Page 174 - Small Animal Internal Medicine, 6th Edition

146 PART I Cardiovascular System Disorders

BOX 7.1
VetBooks.ir Treatment Outline for Dogs With Dilated Cardiomyopathy Pimobendan (continue or add as soon as oral

Occult CM (Stage B)
Client education (about disease process and early heart administration possible)
failure signs) Consider dobutamine, especially if persistent hypotension
Routine health maintenance (see Box 3.1, p. 62)
Manage other medical problems Antiarrhythmic therapy, if necessary (e.g., lidocaine for
Pimobendan ventricular tachycardia, PO loading or IV diltiazem (or
ACE inhibitor digoxin) for uncontrolled AF, see text and Table 4.2,
±Consider β-blocker titration (e.g., atenolol or metoprolol) p. 90)
Antiarrhythmic therapy, if indicated (e.g., sotalol or Consider cautious use of a vasodilator (nitroprusside,
mexiletine for ventricular tachyarrhythmias; digoxin and hydralazine, or amlodipine) for adjunct afterload
diltiazem combination therapy for atrial fibrillation; see reduction, if necessary, and if blood pressure is not
Chapter 4) low; beware hypotension
Avoid high-salt foods; consider moderately salt-restricted Thoracocentesis, if moderate- to large-volume pleural
diet effusion
Monitor for early signs of CHF (e.g., resting respiratory Chronic Recurrent or Refractory Heart Failure
rate [see p. 74], activity level) Strategies (Stage D)*

Mild to Moderate Signs of CHF (Stage C, Chronic/ Ensure that therapies for stage C are being given at
Outpatient Care)* optimal doses and intervals, including furosemide,
Furosemide, dose as needed pimobendan, ACE inhibitor, spironolactone
Pimobendan Rule out complicating factors: arrhythmias, renal or other
ACE inhibitor metabolic abnormalities, systemic arterial hypertension,
Spironolactone anemia, and other complications
Antiarrhythmic therapy, if indicated (e.g., sotalol or Increase furosemide dose/frequency as needed (and as
mexiletine for ventricular tachyarrhythmias; digoxin and renal function allows)
diltiazem combination therapy for atrial fibrillation; see Increase pimobendan dose frequency to q8h and/or
Chapter 4) increase dose
Client education and manage concurrent problems, as Consider adding digoxin for additional inotropic support
previously mentioned Add (or increase dose of) adjunctive diuretics (e.g.,
Complete exercise restriction until after signs abate spironolactone, hydrochlorothiazide); monitor renal
Moderate dietary salt restriction function and electrolytes closely
Consider dietary supplement (fish oil, ±taurine or carnitine, Consider additional afterload reduction (e.g., amlodipine
if indicated) or hydralazine); monitor blood pressure closely
Monitor resting respiratory rate (see p. 74) ±heart rate at Strictly curtail exercise
home Further restrict dietary salt intake
Thoracocentesis (or abdominocentesis) as needed
Severe CHF Signs (Stage C, Acute/Hospitalized Care)* Hospitalize as needed for acute CHF therapy (see
Box 3.1)
Supplemental O 2 Manage arrhythmias, if present (see Chapter 4)
Cage rest and minimal patient handling
Furosemide (more aggressive doses, parenteral)
ACE, Angiotensin-converting enzyme; AF, atrial fibrillation; CHF, congestive heart failure; IV, intravenous.
*See text, Chapter 3, Tables 3.2 and 3.3 and Box 3.1 for further details and doses.

Clinical status in dogs with DCM can deteriorate rapidly, management of DCM and CHF. Pimobendan is a phospho-
so close patient monitoring is important. Respiratory rate diesterase III inhibitor that increases contractility through a
++
and character, lung sounds, pulse quality, heart rate and Ca -sensitizing effect; the drug also has vasodilator and
rhythm, peripheral perfusion, rectal temperature, body other beneficial effects. Pimobendan improves clinical signs
weight, renal function, mentation, pulse oximetry, and blood and survival in dogs with DCM and CHF. Starting dose is
pressure should be monitored. Because ventricular contrac- 0.2 to 0.3 mg/kg PO q12h. In progressive or refractory cases,
tility is abysmal in many dogs with severe DCM, these pimobendan dose can be uptitrated to 0.5 mg/kg PO q8h.
patients have little cardiac reserve; diuretic and vasodilator This higher dose recommendation is outside of the FDA
therapy can lead to hypotension and even cardiogenic shock. approved labeling for pimobendan, and such off-label use
Long-term therapy should be explained to and approved by the client.
Pimobendan (Vetmedin, Boehringer Ingelheim Vetmed- Furosemide is used at the lowest effective oral dosage for
ica) is the oral positive inotrope of choice for long-term long-term therapy (see Table 3.3). Hypokalemia and other