Management ofChronic Congestive Heart Failure
After discharge, frequency of revisits is determined by the stability of the patient and response to treatment. With standard cases, it is common to extend the reexamination period.
Typically cases are seen at one week, one month, and then every 3 months indefinitely. At the reevaluations, blood samples are taken to assess electrolyte levels and renal function. Blood pressure should also be checked. Other tests such as chest radiographs, echocardiography, and ECG are only requested if there is a change in the patient's condition as tests are only indicated if they change the prognosis or the treatment recommendations.Patients with congestive left heart failure are usually discharged with:
• Diuretics: Furosemide is the usual diuretic at 0.5-2 mg/kg PO TID-BID. The dose range is adjusted to control the resting breathing rate to less than 40 per minute at rest. Higher doses of diuretics are required to get heart failure under control than to maintain control. As a result the initial dose can be decreased with time and the owner's cooperation in monitoring and dose adjustment is vital for long-term management. The main side effects are increased thirst and urination but dehydration and electrolyte depletion can be seen at higher doses especially if the patient becomes anorexic. Ultimately, renal failure can develop and this can be a dose limiting consequence.
• Calcium inodilator: Pimobendan causes vasodilation via phosphodiesterase 3 action and the positive inotropic action is due to increasing the affinity of troponin C for calcium. In both DCM and degenerative valve disease, pimobendan has been shown to extend survival times. Dose are 0.1-0.3mg∕kg BID but the top end of the dosage range is preferred. The drug should not be administered with food as this will limit absorption.
• ACE inhibitor: ACEi have been shown to prolong life in dogs with DCM and degenerative valve disease.
Furosemide and heart failure are potent stimuli of the renin-angi- otensin-aldosterone system. Increased angiotensin II has a number of deleterious effects including water and sodium conservation, vasoconstriction and myocardial remodeling. Enalapril at 0.5 mg/kg SID to BID and benazepril at 0.25-0.5 mg/kg SID are the common agents used although ramapril and quinapril are also available in some countries.• Spironolactone: This potassium sparing diuretic is used mainly for its anti-aldoster- one action. Aldosterone levels increase in heart failure due partly to elevated angiotensin II levels. Although the evidence for the use of aldosterone antagonists is not complete, it is compelling enough to warrant its inclusion. These drugs prolong life but are unlikely to cause a significant change in clinical signs. As a result, they do not have to be added at the initial stages but rather at the one week or one month recheck, especially with client who may become confused with multiple medications and administration times. This drug is fat soluble so administration with food increases absorption.
Other drugs are added as required - see specific diseases.