- Extra-cardiac stimulation of the parasympathetic nervous system(inappropriate stimulation of the parasympathetic nervous system, particularly thevagus nerve (which innervates the heart), can be caused by anxiety and stress due to acute or chronic elevations in glucocorticoids and catecholamines. Gastrointestinal distress such as bloating or indigestion, along with muscular imbalances and poor posture, can also irritate the vagus nerve causing palpitations)
- Sympathetic overdrive (panic disorders, hypoglycemia, hypoxia, antihistamines(i.e. levocetirizine), anemia, heart failure, mitral valve prolapse).
- Hyperdynamic circulation (valvular incompetence, thyrotoxicosis, hypercapnia,pyrexia, anemia, pregnancy).
- Cardiac dysrhythmias (ectopic beat, premature atrial contraction, junctional escape beat, premature ventricular contraction, atrial fibrillation, supraventricular tachycardia, ventricular tachycardia, ventricular fibrillation, heart block).