Non-invasive Electrophysiology IEpsilon waves detected by various electrocardiographic recording methodsDisplaying non-linear dynamic properties of the heart using a novel time-frequency analysis technique: the electro spectrogram (ESG)Evaluation and prospect of electrocardiography, vectorcardiography and four-dimensional electrocardiographyHeart rate variability of Uygur elderly in Hetian RegionThe diagnostic work-up and clinical pathway of patients with syncope in clinical practice: results from PICTURE, a large, international, observational multicentre study

# Epsilon waves detected by various electrocardiographic recording methods {#article-title-2} Objective We analysed the shape and distribution of epsilon waves by three various methods of electrocardiographic recording in patients with arrhythmogenic right ventricular cardiomyopathy. Methods Thirty-two patients who met recognized diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy were included in this study (24 men and 8 women; mean age, 42.3 ± 12.9 years). Epsilon waves were detected by standard 12-lead electrocardiography (S-ECG), right-sided precordial lead electrocardiography (R-ECG), and Fontaine bipolar precordial lead electrocardiography (F-ECG). Results We found three types of epsilon waves: wiggle waves, small spike waves, and smooth potential waves that formed an atypical prolonged R′ wave. The most common configuration was small spiked waves. In some circumstances, epsilon waves were evident in some leads (especially in leads V1 through V3), but notches were recorded in the other leads during the corresponding phase. These waves could be detected only by S-ECG in one patient, R-ECG in three patients, and F-ECG in five patients; the rates of epsilon-wave detection by these three methods were 38% (12/32), 38% (12/32), and 50% (16/32), respectively. However, the detection rate using combined methods was significantly higher than that by S-ECG alone (SF-ECG 56% vs. S-ECG 38%, P = 0.0312; and SRF-ECG 66% vs. S-ECG 38%, P = 0.0039). In addition, the rate of widespread T-wave inversion (exceeding V3) was significantly higher in patients with epsilon waves than in those without (48 vs. 9%, P = 0.029), as was ventricular tachycardia (95 vs. 64%, P = 0.019). Conclusion These three electrocardiographic recording methods should be used in combination to improve the detection rate of epsilon waves. # Displaying non-linear dynamic properties of the heart using a novel time-frequency analysis technique: the electro spectrogram (ESG) {#article-title-3} Analysis of self-regulating properties of the heart is complicated by substantial variability of the sources of electrical activity and their large temporal overlap. A new approach based on dynamic spectral analysis (DSA) and high-resolution fragmentary decomposition (FD) techniques resolves these limitations. Where previous methods by fast Fourier transformation (FFT) processed long stationary segments of the electrocardiogram (ECG) time series, this technique provides frequency-based ECG analysis for short recording windows of any length. We define the frequency domain images of these functional elements as the electro spectrogram (ESG). Methods A toolkit of ECG non-stationary time series analysis incorporating the algorithms of DSA and FD was developed to display dynamic components of conventional ECG signals. Surface 12-lead recordings were acquired in subjects with and without heart disease using a standard commercial recorder (Mortara Instrument, Inc.) at sampling rate 1000 Hz, with a frequency response of 0.03–300 Hz. Characteristic control parameters were identified as the natural frequency and damping ratio. ![Figure][1] Results Analysis of single and multiple complexes of various morphologies revealed distinct waveform sub-components within ECG segments. The temporal overlap of major ECG component waves was resolved and we identified discrete signal sources reflecting dynamic elements of underlying control systems. Conclusions The application of non-linear dynamic processing of conventional ECG signals produces a novel image display, the ESG, which promises the exploration of hitherto hidden diagnostic potential of electrophysiological signals. This may facilitate the analysis of dynamic control loops, correlation with mechanical properties of the heart, as well as provide insights into arrhythmogenic mechanisms. # Evaluation and prospect of electrocardiography, vectorcardiography and four-dimensional electrocardiography {#article-title-4} By integrating the key features of three methods electrocardiography (ECG), vectorcardiography (VCG), and four-dimensional electrocardiography (4D-ECG), a more