Study of Heart Rate Variability in Control and Hypertensive Subjects

Autonomic nervous system comprising sympathetic and parasympathetic divisions has important role inregulating the cardiovascular system. Heart rate variability has been shown to give objective assessment ofautonomic function. Peripheral Pulse Analyzer has been used to study heart rate variability in controls andhypertensive subjects for understanding manifestations of hypertension on autonomic activity. Subjects havebeen divided in two age groups; 18-30 years and 31-44 years and variability parameters have been comparedwith respect to gender stratification, age stratification and disease stratification. Statistical analysis hasshown marked reduction in the coefficient of variation for variability parameter expressed as logarithm (to thebase 10) in comparison to raw or average value of the parameter and has yielded higher discriminatorystrength in various stratified groups. Excluding age and gender sensitive parameters, significant differenceis observed in amplitude of low frequency component for lower age group male/female hypertensives andamplitude as well as area of low frequency component for higher age group female hypertensives. Theseobservations are in agreement with similarly targeted previous studies. Higher age group male controls andhypertensives, however, could not be discriminated by variability study probably due to similar changesmanifested by senility and hypertension. Thus amplitude and area of low frequency component in heart ratevariability spectrum is identified as hypertension specific parameter.

Asymptomatic Patient with Unrecordable Blood Pressure: Could It be Takayasu.

Takayasu‖s arteritis is a rare, systemic inflammatory vasculitis of large vessels that usually affects women of childbearing age. Also known as pulseless disease or occlusive thromboaortopathy, the disease is named after the Japanese ophthalmologist who in 1905 described a form of retinal arteriovenous anastomoses due to retinal ischemia caused by large vessel vasculitis. We present here a case of a young female who presented with stroke. The patient had stroke which eventually recovered but now was referred for evaluation of her unrecordable blood pressure.

Takayasu’s Arteritis.

Takayasu’s arteritis is a chronic nonspecific arteritis due to inflammatory process of the large vessels usually affecting young women. Occlusion of aorta and its various major branches can result in many of its clinical manifestations, the most devastating being stroke. As with other noninfectious inflammatory diseases, steroid remains the mainstay of treatment with many other avenues being searched for.

Seventy-five Years of Use of Impedance Plethysmography in Physiological Data Acquisition and Medical Diagnostics.

Impedance plethysmography (IPG) came into existence in 1940 as a result of Jan Nyboer’s pioneering work in the noninvasive assessment of central and peripheral blood flow. The technique got an impetus after introduction first-time derivative of the impedance for accurate determination of stroke volume (SV) and various cardiac intervals. Later, this signal was employed by Parulkar et al for estimation of blood flow index (BFI) and differential pulse arrival time (DPAT) in various segments of the extremity, which were adequate to detect the aortic and peripheral arterial blocks and estimate collateral circulation and distal arterial runoff. The technique was widely used for measurement of respiration and body water. All these applications have resulted into use of bioimpedance for body composition analysis and continuous monitoring of cardiac output as US Food and Drug Adminstration (FDA) approved technologies, which are being used worldwide. Physiological variability has added more value to this technique as single data acquisition gives variability in heart rate and SV (or peripheral blood flow). Morphology index thus derived is very useful in screening patients suspected with coronary artery disease (CAD). All these milestones are briefly described in this paper.

Dengue : A Review.

Dengue is the most common arboviral disease in the world with over 50 million people being affected all over. Caused by the virus from genus Flaviviridae, it can result from nonspecific viral illness. Early diagnosis, rapid identification of the complications, and fluid restoration are the cornerstone of management of this disease.

Peripheral Pulse Morphology for Early Detection of Coronary Artery Disease.

Based on the past observation of recording abnormal impedance cardiogram (ICG) in 13% normal subjects and subsequent detection of coronary artery disease (CAD) in majority of these cases, led the authors to record peripheral impedance plethysmograms (IPG) in control subjects and patients using impedance cardiovasograph, developed by electronics division, Bhabha Atomic Research Centre (BARC). Analysis of peripheral plethysmograms, thus recorded, has shown 8 dominant morphological patterns of the peripheral pulses depending upon their status of health. In cognizance of these observations, different methods of pattern analysis were used for pattern identification. Fourier Transform based method has been observed to yield higher diagnostic yield. Morphology index (MI) of the peripheral pulse derived from this method was observed to vary from 0.28 to 1, the former indicating the poorest and later the normal health. Among 100 subjects suffering from various disorders, 8 patients with coronary artery disease have recorded average index to be between 0.30 and 0.45.

Thrombotic microangiopathies presenting as an obstetric emergency.

Thrombotic microangiopathies are disorders that arise due to a diffuse endothelial damage. They predominantly manifest either as thrombotic trombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS). When they arise as a complication of pregnancy and associated disorders they are associated with a high mortality and morbidity.

Comparative evaluation of immunogenicity, reactogenecity and safety of purified chick embryo cell rabies vaccine and neural tissue rabies vaccine.

OBJECTIVES: 1. To compare the protective antibody titres on day 14, 30 and 90 after giving intramuscular (IM) injections of PCECV and subcutaneous injections of Nervous Tissue Vaccine. 2. To compare the immunogenicity and safety of PCECV and NTV. METHODS AND MATERIALS: The study enrolled cases in three groups.Group 'C' or control group: (n = 38) : This group comprised of 38 normal healthy volunteers without dog-bite. Group 'A' (n = 102): This group included cases of dog-bite fulfilling inclusion/exclusion criteria. Each one of Group A and C were given PCECV as post exposure treatment (PET) on day 0-3-7-14-30 and 90. Group 'B' (n = 50): This group included 50 cases of dog-bite who received NTV. The rabies virus neutralizing antibody titres were estimated by RFFIT (Rapid Fluorescent Focus Inhibition Test) on day 0, 14, 30 and 90 days. 45 recipients of PCECV were re-tested for persistence of Protective Antibodies at the end of 1 year. RESULTS: Of these 37, 91 and 45 cases were evaluable in Groups C, A and B respectively. The antibody titres in Groups A, B, C were 13.4, 3.2, 22.8 IU/ml respectively; the protective titre being 0.5 IU/ml.5% PCECV recepients had delayed response on day 30.14% of NTV recepients did not seroconvert. CONCLUSIONS: The Immunogenicity, Reactogenicity and safety of PCECV is well established. 5% of PCECV receipients showed a delayed sero conversion. 14% of NTV receipients did not sero convert at all.Therefore it is desirable to estimate antibody titres on day 14 after vaccination. If difficult, then all the cases of animal bite must receive passive immunization with rabies immunoglobulins.