Some people who have abnormal heartbeats may not even be aware of them. Awareness of heartbeats (called palpitations) varies widely among people. Some people can feel normal heartbeats, and most people can feel heartbeats when they lie on their left side.
Arrhythmias have consequences that range from harmless to life threatening. The seriousness of an arrhythmia may not be closely linked with the severity of the symptoms it causes. Often, the nature and severity of the underlying heart disease are more important than the arrhythmia itself. Some life-threatening arrhythmias cause no symptoms. Otherwise inconsequential arrhythmias can cause severe symptoms.