Cardiovascular System (CVS)

Heart failure (HF)

Clinical syndrome caused by structural and functional defects in myocardium resulting in impairment of ventricular filling or the ejection of blood.

Clinical syndrome caused by structural and functional defects in myocardium resulting in impairment of ventricular filling or the ejection of blood.


Global distribution:

Global epidemiology of heart failure
Global epidemiology of heart failure. | Choi, H. M., Park, M. S., & Youn, J. C. (2019). Update on heart failure management and future directions. The Korean journal of internal medicine, 34(1), 11–43.

Rule of halves:

Rule of halves for ventricular dysfunction and for heart-failure therapy
Rule of halves for ventricular dysfunction and for heart-failure therapy | Ventricular dysfunction: about half of patients with systolic dysfunction receive treatment for chronic heart failure and half of these seem to receive appropriate therapy. Heart-failure therapy: only about half of patients who receive heart-failure therapy have left-ventricular dysfunction on investigation and only half of these are on appropriate therapy | Cleland, JGF. Screening for left ventricular dysfunction and chronic heart failure: should it be done and if so, how?. Dis Management Health Outcomes. 1997; 1: 169–184


Based on functional status of heart:

Based on left ventricular ejection fraction (LVEF)
  • HF with preserved ejection fraction (HFpEF): Normal LVEF (≥ 50%)
    • Normal LV volume , but LV wall is thickened and stiff; hence ↑ ratio of LV mass/end-diastolic volume
  • HF with reduced ejection fraction (HFrEF): ↓ LVEF (< 40%)
    • Dilated LV, and normal/↓ LV mass/end-diastolic volume ratio
  • HF with mid-range ejection fraction (HFmrEF): LVEF 40-49%
    • LV cavity is typically dilated, and the ratio of LV mass/end-diastolic volume is either normal or reduced.

New York Heart Association (NYHA) functional classification:

Classifies heart failure by symptom severity
The New York Heart Association (NYHA) functional classification
The New York Heart Association (NYHA) functional classification is based on the amount of activity needed to elicit symptoms from the patient. | Functional Classification of Heart Failure: Jorge Muniz, PA-C

American College of Cardiology (ACC)/American Heart Association (AHA) working group classification:

Describes stages of evolution of heart failure
American College of Cardiology/American Heart Association Classification of Heart Failure
American College of Cardiology/American Heart Association Classification of Heart Failure | Ramani, G. V., Uber, P. A., & Mehra, M. R. (2010). Chronic heart failure: contemporary diagnosis and management. Mayo Clinic proceedings, 85(2), 180–195.


Low output failure (common):

Characterized by insufficient forward cardiac output, particularly during times of increased metabolic demand.
  • LV dysfunction d/t large MI
  • RV dysfunction d/t acute pulmonary embolus
  • Biventricular dysfunction

High-output failure (uncommon):

This occurs as a result of ineffective blood volume and pressure, which stimulate the sympathetic nervous system and renin-angiotensin-aldosterone system (RAAS), causing the release of antidiuretic hormone (ADH), which all together ultimately lead to ventricular enlargement, negative ventricular remodeling and HF.

Characterized by resting cardiac index > 2.5–4.0 L/min/m2 and low systemic vascular resistance.

  • Severe anemia
  • Vascular shunting
  • Hyperthyroidism
  • Vitamin B1 deficiency

More than two-thirds of all cases of HF are attributable to ischemic heart disease, COPD, hypertensive heart disease, and rheumatic heart disease.

Coronary artery disease (CAD): > 70% of cases

Chronic and acute ischemia causes direct damage to myocardium leading to remodeling and scar formation, resulting in inadequate relaxation in diastole and impaired contraction in systole, which decreases contractility and cardiac output (CO)
  • Myocardial infarction (MI): Causes dyssynchronous contraction of the infarcted segment, subsequent remodeling of the ventricle, ventricular dilatation with annular dilation, and mitral regurgitation that predispose to HF and decrease the CO
  • Tachyarrhythmias (atrial fibrillation/atrial flutter or non sustained ventricular tachycardia) is common in patients with CAD and can deteriorate the cardiac function more

Hypertension (HTN):

HTN is an independent risk factor for CAD. HTN increases vascular resistance and activates the renin-angiotensin-aldosterone system (RAAS) resulting in a higher afterload, which increases myocardial mass as a compensatory mechanism to maintain a normal CO and that causes left ventricular hypertrophy (LVH). If blood pressure (BP) remains uncontrolled, apoptosis and fibrosis may result. LVH increases the myocardial stiffness and can cause ischemia, which leads to HFpEF or HFrEF.

