According to the Centers for Disease Control and Prevention, “about 610,000 people die of heart disease in the United States every year–that’s 1 in every 4 deaths.” Heart disease is a complex illness with a myriad of symptoms—some obvious and others, not as obvious. The heart is one of the most vital organs in the body, and it is essential that you monitor patients who show any symptoms. If you understand how to look for the signs you should test your patient for heart disease, you’ll be able to intervene early in the unlikely case they are suffering from cardiac illness.

1. CHEST DISCOMFORT

Chest pain, also known as angina, is discomfort caused when your heart muscle doesn’t receive enough oxygen. Angina is usually a symptom of coronary heart disease when one or more of the heart arteries become narrowed or blocked. You won’t necessarily feel chest pain in the center of your chest—it may radiate out into the arms, neck, jaw, and back.

2. HEARTBURN

Digestive acid making its way up the tube of your esophagus is what causes heartburn. Heartburn is the most commonly reported symptom prior to a heart attack. If the pain is persistent, call 911 immediately.

3. FATIGUE

Fatigue is the overall lack of motivation and energy—physically and emotionally. Fatigue differs from drowsiness as drowsiness refers to the inclination to sleep constantly. Though fatigue by itself is a nonspecific symptom associated with many medical conditions, it can be a precursor to heart disease when coupled with some of the other symptoms listed.

4. SHORTNESS OF BREATH

Shortness of breath can sometimes be a sign of heart failure. In the early stages, exercise may get more and more difficult, until eventually, you find it challenging to even get dressed in the morning. Conditions that precede heart failure include heart disease caused by a variety of other conditions such as coronary artery disease, hypertension, cardiomyopathy, myocarditis, and congenital heart defects.

5. IRREGULAR HEARTBEAT

Harmless everyday occurrences like anxiety, high caffeine intake or dehydration can cause heart palpitations. However, you should consider speaking with your doctor if the irregular heartbeat is consistent and comes from no direct environmental causes. If shortness of breath, chest pain, dizziness, or fainting accompany your palpitations, they can be a sign of heart disease or abnormal heart valves. In case of an arrhythmia, a stress echo bed may be necessary to examine the heart’s structure and function.