Cardiogenic shock (CS) is a medical emergency resulting from inadequate blood flow due to the dysfunction of the
ventricles of the
heart
The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as ca ...
.
[Textbooks of Internal Medicin]
Harrison's Principles of Internal Medicine
16th Edition, The McGraw-Hill
McGraw Hill is an American educational publishing company and one of the "big three" educational publishers that publishes educational content, software, and services for pre-K through postgraduate education. The company also publishes refere ...
Companies
Cecil Textbook of Medicine
by Lee Goldman, Dennis Ausiello, 22nd Edition (2003), W. B. Saunders Company
The Oxford Textbook of Medicine
Edited by David A. Warrell, Timothy M. Cox and John D. Firth with Edward J. Benz, Fourth Edition (2003), Oxford University Press
Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print book ...
, [Shock: An Overview](_blank)
PDF by Michael L. Cheatham, MD, Ernest F.J. Block, MD, Howard G. Smith, MD, John T. Promes, MD, Surgical Critical Care Service, Department of Surgical Education, Orlando Regional Medical Center
Orlando Regional Medical Center (ORMC) is an 808-bed tertiary hospital in downtown Orlando, Florida designed by HKS, Inc. (architect) and Walter P Moore (structural engineer). It is the flagship of the Orlando Health system.
Background
ORMC is al ...
Orlando, Florida Signs of inadequate blood flow include low urine production (<30 mL/hour), cool arms and legs, and altered level of consciousness. People may also have a severely low blood pressure and heart rate.
Causes of cardiogenic shock include
cardiomyopathic, arrhythmic, and mechanical. CS is most commonly precipitated by
acute myocardial infarction. People can have combined types of shock.
Treatment of cardiogenic shock depends on the cause with the initial goals to improve blood flow to the body. This can be done in a number of ways—fluid resuscitation, blood transfusions, vasopressors, and ionotropes. If cardiogenic shock is due to a
heart attack
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
, attempts to
open the heart's arteries may help. An
intra-aortic balloon pump
The intra-aortic balloon pump (IABP) is a mechanical device that increases myocardial oxygen perfusion and indirectly increases cardiac output through afterload reduction. It consists of a cylindrical polyurethane balloon that sits in the aorta, ...
or
left ventricular assist device may improve matters until this can be done.
Medications that improve the heart's ability to contract (positive inotropes) may help; however, it is unclear which is best and at present there is no convincing evidence supporting
inotropic
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term ''inotro ...
or
vasodilating therapy to reduce mortality in
hemodynamically unstable patients.
Norepinephrine
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad ...
may be better if the blood pressure is very low whereas
dopamine or
dobutamine may be more useful if only slightly low.
Cardiogenic shock is a condition that is difficult to fully reverse even with an early diagnosis. With that being said, early initiation of mechanical circulatory support, early
percutaneous coronary intervention,
inotropes, and
heart transplantation may improve outcomes.
Care is directed to the dysfunctional organs (dialysis for the kidneys, mechanical ventilation for lungs dysfunction).
Mortality rates have been decreasing in the United States. This is likely due to the rapid identification and treatment of the CS. Some studies have suggested that this possibly related to the increased use of coronary reperfusion strategies, like heart stents. Nonetheless, the mortality rates remain high. Multi-organ failure is associated with higher rates of mortality.
Signs and symptoms
The presentation is the following:
* Anxiety, restlessness,
altered mental state
An altered state of consciousness (ASC), also called altered state of mind or mind alteration, is any condition which is significantly different from a normal waking state. By 1892, the expression was in use in relation to hypnosis, though there ...
due to decreased blood flow to the brain and subsequent
hypoxia.
*
Low blood pressure due to decrease in
cardiac output.
* A rapid, weak, thready pulse due to decreased circulation combined with tachycardia.
* Cool, clammy, and mottled skin (
cutis marmorata) due to vasoconstriction and subsequent hypoperfusion of the skin.
* Distended
jugular veins due to increased
jugular venous pressure.
*
Oliguria (low urine output) due to inadequate blood flow to the kidneys if the condition persists.
* Rapid and deeper respirations (hyperventilation) due to sympathetic nervous system stimulation and acidosis.
*
Fatigue due to
hyperventilation and hypoxia.
* Absent pulse in fast and
abnormal heart rhythms.
*
Pulmonary edema
Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due ...
, involving fluid back-up in the lungs due to insufficient pumping of the heart.
Causes
Cardiogenic shock is caused by the failure of the heart to pump effectively. It is due to damage to the
heart muscle, most often from a
heart attack
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...
or
myocardial contusion.
Other causes include
abnormal heart rhythms,
cardiomyopathy,
heart valve problems, ventricular outflow obstruction (i.e. systolic anterior motion (SAM) in
hypertrophic cardiomyopathy), or ventriculoseptal defects. It can also be caused by a sudden decompressurization (e.g. in an aircraft), where air bubbles are released into the bloodstream (
Henry's law), causing
heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
.
[Cardiogenic shock](_blank)
Department of Anaesthesia and Intensive Care of The Chinese University of Hong Kong
Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China (abbr. Hong Kong SAR or HKSAR), is a List of cities in China, city and Special administrative regions of China, special ...
