PROCEDURES PRO h CARDIOLOGY h PEER REVIEWED The Clinical Cardiology History & Diagnostics Wendy W. Mandese, DVM Amara H. Estrada, DVM, DACVIM (Cardiology) University of Florida For a comprehensive outline of the cardiology with dilated cardiomyopathy occurring most often.2 physical examination, see The Basic Cardiology In cats, more than 60% of heart disease cases are caused by hypertrophic cardiomyopathy.3 Dogs and cats Examination by Drs. Mandese and Estrada on may be presented with subclinical signs or emergently. page 91. Clinical signs vary depending on the species, disease process, and stage of cardiac disease. Recognizing subclinical heart disease in a healthy patient can be challenging. When heart disease is Because clinical signs of cardiac disease can be subtle, suspected, a patient may be referred to a board-certifi ed obtaining a complete history is essential. Th e history cardiologist for diagnosis and treatment; however, spe- should include specifi c questions about signs that the cialist care may not be an option for all patients because client might not associate with heart disease. of limited client fi nances, inconvenience of multiple vet- erinary appointments, and distance required to travel to Signalment a specialty practice. Primary care veterinarians should Age be profi cient in performing cardiology evaluations and Clinical signs of cardiac disease in puppies and kittens examinations to establish diff erential and defi nitive may indicate a physiologic or congenital disease pro- diagnoses in patients with cardiac conditions. cess. Puppies and kittens with a physiologic heart mur- mur do not show clinical signs of cardiac disease; the Valvular disease accounts for 75% to 80% of canine murmur in these patients is low grade (grade 1-2/6) and heart disease cases1 and is especially prevalent in small resolves before adulthood. Th e murmurs are usually breeds. Myocardial disease is also common in dogs, systolic and loudest along the left sternal border.4 May 2017 cliniciansbrief.com 79 PROCEDURES PRO h CARDIOLOGY h PEER REVIEWED Breed TABLE 1 Many purebred dogs or cats are predisposed to specific congenital and/or acquired cardiac COMMON BREED PREDILECTIONS FOR 5-9 diseases (Tables 1 and 2). Certain breeds may CONGENITAL CARDIAC ABNORMALITIES benefit from screening (eg, auscultation, ECG, echocardiogram) during annual exam- inations. Clients should be educated about Congenital Abnormality Breed Predisposition potential clinical signs. Patent ductus arteriosus American cocker spaniel, bichon frise, History Chihuahua, collie, English springer spaniel, German shepherd dog, keeshond, Kerry blue Cough terrier, Labrador retriever, Maltese, miniature In addition to cardiac disease, coughing can and toy poodle, Newfoundland, Pomeranian, be a sign of another disease process. Cough- Shetland sheepdog, Welsh corgi, Yorkshire ing after eating or drinking suggests laryn- terrier geal dysfunction. Nocturnal coughs occur with cardiac insufficiency, pulmonary edema, Subaortic stenosis Bouvier des Flandres, boxer, English bulldog, 10 German shepherd dog, German shorthaired and psychogenic conditions. If the cough is pointer, golden retriever, Great Dane, a dry hack or a goose-like honk, consider tra- Newfoundland, rottweiler, Samoyed cheitis, tracheal collapse, and compression of mainstem bronchi by left atrial enlargement Pulmonic stenosis Airedale terrier, American cocker spaniel, basset hound, beagle, Boykin spaniel, boxer, or masses. Infectious tracheobronchitis or Chihuahua, chow chow, English bulldog, fox chronic bronchitis in dogs causes a produc- terrier, Labrador retriever, mastiff, miniature tive cough and gagging. Cats with bronchial pinscher, miniature schnauzer, Newfoundland, disease can experience episodic coughing, Samoyed, Scottish terrier, West Highland white expiratory wheezes, and dyspnea. A soft, terrier, and other terriers and spaniels moist cough suggests pneumonia, parasitic Tetralogy of Fallot English bulldog, keeshond or allergic disease, pulmonary thromboem- bolism, or edema.10 Atrial septal defect Boxer, Doberman pinscher, Samoyed, and Chartreux, domestic shorthair, Persian If coughing at home has been noted, the cli- Ventricular septal defect English bulldog, English springer spaniel, ent should be asked what induces the cough keeshond, West Highland white terrier, and (eg, exercise, excitement), about the quality cats of the cough (eg, dry, productive, moist), and how often the cough occurs. Clients often do Mitral valve dysplasia Bull terrier, dalmatian, German shepherd dog, golden retriever, Great Dane, mastiff, not report coughing in cats but may report Newfoundland, rottweiler, and cats that the patient is gagging or retching, which sometimes progresses to vomiting. Thoracic