When someone goes into cardiac arrest, the first line of treatment is often cardiopulmonary resuscitation (CPR) depending on the access to emergency medical care. CPR does not “cure” cardiac arrest, but it keeps the person alive until a defibrillator can be used to shock the heart back into a normal rhythm. Early CPR intervention does more than keep a person alive until help arrives. It can also prevent or mitigate permanent injury, such as brain damage.

Restarting or “resetting” a heart in cardiac arrest usually requires a defibrillator. Portable defibrillators were once available only on some ambulances and other emergency vehicles, but are now becoming more widely accessible. Police cars, airlines and businesses have been equipped with automatic external defibrillators (AEDs), with more people trained to use them.

AEDs are external devices that can be used in emergency situations by a person with a minimum amount of training. AEDs read the patient’s heart rhythm and administer an electric shock to restart or reset the heart.

The combination of training in both CPR and the use of AEDs has been proven to double survival rates, according to the results of the Public Access Defibrillation trial. This study shows that having a trained team and early access to an AED doubled the chances of survival for victims of cardiac arrest. Additional studies have shown that resuscitation that occurs within four minutes of the onset of sudden cardiac death greatly reduces the chances of long-term organ damage.  Local schools that offer CPR courses may offer courses in using AEDs, and Congress has made money available for the purchase and training of AEDs. 

Once the person has reached the hospital, they will often be put onto advanced life support, which will supply ventilation, stabilize blood pressure, control arrhythmias and restore blood flow to the organs. Depending on their circumstances, the person may require a ventilator to help them breathe, at least temporarily.

For patients in cardiac arrest due to ventricular fibrillation, lidocaine and amiodarone are commonly used drugs when an automatic external defibrillator is not able to shock the heart back into rhythm.

Researchers are also investigating methods to enhance survival and prevent brain damage after the onset of cardiac arrest. Rapid, mild cooling of the body (hypothermia) is one method being currently explored. Hypothermia has been used in some heart operations, sparing the brain from damage by temporarily reducing its oxygen requirements. Researchers have tested this approach in groups of cardiac arrest patients who stayed in a coma after being resuscitated. Compared to those not receiving the treatment, patients undergoing hypothermia had significantly higher rates of survival, with mild or no neurologic (brain) damage. 

Patients who survive cardiac arrest without irreversible damage to their central nervous systems will likely undergo extensive diagnostic and therapeutic testing, including cardiac catheterization and/or an electrophysiology study. If they have underlying heart disease, such as coronary artery disease, this will likely be aggressively managed with medications and lifestyle changes. In addition, many patients may have an implantable cardioverter defibrillator implanted during their hospitalization. This device monitors the heart rhythm and, in the case of a serious arrhythmia, delivers a shock that jolts the heart back into a normal rhythm. These devices can be combined with pacemakers.