Equivalence of Analog and Digital High-Frequency Electrocardiogram: Validating Sydäntek for Ischemia Detection

High-frequency electrocardiography (HF-ECG) in the 100–500 Hz range enhances ischemia detection by capturing microvolt-level QRS changes, yet its clinical adoption requires the validation of digital systems against analog standards. HF-ECG signals were recorded simultaneously from 12 healthy subjects (84 beats total) using a 5-stage analog system (100–500 Hz bandpass, gold connectors) and Sydäntek’s 10x capacitive sensors, both digitized via Texas Instruments ADS1298. Signals underwent 10x amplification (low-noise op-amp), with analog scaled to match, and were processed by PulseTek™ and stored in PulseVault™. Amplitude, root mean square (RMS), kurtosis, and frequency content were analyzed using Bland-Altman methods, with analog as the standard; values reflect pre-amplified measurements in microvolts (µV). Mean differences (analog minus Sydäntek) were minimal—RMS: 6.39 µV (95% LOA: -49.74 to 62.52 µV), amplitude: 1.82 µV (-57.09 to 60.73 µV), kurtosis: 1.93 (-5.13 to 1.54), frequency: 2.1 Hz (-5.8 to 6.2 Hz)—all within 5% clinical tolerance when scaled 10x (~ 10–20 mV). Sydäntek matched analog fidelity, with frequency peaks at ~ 150 Hz. Sydäntek’s digital HF-ECG performance is equivalent to analog systems, validated by tight agreement in key metrics. Its wearable design and cloud integration via PulseVault™ and PulseTek™ offer a portable, reliable alternative for ischemia detection, supporting broader clinical applications.