Impact on Public health in Ontario.

There are approximately 300 hospital admissions per 100,000 population in Ontario for CHF annually. This incidence rises dramatically with age. Of these hospitalized patients 58%  are over the age of 75 years and 85% are over the age of 65 years. The average 30 day mortality for the over 75 year group is 15% and the one-year mortality is 40%. Below the age of 65 years the prognosis is much better, with a 5% 30 day and 20% one year mortality. For every hospital admission there are approximately 4 physician office visits. About 35% of patients are readmitted within 90 days of discharge.

Etiology and Pathophysiology.

Left ventricular systolic dysfunction makes up 80-90% of all patients with chronic CHF. The principal hallmark is a reduced left ventricular ejection fraction usually <40%. Coronary artery disease is responsible for 66% of all patients with LV systolic dysfunction. Other causes of non-ischemic cardiomyopathy include, Idiopathic, hypertension, alcohol, myocarditis and thyroid disease.

Evaluation of Patients.

The functional status of the patient with chronic CHF is most commonly assessed using the New York Heart Association  classification. Exercise testing, the 6 minute walk test and QOL  (quality of life) questionnaires are reserved for CHF studies.

                    NYHA I     Symptoms only at the same level as normal individuals.

                    NYHA II    Symptoms on ordinary physical exertion 

                    NYHA III   Symptoms on less than ordinary physical exertion.

                    NYHA IV   Symptoms at rest.

Assessment of the fluid status is the critical factor that determines the use of diuretics in chronic CHF. The crucial elements here are, body weight, the jugular venous pressure, pulmonary congestion and the presence and magnitude of peripheral edema. Short-term changes in fluid status is best judged by changes in body weight.

The single most important measurement in the patient with chronic CHF is the assessment of left ventricular ejection fraction. ECHO/Doppler has major advantages in this regard, since the physician obtains all the following information,

(1)   LV ejection fraction.

(2)   Dimensions, wall thickness and geometry.

(3)   Regional wall motion.

(4)   Valvular structure and function.

(5)   Diastolic function.

(6)   Pericardial disease.

Management of Congestive Heart Failure.

(A) GENERAL MEASURES

(1)    Reducing the risk of a new cardiac injury.

(a)    Cessation of smoking

(b)   Weight reduction if obese

(c)   Control of hypertension

(d)   Control of hyperlipidemia

(e)    Control of diabetes mellitus

(f)     Abstinence from alcohol

(2)   Maintenance of fluid balance

(a)   Salt restriction

(b)  Daily weight measurement

(3)   Measures to improve physical conditioning

Patients with CHF should be encouraged to engage in moderate degrees of physical exercise to prevent or reverse physical deconditioning.

(4)   Measures recommended in selected patients.

(a)   Control of ventricular response inpatients with atrial fibrillation.

(b)  Anticoagulation in patients with atrial fibrillation or a previous embolic event.

(c)  CABG especially inpatients with angina or evidence of ischemic or viable myocardium.

(5)   Other general measures.

(a)    Influenza vaccine

(b)   Pneumococcal vaccine

(6)   Pharmacologic measures to be AVOIDED.

(a)    Antiarrhythmic agents for ventricular arrhythmias in asymptomatic patients 

(b)   Calcium channel blockers

(c)   Non steriodal anti-inflammatory agents.

(B) DIURETICS

Diuretics are prescribed for patients with symptomatic CHF who have evidence of fluid retention. The goal is to eliminate signs of fluid retention without hypotension, azotemia or hypokalemia. The simplest way to monitor diuretic efficacy is daily body weight. Accurate dosing is crucial underdosing can lead to fluid retention and ACE inhibitor resistance and increase the risk of exacerbating acute heart failure with betablockers. Overdosing can lead to volume depletion increasing the likelihood of symptomatic hypotension and exacerbate renal insufficiency with ACE inhibitors. Diuretic resistance can be overcome with IV dosing or by adding metolazone to furosemide. Diuretic resistance can also be overcome by the short term use of  IV inotropes like dobutamine. NSAIDS can be a cause of diuretic resistance. SPIRONOLACTONE, Deserves special mention. Recent evidence indicates that the addition of this drug to the usual regimen of Digoxin, diuretics and ACE inhibitors reduces mortality by 28%.

(B) DIGOXIN

Digoxin is effective in patients with CHF due to LV systolic dysfunction and must be used. Measuring the digoxin level is not useful. Toxicity is a clinical  and electrocardiographic diagnosis. Digoxin does not improve survival. Survival is equivalent to placebo. Digoxin does improve symptomatic functional status and reduces the risk of rehospitalisation for CHF by 28%. 

(C) ACE INHIBITORS

All patients with CHF due to LV systolic dysfunction must receive an ACE inhibitor unless they have an intolerance or contraindication. ACE inhibitors are also effective in improving survival and delaying the onset of symptoms in patients who are asymptomatic. Symptomatic patients must be advised that improvement may not occur for weeks or even months after initiating treatment. Although clinical trials suggest that all ACE inhibitors are effective in improving  clinical outcome, preference should be given to those evaluated in large scale clinical trials. ACE inhibitors should be titrated to the doses used in such trials. Five ACE inhibitors have been approved by the FDA for treatment in chronic CHF,

(1)    Captopril.

(2)    Enalapril.

(3)    Fosinopril.

(4)    Lisinopril.

(5)    Quinapril.

(6)    Ramipril.

 (D) BETA BLOCKERS

All patients with stable class II or III CHF due to left ventricular systolic dysfunction should receive a beta blocker unless they have a contraindication to its use or have been unable to tolerate treatment with the drug. Beta blockers are now also indicated in patients with class IV chronic CHF.

(E) ANGIOTENSIN RECEPTOR BLOCKERS

These drugs are currently not approved for treatment of chronic CHF. However until further studies become available it makes intuitive sense to use this class of drugs in patients who are ACE inhibitor intolerant.

(F) CALCIUM ANTAGONISTS

Calcium antagonists should NOT be used in the treatment of chronic CHF. Because of the concerns regarding SAFETY, most calcium antagonists should not even be used for the concomitant treatment of angina or hypertension in patients with chronic CHF. The only exception is Amlodipine. There is persuasive evidence that Amlodipine does not adversely affect survival.

(G) ANTIARRHYTHMIC AGENTS

Class I antiarrhythmics should not be used. Some class III agents such as amiodarone do not increase the risk of death in patients with chronic CHF. Amiodarone is preferred for patients with atrial arrhythmias and left ventricular dysfunction. Physicians should monitor serum magnesium and potassium levels in patients with chronic CHF.

(H) ANTICOAGULANTS

Warfarin seems most appropriate in patients with chronic CHF who have either experienced an embolic event or who are in chronic atrial fibrillation.

(I) INOTROPES

All oral inotrope  studies have been universally detrimental.  Intermittent outpatient inotropic infusions cannot be recommended.

END.