Chronic obstructive pulmonary disease (COPD):

COPD increases the risk of CAD and other smoking-related illnesses, cardiac dysrhythmias, and can cause pulmonary hypertension and right heart failure.

Valvular heart disease:

Aortic and pulmonary stenosis increases the ventricular afterload and may cause HF. In valve regurgitation, a persistent volume overload can cause ventricular enlargement and functional impairment that may lead to HF.
  • Degenerative valve disease (developed countries)
  • Rheumatic valve disease (low-income countries)

Cardiomyopathies (CMP):

Functional and structural heart muscle abnormalities in the absence of CAD, HBP, valvular, or congenital heart disease. CMP can cause HFrEF, HFpEF, or HFmrEF.
  • Dilated cardiomyopathy (DCM)
  • Hypertrophic cardiomyopathy (HCM)
  • Restrictive cardiomyopathy (RCM)
  • Arrhythmogenic right ventricular cardiomyopathy (ARVC)
  • Unclassified cardiomyopathies (isolated noncompaction of the left ventricle [INLV] and Takotsubo syndrome).

Other precipitating causes:

  • Infections (especially pneumonia)
  • Anaemia
  • Alcohol excess
  • Iatrogenic cause (eg. postoperative fluid replacement or administration of steroids or NSAIDs)
  • Poor drug compliance, especially in antihypertensive treatment
  • Thyrotoxicosis
  • Pregnancy


Heart failure (HF)­
Heart failure (HF)­ is defined as the inability of the heart to provide sufficient output to meet the metabolic demands of the body. There are many possible etiologies. Low output failure occurs with conditions associated with impaired cardiac contractility, impaired cardiac filling, excess afterload, or arrhythmias. High output failure describes a condition in which the signs and symptoms of heart failure occur in the setting of increased cardiac output, reduced systemic vascular resistance, and increased metabolic demand. Compensatory mechanisms develop to improve cardiac output, but in time these responses only serve to exacerbate the underlying cardiac problem. | Jorge Muniz/Medcomic

Left-sided heart failure:

Left heart failure pathogenesis
The Calgary Guide |

Right-sided failure:

Right heart failure
The Calgary Guide |

Neurohormonal activation:

Neurohormonal systems, which are normally stimulated under conditions of acute volume depletion, are activated by the low cardiac output and arterial pressure. However, sustained and chronic activation of these systems, as occurs in congestive heart failure (CHF), can cause progressive ventricular remodeling and worsening heart failure.

Principal neurohumoral systems involved in the response to HF:

  • Sympathetic (adrenergic) nervous system (SNS)
  • Renin–angiotensin–aldosterone system (RAAS): Maintain cardiac output through increased retention of salt and water,
  • Antidiuretic hormone (ADH)
Left heart failure neurohormonal activation

Systolic dysfunction:

Due to poor left ventricular (LV) contraction, usually expressed as ejection fraction (EF)

Diastolic dysfunction (common in elderly):

Normal LV ejection fraction; the defect seems to lie in relaxation of the left ventricle and is associated with delayed filling
Systolic dysfunctionDiastolic dysfunction
↓ EFPreserved EF
↑ EDVNormal EDV
↓ contractility often 2° to ischemia/MI or dilated cardiomyopathy.↓ compliance (↑ EDP) often 2° to myocardial hypertrophy.
Systolic vs diastolic heart failur
The terms “systolic dysfunction” and “diastolic dysfunction” refer to abnormalities in the mechanical function of the heart during contraction and relaxation. In the context of heart failure, the terms represent clinical syndromes that include the signs and symptoms of heart failure (e.g. systolic heart failure, diastolic heart failure) | Heart Failure: Systolic vs. Diastolic Dysfunction: Jorge Muniz, PA-C


Typical features:

Symptoms are more severe with exertion
  • Symptoms secondary to fluid accumulation:
    • Dyspnea, orthopnea
    • Oedema
    • Abdominal discomfort (hepatic congestion)
    • Ascites (in the setting of right heart failure)
  • Symptoms due to decreased cardiac output:
    • Fatigue, anorexia, and weakness

Atypical symptoms:

  • Nocturnal cough
  • Loss of appetite
  • Wheezing
  • Palpitations
  • Depression
  • Dizziness, syncope
  • Bendopnea (short of breath while bending forward)
Left-sided failureFailure of either sideRight-sided failure





Rales in chest

Cardiac enlargement


Gallop rhythm (S3)

Peripheral cyanosis

Small volume pulse

Lack of weight gain (children)

Hepatomegaly (nutmeg liver)


Jugular venous engorgement

Peripheral oedema

Left heart failure findings on history
The Calgary Guide |

Physical examination:

