heart failure

HEART FAILURE

Heart failure can result from any structural or functional cardiac disorder that impairs ability of ventricle to fill with or eject blood.

 Heart failure is a complex clinical syndrome that results from structural or functional impairment of ventricular filling or ejection of blood, which in turn leads to the cardinal symptoms of dyspnoea , fatigue  and other signs of HF, namely edema and rales. The term “heart failure” is preferred over the older term “congestive heart failure” because many patients present without signs or symptoms of volume overloaded.HF is a burgeoning problem worldwide, with more than 20 million people affected.The overall prevalence of HF in the adult population in developed countries is 2% whereas very little is known about the prevalence risk of developing HF in emerging nations because of the lack of population based studies in these countries. HF prevalence follows an exponential pattern, rising with age, and affects 6-10% of people over age 65.The relative incidence of HF is lower in women than in men.HF was once thought to arise primarily in the setting of a depressed left ventricular ejection fraction; however, epidemiological studies have shown that approximately one-half of patients who develop HF have normal or preserved Ejection fraction (50%).

HF patient are now broadly categorized into:

HF with reduced Ejection fraction (HFrEF; formerly systolic failure) and

HF with a preserved Ejection fraction (HRpEF; formerly diastolic failure)

ETIOLOGIES OF HEART FAILURE

Depressed Ejection fraction (<40%)

Coronary artery disease
1.Myocardial infraction
2.Myocardial ischemia
In the industrialized countries, CAD has become the predominant cause in men and women and
is responsible for 60-75% of cases of HF.

Chronic pressure overload
1.Hypertension
2.Obstructive valvular disease
Hypertension contributes to the development of HF in 75% of patient.

Chronic volume overload
1.Regurgitant valvular disease
2.Intracardiac (left to right) shunting
3.Extracardia shunting

Chronic lung disease
1.Cor pulmonale
2.Pulmonary vascular disorder

Nonischemic dilated cardiomyopathy
1.Familial/genetic diorders
2.Infiltrative disorders
20-30% of the cases of HF with a depressed EF, the exact etiologic basis is not known.
These cases are refer as nonischemic, dilated, or idiopathic cardiyomyopathy.
Large no. of cases of dilated cardiomyopathy are secondary to specific genetic defects, most notably
those in cytoskeleton.

Toxic /drug - induced damage
1.Metabolic disorder
2.Viral
 prior viral infection or toxic exposure also may lead to dilated cardiomyopathy.

Chagas’ disease

Disorder of rate and rhythm
1.Chronic bradyarrhythmias
2.Chronic trachyarrhythmias

Preserved ejection fraction (>40-50%)

Pathologic hypertrophy

1.Primary (hypertrophic cardiyomyopathies)

2.Secondary (hypertension)

Aging

Restrictive cardiomyopathy

1.Infiltrative disorder (amyloidosis, sarcoidosis)

2.Storage disease (hemochromatosis)

Fibrosis

Endomyocardial disorders

High – output states

Metabolic disorders - Thyrotoxicosis

Excessive blood flow requirements

1.Systemic arteriovenous  shunting

2.Chronic anemia

Nutritional disorders (beriberi)

New York Heart Association  Classification

Class I

patients with cardiac disease but without resulting limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitations, dyspnea, or anginal pain.

Class II

patients with cardiac disease resulting in slight limitation of physical activity. They are comfortable at rest. Ordinary physical activity result in fatigue, palpitation, dyspnea, or anginal pain.

Class III

 patients with cardiac disease resulting in marked limitation of physical activity. They are comfortable at rest. Less than ordinary activity causes fatigue, palpitation, dyspnea or anginal pain.

Class IV

 Symptoms of congestive heart failure are present, even at rest. With any physical activity increased discomfort is experienced (symptomatically ‘severe’ heart failure)