1. What Is Accelerated Photoplethysmograph?
APG (Accelerated Photo plethysmograph) uses the second derivative of the waveform of the phtopletysmography to stabilize the baseline and to separate components of the waveform more clearly than the first derivative. In this way, arterial vessel elasticity, peripheral vessel elasticity, and aging index can be analyzed. Along with the cardiac output, waveforms travel all the way to the peripheral areas and come back to the heart. This cycle is related with the cardiac pump and blood flow and it provides valuable information evaluating the cardiovascular status. Accelerated Photoplethysmograph can reveal some points of inflection that is not visible in photoplethysmograph. Therefore, it helps us to understand and apply the clinical interpretation more clearly.

2. How Does the Accelerated Photoplethysmograph Work?    
The Near-infrared rays easily penetrate biological tissues and are absorbed by the oxidized hemoglobin in the blood. When the near-infrared rays are released to the subject area, the reflected light can be detected. We use a transmission method that can detect how much infrared light is absorbed by the nail of the index finger. In this way, the blood circulation status along with the cardiac output and the early detection of arteriosclerosis can be indicated.

3. Cautions for APG Measurement
1) It should be a room temperature for the measurement.
2) Patients must take a rest at least for 10 minutes before the measurement.
3) During the test, do not move or talk.
4) If the shoulder or arm on the side of the finger being measured is in pain, it is likely to affect the test result.
5) Mental anxiety, nervousness, and stress can influence the amount of blood flow.
6) Remove the nail polish
7) Left index finger is recommended for the measurement.
8) Sit on a chair and place your left hand on your left lap during the test. (If it is placed above the heart, the gravity keeps the
    blood flow from reaching the peripheral area. Then, the result will not be accurate.)
9) Keep your fingers relaxed during the measurement.
    (If you give too much pressure on your fingers, circulation status will be considered bad.)
10) Exercise or eating good are not allowed right before the measurement
11. Drinking alcohol is not allowed at least 24 hours before the measurement
12. You are invited to have a comfortable position before the measurement.

4. Why Do Left and Right Hand Have a Different Result?
Even the blood pressure measurement is also different on both arms. The blood flow can be also different on both sides for many reasons. The test result of both sides can be different due to pain in the arm, blockage of circulation, arteriosclerosis, numbness in the arm, shoulder pain, neck pain, or other nerve disorders.

5. In Terms of 7 Wave Types, Why Are the Multiple Percentages of Types Indicated?
Since the vessel status is flexible, the blood flow status also changes. Furthermore, if there are obstacles to the flow, various
stages appear together. In this regard, each waveform is analyzed, and all the percentages of stages are indicated.

6. In Case of Cold Fingers or a Winter Season, Is It Possible to Have the Test?
If someone has cold fingers or the temperature is too low in winter, peripheral vessels contract, and the waveforms are barely
detected. In this case, keep the fingers warm and have the test again.

7. What Does the APG Test Show?
– Peripheral vessels elasticity and blood circulation disorder
– Early detection of arteriosclerosis
– Cardiovascular disorder such as myocardial infarction
– Indicator of blood vessels health
– Determination of drug effect

8. Which Wave Type Can Indicate the Possibility of Arteriosclerosis?
The wave type 4 is a stage where we warn our customers. If the type 5, 6 or 7 is detected, there is a high possibility of
arteriosclerosis. In this case, other medical checkups and treatment are required.

9. What Is the Difference between APG and PWV?
PWV (Pulse Wave Velocity) is a measurement of time when the heart rate travels to get the arterial stiffness. In this way, it is possible to know arteriosclerosis status. Also using the blood pressure on both arms and legs, it is possible to know arteriosclerosis status. Ankle Brachial Index: Since the resistance in peripheral areas (Ankle) is stronger, blood pressure is 1.2 to 1.4 times higher than the one from chest to arms. However, if it is less than 0.9 times, there is a high possibility of blood circulation disorder. Therefore, the PWV measurement can indicate the status of arteriosclerosis based on the velocity of blood flow. 

APG Accelerated Photoplethysmograph is a waveforms of the change of blood volume in the peripheral area. APG (Accelerated Photo plethysmograph) uses the second derivative of the waveform of the photopletysmography to stabilize the baseline and to separate components of the waveform more clearly than the first derivative. The blood volume change by a left ventricle contraction is delivered to the peripheral areas at every 1.16 sec, and it can be indicated as waveforms. In this way, valuable information on arterial and peripheral circulation status, and early detection of arteriosclerosis.   

Both APG and PWV are a measurement for arteriosclerosis. However, APG uses waveforms from the blood volume change, and PWV uses the velocity of blood flow. In terms of PWV, it is a common method among doctors but it costs a lot of money and requires a lot of time for the test. On the other hand, APG test is cheaper than PWV and takes a short time.