  • Resting sinus tachycardia, diaphoresis, narrow pulse pressure (< 25 mmHg d/t ↓ CO)
  • Peripheral vasoconstriction (cool and pale extremities d/t ↓ perfusion)
  • Volume overload manifestations:
    • Peripheral edema (extremities edema, ascites, scrotal edema, and hepatosplenomegaly)
    • ↑ Jugular venous pressure (JVP)
    • Pulmonary congestion (rales on examination and pleural effusions)
  • Sign of LV enlargement: Displaced apical impulse (laterally past the midclavicular line)
  • Sign of RV enlargement: Parasternal lift
  • S3 gallop
Left heart failure physical examination findings
The Calgary Guide |



  • Atrial fibrillation
  • Ventricular arrhythmias (ventricular tachycardia/fibrillation)
  • Bradyarrhythmias


  • Stroke
  • Peripheral embolism
  • Deep venous thrombosis (DVT)
  • Pulmonary embolism

Gastrointestinal complications:

  • Hepatic congestion
  • Hepatic dysfunction
  • Malabsorption

Musculoskeletal complications:

  • Muscle wasting

Respiratory complications:

  • Pulmonary congestion
  • Respiratory muscle weakness
  • Pulmonary hypertension (rare)


Chest X-ray:

Useful in evaluating heart size, pulmonary congestion and to detect alternative cardio-pulmonary diseases that may cause or contribute to the patient’s symptoms
Chest radiograph of an lung with distinct Kerley B lines, as well as an enlarged heart
Chest radiograph of an lung with distinct Kerley B lines, as well as an enlarged heart (as shown by an increased cardiothoracic ratio, cephalization of pulmonary veins, and minor pleural effusion as seen for example in the right horizontal fissure. Yet, there is no obvious lung edema. Overall, this indicates intermediate severity (stage II) heart failure. | By Mikael Häggström – CC0,
Left heart failure CXR findings
The Calgary Guide |

Transthoracic echocardiography (TTE):

Useful in providing immediate information, including systolic and diastolic function of LV and right ventricle (RV), chamber size, wall thickness, and valve abnormalities.

Differential diagnosis:

  • Cardiac arrest and asystole: No cardiac output at all → Sudden death (without treatment)
  • Myocardial infarction (“Heart attack“): Heart muscle damage due to insufficient blood supply, usually as a result of a blocked coronary artery. 
  • Cardiomyopathy: Problems within the heart muscle, resulting in heart failure.
    • Ischemic cardiomyopathy: Cause of muscle damage is coronary artery disease. 
    • Dilated cardiomyopathy: Muscle damage has resulted in enlargement of the heart. 
    • Hypertrophic cardiomyopathy: Enlargement and thickening of the heart muscle


Four-pronged management principle:

  1. Reducing cardiac load
  2. Augmenting myocardial contractility
  3. Improving cardiac performance
  4. Correcting underlying cause
tepwise approach to heart failure care.
Stepwise approach to heart failure care. | ACC = American College of Cardiology; ACEI = angiotensin-converting enzyme inhibitor; AHA = American Heart Association; ARB = angiotensin II receptor blocker; CRT = cardiac resynchronization therapy; ICD = implantable cardioverter-defibrillator; LVAD = left ventricular assist device; NYHA = New York Heart Association. | Ramani, G. V., Uber, P. A., & Mehra, M. R. (2010). Chronic heart failure: contemporary diagnosis and management. Mayo Clinic proceedings, 85(2), 180–195.

Medical management:

First-line: Diuretics (↓ volume overload to improve symptoms) + [angiotensin system blocker (ACEi, ARB, or ARNI) or hydralazine + nitrate] + beta-blocker
  • Diuretics (thiazides, loop diuretics and potassium sparing) + salt restriction: Reduce oedema by reduction of blood volume and venous pressure for symptomatic relief
  • Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs): Neuro-hormonal modification, vasodilatation and improvement in LVEF
    • Alternative (if unresponsive): Hydralazine ± nitrates
  • β-adrenergic blockers: Neuro-hormonal modification, improvement in symptoms and LVEF, survival benefit, arrhythmia prevention and control of ventricular rate
  • Aldosterone antagonists: Adjunct to other drugs for additive diuresis, heart failure symptom control, improved heart rate variability, decreased ventricular arrhythmias, reduction in cardiac workload, improved LVEF and an increase in survival
  • Digoxin: Small increase in cardiac output, improvement in heart failure symptoms and a decreased rate of heart failure hospitalizations
  • Anticoagulants: Decrease risk of thromboembolism
  • Inotropic agents: Restore organ perfusion and reduce congestion in patients with heart failure with reduced ejection fraction, so as to increase in cardiac output and reduce neuro-humoral activation
Treating Congestive Heart Failure

Leave a Reply

%d bloggers like this: