ABSTRACT
Palpitations associated with particular situations may occur in patients with phobic or panic disorders. Palpitation may result from two primary mechanisms: abnormal pulse rate or rhythm; and abnormally forceful cardiac contraction. The diagnosis is considerably easier if the symptoms are present at the time of the patient's clinical assessment. In this instance, an Electrocardiogram may reveal a cardiac arrhythmia, thus allowing the cause of the symptoms to be determined immediately. An abnormal pulse rate or rhythm may represent sinus tachycardia of any cause, or a cardiac arrhythmia. An abnormally forceful cardiac contraction occurs as a result of sympathetic system overactivity, which has a variety of causes, including hypoglycaemia and hyperthyroidism. A regular pounding sensation in the neck is characteristic of atrioventricular nodal re-entry tachycardia. Polyuria may occur during and following a supraventricular tachycardia, due to the release of atrial natriuretic peptide and the inhibition of antidiuretic hormone release, mediated by atrial stretch receptors.
