KardioAS Research
Publications & Research

Technical research behind the measurement systems

Preprints by Safin Aydar covering transmissive photoplethysmography, pulse-to-pulse interval measurement and technical validation against reference ECG.

Preprint Published June 15, 2026 Version 1

LifePulsePro as an intelligent transmissive PPG sensor for heart rate variability assessment

Safin Aydar

01

This paper describes LifePulsePro as a transmissive photoplethysmographic system for pulse-wave acquisition, pulse-interval extraction and HRV analysis under standardized resting conditions. The device combines optical sensing, mechanical finger fixation, embedded signal processing, quality control and wired communication with external software.

Methodological focusExplains the physiological difference between ECG RR intervals and PPG-derived pulse intervals.
System conceptEmbedded pulse detection, interval calculation, quality control and structured data transfer.
Practical conclusionUnder stable resting conditions, pulse interval dynamics can closely reproduce ECG-derived timing for HRV assessment.
Read full text on Zenodo ↗ Zenodo record 20707180
Preprint Published June 8, 2026 Version 1

Comparison of Transmissive and Reflective Photoplethysmography for Pulse Wave Recording and Pulse Variability Analysis

Safin Aydar

02

The paper compares transmissive and reflective PPG with emphasis on a demanding use case: obtaining a reliable sequence of pulse-to-pulse intervals for subsequent HRV/PRV analysis, rather than merely displaying a visible pulse waveform.

Transmissive clip

Mechanical finger fixation and USB data transfer provide a more stable primary signal for interval-based analysis.

Reflective sensor

Suitable for approximate pulse monitoring in the described implementation, but scientific pulse-variability use requires further validation, strict signal-quality control and artifact handling.

Read full text on Zenodo ↗ Zenodo record 20594659
Preprint Published June 15, 2026 Version v2

Accuracy assessment of the LifePulsePro photoplethysmographic sensor for pulse interval measurement compared with reference electrocardiography

Safin Aydar

03

A pilot technical validation compared consecutive LifePulsePro pulse intervals with ECG RR intervals recorded using the BTL Flexi 12 ECG system and BTL CardioPoint software. Recordings were made at rest in the supine position and synchronized interval by interval.

3subjects
6paired recordings
139matched intervals
1.90–8.97 msmean absolute error
0.20–1.03%mean absolute percentage error
0.9726–0.9978Pearson correlation
Key result

The largest individual absolute difference was 25.35 ms. Bland–Altman analysis reported a mean bias of 0.00 ms with 95% limits of agreement from −10.77 to +10.77 ms. The study presents these results as pilot evidence of good agreement under stable resting conditions, not as evidence that PPG replaces diagnostic ECG.

Read full text on Zenodo ↗ Zenodo record 20706051
Research context

Why these studies matter

Together, the three papers address complementary questions: how a transmissive PPG system can be designed for interval analysis, how transmissive and reflective acquisition differ for pulse-variability work, and how LifePulsePro interval measurements compare with reference ECG in a pilot resting study.