High voltage pulsed galvanic stimulation (HVPGS) is a form of electrical stimulation using very brief high voltage pulses to stimulate nerve and muscle fibers. HVPGS uses pairs of pulses lasting 0.1 milliseconds with peak currents of 2-2.5 amps applied at a frequency of 2-100 Hz. The brief pulses allow the current to pass easily through tissue. HVPGS is used to strengthen muscles, reduce pain, and aid wound healing by increasing blood flow and reducing edema. The document provides details on the parameters and generator of HVPGS and discusses its various applications.

1. HIGH VOLTAGE PULSED
GALVANIC STIMULATION
Prof. Dr. M. Rajesh, PT, M.P.T(cardio), BCRC
TRINITY MISSION AND MEDICAL
FOUNDATION
MADURAI

2. INTRODUCTION
 This form of currents was originally developed in the USA and
given this name. That twin pulse waveform has almost
instantaneous arises with exponential Falls.

3. HVPGS PARAMETERS
 The pair of pulses last for only 0.1 millisecond and each peak
lasts for only few microseconds; the shape and duration are
normally fixed. The frequency of the double pulse can be varied
usually from 2 - 100Hz. With search shorts peaks very high
voltages are needed to provide enough currents to stimulate
nerve fibers. Peak currents of 2 - 2.5A maybe generated during
the few microseconds of peak voltage, but of course the total
average current is very low at around 1.2 to 1.5 milliamp.

5.  Such pulsed current will pass easily through the tissues,
because they are so brief and will be relatively comfortable due
to their wide discrimination between sensory, motor and
nociceptor nerve fibers.

6. HVPGS GENERATOR
 As well as the frequency the intensity can be varies 0 to 500
volts and the polarity altered. The pattern of currents can be
changed by mode switch. In continuous mode the train of Twin
pulses is delivered continuously. Reciprocate mode refers to the
alternate application of trains of pulses to one or other of to
active pads and does not mean that's the current direction is
reversed. Surge mode gives a train of pulses. A meter to
indicate peak currents may be provided. On some machines the
interval between the two peaks may be altered; this is called
the interpulse interval. The current is applied by flexible
electrodes and sponges. The electrodes are usually small
and are sometimes mounted on a handle. Various special
electrodes are available.

8. USES OF HVPGS
WOUND HEALING
Since a direct current albeit of very low total intensity is being
applied. There seems to be e evidence that low-intensity
currents lead to tissue healing.

9. MUSCLE STIMULATION
 HVPGS is used for the stimulation of innervated muscle and due
to the short pulses and hence good transmission in the tissues it
is an efficient way of doing so. Consider the strength duration
curve which shows that short pulses at high intensities will be
more selective insulating motor, rather than pain nerves. HVPGS
has therefore been used for muscle strengthening and the
reduction of disuse atrophy of innervated muscle. Frequency of
around 30 Hz has been suggested with long intervals between
bouts of tetanic contraction as the optimum schedule.

10. PAIN MODULATION
 How pain may controlled by electrical stimulation already been
discussed since both the frequency and intensity of HVPGS can
be controlled it is possible to apply both high frequency, low
frequency stimulation for pain gate control and low frequency
high frequency stimulation for encephalin type pain control.
HVPGS has been recommended for controlling all kinds of pain
success acute, chronic, Neurogenic pain from many sources.

11. OTHER USES
 Effects on vascular system are claimed in that rhythmical
muscle contraction and relaxation due to HVPGS of motor
nerves will have a pumping effects, increasing blood flow in
muscle and surrounding tissues as considered earlier. This
effects can aid in the relation of tissue edema. Fish et al found
that anodal high voltage pulsed current did not curb edema
formation in frog Hind Limbs. This contrast markedly with
significant treatment effects found with cathodal HVPGS. Direct
effects on autonomic nerve leading to local vasodilation
increasing fluid exchange in the tissues and other beneficial
effects have been claimed.

12.  Consequent upon its ability to stimulate innervated muscle
HVPGS has been recommended in the treatment of muscle
spasm and to increase joint mobility. Some uncertainty exist
over the advantages of the Twin peaks waveform which is what
makes this current unique. It has been suggested that's a single
pulse could be just as effective.

13. THANK YOU
Prof. Dr. M. RAJESH, PT,M.P.T(cardio),B.C.R.C
TRINITY MISSIOIN AND MEDICAL
FOUNDATION
MADURAI.
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