[Autonomic and somatic neuropathy in the diabetic patient: electric clinical analysis]. / Neuropatía autonómica y neuropatía somática en el paciente diabético: análisis electroclínico.

INTRODUCTION AND OBJECTIVE: Neuropathy is the more often complication in the diabetic patients. The relationship between somatic and autonomic neuropathy has not been studied on these patients, so we decided to compare both situations. PATIENTS AND METHODS: We have performed a comparative study among clinical elements, the nerve conduction study (NCS) and the autonomic cardiovascular function in 120 insulin dependent diabetics patients. We use clinical scales, the NCS and the heart rate variability study (HRVS) to know de autonomic cardiovascular function. RESULTS: Sensation was the clinical manifestation more compromised and there was not correlation between clinical manifestation and the HRVS. In the NCS the nerve conduction velocity was the element more affected and the nerve more compromised was the sural; there was good correlation between NCS and HRVS. Fifty per cent of patients had some degree of neuropathy, and the duration of the disease was an important factor on this damage. The clinical elements, the NCS and the HRVS together let us classified patients in: patients without neuropathy (10 cases), patients with somatic neuropathy (31 cases), patients with autonomic neuropathy (7 cases), patients with somatic-autonomic neuropathy (72 cases). CONCLUSIONS: To defined the diagnosis of cardiovascular autonomic neuropathy (CAN) is necessary the HRVS, the subclinical presentations of CAN are often without manifestation. There is a close relationship between the somatic and autonomic nerve damage, influenced by the duration of the disease.

Cardiovascular autonomic dysfunction in sickle cell anemia: a possible risk factor for sudden death?

Cardiovascular autonomic function tests were performed in 24 patients with sickle cell anemia (SCA). Twenty-five healthy Afro-Caribbean black subjects and 38 healthy white subjects of Hispanic origin served as controls. Measurements based on heart rate variability (HRV) included the coefficient of variation (the standard deviation of the distribution of R-R intervals divided by the mean) and spectral analysis (low- and high-frequency bands) at rest, HRV during deep breathing (expiration-inspiration difference), Valsalva maneuver (Valsalva ratio) and lying-to-standing test (30:15 ratio). Fourteen patients (58.3%) were found to have cardiovascular autonomic dysfunction based on abnormal values for at least two cardiovascular autonomic function tests, whereas ten (41.7%) had preserved cardiovascular autonomic function. In contrast, all control subjects had normal cardiac autonomic function. SCA is known to be associated with sudden death. Involvement of autonomic nervous dysfunction in sudden death has been reported in various diseases and we suggest that this may be the case in SCA.

[Studies of cardiovascular autonomic function and duration of QTc interval in smokers]. / Estudios de función autonómica cardiovascular y duración del intervalo QTc en sujetos fumadores.

OBJECTIVES: A total of 97 apparently healthy subjects were studied in order to establish the influence of smoking habits in studies on neurocardiovascular control and the QTc interval duration. MATERIAL AND METHODS: The study group consisted of 37 smokers and 60 non-smokers as the control. A 12-lead electrocardiogram was performed on all subjects to determine the duration of the QTc interval. Other aspects studied include heart rate variability at rest during 150 cardiac cycles using time domain: coefficient of variation and root mean squared successive difference; and frequency domain: low frequency band (0.04-0.15 Hz) and high frequency band (0.15-0.50 Hz), to determine total energy logarithm and maximum energy frequency. Additionally, conventional cardiovascular autonomic function tests, such as orthostasis, Valsalva maneuver and deep breathing were performed. RESULTS: No significant differences were observed in the duration of the QTc interval nor in time and frequency domain parameters, except in the maximum frequency in the high frequency band, which appeared significantly lower (p < 0.05) in smokers when compared to non-smokers (0.28 +1- 0.1 vs 0.33 +/- 0.1 Hz). No modifications were noted in the cardiovascular autonomic function tests applied to smokers and non-smokers, and the QTc interval was not linked to the rest of the variables studied. CONCLUSIONS: To conclude, smoking habits do not seem to have a significant influence in studies addressed to determine the impact of the autonomic nervous systems on cardiovascular control.