Diagnostic management of patients with palpitations of unknown origin.

The first-line investigations in the diagnostic management of patients with palpitations include history taking, physical examination and ECG. These investigations yield a definitive or probable diagnosis in a good proportion of patients. If the patient is suffering from heart disease, or if the palpitations are frequent or poorly tolerated, ambulatory ECG monitoring and electrophysiological study should be undertaken. Holter monitoring (useful when symptoms occur daily) has a rather low sensitivity, while event recorders (useful in compliant patients with infrequent palpitations that are fairly long-lasting) and external loop recorders (recommended in cases of infrequent short-lasting palpitations associated with hemodynamic impairment) have proved to have a higher sensitivity. The diagnostic yield of the electrophysiological study (generally recommended when the recording attempts using ambulatory ECG monitoring fail to provide a diagnosis) depends on the stimulation protocol used, the clinical characteristics of the patients studied, and the type of arrhythmias induced. Implantable loop recorders may be recommended in patients with rare, highly symptomatic palpitations associated or not with hemodynamic impairment, when the other diagnostic modalities prove to be inconclusive.