It starts with an uncomfortable pressure gripping the center of your chest. A sharp pain shoots through your arms, neck and jaw. Your breath starts to shorten; you feel a growing urge to vomit.
What do you do next? Nearly half of Americans do nothing.
A report from the US Centers for Disease Control and Prevention on the early warning signs of heart attacks discovered that "about 47% of sudden cardiac deaths occur away from hospital." This suggests, the report continues, that "many people with heart disease do not act on early warning signs."
Not only are the symptoms of a heart attack frightening by themselves, but testing for them at a hospital in the United States can run into the tens of thousands of dollars. Most important: The longer a heart attack goes undetected, the greater the damage to the victim's heart.
"Time is muscle. We know the heart muscle can live without blood for four to six hours, so if you are opening the artery after four hours, there will be a lot of damage to the heart," said Dr. Chaim Lotan, director of the Heart Institute and Cardiovascular Division at Hadassah Ein Kerem Medical Center in Jerusalem. "If you open the artery early, you can save a lot of muscle."
But a device developed in Israel could radically change how we detect heart attacks by making the process simpler, quicker and cheaper. It is the brainchild of Emil Katz, founder and CEO of Novamed, a life-sciences company that makes medical products, who was alarmed at how quickly a number of his friends suddenly died from heart attacks.
"Some of them had symptoms that lasted one, two and three days, but they neglected them and said, 'it is not strong enough; let us wait,' " Katz recalled. "Then I started to read the statistics about how many people in the world die from a heart attack before getting medical aid, and I was shocked. Something had to be done."
In the US, heart disease is the leading cause of death, according to the CDC, with more than 600,000 deaths each year. One in three American adults -- about 80 million people -- has high blood pressure, which increases the risk of heart attack and other major health problems, according to the American Heart Association. The World Health Organization found that cardiovascular diseases are the No. 1 cause of death globally, killing 17.7 million people in 2015.
Katz's solution: a device called SensAheart, roughly the size of a USB stick, which is as easy to use as a blood sugar or pregnancy test and just as quick.
A five-minute test
In his office, I receive a demonstration. A nurse pricks my finger, placing a drop of blood on a testing strip. She then applies a special liquid. The device is checking my blood for evidence of a reaction between two types of proteins -- HFABP and troponin -- and any antibodies my body would have produced in the event of a heart attack.
A damaged heart releases both types of protein into the bloodstream, and by searching for evidence of their reaction with antibodies, the experimental test can identify heart attacks that have occurred as recently as an hour ago, or as long ago as several days.
Existing blood tests can take up to six hours to deliver a result, after a patient shows symptoms of a heart attack. I wait roughly five minutes for the result of my test. I am told that a positive result will generate two lines on the strip. If that happens, I will receive immediate medical attention, Lotan assures me.
"The [waiting] lines [at the hospitals] are long, and if the patient [arrives] in pain, he can wait in the emergency room until there is time [to see] him," Lotan said. "But if that patient comes into the hospital with a positive test, they will be a priority, because we will believe with a very high certainty that something is wrong with his heart."
My results come back. The device shows only one line. Even though I have not suffered any symptoms, it is still something of a relief to be told I have not suffered a heart attack. I have a history of heart disease in the family, so it brings me a little peace of mind.
Lotan and his medical team at the Hadassah Hospital have been assessing the accuracy of the device. They discovered that SensAheart is more accurate than the current available test.
If the result is positive, the likelihood that SensAheart is mistaken is very small, they say -- and the recommendation for the individual is to go immediately to a hospital.
If the result comes back negative, it is important to keep in mind the possibility that the test might have failed; in a trial of people who had all suffered heart attacks, SensAheart failed to detect the attack on 23% of occasions.
The advice in the case of a negative result, and in which the symptoms go away, is to nevertheless repeat the test after three hours. If the result of the second test is also negative, the individual can be pretty much certain they have not suffered a cardiac event.
In all other eventualities, the advice is to go to a hospital and get checked.
"There is never 100% in anything," Lotan said. "First of all, you have to combine the symptoms. It is not only the test, you [also] have to take into consideration the entire history of the patient."
Katz also stresses that this is not a crystal ball. It cannot detect a heart attack before it happens.
"You cannot rely on the test [to predict] the future. Like every disease, at that particular moment things might be OK, but a little bit later, something might happen," he said.
The device is available in Europe and Israel. Katz says he is working to introduce it into the US.
SensAheart is still relatively unknown in the US, and it is very unlikely that American consumers will be able to find the product in a pharmacy or hospital anytime soon, according to Dr. Steven Nissen, chairman of cardiovascular medicine at the Cleveland Clinic. He describes "enormous hurdles" to cross before approval from the Food and Drug Administration.
"The regulatory pathway for approval of such a device in the United States is daunting," Nissen said. "When you're dealing with a life-threatening disorder, [a product developer] would need to invest an enormous amount of money in proving it was safe and effective, especially for home use."
Nissen believes that process could take up to a decade.
For the moment, Israel's Ministry of Health's Medical Devices Department states that only medical professionals may use the test. Katz hopes that the restrictions will be eased and that his product will be seen from bathroom medicine cabinets to airplanes -- meaning an end, perhaps, to those "is there a doctor on board?" emergencies.
How much will one of the kits cost? Well, it is cheaper than rushing to the emergency room for something that turns out not to be a heart attack.
"It will be $10 to $20 per test," Katz insisted. "Not big money for your health."