Heart rate variability in risk stratification of cardiac patients.
Heart rate (HR) variability has been extensively studied in cardiac patients, especially in patients surviving an acute myocardial infarction (AMI) and also in patients with congestive heart failure (CHF) or left ventricular (LV) dysfunction. The majority of studies have shown that patients with reduced or abnormal HR variability have an increased risk of mortality within a few years after an AMI or after a diagnosis of CHF/LV dysfunction. Various measures of HR dynamics, such as time-domain, spectral, and non-linear measures of HR variability have been used in risk stratification. The prognostic power of various measures, except of those reflecting rapid R-R interval oscillations, has been almost identical, albeit some non-linear HR variability measures, such as short-term fractal scaling exponent have provided somewhat better prognostic information than the others. Abnormal HR variability predicts both sudden and non-sudden cardiac death. Because of remodeling of the arrhythmia substrate after AMI, early measurement of HR variability to identify those at high risk should likely be repeated later in order to assess the risk of fatal arrhythmia events. Future randomized trials using HR variability/turbulence as one of the pre-defined inclusion criteria will show whether routine measurement of HR variability/turbulence will become a routine clinical tool for risk stratification of cardiac patients.
Institute of Clinical Medicine, Department of Internal Medicine, University of Oulu, and University Hospital of Oulu, Oulu, Finland. Electronic address: heikki.huikuri@oulu.fi.
Heikki V
HV
Huikuri
Phyllis K
PK
Stein
D006333:Heart Failure / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009203:Myocardial Infarction / Q000503:physiopathology*; D011379:Prognosis; D018570:Risk Assessment; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*
AMI; ATRAMI; Autonomic Tone and Reflexes After Myocardial Infarction; BHAT; Beta-Blocker Heart Attack Trial; CABG; CARISMA; CHF; Cardiac Arrhythmias and RIsk Stratification after Myocardial infArction; DEFINITE; DIAMOND; DYNAMIT; Danish Investigations of Arrhythmia and Mortality ON Dofetilide; Defibrillator in Acute Myocardial Infarction Trial; Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation; HF; HR; Heart failure; ICD; LF; LV; LVEF; MI; MPIP; Mortality; Multicenter Post-Infarction Project; Myocardial infarction; REFINE; Risk Estimation After Infarction, Noninvasive Evaluation; SDNN; acute myocardial infarction; congestive heart failure; coronary artery bypass grafting; heart rate; high frequency; implantable cardioverter defibrillator; left ventricular; left ventricular ejection fraction; low frequency; myocardial infarction; standard deviation of N–N intervals