T-wave alternans and arrhythmogenesis in cardiac diseases

T-Wave Alternans and Arrhythmogenesis in Cardiac Diseases

T-wave alternans, a manifestation of repolarization alternans at the cellular level, is associated with lethal cardiac arrhythmias and sudden cardiac death. At the cellular level, several mechanisms can produce repolarization alternans, including: 1) electrical restitution resulting from collective ion channel recovery, which usually occurs at fast heart rates but can also occur at normal heart...

Cardiac dynamics: Alternans and arrhythmogenesis

Pre-existing heterogeneities present in cardiac tissue are essential for maintaining the normal electrical and mechanical functions of the heart. Exacerbation of such heterogeneities or the emergence of dynamic factors can produce repolarization alternans, which are beat-to-beat alternations in the action potential time course. Traditionally, this was explained by restitution, but additional fa...

T-wave alternans and sudden cardiac death.

Sudden cardiac death (SCD) is the leading cause of mortality in patients with ischemic heart disease and left ventricular dysfunction. The majority of SCD are due to ventricular tachyarrhythmias. SCD strikes many asymptomatic patients and often is the first manifestation of heart disease. Thus, reliable determination of arrhythmic risk is warranted to guide preventive therapy. To highlight the ...

Malignant T-wave alternans.

A36-year-old woman was referred after her son had syncopal episodes associated with a markedly prolonged QT interval, which was treated with b-blockers and a subsequent pacemaker. The mother had a history of “seizures” as a child that had been treated with various medications, which did not appear to affect her events. She continued to have episodes 2 to 3 times a year, and witnesses said she w...

Drug-induced T wave alternans.