2. Rapid Heartbeat
During a heart attack, your heart is struggling to get blood around your body. As a result, it will often begin to struggle which will result in a sudden acceleration in the heartbeat. This might also feel like a pounding in the chest.
Note however that there are other potential causes for your heart rate to increase. One of the most common is a panic attack. Many people actually mistake a panic attack for a heart attack, which ironically has the effect of making them more anxious and exacerbating the condition!