New micro waveforms firstly recorded on electrocardiogram in human

A method for noninvasive beat-by-beat visualization of His bundle signals

BACKGROUND

Invasive recording of His bundle signals (HBS) in electrophysiological study (EPS) is important in determining HV interval, the time taken to activate the ventricles from the His bundle. Noninvasive surface measurements of HBS are attempted by averaging typically 100-200 cardiac cycles of ECG time series in body surface potential mapping (BSPM) and in magnetocardiography (MCG) which records weak cardiac magnetic fields by highly sensitive detectors. However, noninvasive beat-by-beat extraction of HBS is challenged by ramp-like atrial signals and noise in PR segment of the cardiac cycle.

METHODS

By making use of a signal-averaged trace showing prominent HBS as a guide trace, we developed a method combining interval-dependent wavelet thresholding (IDWT) and signal space projection (SSP) technique to eliminate artifacts from single beats. The method was applied on MCG recorded on 21 subjects with known HV intervals based on EPS and noninvasive signal-averaging, including five subjects with BSPM recorded subsequently. The method was also applied on stress-MCG of a subject featuring autonomic dynamics.

RESULTS

HBS could be extracted from 19 out of 21 subjects by signal-averaging whose timing differed from EPS between -8 and 11 ms as tested by 2 observers. HBS in single beats were seen as aligned patterns in inter-beat contours and were appreciable in stress-MCG and conspicuous than BSPM. The performance of the method was evaluated on simulated and measured MCG to be adequate if the signal-to-noise ratio was at least 20 dB.

CONCLUSIONS

These results suggest the use of this method for noninvasive assessments on HBS.

Detection of Acute Myocardial Infarction in a Pig Model Using the SAN-Atrial-AVN-His (SAAH) Electrocardiogram (ECG), Model PHS-A10, an Automated and Integrated Signals Recognition System

BACKGROUND The aim of this study was to compare the use of the standard 12-lead electrocardiogram (ECG) with the SAN-Atrial-AVN-His (SAAH) ECG (Model PHS-A10), a new automated and integrated signals recognition system that detects micro-waveforms within the P, QRS, and T-wave, in a pig model of acute myocardial infarction (MI). MATERIAL AND METHODS Six medium-sized domestic Chinese pigs underwent general anesthesia, and an angioplasty balloon was placed and dilated for 120 minutes in the first diagonal coronary artery arising from the left anterior descending (LAD) coronary artery. A standard ECG and a SAAH ECG (Model PHS-A10) were used to evaluate: 1) the number of wavelets in ST-T segment in lead V5; 2) the duration of the repolarization initial (Ri), or duration of the wavelets starting from the J-point to the endpoint of the wavelets in the ST interval; 3) the duration of the repolarization terminal (Rt), of the wavelets, starting from the endpoint of the wavelets in the ST interval to the cross-point of the T-wave and baseline; 4) the ratio Ri: Rt. RESULTS Following coronary artery occlusion, duration of Ri and Ri/Rt increased, and Rt decreased, which was detected by the SAAH ECG (Model PHS-A10) within 12 seconds, compared with standard ECG that detected ST segment depression at 24 seconds following coronary artery occlusion. CONCLUSIONS The findings from this preliminary study in a pig model of acute MI support the need for clinical studies to evaluate the SAAH ECG (Model PHS-A10) for the early detection of acute MI.

Electrocardiogram: his bundle potentials can be recorded noninvasively beat by beat on surface electrocardiogram

Background

The micro waveform of His bundle potential can’t be recorded beat-to-beat on surface electrocardiogram yet. We have found that the micro-wavelets before QRS complex may be related to atrioventricular conduction system potentials. This study is to explore the possibility of His bundle potential can be noninvasively recorded on surface electrocardiogram.

Methods

We randomized 65 patients undergoing radiofrequency catheter ablation of paroxysmal superventricular tachycardia (exclude overt Wolff-Parkinson-White syndrome) to receive “conventional electrocardiogram” and “new electrocardiogram” before the procedure. His bundle electrogram was collected during the procedure. Comparative analysis of PA_s (PA interval recorded on surface electrocardiogram), AH_s (AH interval recorded on surface electrocardiogram) and HV_s (HV interval recorded on surface electrocardiogram) interval recorded on surface “new electrocardiogram” and PA, AH, HV interval recorded on His bundle electrogram was investigated.

Results

There was no difference (P > 0.05) between groups in HV_s interval (49.63 ± 6.19 ms) and HV interval (49.35 ± 6.49 ms). Results of correlational analysis found that HV_S interval was significantly positively associated with HV interval (r = 0.929; P < 0.01).

Conclusions

His bundle potentials can be noninvasively recorded on surface electrocardiogram. Noninvasive His bundle potential tracing might represent a new method for locating the site of atrioventricular block and identifying the origin of a wide QRS complex.

Electrophysiocardiogram: For the first time EPCG has been recorded on human body surface

Since ECG was invented in 1903, this is the first time in history that a full information multi-band and multi-linear electrophysiological cardiogram has been used to successfully scan and record on the human body surface. Since it is able to record various multi-band, multi-track linear electric signals of cardiac electrophysiological activities that correspond to different regions of the entire heart, it has thus been denominated as "electrophysiocardiogram" (EPCG). A traditional ECG is always represented by a characteristic wave form, which resembles a string. For a long period of time, ECG has had a lot of mysteries surrounding it, it maybe because ECG has a lot of mixed signals buried in such convolutionary forms, which limits the amount of the signals that are discernable and determinable. For the first time, the EPCG technology has allowed cardiac signals to be convoluted into the linear wave form, which is then processed through various new approaches featuring multiple frequency bands, multiple dimensions and multiple patterns, and consequentially recorded as the following types of signals within the ranges of P wave and T wave: multiple frequency band signals, signals of different regions and different locations, forward waves and negative waves. Therefore, EPCG may help to solve many puzzling scientific questions regarding heart, such as exactly how many electric signals are involved in heart excitation, pacing, conduction and action, as well as many other intriguing questions about heart, and thus would become a very helpful tool in clinical practice.