[Introduction to management of shock for junior ICU trainees and medical students](_blank)
Department of Anaesthesia and Intensive Care of The Chinese University of Hong Kong
Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China (abbr. Hong Kong SAR or HKSAR), is a List of cities in China, city and Special administrative regions of China, special ...
Diagnosis
Electrocardiogram
An
electrocardiogram helps to establish the exact diagnosis and guides treatment, it may reveal:
*
Abnormal heart rhythms, such as
bradycardia
Bradycardia (also sinus bradycardia) is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, ...
(slowed heart rate)
* myocardial infarction (ST-elevation MI,
STEMI, is usually more dangerous than
non-STEMI
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may tra ...
s; MIs that affect the ventricles are usually more dangerous than those that affect the atria; those affecting the left side of the heart, especially the left ventricle, are usually more dangerous than those affecting the right side, unless that side is severely compromised)
* Signs of
cardiomyopathy
Echocardiography
Echocardiography may show poor ventricular function, signs of PED, rupture of the
interventricular septum
The interventricular septum (IVS, or ventricular septum, or during development septum inferius) is the stout wall separating the ventricles, the lower chambers of the heart, from one another.
The ventricular septum is directed obliquely backwar ...
, an obstructed outflow tract or cardiomyopathy.
File:UOTW 7 - Ultrasound of the Week 2.webm, Ultrasound showing cardiogenic shock due to myocarditis[
File:UOTW 7 - Ultrasound of the Week 3.webm, Ultrasound showing cardiogenic shock due to myocarditis][
]
Swan-Ganz catheter
The
Swan–Ganz catheter or pulmonary artery catheter may assist in the diagnosis by providing information on the
hemodynamics.
Biopsy
When cardiomyopathy is suspected as the cause of cardiogenic shock, a
biopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...
of heart muscle may be needed to make a definite
diagnosis
Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine "cause and effect". In systems engin ...
.
Cardiac index
If the
cardiac index Cardiac index (CI) is a haemodynamic parameter that relates the cardiac output (CO) from left ventricle in one minute to body surface area (BSA), thus relating heart performance to the size of the individual. The unit of measurement is litres per mi ...
falls acutely below 2.2 L/min/m
2, the person may be in cardiogenic shock.
Treatment
Depending on the type of cardiogenic shock, treatment involves infusion of fluids, or in shock refractory to fluids,
inotropic
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term ''inotro ...
medications. In case of an
abnormal heart rhythm immediate synchronized cardioversion or anti-arrhythmic agents may be administered, e.g.
adenosine.
Positive
inotropic
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction.
The term ''inotro ...
agents (such as dobutamine or
milrinone), which enhance the heart's pumping capabilities, are used to improve the contractility and correct the low blood pressure. Should that not suffice an
intra-aortic balloon pump
The intra-aortic balloon pump (IABP) is a mechanical device that increases myocardial oxygen perfusion and indirectly increases cardiac output through afterload reduction. It consists of a cylindrical polyurethane balloon that sits in the aorta, ...
(which reduces
workload for the heart, and improves perfusion of the
coronary arteries
The coronary arteries are the arterial blood vessels of coronary circulation, which transport oxygenated blood to the heart muscle. The heart requires a continuous supply of oxygen to function and survive, much like any other tissue or organ ...
) or a left
ventricular assist device (which augments the pump-function of the heart) can be considered.
Mechanical ventilation
Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for using a machine called a ventilator to fully or partially provide artificial ventilation. Mechanical ventilation helps move a ...
or
ECMO may be used to help stabilize people with severe or refractory cardiogenic shock until they can be given some type of definitive treatment, such as a ventricular assist device.
Finally, as a last resort, if the person is stable enough and otherwise qualifies,
heart transplantation, or if not eligible an
artificial heart
An artificial heart is a device that replaces the heart. Artificial hearts are typically used to bridge the time to heart transplantation, or to permanently replace the heart in the case that a heart transplant (from a deceased human or, exper ...
, can be placed. These invasive measures are important tools—more than 50% of patients who do not die immediately due to cardiac arrest from a lethal abnormal heart rhythm and live to reach the hospital (who have usually experienced a severe acute myocardial infarction, which in itself still has a relatively high mortality rate), die within the first 24 hours. The mortality rate for those still living at time of admission who develop complications (among others, cardiac arrest or further abnormal heart rhythms,
heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...
,
cardiac tamponade, a ruptured or dissecting aneurysm, or another heart attack) from cardiogenic shock is even worse around 85%, especially without drastic measures such as ventricular assist devices or transplantation.
Cardiogenic shock may be treated with intravenous
dobutamine, which acts on β
1 receptors of the heart leading to increased contractility and heart rate.
[Rang and Dale's Pharmacology, H. P. Rang, M. M. Dale, J. M. Ritter, R. J. Flower, Churchhill Livingstone, Elsevier, 6th Edition]
References
External links
Cardiogenic Shockby
eMedicine
{{DEFAULTSORT:Cardiogenic Shock
Heart diseases
Medical emergencies
Intensive care medicine
ja:心停止