC, MRCVS, DACVIM (Cardiology), DECVIM-CA (Cardiology)
This capsule is part of the WSAVA Global Edition of Clinician's Brief.