Diagnosis and Treatment of Heart Failure / Classifications of Heart Failure

Diagnosis and Treatment of Heart Failure in 2010 

Introduction:

Chronic heart failure (CHF) traditional therapy (for CHF secondary to chronic degenerative valvular disease etc.) still provides a guarded prognosis. Though current standard treatment regimens provide a good quality of life for many canine patients, complications can lead to early patient loss. Ongoing congestion or syncope can be concerns, sudden death due to arrhythmias, or client-elected euthanasia due to poor quality of life may also lead to loss.

Pathophysiology:

Eccentric ventricular hypertrophy is associated with reduced left ventricular systolic function. Reduced cardiac output results in lethargy and exercise intolerance. Mitral regurgitation is associated with progressive annular dilation in the valve during advanced disease, in association with progressive cardiomegaly.

Treatment:

Combination therapy is essential and must be customized to each patient. Different stages of heart failure, and differences in types of failure depending on breed, etiology, and concurrent illness make it necessary to fine tune therapy both on a per-patient basis, and within the patient, to adjust therapy based on response or non-response during the treatment timeline.

The choice of drugs is dependent on the stage of the clinical heart failure:

·               Asymptomatic

·               Mild to Moderate

·               Advanced

Classifications of Heart Failure

Asymptomatic Heart Disease. At this level, a cardiac murmur or an ultrasound diagnosis of heart disease has occurred, but clinical signs are absent. Re-evaluation is the standard, and medication is not required. Some of these patients benefit from a lower-salt diet, such as a kidney diet.

Mild to Moderate Heart Failure. Clinical signs of heart failure are evident at rest or during mild exercise, and begin to interfere with normal activities. Typical signs include:

·               Dyspnea +/- tachypnea

·               Exercise intolerance

·               Cough

·               Mild to moderate ascites.

We often recommend starting therapy at home. Mitral valvular endocardiosis patients for example, generally receive diuretic therapy, ACEI therapy, sodium-restricted diets, and pimobendan in the moderate cases of heart failure.

Dilated cardiomyopathy is best treated with pimobendan, digitalis (especially those with atrial fibrillation), diuretics, ACEI, Na-restricted diets, pimobendan, Omega-3 fatty acids, taurine nutraceuticals (especially for Cocker Spaniels), +/- a beta blocker.

Advanced Heart Failure. Clinical signs of advanced congestive heart failure are obvious, and include:

·               Dyspnea

·               Marked ascites

·               Severe exercise intolerance

·               Hypo-perfusion at rest.

Hospitalization is mandatory for most patients, at least until stabilized.

Treatment for advanced heart failure includes ACEI, oxygen therapy, aggressive diuretic therapy, topical nitroglycerin ointments, digitalis (if atrial arrhythmias), and in really advanced cases, one would add either dobutamine or sodium nitroprusside. New cardiac drugs, such as pimobendan, are also indicated.

Most dogs with heart failure should receive an ACEI, such as benazepril (Fortekor®), a diuretic (furosemide), and pimobendan. Digoxin is indicated when there is an atrial arrhythmia, especially atrial fibrillation.

Triple Therapy in Advanced Heart Failure is the Current Approach to Treating heart Failure: Benazepril, Furosemide, and Pimobendan. Omega-3 Fatty Acids are also important in every case.

Fonte:  CANINE & FELINE Cardiology

                  DIAGNOSIS & TREATMENT

                  Larry P. Tilley, DVM, DACVIM (Internal Medicine)

                  Santa Fe, New Mexico