Introduction: Rate Based Arrhythmia Detector Using Arduino
Heart arrhythmias afflict approximately four million Americans each year (Texas Heart Institute, par. 2). While every heart experiences permutations in rhythm and rate, chronic cardiac arrhythmias can be fatal for their victims. Many cardiac arrhythmias are also transient, meaning that diagnosis can be difficult. In addition, the detection process can be costly and inconvenient. A patient may be required to wear a Holter or event monitor over a period ranging from several days to one month, undergo cardiac catheterization, or have a loop recorder implanted under the skin. Many patients decline diagnostic tests due to nuisance value and cost (NHLBI, pars. 18-26).
Recently, several cases have been reported in which smart watches such as the Apple Watch perceived rhythmic anomalies on their pulse sensors, spurring the wearers to seek medical treatment (Griffin, pars.10-14). However, smart watches are expensive, so they are not used by a majority of the population. Financial resources factored as both a criterium and a constraint for the Rate-Based Arrhythmia Detector (RAD), as high-priced components could not be afforded, and the device needed to be both relatively affordable and convenient while still accurately recognizing arrhythmias.
Step 1: Materials
- Arduino UNO circuit board
- twenty-six jumper wires
- A10K Ohm Potentiometer
- A 6x2 LCD
- A pulse sensor
- An Alkaline 9V Battery
- A USB 2.0 A to B Male/Male type peripheral cable
- An Alkaline battery/9V DC input
- A one-row Breadboard, soldering and unsoldering tools
- 16 columns of breakaway pins
- The Arduino IDE downloaded for coding and the pin connections
Step 2: Design and Methodology
The Rate-Based Arrhythmia Detector was initially designed as a bracelet. However, it was later recognized that its hardware was not compact enough to fit in this form. RAD is currently attached to a 16.75x9.5cm. styrofoam board, making it still portable, lightweight, and convenient when compared to other forms of arrhythmia detection. Alternatives were explored as well. RAD was proposed to recognize abnormalities in the electrical PQRST complex, but cost and size restraints did not allow for the device to possess electrocardiogram (EKG) capabilities.
RAD is user-oriented. It simply requires a user to rest his or her finger on its pulse sensor and allow it approximately ten seconds to stabilize. If a patient’s pulse falls into a range associated with erratic heart behaviors such as bradycardia or tachycardia, the LCD will notify the patient. RAD can recognize seven major cardiac pace abnormalities. RAD was not tested on patients with previously diagnosed arrhythmias, but the device did detect “arrhythmias” simulated by putting the engineers under physical strain prior to testing the device and by mimicking a pulse for the infrared sensor to detect. While RAD possesses primitive input hardware compared to other arrhythmia diagnostic devices, it serves as an economical, user-oriented monitoring device that can be especially helpful to patients with genetic or lifestyle predispositions to arrhythmia development.
Step 3: Heart Sensor
The heart sensor used in this project uses infrared waves that passes through skin and gets reflected from the designated vessel.
The waves are then reflected from the vessel and read by the sensor.
The data are then transferred to the Arduino for the LCD to be shown.
Step 4: Connections
1. The first pin of the LCD (VSS) was connected to the ground (GND)
2. The second pin of the LCD (VCC) was connected to the 5V power input of the Arduino
3. The third pin of the LCD (V0) was connected to the second input of the 10K Potentiometer
4. Either of the pins of Potentiometer was connected to the ground (GND) and the 5V power input
5. The fourth pin of the LCD (RS) was connected to pin twelve of the Arduino
6. The fifth pin of the LCD (RW) was connected to the ground (GND)
7. The sixth pin of the LCD (E) was connected to pin eleven of the Arduino
8. The eleventh pin of the LCD (D4) was connected to pin five of the Arduino
9. The twelfth pin of the Arduino (D5) was connected to pin four of the Arduino
10. The thirteenth pin of the LCD (D6) was connected to pin three of the Arduino
11. The fourteenth pin of the LCD (D7) was connected to pin two of the Arduino
12. The fifteenth pin of the LCD (A) was connected to the 5V power input
13. Lastly, the sixteenth pin of the LCD (K) was connected to the ground (GND).
14. The S wire of the Pulse Sensor was connected to the A0 pin of the Arduino,
15. The second wire was connected to the 5V power input, and the third pin was connected to the ground (GND).
The scheme is posted for better understanding the connections.
Step 5: IDE and the Codes
The codes were implemented on the Arduino IDE. C and Java programming languages were used to code the IDE. Initially, LiquidCrystal library was called by the #include method, then fields and parameters of twelve, eleven, five, four, three, two corresponding to the used Arduino pins connected to the LCD were inserted. Variable initializations were performed and the conditions for the BPM measurements and comments were set to the desired outputs to be shown on the LCD. The code was then completed, verified, and uploaded to the Arduino board. The LCD display was calibrated using the Potentiometer to view the comments ready for the trials.
Step 6: Conclusion
RAD does serve as a less expensive and more convenient and portable form of cardiac arrhythmic detection. However, much more testing is necessary in order for RAD to be considered a reliable arrhythmic diagnostic device. In the future, trials will be conducted on patients with previously-diagnosed arrhythmias. More data will be collected in order to determine if any arrhythmias correspond to fluctuations in the time gap between heartbeats. Hopefully, RAD can be further improved to detect these irregularities and link them to their respective arrhythmias. While there is much to be done in terms of development and testing, the Rate-Based Arrhythmia Detector meets its objective by successfully recognizing several arrhythmias and evaluating heart health under its economic and size constraints.
Holter Monitor: $371.00
Event Monitor: $498.00
Cardiac Catheterization: $9027.00
Chest X-Ray (CXR): $254.00
Electrocardiogram (ECG/EKG): $193.00
Tilt Table Test: $1598.00
Transesophageal Echocardiography: $1751.00
Radionuclide Ventriculography or Radionuclide Angiography (MUGA Scan): $1166.00
Rate-Based Arrhythmia Detector (RAD): $134.00
Step 7: The Last One!
After the connection the LCD on the Heart sensor should turn on,
Simply place your finger on the LED for about 10 seconds.
Read the heart beat from the 16X2 LCD... Stay Heathy!
Participated in the
Arduino Contest 2019