TAMPA (FOX 13) - Every four seconds, someone in the U.S. has a heart attack.
Some do not even know it's happening while others develop rhythm problems, leading to sudden death.
About half the time, there's no one else around when the cardiac arrest happens.
If you find yourself alone when heart attack symptoms start, Florida Hospital cardiologist Dr. Charles Lambert says the first thing you should do is pick up the phone.
"Don't get into a car! Call 911," he says.
Knowing when to call 911 may not be as clear because symptoms can be subtle. They can include indigestion, jaw pain, arm pain, fluttering in the chest, or classic pressure in your chest.
If you are not sure, make the call anyway.
Dispatchers may direct you to lie down, take aspirin, or take nitroglycerin. However, if you begin to fade, you may be asked to do something unusual.
"One cough per second if you can do it. Cough, cough, cough until your symptoms abate," explains Dr. Lambert.
Coughing began in hospitals years ago.
Dyes injected into heart arteries sometimes caused fatal heart rhythm disturbances. Overcoming them often involved asking patients to cough.
The American Heart Association says cough CPR is not a form of traditional resuscitation and doesn't recommend teaching it to people who are not medical professionals. Some studies have shown coughing could raise blood pressure.
So in spite of its potential benefit, some worry that if coughing begins at the wrong time, it may instead de-stabilize the heart.
Another tool you can use is a portable defibrillator, but you are not likely to have one at home. If you are in a public place, however, ask someone to help you find one quickly.
"Think about where there is an automatic external defibrillator because wherever one of those is there's usually help," says Dr. Lambert.
That help can boost the odds of survival.