An implantable loop recorder may be helpful in people with very infrequent but disabling symptoms. This recorder is implanted under the skin on the front of the chest, like a pacemaker. It can be programmed and the data examined using an external device that communicates with it by means of a radio signal.Investigation of heart structure can also be important. The heart in most people with palpitation is completely normal in its physical structure, but occasionally abnormalities such as valve problems may be present. Usually, but not always, the cardiologist will be able to detect a murmur in such cases, and an ultrasound scan of the heart (echocardiogram) will often be performed to document the hearts structure. This is a painless test performed using sound waves and is virtually identical to the scanning done in pregnancy to look at the fetus. Evaluation
A 12-lead electrocardiogram must be performed on every patient complaining of palpitations. The presence of a short PR interval and a delta wave (Wolff-Parkinson-White syndrome) is an indication of the existence of ventricular pre-excitation. Significant left ventricular hypertrophy with deep septal Q waves in I, L, and V4 through V6 may indicate hypertrophic obstructive cardiomyopathy. The presence of Q waves may indicate a prior myocardial infarction as the etiology of the palpitations, and a prolonged QT interval may indicate the presence of the long QT syndrome.Laboratory studies should be limited initially. Complete blood count can assess for anemia and infection. Serum urea, creatinine and electrolytes to assess for electrolyte imbalances and renal dysfunction.
Causes
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. Palpitations are a widely diffused complaint and particularly in subjects affected by structural heart disease. The list of etiologies of palpitations is long, and in some cases, the etiology is unable to be determined. In one study reporting the etiology of palpitations, 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 palpitations 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, Pagets 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).Palpitation 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.