Heart Failure

Introduction

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.” 

Acute precipitating factors of heart failure

• Excessive Na+ intake,
• Noncompliance with heart failure
  medications,
• Acute MI (may be silent),
• Exacerbation of hypertension,
• Acute arrhythmias,
• Infections and/or fever,
• Pulmonary embolism,
• Anaemia,
• Thyrotoxicosis,
• Pregnancy,
• Acute myocarditis or infective endocarditis, and
• Certain drugs (e.g., nonsteroidal anti-inflammatory agents, verapamil).

Aetiology of Heart Failure

• Ischemic heart disease,
• Chronic obstructive pulmonary disease (COPD),
• Hypertensive heart disease
• Rheumatic heart disease
• Valvular heart disease
• Hypertension
• Cardiomyopathy; inflammatory and infiltrative cardiomyopathy
• Obesity
• Thyrotoxicosis

Classification of Heart failure

Using Left ventricle ejection fraction (LV EF):

• HF with reduced ejection fraction (HFrEF): LV EF ≤ 40% 
• HF with mildly reduced ejection fraction: LV EF 41% – 49% and evidence of HF (elevated cardiac biomarkers or elevated filling pressures)
• HF with preserved ejection fraction (HFpEF): LV EF ≥ 50% and evidence of HF (elevated cardiac biomarkers or elevated filling pressures) 
• HF with improved ejection fraction: LV EF >40%, with previously documented LV EF ≤ 40%

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:

• Class I: Symptom onset with more than ordinary level of activity
• Class II: Symptom onset with an ordinary level of activity
• Class III: Symptom onset with minimal activity
  • Class IIIa: No dyspnea at rest
  • Class IIIb: Recent onset of dyspnea at rest
• Class IV: Symptoms at rest

The American College of Cardiology/American Heart Association (ACC/AHA) staging system is defined by the following four stages:

• Stage A: High risk of heart failure but no structural heart disease or symptoms of heart failure
• Stage B: Structural heart disease but no symptoms of heart failure
• Stage C: Structural heart disease and symptoms of heart failure
• Stage D: Refractory heart failure requiring specialized interventions

Additional ACC/AHA/ and Heart Failure Society of America (HFSA) disease-staging terminology characterizes the syndrome as a continuum:

• “At risk for HF” for stage A: Applied to asymptomatic patients with risk factors such as diabetes or hypertension but no known cardiac changes
• “Pre-HF” for stage B: Adds cardiac structural changes or elevated natriuretic peptides, still in the absence of symptoms
• “Symptomatic HF” for stage C: Structural disease with current or previous symptoms
• “Advanced HF” for stage D: Characterized by severe debilitating symptoms or repeated hospitalizations even with guideline-directed medical therapy (GDMT)

Diagnosis

Symptoms: fatigue, dyspnea, orthopnea, paroxysmal nocturnal dyspnea, peripheral edema
Physical Examination: Jugular venous distention, S3, pulmonary congestion (rales, dullness over pleural effusion), peripheral edema, hepatomegaly, and ascites. Sinus tachycardia is common.
In patients with diastolic dysfunction, an S4 is often present

The Framingham criteria for the diagnosis of heart failure consists of the concurrent presence of either two major criteria or one major and two minor criteria.
Major criteria comprise the following:

• Paroxysmal nocturnal dyspnea
• Weight loss of 4.5 kg in 5 days in response to treatment
• Neck vein distention
• Rales
• Acute pulmonary edema
• Hepatojugular reflux
• S ₃ gallop
• Central venous pressure greater than 16 cm water
• Circulation time of 25 seconds or longer
• Radiographic cardiomegaly
• Pulmonary edema, visceral congestion, or cardiomegaly at autopsy

Minor criteria (accepted only if they cannot be attributed to another medical condition) are as follows:

• Nocturnal cough
• Dyspnea on ordinary exertion
• A decrease in vital capacity by one third the maximal value recorded
• Pleural effusion
• Tachycardia (rate of 120 bpm)
• Hepatomegaly
• Bilateral ankle edema

Investigations

The following tests may be useful in the evaluation

• Full blood cell (FBC) count
• Urinalysis
• Electrolyte, urea and creatinine levels
• Liver function studies
• Fasting blood glucose levels
• Lipid profile
• Thyroid stimulating hormone (TSH) levels
• B-type natriuretic peptide levels
• N-terminal pro-B-type natriuretic peptide levels
• Electrocardiography
• Chest radiography
• Two-dimensional (2-D) echocardiography

Management

Treatment includes the following:

• Nonpharmacologic therapy: Oxygen and noninvasive positive pressure ventilation, dietary sodium and fluid restriction, physical activity as appropriate, and attention to weight gain
• Pharmacotherapy: Diuretics, vasodilators, inotropic agents, anticoagulants, beta blockers, ACEIs, ARBs, CCBs, digoxin, nitrates, B-type natriuretic peptides, SGLT2Is, and MRAs

Drugs with mortality benefit in heart failure

1. SGLT-2 inhibitors (empagliflozin, canagliflozin, and dapagliflozin) significantly reduce the composite of heart failure hospitalization or cardiovascular death
2.  Sacubitril-valsartan has proven benefits in patients with an ejection fraction of less than 40%

Surgical options

Surgical treatment options include the following:

• Electrophysiologic intervention
• Revascularization procedures
• Valve replacement/repair
• Ventricular restoration
• Extracorporeal membrane oxygenation
• Ventricular assist devices
• Heart transplantation
• Total artificial heart