Heart failure is often called congestive heart failure. It is a clinical syndrome rather than a heart disease on its own. During a persisting heart disease, such as pathological hypertrophy caused by long-term hypertension, the heart develops a depressed workforce and increased venous pressure. These changes in hemodynamics lead to molecular changes, such as activation of different signalling pathways and death of cardiomyocytes. As a result the heart progresses from the initial disease state to a failing heart. Heart Failure can be further categorised into different subtypes (systolic/diastolic heart failure and backward/forward failure).



Cause:

  • Pathological hypertrophy
  • Heart attack

 

Molecular/biological characteristics:

  • Heart size ↑ or ↔
  • Heart function ↓
  • Cardiomyocyte cell size ↑ or ↔
  • Fibrosis ↑
  • Apoptosis ↑

 

Symptoms:

  • Fatigue
  • Shortness of breath
  • Drowsiness
  • Insomnia
  • Cough
  • Anxiety
  • Depression

 

Treatment:

Surgical implantation of the left ventricular assist device (LVAD):

  • It is used for mechanical unloading of the heart (usually left ventricle) and thereby restores normal blood flow.
  • It increases the survival rate of patients with end-stage heart failure while waiting for a donor heart (sometimes up to 2 years).
  •  Some hearts recover on their own which may take from days to 1 year of usage.
  • The long-term effects of using LVAD are still uncertain.

Medication to decrease blood pressure such as:

  •  Angiotensin-converting enzyme inhibitors = ACEIs  (ACE converts angiotensinI to angiotensinII which constricts blood vessels)
  • Angiotensin receptor blockers (inhibitors) = ARBs (by using them angiotensin is unable to dock at its receptors -> reduced constriction of blood vessels)
  • β(beta)-blockers (lower blood pressure by blocking noradrenaline-> lower heart beat and less force on heart)
  • Loop diuretics (have natriuretic effects by causing sodium excretion)

 

Note:

Heart failure is sometimes categorised as acute or chronic heart failure. Acute heart failure includes 'urgent' symptoms such as difficulty in breathing, tachycardia (fast heart beat) and pulmonary or peripheral oedema (fluid retention in lungs or extremities). In contrast, chronic heart failure is characterised by symptoms that may develop over a longer period of time due to the acute symptoms such as persistent cardiac dysfunction, limited exercise abilities and pathophysiological changes to other organs.

Systolic heart failure versus diastolic heart failure

Systolic and diastolic heart failures are two clinical subsets of heart failure. The difference between both types usually relies on differences in ejection fraction:

Ejection fraction = Amount of blood pumped out of LV ventricle / Total amount of blood in LV ventricle





Backward failure versus forward failure

The definition of heart failure is further divided into backward and forward failure. Backward failure is characterised by increased systemic venous pressure in the right heart side and increased pulmonary venous pressure in the left heart side. For example, development of fluid retention raises the workload and thereby worsens backward failure.

In contrast, forward failure shows a reduced blood flow volume (ejection) into the aorta (left heart side) and pulmonary artery (right heart side). Forward heart failure worsens by increased vasoconstriction which further reduces the ejection. In contrast, vasodilators improve it.

 

Note:

Backward failure and forward failure can NOT exist on their own: Impaired filling reduces ejection and impaired ejection causes reduced filling.



Literature

Chatterjee K, Massie B. Systolic and diastolic heart failure: differences and similarities. Journal of cardiac failure. 2007;13:569-76.

De Keulenaer GW, Brutsaert DL. Systolic and diastolic heart failure are overlapping phenotypes within the heart failure spectrum. Circulation. 2011;123:1996-2004.

http://www.ncbi.nlm.nih.gov/books/NBK2218/

http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001211/

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