Stress, depression and cardiac arrhythmias

A relationship between behavioural factors and cardiac arrhythmogenesis in humans has been described. Three sets of conditions contribute to the occurrence of arrhythmias: myocardial electrical instability, most often due to coronary artery disease; an acute triggering event, frequently related to mental stress; and a chronic, pervasive, and intense psychological state, often including depression and hopelessness. The autonomic nervous system plays an important role in the occurrence of cardiac arrhythmias and it is well documented that mood alterations as mental stress and depression influence cardiac autonomic balance. There is an increasing body of evidence that patients with the greatest changes in cardiac neural regulation with decreased parasympathetic tone coupled with increased sympathetic activity are at the greatest risk for developing fatal ventricular arrhythmias. These patients have a reduced heart rate variability, increased QT-dispersion and a decreased baroreceptor sensitivity. The influence of stress and depression on the autonomic nervous system and the impact on the occurrence of both atrial and ventricular arrhythmias is being discussed.