Thyroid function tests may demonstrate a hyperthyroid state.Most patients have benign conditions as the etiology for their palpitations. The goal of further evaluation is to identify those patients who are at high risk for an arrhythmia. Recommended laboratory studies include an investigation for anemia, hyperthyroidism and electrolyte abnormalities. Echocardiograms are indicated for patients in whom structural heart disease is a concern.Further diagnostic testing is recommended for those in whom the initial diagnostic evaluation (history, physical examination, and EKG) suggest an arrhythmia, those who are at high risk for an arrhythmia, and those who remain anxious to have a specific explanation of their symptoms. People considered to be at high risk for an arrhythmia include those with organic heart disease or any myocardial abnormality that may lead to serious arrhythmias. These conditions include a scar from myocardial infarction, idiopathic dilated cardiomyopathy, clinically significant valvular regurgitant, or stenotic lesions and hypertrophic cardiomyopathies.An aggressive diagnostic approach is recommended for those at high risk and can include ambulatory monitoring or electrophysiologic studies. There are three types of ambulatory EKG monitoring devices: Holter monitor, continuous-loop event recorder, and an implantable loop recorder.People who are going to have these devices checked should be made aware of the properties of the devices and the accompanying course of the examination for each device. The Holter monitor is a 24-hour monitoring system that is worn by exam takers themselves and records and continuously saves data. Holter monitors are typically worn for a few days.
It is also very helpful to know how they start and stop (abruptly or not), whether or not they are regular, and approximately how fast the pulse rate is during an attack. If the person has discovered a way of stopping the palpitations, that is also helpful information.A complete and detailed history and physical examination are two essential elements of the evaluation of a patient with palpitations. The key components of a detailed history include age of onset, description of the symptoms including rhythm, situations that commonly result in the symptoms, mode of onset (rapid or gradual), duration of symptoms, factors that relieve symptoms (rest, Valsalva), positions and other associated symptoms such as chest pain, lightheadedness or syncope. A patient can tap out the rhythm to help demonstrate if they are not currently experiencing the symptoms. The patient should be questioned regarding all medications, including over-the-counter medications. Social history, including exercise habits, caffeine consumption, alcohol and illicit drug use, should also be determined. Also, past medical history and family history may provide indications to the etiology of the palpitations.Palpitations that have been a condition since childhood are most likely caused by a supraventricular tachycardia, whereas palpitations that first occur later in life are more likely to be secondary to structural heart disease. A rapid regular rhythm is more likely to be secondary to paroxysmal supraventricular tachycardia or ventricular tachycardia, and a rapid and irregular rhythm is more likely to be an indication of atrial fibrillation, atrial flutter, or tachycardia with variable block.