Heart rate turbulence: a 5-year review.

April 2004 marks the fifth anniversary of the first heart rate turbulence (HRT) publication, which demonstrated the usefulness of HRT in predicting cardiac death in postmyocardial infarction patients. Since then, HRT has been shown to predict prognosis of patients with dilated cardiomyopathy and of patients with heart failure of mixed etiology. HRT also has been shown to be predictive even in the current lower-mortality era of acute revascularization therapy for myocardial infarction. We discuss the latest criteria for obtaining reliable measurements of HRT, review factors that influence HRT values, and consider recent clinical studies.