Cardiac autonomic dysfunction in elderly women with myocardial infarction

Abstract

Aims:

Elderly women with myocardial infarction (MI) show poorer outcomes than men. In patients with MI, reduced heart rate variability (HRV) is associated with an increased risk of mortality. Thus, we aimed to investigate HRV in elderly women with MI.

Methods:

HRV indexes in women 50 years of age or older were compared to those in age-adjusted men with MI: geometric (triangular index), linear (low frequency [LF, ms²], high frequency [HF, ms²], standard deviation (SD) of normal R-R wave intervals [SDNN], square root of the mean of the sum of the squares of differences between adjacent normal R wave intervals [RMSSD]) and nonlinear Poincaré analysis [SD1 and SD2, ms].

Results:

Women had higher MI recurrence than men (11% vs. 5% with two MIs; 6% vs. 1% with three MIs). Overall HRV, the triangular index and SDNN were considerably lower in women than men (3.1 [2.5–4.4] vs. 4.5 [3.2–5.9] and 9.3 [6.9–15.8] vs. 19.2 [11.4–26.4] respectively; p < 0.001). Moreover, HRV indexes (HF, LF/HF, RMSSD, and SD1) were significantly lower in women (62.2%, 55.6%, 37.1%, and 37.2% respectively; p < 0.01).

Conclusion:

This study suggests that elderly women with MI may have a worse prognosis than men, indicated by cardiac autonomic dysfunction. Since our study is cross-sectional and cannot infer causality, causation should be confirmed in further longitudinal studies.

Keywords: :

• Cardiac dysfunction
• Elderly women
• Heart rate variability
• Myocardial infarction
• Sex differences

Transparency

Declaration of funding

This research was supported by Sao Paulo Research Foundation – FAPESP (13/06698-0) and The Brazilian National Council for Scientific and Technological Development – CNPq (301706/2013-1).

Author contributions: L.A.C., A.O.P., V.L.P. and O.C.B. contributed to the conception and design, analysis and interpretation of the data. O.C.B. and L.A.C. contributed to the drafting of the article or revising it critically for important intellectual content. A.O.P., V.L.P. and O.C.B. helped with the final approval of the version to be published. L.A.C. is the guarantor of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Andreia de Oliveira Pinheiro

Valter Luis Pereira Jr

Ovidiu Constantin Baltatu

Luciana Aparecida Campos

Declaration of financial/other relationships

A.O.P., V.L.P., O.C.B., and L.A.C. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

The authors gratefully acknowledge Prof. Dr. Hans Koch and Prof. Dr. Michael Oeff for making available the ECG database to PhysioNet. No assistance in the preparation of this article is to be declared.