Why “New electrocardiogram” can record the micro waveform before QRS complex which conventional electrocardiogram couldn’t?
The PHS-A10 electrocardiogram is a new device created by EmCG US company using the latest technology of the software and the hardware, and the signal processing technology. These are based on a collection of various US patents and International patents. The PhySio’s PHS-A10 is highlighted by its success in employing a novel Adaptive Mixture Technology within the electrocardiogram Signal Spectrum enabled by PhySio’s Smart Data Acquisition Module. Along with traditional electrocardiogram scanning/recording, PHS-A10 is able to accurately extract a variety of time-domain electrocardiogram electric potentials in the 0-150Hz range, and perform automated integrating signals recognition. Therefore, not only the P-QRS-T waves but also the micro-wavelets before P wave, before QRS complex (overlapped on P wave and in PR segment), after QRS complex (ST segment and upstroke of T wave) can be recorded on surface electrocardiogram (Fig. 1a, b, c segments). Besides, on base of new wavelets recorded by “new electrocardiogram”, the Electrophysiocardiogram has further been created by EmCG US company. Electrophysiocardiogram has separated the acquired convoluted signals into a plurality of different linear wave forms in various frequency ranges, for examples, for the frequency range from 1 to 150 Hz (conventional electrocardiogram), and it has been divided into 32 linear wave forms. Therefore, these wavelets can be revealed more clearly . The resulting electrocardiogram wavelet signals are displaying the natural signals of various parts of the heart (before P wave, before QRS complex and after QRS complex) without interfering artifacts in our 100 healthy volunteers . In our study, we only discuss the wavelet before QRS complex.
According to the micro-wavelets before QRS complex, PR interval was divided into PAs, AHs and HVs interval on “New electrocardiogram”
(1) In 100 healthy individuals, we have found that the new electrocardiogram can record characteristic wavelets before QRS complex: two wavelets in PR segment with higher amplitude closest to QRS complex and one to three wavelets with lower amplitude before these two wavelets) . The wavelets in P wave and PR segment might be related to atrioventricular node and His bundle- bundle potentials due to cardiac anatomy and the sequence of electrical activation. (2) In patients with atrial (atrial contraction, atrial tachycardia, atrial flutter, atrial fibrillation) and junctional arrhythmias (premature junctional contraction, junctional escape), we also have found the characteristic wavelets above. In patients with ventricular arrhythmias (premature ventricular contraction, ventricular tachycardia, ventricular pacing), there was no micro waveform before the wide QRS complex . These suggested the wavelets before QRS complex might be related to atrioventricular conduction system potentials. (3) In patients with second degree atrioventricular block type I (atrioventricular node level block), we have found that two wavelets in PR segment with higher amplitude closest to QRS complex were constant and several wavelets with lower amplitude before these two wavelets (overlapped in P wave and after the P wave) were progressive increased according to the progressive lengthening PR interval . These suggested this two wavelets closed to the QRS complex with high amplitude might be related to His bundle and bundle branch potentials. (4) Based on the above study, we preliminary recognized that PR interval was divided into PAs interval (the time interval from the initiation of the P wave to the first notch of the P wave), AHs interval (the time interval from the first notch of the P wave to the initiation of the second wavelet with higher amplitude closed to the QRS complex) and HVs interval (the time interval from the initiation of the second wavelet with higher amplitude closed to the QRS complex to the start of the QRS complex). A finding in our 100 healthy individuals was that the PAs, AHs and AHs intervals were consistent with the intra-atrial measurement PA, AH and HV intervals . In the patient with first-degree atrioventricular block at atrioventricular nodal level which verified by intracardiac electrogram, we have observed on new electrocardiogram that two wavelets in PR segment with higher amplitude closest to QRS complex maintained unchanged and the number of wavelets with lower amplitude before these two wavelets was increased. Thus, these confirmed that PR interval was divided into PAs, AHs and HVs interval.
Comparative study of PAs, AHs and HVs interval recorded on “New electrocardiogram” and PA, AH and HV interval recorded on His bundle electrogram
(1) A finding of Paired t tests in our study in 65 paroxysmal supraventricular tachycardia underwent “New electrocardiogram” and His bundle electrogram (these two weren’t simultaneously recorded) was that there was no difference (P > 0.05) between groups in HVs interval and HV interval. Results of correlational analysis found that HVS interval was significantly positively associated with HV interval (r = 0.929; P < 0.01). These suggested two wavelets closed to the QRS complex with high amplitude in HVs interval was His bundle and bundle branch potentials on surface electrocardiogram. (2) A finding of Paired t tests revealed there were differences (P < 0.05) between groups in AHs interval (79.86 ± 15.35 ms) and AH interval (77.20 ± 16.04 ms). The means difference of AHs and AH interval was in a few milliseconds and was in the range of physiological changes (autonomic nerve change) of AH interval (20–50 ms) . Therefore, there was no clinical significance. Besides, results of correlational analysis found that AHs interval was significantly positively associated with AH interval (r = 0.792; P < 0.01). Therefore, the wavelets (overlapped in P wave and after the P wave) in AHs interval may be atrioventricular nodal potential.
(1) “New electrocardiogram” and His bundle electrogram weren’t simultaneously recorded. Therefore, autonomic nerve change may have effect on atrioventricular nodal, leading to differences between groups in AH interval and PR interval. (2) The paper speed of “New electrocardiogram” weren’t consistent with His bundle electrogram. The paper speed of “New electrocardiogram” was 25 mm/s and the paper speed of His bundle electrogram was 100 mm/s. If the paper speed of “New electrocardiogram” was 100 mm/s, the acute angle of the wavelet before QRS complex became blunt. Therefore, it was difficult to determine the starting point. To reduce the impact of paper speed, the body surface measurements were amplified (four magnification) on the computer. It can not completely exclude the impact of paper speed. (3) In AHs interval, the A point was the initiation of the first notch of the P wave (not an acute angle), but the starting point of A wave in His bundle electrogram was clear. Although these limitations didn’t have effect on clinical significance of our result, the normal scope of PAs, AHs and HVs interval can’t be applied mechanically according to the intracardiac electrophysiology study. It still required statistical analysis of large sample.