Electrocardiogram: his bundle potentials can be recorded noninvasively beat by beat on surface electrocardiogram
© The Author(s). 2017
Received: 26 November 2016
Accepted: 8 March 2017
Published: 15 March 2017
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.
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 PAs (PA interval recorded on surface electrocardiogram), AHs (AH interval recorded on surface electrocardiogram) and HVs (HV interval recorded on surface electrocardiogram) interval recorded on surface “new electrocardiogram” and PA, AH, HV interval recorded on His bundle electrogram was investigated.
There was no difference (P > 0.05) between groups in HVs interval (49.63 ± 6.19 ms) and HV interval (49.35 ± 6.49 ms). Results of correlational analysis found that HVS interval was significantly positively associated with HV interval (r = 0.929; P < 0.01).
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.
KeywordsElectrocardiogram His bundle electrogram New wavelets His bundle potential
An electrocardiogram exam plays an irreplaceable role in the diagnosis of arrhythmia . To our knowledge, the potentials of specialized conduction system on surface electrocardiogram have not been recorded yet in human. Therefore, it is difficult to evaluate the sinoatrial function, locate the site of atrioventricular block and identify the origin of a wide QRS complex on surface. Although sinoatrial node potential [2–5] and His bundle potential [6–15] can be recorded in intracardiac electrophysiology study, it isn’t in a wide range of applications due to its invasive exam. With the clinical expectation, we used new electrocardiogram machine (model PHS-A10) and not only the P-QRS-T waves but also the micro-wavelets on surface electrocardiogram were firstly recorded in healthy and arrhythmia volunteers. In healthy and arrhythmias volunteers, we have found that the micro-wavelets before QRS complex (overlapped on P wave and in PR segment) may be related to atrioventricular conduction system potentials [16, 17]. In this study, we further verified the relationships between the micro-wavelets before QRS complex and atrioventricular conduction system potentials. According to the position and characteristics of these micro-wavelets before QRS complex, PR interval recorded on “new electrocardiogram” was divided into three intervals: PAs (PA interval recorded on surface electrocardiogram) interval, AHs (AH interval recorded on surface electrocardiogram) interval and HVs (HV interval recorded on surface electrocardiogram) interval. Comparative analysis of PAs, AHs and HVs interval recorded on surface “new electrocardiogram” and PA, AH, HV interval recorded on His bundle electrogram was investigated in 65 patients undergoing radiofrequency catheter ablation of paroxysmal superventricular tachycardia. Now we present our preliminary analysis.
Sixty-five patients who were proved to have a paroxysmal supraventricular tachycardia formed the subjects of this study in the First Affiliated Hospital of Liaoning Medical University. There were 31 males and 34 females, with a mean age of 52 ± 13 years (ranging from 14 to 84 years). All patients were included 4 groups according to the intracardiac electrophysiology study: 33 patients with atrioventricular nodal reentrant tachycardia; 29 patients with atrioventricular reentrant tachycardia (exclude overt Wolff-Parkinson-White syndrome); one patient with atrial tachycardia; two patients with paroxysmal atrial fibrillation. We used a “new electrocardiogram” machine (model PHS-A10) designed and developed by EmCG US company to record surface electrocardiogram. The intracardiac electrophysiology study was performed by an electrophysiological recording and the analysis system Model CardioLab 7000 (GE Co., USA).
- 1.Recording conditions: The subject’s skin was firstly pretreated with sandpaper, and then special electrodes (non-cytotoxic silver/silver chloride substrate) are used to perform the test, in which the arrangement of electrodes were the same as that in a 12 lead electrocardiogram. In addition, both “new electrocardiogram” [It was coined the term of saahECG (SAN-Atrial-AVN-His ECG) by the developers] and “conventional electrocardiogram” have been detected synchronously by the “new electrocardiogram” machine. Moreover, the scanning speed (25 mm/s) and amplitude (10 mm/mV), and the measuring speed (25 mm/s) and amplitude (20 mm/mV) in long trace leads were selected. The micro-wavelets before P wave, before QRS complex (in P wave and PR segment) and after QRS complex (ST segment and upstroke of T wave) can be recorded by the “new electrocardiogram” machine (Fig. 1a, b and c segments, the wavelet mechanism refers to discussion part 1).
- 2.Mapping of HVs, AHs and PAs intervals on surface electrocardiogram was as following: 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). The values of each intervals measured by the computer were seen in Fig. 2 (principle refer to discussion part 2). These micro-wavelets (the paper speed of electrocardiogram was 25 mm/s and the gain was 20 mm/mV) were amplified (four magnification) on the computer to determine the distinct measuring point (always in leads II or V5). The values of each intervals (ms) measured by the computer.
Details concerning electrophysiologic study (including His bundle electrogram record and PA, AH, HV interval measurement) were obtained as previously described . They were recorded at paper speeds of 100 mm/sec and be analyzed by ruler in computers (manual selection of measurement points).
The results were given as means ± s.d., Paired t tests were used to compare the index of “new electrocardiogram” and His bundle electrogram. The correlation between the same variables measured by the two methods was analyzed by using Pearson correlation analysis. All statistical analysis was performed using SPSS 16.0. A P-value <0.05 was considered significant.
Comparative analysis of intervals recorded on “new electrocardiogram” and His bundle electrogram
Comparative analysis of intervals recorded on “new electrocardiogram” and His bundle electrogram
31.34 ± 4.17 a
79.86 ± 15.35 a
49.63 ± 6.19
160.83 ± 17.92 a
His bundle electrogram
30.14 ± 4.91
77.20 ± 16.04
49.35 ± 6.49
156.52 ± 19.09
Pearson correlation analysis between PAs, AHs, HVs, PRs intervals recorded on “new electrocardiogram” and PA, AH, HV, PR interval recorded on His bundle electrogram
Why “New electrocardiogram” can record the micro waveform before QRS complex which conventional electrocardiogram couldn’t?
According to the micro-wavelets before QRS complex, PR interval was divided into PAs, AHs and HVs interval on “New electrocardiogram”
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.
In conclusion, our study revealed that His bundle potential can be noninvasively recorded beat by beat in human. It has only begun with a prologue for a new research and still requires a great number of clinical and animal experiments in order to verify the clinical significance, normal scope, characteristics and mechanism of these micro waveforms. The purpose of this study is to put forth in the hope that more doctors and scientists will join hand to greet the second spring of the electrocardiogram.
- AHs :
AH interval recorded on surface electrocardiogram
- HVs :
HV interval recorded on surface electrocardiogram
- PAs :
PA interval recorded on surface electrocardiogram
Special thanks to EmCG US company for their help on record technique. Special thanks to all volunteers. The individuals tested in order to obtain these results were due to non-profit circumstances.
This research is supported by the President Fund of Liaoning Medical University under Grant NO. XZJJ20140202.
Availability of data and materials
All relevant data supporting the conclusions of this article is included within the article.
All authors fulfill the criteria for authorship. RGL conceived and designed the research. GPW, RGL, QHC, ZLX, YJZ, DZP acquired the data. GPW, RGL, QHC, ZLX, YJZ, DZP performed statistical analysis. QHC handled funding and supervision. GPW, RGL, QHC, ZLX, YJZ, DZP drafted the manuscript and made critical revision of the manuscript for key intellectual content. All authors read and approved the final version of the manuscript. All authors have agreed to authorship and order of authorship for this manuscript.
The authors declare that they have no competing interests.
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Ethics approval and consent to participate
All of the subjects gave their informed consent, and the study was approved by the Local Ethics Committee of Liaoning Medical University.
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