comprehensive and precise understanding of the myocardial electro-chemical spreading can be achieved. This integrated method could reveal the most comprehensive, detailed, accurate, concise, practical, and unique inspection of cardio-electrical activities. Based on geometry concept in mathematics, it can classify the traditional electrocardiography into two-dimensional electrocardiogram (2D-ECG), the vectorcardiography into three-dimensional planar electrocardiogram (3D-ECG), and the orthogonal axis vs. time electrocardiography into four-dimensional electrocardiogram (4D-ECG). Although they use different lead systems, they can be integrated. The structure and conducting function of conduction bundles, myocardial cells, and the spreading electro-chemical activities produce the three-dimensional vector. The three-dimensional vector project on the frontal, horizontal, and side plane forms the planar VCG (first projection). The planar VCG from frontal and horizontal plane furthers the project onto certain angled-axis to produce linear ECG (second projection). In fact, 2D-ECG, 3D-ECG, and 4D-ECG all are recording bioelectricity activity from heart, but express in three different forms. Each of them has its strengths. We have successfully integrated various lead systems to produce one integral machine that records the electro-cardiac signals synchronically, interchangeable from all angle and all direction, thus providing better and clearer picture of the heart activities resulting in early diagnosis of most heart problems. # Heart rate variability of Uygur elderly in Hetian Region {#article-title-5} Objective It is believed that heart rate variability (HRV) has strong prognostic value in elderly. But there are few reports on HRV of healthy longevity. The heart rate variability of Uygur elderly in Hetian, including 108 longevity was studied, and the HRV characters of them were evaluated. Methods A total of 250 Uygur subjects ages from 60 to 109 years old in Hetian region were selected as study group and divided into three groups, including Uygur longevity group, Uygur pre-longevity group, and Uygur old group. Forty-two subjects from Han nationality were selected as control. All subjects were physically healthy with no history of hypertension, diabetes, and their routine blood chemistry, electrocardiography did not show any significant abnormalities. Holter records were obtained by using Japan Avionic Delmar Cardiorecorders. Subjects were asked to keep their daily activities during recording. Results No HRV differences were noticed among Uyghur groups, but the HRV between two nationalities were different. There were day to night and sex differences in Uygur groups. Conclusions The unique autonomic nerve balance is one of the causes of longevity in Hetian Uygur elderly. # The diagnostic work-up and clinical pathway of patients with syncope in clinical practice: results from PICTURE, a large, international, observational multicentre study {#article-title-6} Background and objectives Identification of the mechanism of syncope is often costly and time consuming, requiring extensive investigation. PICTURE aimed to describe the clinical pathway and burden of diagnostic tests of patients with syncope until a decision to implant an implantable loop recorder (Reveal®, Medtronic Inc.) was made. Methods PICTURE is an observational, international, multicentre study, carried out at 71 sites in 11 countries. Patients received their Reveal® on clinical indications, and were followed for 10 ± 6 months. Demographics, previous healthcare contacts, and tests were analysed. Results Five hundred and seventy patients (61 ± 17 years, 54% women) were included. In their care pathway, they met general and emergency medicine practitioners ( n = 357, 63% and n = 207, 36%), cardiologists and electrophysiologists ( n = 521, 91% and n = 166, 29%), Internists ( n = 214, 38%) and neurologists ( n = 270, 47%). An average of three (IQ 2–4) different specialists was consulted, and the median number of tests was 13 (IQ range 9–20). In PICTURE, 22% of patients received their Reveal® in the initial phase of the diagnostic work up. Once Reveal® was implanted, 78% of recurrent syncope episodes were diagnosed. Conclusions A high number of tests prescribed by an average of three different physicians represented a high burden on healthcare resources. The PICTURE results imply that an earlier use of Reveal® ILR might lead to earlier diagnosis and treatment, while the number of diagnostic tests and physician visits could have been reduced. The PICTURE results support the recommendations in the ESC 2009 guidelines for the diagnosis and management of syncope. [1]: pending:yes