Palpitations

Subjective awareness of rapid, forceful, or irregular heartbeats, often reflecting tachyarrhythmias, ectopic beats, heightened perception of normal sinus rhythm, or noncardiac hyperadrenergic states. Possible causes are stress/anxiety/fear, drugs (caffeine, nicotine, cocaine, amphetamine, alcohol), strenuous physical exercise, pregnancy, hyperthyroidism, fever, dehydration, hypoglycemia, anemia, arrhythmias, valve disease, and medications (pseudoephedrine, asthma inhalers).