Effect of vibrations with various duration exposure on the P-R interval of ECG

ECG analysis of a human body subjected to vertical vibrations of various durations was carried out. Results obtained from a representative subject show that the exposure period has different effects on the P-R time interval of the ECG waves. Vibration increases the Percent Normalized Difference (PND) of the P-R time interval with time till it reaches a steady state value of 29.5. An increase of the exposure duration increases the time constant, while the steady state value remains constant. The PND behavior can be mathematically modeled as a first order system.