We've all read the signs of a heart attack listed on posters in the hospital waiting room. But what if there were other, earlier signs that could alert you ahead of time that your heart was in trouble?

It turns out there are. Researchers have done a lot of work in recent years looking at the signs and symptoms patients experienced in the months or even years leading up to a heart attack. "The heart, together with the arteries that feed it, is one big muscle, and when it starts to fail the symptoms can show up in many parts of the body," says cardiologist Jonathan Goldstein of St. Michael's Medical Center in Newark, New Jersey. Here are five surprising clues that your heart needs checking out. Any of these signs -- and particularly two or more together -- is reason to call your doctor for a workup, says Goldstein.

1. Neck pain

Feel like you pulled a muscle in the side of your neck? Think again, especially if it doesn't go away. Post-heart attack, some patients remember noticing that their neck hurt and felt tight, a symptom they attributed at the time to muscle strain. People commonly miss this symptom because they expect the more dramatic acute pain and numbness in the chest, shoulder, and arm. Women in particular are less likely to experience heart pain that way, and more likely to feel twinges of pain and a sensation of tightness running along the shoulder and down the neck, says Margie Latrella, an advanced practice nurse in the Women's Cardiology Center in New Jersey and coauthor of Take Charge: A Woman's Guide to a Healthier Heart (Dog Ear, 2009). The pain might also extend down the left side of the body, into the left shoulder and arm.

Why it happens:
Nerves from damaged heart tissue send pain signals up and down the spinal cord to junctures with nerves that extend out into the neck and shoulder.

What distinguishes it:
The pain feels like it's radiating out in a line, rather than located in one very specific spot. And it doesn't go away with ice, heat, or muscle massage.

2. Sexual problems

Having trouble achieving or keeping erections is common in men with coronary artery disease, but they may not make the connection. One survey of European men being treated for cardiovascular disease found that two out of three had suffered from erectile dysfunction for months or years before they were diagnosed with heart trouble. Recent studies on the connection between ED and cardiovascular disease have been so convincing that doctors now consider it the standard of care to do a full cardiovascular workup when a man comes in complaining of ED, according to cardiologist Goldstein says. "In recent years there's been pretty clear evidence that there's a substantially increased risk of heart attack and death in patients with erectile dysfunction," Goldstein says.

Why it happens:
Just as arteries around the heart can narrow and harden, so can those that supply the *****. And because those arteries are smaller, they tend to show damage much sooner -- as much as three to four years before the disease would otherwise be detected.

What distinguishes it:
In this case, the cause isn't going to be immediately distinguishable. If you or your partner has problems getting or maintaining an erection, that's reason enough to visit your doctor to investigate cardiovascular disease as an underlying cause. "Today, any patient who comes in with ED is considered a cardiovascular patient until proven otherwise," says Goldstein.

3. Dizziness, faintness, or shortness of breath

More than 40 percent of women in one study published in Circulation: Journal of the American Heart Association, reported having experienced shortness of breath in the days before a heart attack. You might feel like you can't breathe, or you might feel dizzy or faint, as you would at high altitude. If you can't catch your breath while walking upstairs, vacuuming, weeding the garden, or doing other activities that previously caused you no trouble, this is a reason to be on the alert.

Why it happens:
Not enough blood is getting through the arteries to carry sufficient oxygen to the heart. The heart muscle pain of angina may also make it hurt to draw a deep breath. Coronary artery disease (CAD), in which plaque builds up and blocks the arteries that feed the heart, prevents the heart from getting enough oxygen. The sudden sensation of not being able to take a deep breath is often the first sign of angina, a type of heart muscle pain.

What distinguishes it:
If shortness of breath is caused by lung disease, it usually comes on gradually as lung tissue is damaged by smoking or environmental factors. If heart or cardiovascular disease is the cause, the shortness of breath may come on much more suddenly with exertion and will go away when you rest.

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4. Indigestion, nausea, or heartburn

Although most of us expect pain from any condition related to the heart to occur in the chest, it may actually occur in the abdomen instead. Some people, particularly women, experience the pain as heartburn or a sensation of over-fullness and choking. A bout of severe indigestion and nausea can be an early sign of heart attack, or myocardial infarction, particularly in women. In one study, women were more than twice as likely as men to experience vomiting, nausea, and indigestion for several months leading up to a heart attack.

Why it happens:
Blockages of fatty deposits in an artery can reduce or cut off the blood supply to the heart, causing what feels like tightness, squeezing, or pain -- most typically in the chest but sometimes in the abdomen instead. Depending on which part of your heart is affected, it sends pain signals lower into the body. Nausea and light-headedness can also be signs that a heart attack is in progress, so call your doctor right away if the feeling persists.

What distinguishes it:
Like all types of angina, the abdominal pain associated with a heart problem is likely to worsen with exertion and get better with rest. Also, you're likely to experience repeated episodes, rather than one prolonged episode as you would with normal indigestion or food poisoning.

5. Jaw and ear pain

Ongoing jaw pain is one of those mysterious and nagging symptoms that can have several causes but can sometimes be a clue to coronary artery disease (CAD) and impending heart attack. The pain may travel along the jaw all the way to the ear, and it can be hard to determine which it's coming from, says cardiovascular nurse Margie Latrella. This is a symptom doctors have only recently begun to focus on, because many patients surveyed post-heart attack report that this is one of the only symptoms they noticed in the days and weeks leading up to the attack.

Why it happens:
Damaged heart tissue sends pain signals up and down the spinal cord to junctures with nerves that radiate from the cervical vertebrae out along the jaw and up to the ear.

What distinguishes it:
Unlike the jaw pain caused by temporomandibular joint disorder (TMJ), tooth pain, or ear infection, the pain doesn't feel like it's in one isolated spot but rather like it's radiating outward in a line. The pain may extend down to the shoulder and arm -- particularly on the left side, and treatments such as massage, ice, and heat don't affect it.

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