Optimal parameters of short-term heart rate spectrogram for routine evaluation of diabetic cardiovascular autonomic neuropathy.

Our aim was to select those parameters of heart rate variability (HRV) within its short-term power spectral analysis (PSA), which have a capability similar to that of the standard Ewing battery of cardiovascular function tests in determining different degrees of cardiovascular autonomic neuropathy (CAN) in diabetes and to compare the usefulness of both methods for diagnostic purposes in the everyday routine. Commonly used standard battery of cardiovascular autonomic function tests evaluated as total Ewing score as well as short-term PSA of HRV were used in 119 diabetic patients (age: 52.7 +/- 9.8, diabetes duration: 22.2 +/- 12.7 years). From this cohort, patients were selected according to the total Ewing score by matching for age, gender, BMI and diabetes type for 3 groups, each of 17 patients, with no CAN (total Ewing score 0-0.5), with early involvement (score 1.0-2.5) and with definite or severe CAN (score 3.0-5.0). Short-term PSA of HRV performed in three positions (supine1-standing-supine2) included frequency-domain and time-domain parameters of HRV. Cumulative spectral power of total frequency band (0.06-0.50 Hz) and spectral power of low-frequency band (0.06-0.15 Hz) during both supine positions proved to be the most selective and discriminating among all patient groups in inter-group comparison and in analysis of discriminance. The correlation between the total Ewing score and the cumulative spectral power of total frequency band was r = -0.87 (P < 0.001). About 83.2% of cases classified by short-term PSA of HRV using the variables selected by analysis of discriminance was congruent with the classification by the total Ewing score alone. Time expenditure for the performance of each examination was 31 +/- 10 min for Ewing test battery vs. 14 +/- 2 min for short-term PSA of HRV (P < 0.001). In summary, the latter method showed similar diagnostic value concerning the CAN as the classical Ewing standard battery of cardiovascular function tests, although its application proved to be shorter, less stressful and more independent from patient cooperation. Cumulative spectral power of total frequency band (LFHF cumpower) can be used for overall description of the degree of cardiac denervation in diabetes while using short-term PSA of HRV.