Page 103 - Small Animal Internal Medicine, 6th Edition

CHAPTER 3 Management of Heart Failure 75

and can precipitate congestive signs. It is important to char- Suggested Readings
acterize the type and severity of the arrhythmia to guide Pathophysiology of Heart Failure
VetBooks.ir treatment. Effective antiarrhythmic therapy can help control Cunningham SM, Rush JE, Freeman LM. Systemic inflammation
CHF signs. For AF, therapy is adjusted to maintain a heart
and endothelial dysfunction in dogs with congestive heart failure.
rate of <140 or 150 beats/min in the hospital, or between 80
J Vet Intern Med. 2012;26:547–557.
and 110 beats/min at home, (for example, by a gradual Freeman LM, et al. Antioxidant status and biomarkers of oxidative
increase in diltiazem dosage, and using serum digoxin con- stress in dogs with congestive heart failure. J Vet Intern Med.
centration measurement to optimize digoxin dose; see 2005;19:537–541.
Chapter 4 for additional information). Referral to a veteri- Mochel JP, Danhof M. Chronobiology and pharmacologic modula-
nary cardiologist, or internist with extensive experience tion of the renin-angiotensin-aldosterone system in dogs: what
have we learned? Rev Physiol Biochem Pharmacol. 2015;169:
managing CHF, is encouraged and appropriate for patients 43–69.
with advanced cardiac disease and CHF. Specialty consulta- Scollan KF, Sisson DD. Pathophysiology of heart failure. In: Ettinger
tion can help further characterize the patient’s cardiac status SJ, Feldman EC, Cote E, eds. Textbook of veterinary internal medi-
and any complicating factors, optimize therapy, and provide cine. 8th ed. St. Louis: Elsevier; 2017:1153–1163.
support with ongoing patient care. Spratt DP, et al. Cardiac troponin I: evaluation of a biomarker for
Refractory, stage D, heart failure is considered to be the diagnosis of heart disease in the dog. J Small Anim Pract.
present when the patient requires over 8-12 mg/kg/day of 2005;46:139–145.
furosemide to control edema, despite other standard heart Tidholm A, Haggstrom J, Hansson K. Vasopressin, cortisol, and
failure therapy previously outlined. Acute pulmonary edema catecholamine concentrations in dogs with dilated cardiomyopa-
requiring hospitalization is managed as outlined in Box 3.1. thy. Am J Vet Res. 2005;66:1709–1717.
Additional strategies for chronic CHF management are Therapy of Heart Failure
described here; they usually are instituted one at a time (not Adin DB, et al. Intermittent bolus injection versus continuous infu-
necessarily in the order presented) so that effectiveness can sion of furosemide in normal adult greyhound dogs. J Vet Intern
be evaluated. As always, therapy must be tailored for the Med. 2003;17:632–636.
individual patient’s needs. Additional afterload reduction Atkins C, et al. Guidelines for the diagnosis and treatment of canine
(amlodipine or hydralazine) can be helpful for dogs with chronic valvular heart disease. (ACVIM Consensus Statement).
MR and sometimes DCM; start with low doses and gradually J Vet Intern Med. 2009;23:1142–1150.
titrate the dose upward as needed, while monitoring blood Atkins CE, et al. Results of the veterinary enalapril trial to prove
pressure. An arteriolar vasodilator is not recommended reduction in onset of heart failure in dogs chronically treated
with enalapril alone for compensated, naturally occurring mitral
for cats with HCM or dogs with fixed ventricular outflow valve insufficiency. J Am Vet Med Assoc. 2007;231:1061–1069.
obstruction (e.g., subaortic stenosis). Pimobendan dosing Bernay F, et al. Efficacy of spironolactone on survival in dogs with
frequency can be increased to every 8 hours, or dosage raised naturally occurring mitral regurgitation caused by myxomatous
up to 0.4 to 0.5 mg/dose. For most cats with refractory CHF, mitral valve disease. J Vet Intern Med. 2010;24:331–341.
pimobendan can be added to therapy or its dosage increased. Bonagura JB, Lehmkuhl LB, de Morais HA. Fluid and diuretic
For dogs with severe pulmonary hypertension and collapse therapy in heart failure. In: DiBartola SP, eds. Fluid, electrolyte,
episodes or right-sided CHF signs, addition of sildenafil and acid-base disorders in small animal practice. 4th ed. St Louis:
(1-2 mg/kg q12h PO) can reduce clinical signs. Modifica- Elsevier Saunders; 2012:514.
tion of diuretic therapy can be helpful for dogs that require Boswood A, et al. Effect of pimobendan in dogs with preclinical
very high furosemide doses. Torsemide can be used instead myxomatous mitral valve disease and cardiomegaly: the EPIC
of furosemide, beginning at a total daily dose (mg) that is study—a randomized clinical trial. J Vet Intern Med. 2016;30:
1765–1779.
1 12 to 1 10 of the total furosemide dose being given per day. Boyle KL, Leech E. A review of the pharmacology and clinical uses
An alternate strategy, if torsemide is not used, is the addi- of pimobendan. J Vet Emerg Crit Care. 2012;22:398–408.
tion of a third diuretic (thiazide) to furosemide and spi- Chetboul V, et al. Comparative adverse cardiac effects of pimoben-
ronolactone; however, very conservative dosing and close dan and benazepril monotherapy in dogs with mild degenerative
attention to renal function and electrolytes are necessary mitral valve disease: a prospective, controlled, blinded, and ran-
because severe derangements can develop quickly. Digoxin, domized study. J Vet Intern Med. 2007;21:742–753.
if not previously used and not contraindicated, might be Edwards TH, et al. Outcome of positive-pressure ventilation in
useful for additional inotropic support and its barorecep- dogs and cats with congestive heart failure: 16 cases (1992-2012).
tor sensitizing effect. More stringent dietary salt restric- J Vet Emerg Crit Care. 2014;24:586–593.
tion can be tried; however, it is important to support the Esposito CT, et al. Spironolactone improves the arrhythmogenic
patient’s appetite and food intake. Dogs without pulmonary substrate in heart failure by preventing ventricular electrical
activation delays associated with myocardial interstitial fibro-
edema that persistently have a dry cough associated with sis and inflammation. J Cardiovasc Electrophysiol. 2013;24:
bronchomalacia and/or main bronchus compression from 806–812.
marked LA enlargement often benefit from a cough suppres- Freeman LM. Cachexia and sarcopenia: emerging syndromes of
sant. For dogs with concurrent airway disease, a broncho- importance in dogs and cats. J Vet Intern Med. 2012;26:3–17.
dilator also might be helpful as long as it does not provoke Freeman LM. Beneficial effects of omega-3 fatty acids in cardiovas-
tachyarrhythmias. cular disease. J Small Anim Pract. 2010;51:462–470.