Tricuspid valve dysplasia Boxer, German shepherd dog, golden retriever, radiographs should be obtained to determine Great Dane, Labrador retriever, old English if the cough is cardiogenic. Radiographic sheepdog, Weimaraner, and cats findings that indicate cardiomegaly (specifi- Persistent right aortic German shepherd dog, Great Dane, Irish setter cally, left atrial enlargement causing upward arch compression of the trachea and mainstem bronchi) may indicate a cardiac cause. In older, small-breed dogs, which are most com- monly affected by congestive heart failure and airway disease (eg, tracheal collapse, 80 cliniciansbrief.com May 2017 chronic bronchitis), an airway cause for the TABLE 2 cough should always be ruled out before diag- nosing a cardiac cause. Pulmonary edema COMMON BREED PREDILECTIONS FOR may be present radiographically in dogs with ACQUIRED CARDIAC ABNORMALITIES5-9 congestive heart failure but is unlikely to cause cough unless fluid accumulation is severe enough to build up in the airways.11 Acquired Abnormality Breed Predisposition (Dogs & Cats) Activity Level Cardiac disease can be an underlying cause of Cardiac German shepherd dog, golden retriever hemangiosarcoma decreased activity and energy levels, and patients may have difficulty resting comfort- Arrhythmogenic Boxer, English bulldog ably or may seem anxious and unable to relax. right ventricular cardiomyopathy (boxer Collapse Episodes cardiomyopathy) Syncope can be seen secondary to cardiac dis- Aortic and carotid body Boston terrier, boxer ease and is defined as a sudden, transient loss tumors of consciousness originating from a short- term interruption of blood perfusion and oxy- Dilated cardiomyopathy Afghan hound, American cocker spaniel, boxer, dalmatian, Doberman pinscher, Great Dane, genation to the brain. It is characterized by Irish wolfhound, Newfoundland, Portugese sudden onset, short duration, and sponta- water dog, Saint Bernard, Scottish deerhound neous recovery.12 Recovery can be so rapid that owners sometimes mistake the episodes for Hypertrophic American shorthair, Birman, British shorthair, clumsiness or tripping. Collapse episodes can cardiomyopathy Maine coon, Norwegian forest, Persian, ragdoll, Siamese, sphynx also be caused by neurologic incidents or sei- zures; determining whether collapse is caused Sick sinus syndrome Miniature schnauzer by seizure activity or syncope can be difficult. In general, syncopal episodes are more often Myxomatous All small-breed dogs are at risk, especially atrioventricular valve American cocker spaniel, Boston terrier, associated with excitement and exercise, and degeneration Cavalier King Charles spaniel, Chihuahua, signs are less likely to occur leading up to the dachshund, fox terrier, miniature pincher, event. These episodes are usually of a shorter miniature schnauzer, Pekingese, Pomeranian, duration (1-2 seconds), and patients are also toy and miniature poodle, whippet less likely to have signs following the event.12 Other causes of collapse episodes include ane- mia and orthopedic disease. Diagnostics Appetite & Normal Behavior Imaging A decrease in appetite or normal behavior, Radiography can be used to assess general- such as normal grooming behavior and ized cardiomegaly and chamber enlargement. desire to play or go for walks, can be an early Subjectivity, technique, and patient shape sign of cardiac disease. and size can limit the value of radiography, and obtaining diagnostic images can be chal- lenging in cats, brachycephalic (ie, short- For an overview of the physical chested) dogs, and obese patients. Proper examination for the patient with potential technique is important, as a film obtained on cardiac disease, see page 91. expiration or with the patient incorrectly May 2017 cliniciansbrief.com 81 PROCEDURES PRO h CARDIOLOGY h PEER REVIEWED positioned can result in an inaccurate cardiac An ECG should be performed in any patient silhouette and lead to misinterpretation. in which an arrhythmia is detected, includ- ing bradycardia or sustained tachycardia. An Radiography is most useful for detecting ECG ideally should be performed in conjunc- sequelae to cardiac dysfunction, such as great tion with echocardiography to determine the vessel enlargement, pulmonary edema, and underlying cause of the arrhythmia. pleural effusion.13 It can also help rule out other causes of coughing (eg, primary pulmo- Echocardiography should be used to assess nary disease, collapsing trachea) and can be chamber size and contractility of the heart valuable in assessing changes consistent with and to obtain information about cardiac anat- heartworm disease in dogs. omy and function. Echocardiography is the most accurate diagnostic tool for most forms Determining cardiac size can be subjective. of heart