Cardiovascular disease is listed as the world’s number one killer, with 17.9 million dying from it in a year.

According to the World Health Organization, 85 percent of such deaths are because of strokes and heart attacks—and a part of it is because people do not know what symptoms to watch out for and how to address it when it happens to a family member or to themselves.

Despite the availability of information online, heart disease remains a largely misunderstood illness and, in some cases, happen without the presence of risk factors. Truth be told, while some people with certain health issues are more likely to have a heart attack than others, it can still happen unexpectedly to the seemingly healthiest of people. In the United States, dealing with the disease can be doubly problematic because most people live on their own, with nobody else to provide immediate assistance should an emergency arise.

Typical symptoms of a heart attack include pain that starts in the chest and radiates to the upper left arm, jaw and neck; a feeling of pressing or heaviness on your chest, particularly one that occurs on the left side and lasts for around 20 minutes; and a feeling of impending doom with heavy sweating. Health Exchange says that around 90 percent of heart attacks are characterized by these classic symptoms.

Since heart attack is a sneaky disease, we have to arm ourselves with the knowledge of first said measures should it happen to us and there’s nobody around. Here are the most important things to do when you feel a heart attack happening and you are alone.

1. Call 911 right away

When a heart attack happens and you’re alone, go to a safe place and then call for medical help. If you are driving, pull over first and then make that call.

2. While waiting for medical help to come, take an aspirin.

Most heart attacks are caused by a clot in the blood vessels, so taking an aspirin may help—if you’re not allergic. If you have aspirin on hand and there’s no issue with allergies, you may take it while waiting for the ambulance to arrive.

3. Do not cough repeatedly

A heart attack is not simply a slowing down of your heart’s rhythm, so coughing to restore its movement will not help.

4. Do not take nitroglycerin

Nitroglycerin is a prescribed medication that is meant to widen blood vessels temporarily, however it has not been proven to be helpful in improving surviving during a heart attack. It is useful for those who have angina, which is a different case. Do not take it unless you have been cleared to do so by medical services or your doctor.

5. Don’t apply pressure on your chest.

Applying pressure on the chest during a heart attack will not help, unless the heart has stopped beating—and then it is called cardiac arrest. Take note that should someone arrive before the ambulance does, administering CPR for a heart attack is a “no.” Even if that other person is trained to provide the procedure, he or she shouldn’t assume that it’s okay and needed. CPR is only suited for a confirmed arrest.

Cardiovascular disease is listed as the world’s number one killer, with 17.9 million dying from it in a year. Pictured: Jaime Luis Gomez, aka Taboo of the Black Eyed Peas, and a cancer survivor, speaks during an interview with AFP on the eve of the World Cancer Leaders' Summit in Mexico City Getty Images/Pedro Pardo