Discover the key symptoms of heart disease and learn which heart conditions are considered the most dangerous   What Are the Symptoms of Heart Diseases?   Heart diseases don’t always show obvious signs at first, but common symptoms include:   Chest pain or discomfort (pressure, squeezing, or heaviness in the chest).   Shortness of breath during activity or at rest.   Fatigue and weakness—feeling unusually tired with little effort.   Palpitations (fast, irregular, or pounding heartbeat).   Swelling in legs, ankles, or feet due to fluid buildup.   Dizziness or fainting (caused by reduced blood flow to the brain).  …