The current knowledge of the neural pathways responsible for the perception of the heartbeat is not clearly elucidated. It has been hypothesized that these pathways include different structures located both at the intra-cardiac and extra-cardiac level.<unk>  are a widely diffused complaint and particularly in subjects affected by structural heart disease. The list of etiologies of<unk>  is long, and in some cases, the etiology is unable to be determined. In one study reporting the etiology of<unk> , 43% were found to be of cardiac etiology, 31% of psychiatric etiology and approximately 10% were classified as miscellaneous (medication induced, thyrotoxicosis, caffeine, cocaine, anemia, amphetamine, mastocytosis). The cardiac etiologies of<unk>  are the most life-threatening and include ventricular sources (premature ventricular contractions (PVC), ventricular tachycardia and ventricular fibrillation), atrial sources (atrial fibrillation, atrial flutter) high output states (anemia, AV fistula, Paget's disease of bone or pregnancy), structural abnormalities (congenital heart disease, cardiomegaly, aortic aneurysm, or acute left ventricular failure), and miscellaneous sources (postural orthostatic tachycardia syndrome abbreviated as POTS, Brugada syndrome, and sinus tachycardia).<unk> can be attributed to one of four main causes: # Extra-cardiac stimulation of the sympathetic nervous system (inappropriate stimulation of the sympathetic and parasympathetic, particularly the vagus 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<unk>  # Sympathetic overdrive (panic disorder, low blood sugar, hypoxia, antihistamines (levocetirizine), low red blood cell count, heart failure, mitral valve prolapse). # Hyperdynamic circulation (valvular incompetence, thyrotoxicosis, hypercapnia, high body temperature, low red blood cell count, pregnancy). # Abnormal heart rhythms (ectopic beat, premature atrial contraction, junctional escape beat, premature ventricular contraction, atrial fibrillation, supraventricular tachycardia, ventricular tachycardia, ventricular fibrillation, heart block).<unk>  can occur during times of catecholamine excess, such as during exercise or at times of stress. The cause of the<unk>  during these conditions is often a sustained supraventricular tachycardia or ventricular tachyarrhythmia. Supraventricular tachycardias can also be induced at the termination of exercise when the withdrawal of catecholamines is coupled with a surge in the vagal tone.<unk>  secondary to catecholamine excess may also occur during emotionally startling experiences, especially in patients with a long QT syndrome. Psychiatric problems Anxiety and stress elevate the body's level of cortisol and adrenaline, which in turn can interfere with the normal functioning of the parasympathetic nervous system resulting in overstimulation of the vagus nerve. Vagus nerve induced<unk> is felt as a thud, a hollow fluttery sensation, or a skipped beat, depending on at what point during the heart's normal rhythm the vagus nerve fires. In many cases, the anxiety and panic of experiencing<unk>  cause a sufferer to experience further anxiety and increased vagus nerve stimulation. The link between anxiety and<unk> 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<unk>  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<unk> , due to branches of the vagus nerve innervating the GI tract, diaphragm, and lungs. Many psychiatric conditions can result in<unk>  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<unk>  including, hyperthyroidism, hypoglycemia, hypocalcemia, hyperkalemia, hypokalemia, hypermagnesemia, hypomagnesemia, and pheochromocytoma. Medication The medications most likely to result in<unk>  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<unk> .
Palpitations
Tachycardia
Bradycardia
Hyperthymesia
Orthopnea
Chest pain
Apnea
Bigeminy