Cardiogenic shock, also known as cardiac shock, happens when the heart cannot pump enough blood and oxygen to the brain and other vital organs. This is a life-threatening emergency. Without oxygen-rich blood reaching the brain and other vital organs, blood pressure drops, and the pulse slows.

Most often the cause of cardiogenic shock is a serious heart attack. Other health problems that may lead to cardiogenic shock include heart failure, which happens when the heart can’t pump enough blood to meet the body’s needs; chest injuries; and blood clots in the lungs.

Treatment focuses on getting blood flowing properly and protecting organs from damage. Some people may need a heart transplant or a permanently implanted device to help keep blood flowing to the heart. If not treated quickly, cardiogenic shock can be fatal or lead to organ failure or brain injury.

Symptoms of cardiogenic shock vary, depending on how quickly and how low the blood pressure drops. Cardiogenic shock may start with symptoms such as confusion or rapid breathing, or a person may have no symptoms and then suddenly lose consciousness. 

The most common signs of cardiogenic shock are:

• Low blood pressure, which can to complaints of dizziness, confusion, nausea and altered mental status
• Weak or irregular pulse

Symptoms of cardiogenic shock may include:

• Breathing problems, including fast breathing and severe shortness of breath
• Bulging veins in the neck
• Clammy skin
• Cold hands and feet
• Fever
• Loss of consciousness
• Swelling of feet
• Urinating much less than usual or not at all
• Cardiac arrest

Many of these symptoms develop because the heart does not deliver enough blood to the body’s tissues and organs. For example, as blood pressure drops during cardiogenic shock, the body tries to compensate by limiting blood flow to the hands and feet, causing them to cool down.

As blood flow to the brain drops, the person may become confused or lose consciousness. The kidneys may shut down, producing less urine. Reduced blood flow in the lungs may lead to fluid buildup there, making it hard to breathe.

Causes of Cardiogenic Shock

• Atherosclerosis – Atherosclerosis is the buildup of fats, cholesterol and other substances in and on the artery walls. This buildup is called plaque. The plaque can cause arteries to narrow, blocking blood flow. Further, this condition can result in the interference with the circulatory system’s constant dilation and constriction of blood vessels (to maintain blood pressure). Atherosclerosis can result in complete occlusion of blood vessels, which can lead to ischemia (cell hypoxia due to decreased blood flow).
• Rate Related Compromise – Tachycardias and bradycardias can both result in decreased cardiac output. Paramedics spend much time learning how to identify and treat rate related conditions (either speeding up the rate or slowing it down).
• Inadequate pumping – Years of atherosclerosis and multiple heart attacks can result in the patient experiencing a weakened left ventricle and due to pressure of continuous flow of blood through the heart, will stretch and lose it’s elasticity. When the left ventricle becomes enlarged, it’s ability to pump blood is reduced. Once the left ventricle becomes compromised and prone to failure (inability of heart to eject all of the blood), the right ventricle will fail. When the right ventricle fails to eject all of the blood with each contraction, the result is blood pooling in the extremities.
• Inappropriate circulating volume – Too much circulating blood volume (dialysis patient comes to mind) or too little circulating volume can result in cardiogenic shock. The heart is first and foremost a pump. Pumps are always designed to move a specific volume of blood with each contraction.