Stress and sudden death. The case of the long QT syndrome.
The idiopathic long QT syndrome (LQTS) represents a unique clinical example of stress-related sudden cardiac death. LQTS is characterized by the association of several distinctive electrocardiographic features, among which prolongation of the QT interval is the best known, with life-threatening arrhythmias that usually occur under conditions of physical or psychological stress. Effective therapies exist and are represented by antiadrenergic interventions; beta-adrenergic-blocking agents are the treatment of choice. When they fail, left cardiac sympathetic denervation has also proven to be very effective. The latter result suggests a role for alpha-adrenergic mechanisms in the arrhythmias of LQTS. The stressors more frequently associated with syncopal events in LQTS patients include fear, exercise fraught with emotions, swimming, and awakening because of a loud noise. Experimentally, life threatening arrhythmias have been induced during a highly emotional situation in conscious cats with normal hearts in which right stellate ganglia have been ablated, resulting in QT interval prolongation. This selective denervation creates a sympathetic imbalance of the type proposed by one of the pathogenetic hypotheses for LQTS.
Schwartz
P J
PJ
Unità di Studio delle Aritmie, Centro di Fisiologia Clinica e Ipertensione, Milan, Italy.
Zaza
A
A
Locati
E
E
Moss
A J
AJ
D000818:Animals; D002415:Cats; D003645:Death, Sudden / Q000209:etiology*; D004562:Electrocardiography; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008133:Long QT Syndrome / Q000503:physiopathology; D013312:Stress, Physiological / Q000150:complications*; D013315:Stress, Psychological / Q000150:complications*; D013564:Sympathetic Nervous System / Q000503:physiopathology*