Clinical stage of acquired immunodeficiency syndrome in HIV-positive patients impacts the quality of the touch ECG recordings.

INTRODUCTION: HIV patients are at higher risk for cardiovascular disease and cardiac arrhythmias which can be recorded by a handheld single­lead ECG device. Quality of ECG depends on the skin condition, which worsens with the progression of HIV infection. OBJECTIVE: To study the quality of the ECG signal acquired by a mobile ECG device in patients with different clinical stages of human immunodeficiency virus (HIV) infection. PATIENTS AND METHODS: We studied the quality of 30-second single lead ECGs obtained by a handheld ECG device (Kardia; AliveCor Inc., San Francisco, USA) in 263 Kenyan adults (203 women) in various stages of HIV. The recordings were made during routine check-ups at the outpatient clinics. ECG quality was categorized as readable (not interfering with clinical interpretation) or unreadable (impossible clinical interpretation). The progression of the HIV infection was estimated using the World Health Organization AIDS Clinical Staging (WACS) scale, ranging from stage 1 (asymptomatic generalized lymphadenopathy) to stage 4 (wasting syndrome and Kaposi sarcoma). RESULTS: The median age of patients was 46 (39-53) years. ECG was readable in 201 patients (76.4%) and unreadable in 62 (23.6%). The WACS score > 1 was associated with 3.95 odds ratio (95% confidence interval 2.14-7.29; p < 0.0001) for the acquiring an unreadable ECG (univariate logistic regression adjusted to age, sex, body mass index and time since HIV). CONCLUSIONS: ECG quality recorded by a touch ECG device worsens with advancing HIV infection. For this reason, the accuracy of arrhythmia diagnosis by mobile ECG appears to be limited in HIV patients.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry.

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

2017 ISHNE-HRS expert consensus statement on ambulatory ECG and external cardiac monitoring/telemetry.

Ambulatory ECG (AECG) is very commonly employed in a variety of clinical contexts to detect cardiac arrhythmias and/or arrhythmia patterns which are not readily obtained from the standard ECG. Accurate and timely characterization of arrhythmias is crucial to direct therapies that can have an important impact on diagnosis, prognosis or patient symptom status. The rhythm information derived from the large variety of AECG recording systems can often lead to appropriate and patient-specific medical and interventional management. The details in this document provide background and framework from which to apply AECG techniques in clinical practice, as well as clinical research.

Biopotential fiber sensor.

UNLABELLED: We have developed a new biopotential fiber sensor (BFS) technology as an alternative to traditional wet-gel Ag/AgCl electrodes in long-term monitoring applications. Biopotential fiber sensor technology uses proprietary method of bonding copper sulfide to the surface of acrylic fibers, thus creating an electrically conductive medium (10(-1) ohms/cm). Surface modified bundles of acrylic fibers form stable biopotential sensors when doped with proprietary ink comprising organic acids and nano particles of Ag and AgCl. Biopotential fiber sensors are characterized by a small footprint 0.1 mm2 and low mass of 0.005 g. Biopotential fiber sensor systems are disposable 1-piece assemblies combining the functions of the electrodes, lead wires and a patient cable. METHODS: The electric performance characteristics of BFS were obtained according to American National Standards Institute/Association for the Advancement of Medical Instrumentation EC-12:2000 standard and compared with Ag/AgCl wet-gel electrodes. The noise characteristics were determined from 250 hours of 3-lead electrocardiographic (ECG) data recorded with BFS over a period of 10 days from healthy volunteers. RESULTS: The BFS direct current offset voltage was 0.11 mV and alternate current impedance at 10 Hz was 22 ohms. The sensors average longevity on the body surface with no detachments was at least 7 days. BFS demonstrated high immunity to motion and electric field-induced artifacts. CONCLUSIONS: Biopotential fiber sensors are well suited for routine long-term ECG monitoring applications because of increased patient comfort through integration of the electrode, lead wire, and a patient cable, which function into one disposable BFS fiber assembly. Biopotential fiber sensor have electrical characteristics comparable to Ag/AgCl wet electrodes. We observed an improved ECG signal quality, reduced frequent electrode detachments, reduced wire clutter and entanglement, and improved sensor adherence to the skin over longer periods of time.

Development of a new QT algorithm with heterogenous ECG databases.

An algorithm for automated QT interval assessments has been developed and evaluated using the PhysioNet QT database and the electrocardiogram multilead database (2 collections of electrocardiograms with different characteristics, eg, numbers of leads and expert annotations). QRS onset and coarse T offset detection was based on the definition of a short time window, within which the range of signal amplitudes was calculated and compared to given threshold values. The final position of T offset was based on a combination of 3 methods: decreasing thresholds, multiple tangents, and a model based approach. The evaluation was based on the comparison of a waveform marker as computed automatically, and those of the human experts. Mean and standard deviation of those differences compared well to other algorithms and to inter-expert variations. Waveform marker detection was successful in at least 98% of the annotated beats in both databases, thus, indicating the robustness of the proposed method.

State of the art techniques for preservation and reuse of hard copy electrocardiograms.

Baseline examinations and periodic reexaminations in longitudinal population studies, together with ongoing surveillance for morbidity and mortality, provide unique opportunities for seeking ways to enhance the value of electrocardiography (ECG) as an inexpensive and noninvasive tool for prognosis and diagnosis. We used newly developed optical ECG waveform recognition (OEWR) technique capable of extracting raw waveform data from legacy hard copy ECG recording. Hardcopy ECG recordings were scanned and processed by the OEWR algorithm. The extracted ECG datasets were formatted into a newly proposed, vendor-neutral, ECG XML data format. Oracle database was used as a repository for ECG records in XML format. The proposed technique for XML encapsulation of OEWR processed hard copy records resulted in an efficient method for inclusion of paper ECG records into research databases, thus providing their preservation, reuse and accession.