State classification of heart rate variability by an artificial neural network in frequency domain.

This paper examines the feasibility of accurate state classification of autonomic nervous activity (ANA) based on the power spectral pattern of the heart rate fluctuations (HRFs). Some attempts have been made to utilize artificial neural networks (ANNs) to classify HRFs for clinical diagnoses such as ischemic cardiomyopathy, arrhythmia or sleep apnea. To establish the firm bases for making such clinical diagnoses, it may be important to examine the classification accuracy for the data in physiologically well defined conditions by e.g. application of autonomic blocking agents. In this paper the three layered perceptron has been trained by the heart rate data in variety of ANS states yielded by the application of Atropine and Propranolol to 14 healthy male subjects. Six state (control, atropine and propranolol for each of the spine and upright posture) classification based on power spectrum showed average sensitivity of 67.2% and specificity 91.2%. Four state (control, atropine, propranolol and double block for either spine or upright posture) resulted in the average classification sensitivity of 75.7% and specificity 95.5%. The paper revealed that entropy bandwidth and indices originated from characteristic oscillations of blood pressure change improve the classification accuracy.

Spontaneous variability analysis for characterizing cardiovascular responses to water ingestion.

This paper examines the effect of water ingestion on the cardiovascular system, utilizing advanced fluctuation analysis. The ingestion of water has been known to significantly raise the blood pressure in subjects with autonomic disorders, resulting in the effect of preventing syncope occurrences. For precise characterization of the effect of water ingestion, head-up tilt experiments at 80 degrees have been conducted for fourteen healthy subjects, ranging in age from 16 to 24. Systolic/diastolic blood pressures (sBP/dBP), total peripheral resistance index (TRPI) and ECG RR intervals (RRIs) were measured for thirty minutes before and after the isotonic water ingestion of 340 ml. Blood pressures: sBP (2.8%), dBP(3.6%), and TPRI (5.3%) showed statistically significant increases after the water ingestion. RRIs also tended to increase (2.3%), although they were not statistically significant. The data analysis confirmed that the water injection of 340 ml has the acute effect against the syncope occurrences that are mainly due to the increase in TPRI. Then heart rate (HR) spectral analysis with the derivative of the cubic spline interpolation (DCSI) method, and a closed loop system identification technique, which associate fluctuations in sBP and HR, are utilized for further precise characterization of the change in recorded physiologic quantities.

The incidence of internal malignancies in autoimmune bullous diseases.

Autoimmune bullous diseases are classified into pemphigus and pemphigoid. Pemphigus is designated as incurable disease by the Ministry of Health, Labor and Welfare, and it is said that pemphigus is difficult to care and can be fatal. The clinical course of bullous pemphigoid (BP) is better than that of pemphigus. However, as to the incidence of internal malignancies, it is well known that there is a significant difference between the two diseases. As the incidence of internal malignancies is high in BP, it is described in textbooks that patients with BP should be followed by a detailed screening for internal malignancies. We investigated the incidence of internal malignancies in 204 Japanese patients with autoimmune bullous disease who visited Tokai University Hospital in Kanagawa, Japan. We found that the incidence of internal malignancies was 11.2% in patients with pemphigus and 10.4% in patients with BP. Among pemphigus variants, the incidence was as high as 20% for pemphigus erythematosus. No relationship was found between malignancies and the severity of the autoimmune bullous diseases. Therefore it is clinically important to carry out a detailed screening for internal malignancies in patients with pemphigus as well as in patients with BP.