Rh factor and Autonomic Function Test in Normal and Deep Breathing

Background and Aim Studies have revealed a relationship between erythrocytic antigens of the ABO and Rh blood systems and cardiovascular pathology. Reduced heart rate variability (HRV) indicates an increased risk factor for the development of cardiovascular diseases. The present study was aimed to do correlative analysis of Rh blood groups and HRV in normal individuals. Materials and Method This cross sectional study includes 120 healthy medical students (18–22 years) of both sexes, from Kasturba Medical College, Mangalore, The study was approved by institutional ethical committee and study was carried out with written informed consent of students. All the subjects were grouped in to Rh positive blood group and Rh negative blood groups based on the result of standard slide haem agglutination technique. ECG of all the subjects was recorded in lead II for a period of five minutes and HRV was analysed by measuring the R-R intervals using a software “HRV soft 1.1 Version” software package. The HRV was analyzed both by the time domain method and frequency domain analysis during normal breathing. HRV is also analysed by deep breathing test for one minute and analyzed by the time domain method. In the time domain method, RMSSD-the square root of the mean squared differences of successive RR intervals (in milliseconds) SDNN-Standard deviation of RR intervals (in milliseconds), pNN50- percentage of differences between adjacent normal RR intervals exceeding 50 milliseconds were analyzed. In frequency domain method LF nu-Low frequency in normalized units, HF nuHigh frequency in normalized units, LF/HF-Ratio between low frequency and high frequency was measured. Statistical tests included in this study were ANOVA and student's unpaired ttest. P-value was taken as statistically significant at 5 percent confidence level (P<0.05). Results The time domain analysis and the frequency domain analysis of HRV among Rh positive blood group and Rh negative blood group subjects during normal breathing did not show any statistically significant changes. Further, comparison of HRV between Rh positive blood group and Rh negative blood groups during deep breathing using time domain method did not show any statistically significant results. Conclusions The present study, concludes that there were no significant change in the heart rate variability of Rh positive blood group and Rh negative blood groups subjects. Further research is needed including in a larger sample size to confirm these findings and to show the correlation of Rh groups and heart rate variability.