Depending on your genetics and lifestyle, you just never know when you’ll be hit by a heart attack.

Heart attacks are the number one killer of men and women in the United States. Each year, a little more than a million Americans suffer heart attacks, with 460,000 those resulting in death.

Many of these deaths are caused by ventricular fibrillation of the heart that occurs before the victim can reach an emergency room.

Those that do, however, have an excellent prognosis.

According to the Mayo Clinic, survival from a heart attack with modern treatment should exceed 90 percent.

Knowing the early warning signs of a heart attack is critical for prompt recognition and treatment. Many heart attacks start slowly, unlike the dramatic portrayal often seen in the movies. A person experiencing a heart attack may not even be sure of what is happening. Heart attack symptoms vary among individuals, and even a person who has had a previous heart attack may have different symptoms in a subsequent heart attack. Although chest pain or pressure is the most common symptom of a heart attack, heart attack victims may experience a diversity of symptoms that include:

√ Pain, fullness, and/or squeezing sensation of the chest

√ Jaw pain, toothache, headache

√ Shortness of breath

√ Nausea, vomiting, and/or general epigastric (upper middle abdomen) discomfort

√ Sweating

√ Heartburn and/or indigestion

√ Arm pain (more commonly the left arm, but may be either arm)

√ Upper back pain

√ General malaise (vague feeling of illness)

√ No symptoms (Approximately one quarter of all heart attacks are silent, without chest pain or new symptoms. Silent heart attacks are especially common among patients with diabetes mellitus).

Signs and symptoms of a heart attack in women may be different or less noticeable than heart attack symptoms in men. In addition to the symptoms above, heart attack symptoms in women can include:

√ Abdominal pain or "heartburn"

√ Clammy skin

√ Lightheadedness or dizziness

√ Unusual or unexplained fatigue

Even though the symptoms of a heart attack at times can be vague and mild, it is important to remember that heart attacks producing no symptoms or only mild symptoms can be just as serious and life-threatening as heart attacks that cause severe chest pain. Too often patients attribute heart attack symptoms to "indigestion," "fatigue," or "stress," and consequently delay seeking prompt medical attention.

What should you do if you experience these symptoms? Doctors agree that if you're in doubt, get checked out anyway. Even if you're not sure if something is really wrong, you should call 9-1-1 if you experience heart attack symptoms. Prompt administration of drugs can help restore circulation to the heart and increase your chances of survival.