Congestive Heart Failure

Congestive heart failure (CHF), as defined by the American College of Cardiology (ACC) and the American Heart Association (AHA), is "a complex clinical syndrome that results from any structural or functional impairment of ventricular filling or ejection of blood.” Ischemic heart disease is the leading cause of death worldwide and also the leading cause of CHF. CHF is a common disorder worldwide with a high morbidity and mortality rate. With an estimated prevalence of 26 million people worldwide, CHF contributes to increased healthcare costs, reduces functional capacity, and significantly affects quality of life. It is imperative to diagnose and effectively treat the disease to prevent recurrent hospitalizations, decrease morbidity and mortality, and enhance patient outcomes.

The etiology of heart failure (HF) is variable and extensive. The general management aims at relieving systemic and pulmonary congestion and stabilization of hemodynamic status, regardless of the cause. The treatment of HF requires a multifaceted approach involving patient education, optimal medication administration, and decreasing acute exacerbations.

Left ventricle ejection fraction (LV EF) is used to classify HF.

1. HF with reduced ejection fraction (HFrEF): LV EF ≤ 40%

2. HF with mildly reduced ejection fraction: LV EF 41% - 49% and evidence of HF (elevated cardiac biomarkers or elevated filling pressures)

3. HF with preserved ejection fraction (HFpEF): LV EF ≥ 50% and evidence of HF (elevated cardiac biomarkers or elevated filling pressures)

4. HF with improved ejection fraction: LV EF >40%, with previously documented LV EF ≤ 40%

Patients with HFpEF have traditionally been underdiagnosed but comprise between 44% and 72% of CHF cases. On echocardiogram (echo), LV EF ≥ 50% with evidence of impaired diastolic function. The most significant risk factor is hypertension (HTN), and other risk factors include older age, female sex, and diabetes.

The ACC and the AHA together classify HF by stages, with the first 2 stages being asymptomatic and the second 2 being classified by severity of symptoms.

ACC/AHA Heart Failure Stages

1. Stage A: At risk for HF. No symptoms, structural heart disease, or evidence of elevated cardiac biomarkers, but risk factors are present. Risk factors include hypertension, diabetes, metabolic syndrome, cardiotoxic medications, or having a genetic variant for cardiomyopathy.

2. Stage B: Pre-HF. Patients have no signs or symptoms of HF but have structural heart disease, evidence of elevated filling pressures (by invasive or noninvasive assessment), or persistently elevated cardiomarkers in the absence of other reasons for elevated markers, like chronic kidney disease or myocarditis.

3. Stage C: Patients with structural heart disease and current or past history of HF symptoms.

4. Stage D: Patients with refractory symptoms that interfere with daily life or recurrent hospitalization despite targeted guideline-directed medical therapy.

The New York Heart Association Functional Classification is used for patients with symptoms of HF. This system is subjectively determined by clinicians and is widely used in clinical practice to direct therapy.

New York Heart Association Functional Classification

Based on symptoms, the patients can be classified using the New York Heart Association (NYHA) functional classification as follows:

1. Class I: Symptom onset with more than ordinary level of activity

2. Class II: Symptom onset with an ordinary level of activity

3. Class III: Symptom onset with minimal activity

4. 1. Class IIIa: No dyspnea at rest

   2. Class IIIb: Recent onset of dyspnea at rest

5. Class IV: Symptoms at rest