RT-231
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Effects of cardiac
rehabilitation on heart rate variability after myocardial infarction
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Maria Stella Fera, Francesco
Rulli, Alessandro Carunchio, Andrea Mazza, Maurizio Burattini, Maria Margherita
Martinelli, Andrea Porzio, Vincenzo Ceci.
Division of Cardiology, S. Spirito Hospital, Rome, Italy
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Abstract
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Methods. We studied the effects of
cardiac rehabilitation on heart rate variability (HRV) in 74 patients after a first,
uncomplicated acute myocardial infarction. The patients were randomly assigned, 4 weeks
after myocardial infarction, 36 to the 8 weeks' training (group 1) and 38 to usual care
(group 2-control). In both groups of patients, time and frequency domain 24-hour analysis
HRV was assessed, without medication, 4 weeks after myocardial infarction (before the
initiation of exercise training for group 1) and 8 weeks later (3 months after myocardial
infarction).
Results. Training increased the mean of all normal R-R intervals (ms)
by 21% (p < 0.01), the standard deviation of all R-R intervals (SDNN) by 26% (p <
0.01), the standard deviation of 5 min mean R-R intervals ms (SDANN/5) by 37% (p <
0.01), the root mean square of the difference of successive R-R intervals ms (RMSSD) by
62% (p < 0.01), the percentage difference of adjacent normal R-R intervals greater than
50 ms % (pNN 50%) by 133% (p < 0.01) and the ratio of low/high frequency (LF/HF) power
decreased by 41% (p < 0.01).
Conclusion. The exercise training in patients after uncomplicated
acute myocardial infarction shifts in autonomic balance from sympathetic to vagal
predominance with a significant modification on all measures of time and frequency domain
of HRV. A persistent increase of parasympathetic tone after myocardial infarction may be a
beneficial feedback between improvement in cardiovascular function and electrical heart
stability.
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Key Words
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Heart rate variability
post myocardial infarction, cardiac rehabilitation, time domain, frequency domain,
autonomic nervous system, OA
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