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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 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

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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, , , Kerry blue Cough , Labrador retriever, Maltese, miniature In addition to cardiac disease, coughing can and toy , 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, , English , 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, , Samoyed cheitis, tracheal collapse, and compression of mainstem bronchi by left atrial enlargement Pulmonic stenosis Airedale terrier, American cocker spaniel, basset , 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, , miniature tive cough and gagging. Cats with bronchial pinscher, miniature , Newfoundland, disease can experience episodic coughing, Samoyed, Scottish terrier, West Highland white expiratory wheezes, and dyspnea. A soft, terrier, and other 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, , 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, , 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 , 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 , 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 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 , 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

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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 disease. The Vertebral Heart Scale (VHS) provides an objective method for measuring cardiac size in Laboratory Studies dogs. Starting with the cranial edge of the 4th Baseline laboratory studies should be per- thoracic vertebrae: formed on all patients with suspected cardiac disease to identify other underlying disease VHS = (number of vertebral bodies processes that may affect diagnosis and treat- equivalent to long cardiac axis) ment. + (number of vertebral bodies equivalent to short cardiac axis) CBC Increased turbulent blood flow resulting from decreased blood viscosity can be caused by In dogs, normal VHS is 9.7 +/- 0.5 vertebral anemia and results in a physiologic murmur. bodies.14 Studies have shown significant Increased leukocytes may indicate infections breed variation in VHS scores, with chondro- such as endocarditis and myocarditis; these dystrophic breeds having a greater VHS.15 diagnoses should be considered in patients that also have fever, marked lethargy, and a newly diagnosed murmur.

To read more about calculating VHS, Serum Chemistry Profile read by Stacey Vertebral Heart Scale Chronic kidney disease can affect treatment Fox-Alvarez, DVM, MPH, and Amara options and prognosis in patients with heart Estrada, DVM, DACVIM (Cardiology), at cliniciansbrief.com/article/ disease. Increased liver enzyme values may vertebral-heart-scale be seen in patients with right-sided heart fail- ure and in cats with hyperthyroidism.

Urinalysis Urinalysis and urine culture should be per- formed to further assess renal function and Echocardiography is the most evaluate for other underlying disease. accurate diagnostic tool for Thyroid Testing most forms of heart disease. In middle-aged and geriatric cats, hyper- thyroidism is a common cause of cardiac

82 cliniciansbrief.com May 2017 VETORYL® CAPSULES (trilostane) 5 mg, 10 mg, 30 mg, 60 mg and 120 mg strengths Adrenocortical suppressant for oral use in dogs only.

BRIEF SUMMARY (For Full Prescribing Information, see package insert.)

CAUTION: Federal (USA) law restricts this drug to murmurs. Total T4 values should of heartworm antibody and antigen use by or on the order of a licensed veterinarian. be obtained from cats in these age tests is recommended. DESCRIPTION: VETORYL Capsules are an orally groups with a newly diagnosed active synthetic steroid analogue that blocks production of hormones produced in the adrenal murmur. Cardiac Biomarker Tests cortex of dogs. Measurement of NT-proBNP and INDICATION: VETORYL Capsules are indicated for the treatment of pituitary- and adrenal-dependent Heartworm Test cardiac troponin can provide infor- hyperadrenocorticism in dogs.

