# Detection of Ischemic Episodes Based on Two Consecutive Declines in the JT/ST Algebraic Relationship

^{1}

^{2}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Materials and Methods

#### 2.1. The Description of the Experimental Setup

^{2}. Three subjects experienced clinical indications for load limitations, and therefore, the load was kept constant for one minute and then increased by 50 W.

#### 2.2. Corrected versus Noncorrected Cardiac Intervals

#### 2.3. The Algorithm for the JT/ST Algebraic Relationship

#### 2.4. Qualitative Evaluation of Two Consecutive Declines in the JT/ST Algebraic Relationship

## 3. Results

#### 3.1. Person #1

#### 3.2. Healthy Persons #2–#7

#### 3.3. Persons with Suspected Ischemic Heart Disease #8–#10

## 4. Discussion

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 2.**The dynamics of the JT/ST relationship during the load and the recovery processes for person #1 The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 3.**The dynamics of the JT/ST relationship during the load and recovery processes for person #2. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 4.**The dynamics of the JT/ST relationship during the load and recovery processes for person #3. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 5.**The dynamics of the JT/ST relationship during the load and recovery processes for person #4. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 6.**The dynamics of the JT/ST relationship during the load and recovery processes for person #5. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 7.**The dynamics of the JT/ST relationship during the load and recovery processes for person #6. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 8.**The dynamics of the JT/ST relationship during the load and recovery processes for person #7. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 9.**The dynamics of the JT/ST relationship during the load and the recovery processes for person #8. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 10.**The dynamics of the JT/ST relationship during the load and recovery processes for person #9. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

**Figure 11.**The dynamics of the JT/ST relationship during the load and recovery processes for person #10. The x-axis in parts (

**A**,

**B**) represents the time (measured in minutes) from the beginning of the cycle ergometry exercise. The left y-axis in part (

**B**) represents the power of the load in Watts. The right y-axis in part (

**B**) represents the variation of the RR interval in ms. The algebraic JT/ST relationship is represented by the thin dashed black line in part A. The thick black solid vertical line in part A marks the end of the load.

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**MDPI and ACS Style**

Šiaučiūnaitė, V.; Vainoras, A.; Navickas, Z.; Ragulskis, M.
Detection of Ischemic Episodes Based on Two Consecutive Declines in the JT/ST Algebraic Relationship. *Appl. Sci.* **2021**, *11*, 4805.
https://doi.org/10.3390/app11114805

**AMA Style**

Šiaučiūnaitė V, Vainoras A, Navickas Z, Ragulskis M.
Detection of Ischemic Episodes Based on Two Consecutive Declines in the JT/ST Algebraic Relationship. *Applied Sciences*. 2021; 11(11):4805.
https://doi.org/10.3390/app11114805

**Chicago/Turabian Style**

Šiaučiūnaitė, Vaiva, Alfonsas Vainoras, Zenonas Navickas, and Minvydas Ragulskis.
2021. "Detection of Ischemic Episodes Based on Two Consecutive Declines in the JT/ST Algebraic Relationship" *Applied Sciences* 11, no. 11: 4805.
https://doi.org/10.3390/app11114805