Use of the Polar H10 cardiofrequencemeter and Ewing's autonomic function tests in the screening of cardiac autonomic neuropathy in type 1 diabetes mellitus in Yaoundé

Abstract

Cardiac autonomic neuropathy (CAN) is one of the chronic complications of diabetes that can be detected by studying spontaneous or induced changes in heart rate and blood pressure. To investigate and characterize CAN in a group of young type 1 diabetics patients. This was a cross sectional study carrying out in Yaounde Central Hospital. We successively realize a clinical examination, rest electrocardiogram, 3 min heart rate variability measure and five Ewing's functions tests (heart rate response, orthostatic blood pressure, vasalva test, control ventilation and forearm isometric contraction) with a POLAR H10 cardiofrequencemeter. Quantitative variables were express by the mean and his standard deviation; qualitative variables were expressed using frequencies. Sixty type 1 diabetics patients (37 males and 33 females) with a sex ratio of 1.6. The mean age was 19,6 ± 4.3 years, with diabetes of duration 5.9 ± 5.1 year, a mean BMI of 21.7 ± 2.9 kg/m 2 and a mean HbA1c of 9.1 ± 3.1%. Prevalence of CAN was 86.7%. The mean heart rate at rest was 82.9 ± 14.7bpm, a systolic blood pressure of 116.8 ± 18.9 mmHg, diastolic blood pressure of 70.4 ± 11.8 mmHg. The orthostatic blood pressure response was abnormal, restrict, normal respectively for 1 (1.7%), 5 (8.3%) and 54 (90%) subjects. The orthostatic response of the heart rate was abnormal for 20% of subjects and restrict for 10%. 28.3% of subjects had an abnormal Valsalva test. We found an abnormal forearm isometric contraction for 90% of subjects. The HRV index for parasympathetic activity were down low for 93.3% while index for orthosympathetic activity were down low for 90% of subjects. CAN is frequent in type 1 diabetes patients. The five Ewing and Clarke tests are replicable in clinical practice with the H10 polar cardiofrequencemeter. Thus, developing a single standard and universal consensus for the interpretation of these tests is important for a better screening of CAN.