A heartworm antigen test should mation about myocardial damage CONTRAINDICATIONS: The use of VETORYL Capsules is contraindicated in dogs that have be conducted in any dog with sus- (eg, as in hypertrophic cardiomy- demonstrated hypersensitivity to trilostane. Do not pected heart disease, especially if opathy) and may help determine use VETORYL Capsules in animals with primary hepatic disease or renal insufficiency. Do not use in coughing is a clinical sign. Heart- the significance of murmurs in pregnant dogs. Studies conducted with trilostane in laboratory animals have shown teratogenic effects worm disease typically only causes cats. Patient-side snap tests for and early pregnancy loss. a murmur in patients with caval NT-proBNP have been helpful in WARNINGS: In case of overdosage, symptomatic treatment of hypoadrenocorticism with syndrome, a condition in which differentiating between cardiac and corticosteroids, mineralocorticoids and intravenous fluids may be required. Angiotensin converting worms present in the pulmonary noncardiac causes of respiratory enzyme (ACE) inhibitors should be used with caution artery ascend to the right ventricle distress in cats. The test can be per- with VETORYL Capsules, as both drugs have aldosterone-lowering effects which may be additive, and become intertwined with the formed using pleural fluid obtained impairing the patient’s ability to maintain normal electrolytes, blood volume and renal perfusion. tricuspid valve. Because testing for by thoracocentesis, which may elim- Potassium sparing diuretics (e.g. spironolactone) should not be used with VETORYL Capsules as heartworms in cats can be diagnos- inate the need for blood testing and both drugs have the potential to inhibit aldosterone, tically challenging, a combination its associated stress.16 n increasing the likelihood of hyperkalemia. HUMAN WARNINGS: Keep out of reach of children. Not for human use. Wash hands after use. Do not empty capsule contents and do not attempt to divide the capsules. Do not handle the capsules if pregnant or if trying to conceive. Trilostane is associated with teratogenic effects and early pregnancy loss in References laboratory animals. In the event of accidental 1. Olson LH, Häggström J, Petersen HD. 2016. Accessed on Veterinary Information ingestion/overdose, seek medical advice immediately Acquired valvular heart disease. In: Ettinger Network, April 18, 2017. and take the labeled container with you. SJ, Feldman EC, eds. Textbook of Veterinary 9. Hohnadel K. Acquired cardiac disease of Internal Medicine PRECAUTIONS: Hypoadrenocorticism can develop . 7th ed. St. Louis, MO: the dog: disease process, treatment, and at any dose of VETORYL Capsules. A small Saunders Elsevier; 2010:1299-1319. prognosis. Presented at: ACVIM Conference; percentage of dogs may develop corticosteroid 2. Meurs KM. Myocardial disease: canine. In: 2011. Accessed on Veterinary Information withdrawal syndrome within 10 days of starting Ettinger SJ, Feldman EC, eds. Textbook of Network, April 18, 2017. treatment. Mitotane (o,p’-DDD) treatment will reduce Veterinary Internal Medicine. 7th ed. St. Louis, 10. Davies C, Shell L. Cough. In: Davies C, Shell L, adrenal function. Experience in foreign markets MO: Saunders Elsevier; 2010:1320-1327. eds. Common Small Animal Medical Diagnoses: suggests that when mitotane therapy is stopped, an interval of at least one month should elapse before 3. MacDonald K. Myocardial disease: feline. In: An Algorithmic Approach. Saunders; 2002. the introduction of VETORYL Capsules. The use of Ettinger SJ, Feldman EC, eds. Textbook of Accessed on Veterinary Information Network, VETORYL Capsules will not affect the adrenal tumor Veterinary Internal Medicine. 7th ed. St. Louis, April 18, 2017. itself. Adrenalectomy should be considered as an MO: Saunders Elsevier; 2010:1328-1341. 11. Ferasin L, Crews L, Biller DS, Lamb KE, option for cases that are good surgical candidates. Borgarelli M. Risk factors for coughing in dogs The safe use of this drug has not been evaluated in 4. Strickland KN. Congenital heart disease. lactating dogs and males intended for breeding. In: Tilley LP, Smith Jr FWK, Oyama MA, with naturally acquired myxomatous mitral Sleeper MM, eds. Manual of Canine and Feline valve disease. J Vet Intern Med. 2013;27(2):286- ADVERSE REACTIONS: The most common adverse Cardiology. 4th ed. St. Louis, MO: Saunders 292. reactions reported are poor/reduced appetite, Elsevier; 2008:218. 12. Charalambous M, Gomes SA, Papageorgiou S, vomiting, lethargy/dullness, diarrhea, elevated liver enzymes, elevated potassium with or without 5. Nelson RW, Couto CG. Congenital cardiac Orioles M. Epileptic seizures versus syncope: pathophysiology and clinical approach. elevated sodium, elevated BUN, decreased Na/K disease. In: Nelson RW, Couto CG, eds. Small ratio, weakness, elevated creatinine, shaking, and Veterinary Evidence Animal Internal Medicine. 5th ed. St. Louis, MO: . 2017;2(1):103. renal insufficiency. Occasionally, more serious Elsevier; 2014:97. 13. Pion P. Cardiology: making the diagnosis. reactions, including severe depression, hemorrhagic 6. Kittleson MD, Kienle RD. The approach to the Presented at: Atlantic Coast Veterinary diarrhea, collapse, hypoadrenocortical crisis or patient with cardiac disease. In: Kittleson MD, Conference; 2001. Accessed on Veterinary adrenal necrosis/rupture may occur, and may result in death. Kienle RD, eds. Small Animal Cardiovascular Information Network, April 18, 2017. Medicine. Maryland Heights, MO: Mosby 14. Buchanan JW, Bücheler J. Vertebral Elsevier; 2005. Accessed on Veterinary scale system to measure canine heart Information Network, April 18, 2017. size in radiographs. J Am Vet Med Assoc. 7. Côté E, MacDonald KA, Meurs KM, Sleeper 1995;206(2):194-199. MM. Hypertrophic cardiomyopathy. In: Côté E, 15. Jepsen-Grant K, Pollard RE, Johnson LR. MacDonald KA, Meurs KM, Sleeper MM. Atrial Vertebral heart scores in eight dog breeds. Vet Distributed by: Dechra Veterinary Products septal defects. Feline Cardiology. Hoboken, NJ: Radiol Ultrasound. 2013;54(1):1740-8261. 7015 College Boulevard, Suite 525 Wiley-Blackwell; 2011:104-106. 16. Borgeat K, Connolly DJ, Luis Fuentes V. Cardiac Overland Park, KS 66211 8. Fuentes V. Breed-related cardiomyopathy biomarkers in cats. J Vet Cardiol. 2015;(17 Suppl VETORYL is a trademark of in cats. Presented at: ECVIM-CA Conference; 1):S74-S86. Dechra Ltd. © 2015, Dechra Ltd. NADA 141-291, Approved by FDA

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