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264 Heart Rate Variability in Ischemic
Heart Disease and Diabetes

non-autonomic regulatory mechanisms in health
and disease: heart rate variability (HRV), baroreflex
sensitivity, and bedside autonomic function tests.
• The autonomic nervous system, including the
sympathetic and parasympathetic nervous sys-
tems, has an important role in the triggering or
sustaining of malignant ventricular arrhythmia.
• HRV (derived from intervals between normal si-
nus beats NN intervals) can be measured by
many methods, which can be categorized as
time domain measures, frequency domain mea-
sures, nonlinear/complexity-based measures, and
heart rate turbulence

• HRV appears to be highly consistent over 24 hours,
despite marked differences among the five-minute
intervals during a day. The same stability in HRV
appears to be true for patients with ventricular ar-
rhythmias, angina, and heart failure.
• HRV has been shown to be significantly decreased,
compared to normal values, among post-myo-
cardial infarction (MI) patients, although there is
considerable interindividual difference in this. This
decreased HRV is a likely a marker for autonomic
dysregulation and likely reflects both decreased
parasympathetic and increased sympathetic activ-
ity. Reduced HRV has also been associated with
worse outcomes in patients with stable coronary
heart disease, heart failure, and diabetes.

• We do not recommend the routine use of HRV
testing based on clinical Holter scanning at the
moment, but we hope that a refinement of the al-
gorithms by which HRV is interpreted can be im-
plemented and HRV will become useful outside of
the clinical trial setting

GCDC 2017