Kenneth C. Bilchick, MD; Ronald D. Berger, MD, PhD

Disclosures

J Cardiovasc Electrophysiol. 2006;17(6):691-694. 

In This Article

Prognostic Value of HRV in Myocardial Infarction and Heart Failure

After some early reports suggesting that low HRV after myocardial infarction might indicate a worse prognosis, the Multicenter Post infarction Group published in 1987 the results of the first large-scale study on the subject. Over an average follow-up period of 2.5 years, they showed that patients with SDNN < 50 ms had a 5.3 times higher (34%)mortality than those with SDNN > 100 ms (9%).[4]SDNN was the strongest univariate predictor of mortality and remained the most powerful predictor of mortality even after adjustment for clinical, demographic, other Holter features, and ejection fraction.The authors hypothesized that this was due to increased sympathetic tone and vagal withdrawal, which increased the risk for ventricular fibrillation.

In the thrombolytic era, the GISSI-2 group in 1996 studied patients who had received thrombolytics after myocardial infarction and found that patients with SDNN < 70 msec had an adjusted 3-fold increased mortality.[5]The large prospective autonomic tone and reflexes after myocardial infarction (ATRAMI) study with 1,284 post myocardial infarction patients(only 20% treated with beta blockers) followed over an average 21 months further confirmed these results. The investigators showed that SDNN < 70 ms carried a 3.2-fold increased risk of mortality, which was additive when combined with low baroreflex sensitivity and low ejection fraction.[6]

The majority of studies in chronic heart failure of both ischemic and nonischemic etiology have shown that low SDNN predicts mortality.Several studies of HRV in heart failure from the late 1990s showed that low SDNN is associated with increased mortality, although only one study demonstrated an increase in sudden death with lower SDNN.[7]

HRV was used as a risk stratifying entry criterion in the recent DINAMIT study, which randomized patients between implantable cardioverter defibrillator (ICD) and standard care 6-40 days post myocardial infarction and failed to show a benefit for the ICD. It is unclear whether the negative results of this study are due to lack of benefit of the ICD so soon after infarction, or to an inability of HRV to identify patients who can benefit from ICD implantation.

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