Introduction

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What is cardiac insufficiency?

Cardiac insufficiency is a clinical syndrome which is characterized by the inability of the heart to pump well enough to supply all the tissues of the body with blood. Since the heart and peripheral vessels are functionally a joint system, one can also use the term cardiovascular insufficiency as well as cardiac insufficiency.

There are three types of cardiac insufficiency:

  1. Left ventricle insufficiency
  2. Right ventricle insufficiency
  3. Global insufficiency

Depending on the progression of the disease, the insufficiency may be:

  • Acute
  • Chronic

Which are the causes of cardiac insufficiency?

The causes of cardiac insufficiency are multiple and include:

  • Determining factors
  • Factors which lead to the emergence of the disease

How does cardiac insufficiency?

The heart resembles a pump which distributes the blood through all the systems and organs in the body. The amount that the heart is capable of pumping every minute is termed the cardiac debit. This debit is not constant, but rather fluctuates according to the physiological needs of the organism. The capacity that the heart retains in order to increase the debit, depending on the needs of the organism, is called the cardiac reserve. In pathological cases, the potential energy of the heart is reduced, but the heart still attempts to withstand this phenomenon via the following three mechanisms:

Compensatory tachycardia

This occurs when the heart beats faster, hence increases its beat frequency (the number of beats per minute) in order to sustain the needs of organs and tissue for blood. However, this is only a temporary solution, since if the heart operates in this manner, it exhausts itself very quickly. In addition to this, the tachycardia leads to a shorter diastole (the ventricle is not completely filled with blood) which causes the systolic debit to become lower (less blood flowing to the periphery).

Enlargement (dilation) of the heart

Enlargement/dilation of the heart causes the myocardial fibres to elongate along the direction of the diastole more so than in a normal condition. According to the law of Starling, the systolic contraction is more powerful, hence the ventricles are completely empties, which is why the systolic debit is larger. This compensation mechanism has its limits, since when muscle fibres become more elongated, their contractile power is reduced.

Hypertrophy of the heart

The heart becomes hypertrophic which is the usual compensatory mechanism when the hemodynamic overload continues over a long or short period of time. Hypertrophy of the heart occurs when the myocardium fibres become thicker, while their numbers do not change. It should also be noted, that the hypertrophic fibres have upregulated needs for blood flow, but the capillary network remains unchanged.

This causes the development of a relative ischemia, which is the core of a future decompensation. When the compensatory mechanisms are capable of maintaining the cardiac debit at a level where the clinical pathological signs are not experienced, it is stated that the cardiovascular apparatus is compensated. In other cases, the compensatory mechanisms are so greatly diminished, that the heart muscle is not capable of fulfilling the tissues’ needs for blood flow, hence the clinical signs of cardiac insufficiency appear.

Medically Reviewed by a doctor on 19 Jun 2018
Medical Author: Dr. med. Diana Hysi