What is difference between Chronaxie and Rheobase?
What is difference between Chronaxie and Rheobase?
Rheobase is measured as the threshold stimulus current for an active response with a long-duration pulse and chronaxie is the pulse width at twice the rheobase threshold current19).
What is Rheobase and Chronaxie?
Rheobase is the lowest intensity with indefinite pulse duration which just stimulated muscles or nerves. Chronaxie is the tissue-excitability parameter that permits choice of the optimum stimulus pulse duration for stimulation of any excitable tissue.
How is chronaxie calculated?
The Chronaxie is a duration measurement, corresponding to twice the Rheobase. From the graph above, the Rheobase is approximately 0.64 volts, and the Chronaxie is about 0.16 ms….
| Strength (V) | Duration (ms) |
|---|---|
| 0.8 | 0.42 |
| 1.0 | 0.25 |
| 1.2 | 0.18 |
| 1.42 | 0.134 |
What is a strength duration curve?
The strength-duration curve is a plot of the threshold current (I) versus pulse duration (d) required to stimulate excitable tissue. Strength-duration curves are useful in studies where the current required is changed when the pulse duration is changed.
How is Chronaxie calculated?
What is rheobase and its types?
Rheobase can be defined as the lowest stimulus current that continues to capture the heart when the stimulus duration is made very long. From: Clinical Cardiac Pacing, Defibrillation, and Resynchronization Therapy (Third Edition), 2007.
What is the difference between rheobase and threshold?
The threshold , or minimal stimulus , is defined as “the electrical stimulus whose strength (or voltage) is sufficient to excite the tissue. Rheobase is defined as “the minimum strength (voltage) of stimulus which can excite the tissue”.
How do you calculate rheobase?
Step 1 – determine the rheobase, which is the minimum Stimulus Strength that will produce a response. This is the voltage to which the Strength-Duration curve asymptotes. In the example above, this value is 0.35 V. Step 2 – calculate 2´rheobase ( = 0.7 V in the above example).
How do you find the strength duration curve?
METHODS OF Strength Duration Curve : (Sometime two small electrode may be used, one over each end of muscle belly). Current is applied using the longest stimulation first and increased until a minimal contraction is obtained. Intensity of current (or voltage) is noted and impulse is shortened.
What is rheobase voltage?
Step 1 – determine the rheobase, which is the minimum Stimulus Strength that will produce a response. This is the voltage to which the Strength-Duration curve asymptotes. In the example above, this value is 0.35 V.
How do you calculate Rheobase?
How is the chronaxie and the rheobase determined?
Typical strength–duration curve obtained from skeletal muscle. The rheobase is the asymptote to the lower portion of the curve. The chronaxie is the pulse width required to produce a response at twice the rheobase. … Rheobase values obtained from conscious rabbits over a 24-week period of denervation.
Which is excitability constant is twice the chronaxie?
Rheobase is asymptotic threshold current at infinite pulse duration, and chronaxie is an excitability time constant defined as the pulse duration at which threshold current is twice the rheobase [8,14,15].
How are rheobase and chronaxie of denervated muscles measured?
Rheobase and chronaxie were measured noninvasively at weekly intervals by means of a laptop PC, which communicated with the stimulator via a radio-frequency link. At each setting the denervated TA was palpated manually to detect the response of the muscle.
How does chronaxie affect the activity of a tissue?
The speed of activity of tissue and its chronaxie bear a direct relation. A tissue, having shorter chronaxie, has shorter period of action, shorter refractory period and a quicker rate of propagation. Sluggish tissues, such as some form of plain muscle, have longer chronaxies.