Palpitations are perceived abnormalities of the heartbeat characterized by awareness of cardiac muscle contractions in the chest, which is further characterized by the hard, fast and/or irregular beatings of the heart.Symptoms include a rapid pulsation, an abnormally rapid or irregular beating of the heart. Palpitations are a sensory symptom and are often described as a skipped beat, rapid fluttering in the chest, pounding sensation in the chest or neck, or a flip-flopping in the chest.Palpitation can be associated with anxiety and does not necessarily indicate a structural or functional abnormality of the heart, but it can be a symptom arising from an objectively rapid or irregular heartbeat. Palpitation can be intermittent and of variable frequency and duration, or continuous. Associated symptoms include dizziness, shortness of breath, sweating, headaches and chest pain. Palpitation may be associated with coronary heart disease, hyperthyroidism, diseases affecting cardiac muscle such as hypertrophic cardiomyopathy, diseases causing low blood oxygen such as asthma and emphysema; previous chest surgery; kidney disease; blood loss and pain; anemia; drugs such as antidepressants, statins, alcohol, nicotine, caffeine, cocaine and amphetamines; electrolyte imbalances of magnesium, potassium and calcium; and deficiencies of nutrients such as taurine, arginine, iron, vitamin B12.
The link between anxiety and palpitation may also explain why many panic attacks involve an impending sense of cardiac arrest. Similarly, physical and mental stress may contribute to the occurrence of palpitation, possibly due to the depletion of certain micronutrients involved in maintaining healthy psychological and physiological function. Gastrointestinal bloating, indigestion and hiccups have also been associated with overstimulation of the vagus nerve causing palpitations, due to branches of the vagus nerve innervating the GI tract, diaphragm, and lungs.Many psychiatric conditions can result in palpitations including depression, generalized anxiety disorder, panic attacks, and somatization. However one study noted that up to 67% of patients diagnosed with a mental health condition had an underlying arrhythmia. There are many metabolic conditions that can result in palpitations including, hyperthyroidism, hypoglycemia, hypocalcemia, hyperkalemia, hypokalemia, hypermagnesemia, hypomagnesemia, and pheochromocytoma. Medication
The medications most likely to result in palpitations include sympathomimetic agents, anticholinergic drugs, vasodilators and withdrawal from beta blockers.Common etiologies also include excess caffeine, or marijuana. Cocaine, amphetamines,  3-4 methylenedioxymethamphetamine (Ecstasy or MDMA) can also cause palpitations. Pathophysiology
The sensation of palpitations can arise from extra-systoles or tachyarrhythmia. It is very rarely noted due to bradycardia. Palpitations can be described in many ways. The most common descriptions include a flip-flopping in the chest, a rapid fluttering in the chest, or pounding in the neck. The description of the symptoms may provide a clue regarding the etiology of the palpitations, and the pathophysiology of each of these descriptions is thought to be different.