Cardiogenic shock: symptoms, causes, treatment and survival

Shock in medicine does not mean emotional shock. It means that the circulation is failing to deliver enough blood and oxygen to the body. In cardiogenic shock, the cause is the heart itself. A UK clinical reference describes failure of the pump action of the heart, with reduced cardiac output and reduced blood flow to the organs, despite there being enough blood in the circulation.

An NHS hospital trust's patient information explains that blood carries oxygen and energy to organs like the brain, kidneys and liver, and that when the heart cannot pump properly these organs do not get what they need to work normally. Cardiogenic shock can quickly progress to multi-organ failure and death, which is why urgent treatment is needed to diagnose and reverse it.

It differs from other kinds of shock, such as that caused by severe infection (septic shock) or heavy bleeding, in that the problem is not too little fluid in the circulation but a heart that cannot move it. The distinction matters because the treatments differ, and the clinical reference lists the other causes that doctors must rule out as they assess a patient.

The trust says the body shows signs of poor blood flow. The clinical reference notes that symptoms and signs can present abruptly or develop over many hours, and that because many patients have had a heart attack, chest pain, nausea and vomiting, breathlessness, profuse sweating, confusion, palpitations and faintness are all possible.

• Very low blood pressure.

• Cold, pale or clammy skin, sometimes mottled.

• A fast heartbeat.

• Breathing problems, or needing oxygen or a ventilator.

• Confusion, drowsiness or reduced consciousness.

• Low urine output, passing very little urine.

• Chest pain, which is not always present.

Cardiogenic shock is not something to manage at home. The NHS advice on heart attack says to call 999 if you have chest pain that feels tight or like squeezing, chest pain that spreads to the arms, neck or jaw, severe difficulty breathing, pale, blue or grey lips or skin, or if someone has passed out and is not responding normally. It says not to drive yourself to A&E.

While waiting for help the NHS suggests sitting down and resting in a comfortable position, taking aspirin (300mg) if you have it and are not allergic, and using your GTN spray if you have angina. If someone stops responding and stops breathing, start CPR. The NHS signposts St John Ambulance for how to do this.

The trust explains that treatment focuses on supporting the heart and other organs while the cause is treated, with the trust describing a monitored acute cardiac care unit. The clinical reference says the broad areas are assessing airway, breathing and circulation and ventilating if needed, gaining intravenous access and giving fluids if necessary, continuous monitoring including urine output, investigations to find the cause, inotropic support and symptom relief, and treating the underlying cause, for example with revascularisation after a heart attack.

The trust lists the common causes: a heart attack that damages a large part of the heart, severe heart failure, problems with the heart valves, dangerous heart rhythm problems, inflammation of the heart muscle (myocarditis) and complications after heart surgery.

The clinical reference adds mechanical complications of a heart attack such as acute mitral regurgitation, rupture of the wall between the ventricles or of the heart wall, and other heart conditions such as cardiomyopathy and severe valve disease, particularly aortic stenosis. Less commonly, cardiogenic shock results from causes outside the heart: a large pulmonary embolism, fluid around the heart compressing it (pericardial tamponade), tension pneumothorax, heart muscle depression in severe sepsis, some drugs or metabolic disturbances, and thyrotoxic crisis.

It says cardiogenic shock is more likely to develop in the elderly and in people with diabetes, that an anterior or right-ventricular heart attack is associated with increased risk, and that a history of previous heart attack, peripheral vascular disease, cerebrovascular disease and multi-vessel coronary disease increase the likelihood.

The clinical reference says the aim of management is to make the diagnosis, prevent further ischaemia and treat the underlying cause. It lists the first-line investigations as blood tests including kidney and liver tests, troponin and brain natriuretic peptide, an ECG, a chest X-ray, a pregnancy test where relevant and further imaging as guided by the clinical picture, with an echocardiogram to look at heart function. The trust also lists blood tests and heart scans (echocardiogram).

Doctors keep other correctable causes of shock in mind during the assessment, including a collapsed lung, a large pulmonary embolism, bleeding or low blood volume, sepsis, fluid around the heart, anaphylaxis and respiratory failure. This means many tests and treatments can be started at the same time.

The trust says cardiogenic shock is a very serious illness and recovery can be uncertain. Outcomes depend on the cause, how quickly treatment started, age and overall health and how other organs are affected. Possible outcomes include partial or full recovery of heart function, ongoing heart failure needing long-term treatment, and in some patients the need for long-term heart support or transplant. It says sadly half of patients with cardiogenic shock do not survive, and that doctors and nurses will be honest and update families as things change.

The clinical reference says mortality is over 50%, with some sources quoting as high as 80%, with higher early risk at age 75 or over and in peripheral arterial disease, chronic kidney disease and female sex. It also notes that among those who survive 30 days after a ST-segment elevation heart attack complicated by shock, annual mortality of 2 to 4% was about the same as in patients without shock. Early revascularisation was associated with reduced risk of death.

Many patients are very unwell and may be sedated so that their body can cope with treatment. The trust says families can help by being present if allowed, asking questions, looking after themselves and speaking to the team about emotional or spiritual support. If the heart does not recover, doctors may discuss transfer to a regional advanced heart failure centre for assessment for longer-term heart support or transplant for selected patients, or a focus on comfort and quality of life, with families involved.

The clinical reference says early coronary revascularisation after a heart attack and adequate treatment of structural heart disease may help prevent cardiogenic shock, that better treatment of acute coronary syndrome seems to be reducing its rate, and that better management of cardiovascular risk factors should reduce heart attacks and so cardiogenic shock. For individuals the practical message is the NHS one: do not delay in calling 999 with heart attack symptoms, and take preventive medicines and lifestyle advice seriously.

Cardiogenic shock is an emergency that is always treated in hospital, so the route into care is a 999 call and an emergency admission, whether you are an NHS or private patient. An NHS hospital trust describes care in a monitored cardiac care unit under a specialist multidisciplinary team, and says it accepts referrals from other hospitals in its area, and sometimes beyond, for patients who need this level of care.

Because treatment may include mechanical heart support, which is only available in some hospitals, a patient may be moved between hospitals. Ask the team where care will take place and who will update the family.