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Waveform Length Based Reliability Analysis for the Detection of Murmur from PCG Records
Published in P. C. Thomas, Vishal John Mathai, Geevarghese Titus, Emerging Technologies for Sustainability, 2020
P. Careena, M. Mary Synthuja Jain Preetha, P. Arun
Coronary artery disease (CAD) is one of the reasons of mortality and morbidity worldwide. Based on the report of World Health Organization (WHO), in 2016 almost 17.9 million humans expired due to CVDs, representing 31% of all global deaths. Out of this, 85% are due to heart attack and stroke [1]. The biological records like Electrocardiogram (ECG), Electroatriogram (EAG), Electroventriculogram (EVG), intracardiac electrogram (EGM), Electromyogram (EMG), echocardiogram, Photoplethysmogram (PPG) and Phonocardiogram (PCG) can be used for analyzing the heart functionality. Of this, the methodologies based on the features extracted from PCG records may be used to detect murmur from heart sound [2]. A few methods that incorporates Waveform length to identify problems of numerous sectors are presented in the literature. Naji et al. [3] proposed a method to find the best feature spaces that discriminate among postural tasks involving different trunk flexion angles using the time domain feature waveform length of the pre-processed EMG signal. In the analysis of surface electromyography (sEMG) signals. Angkoon et al. [4] selected waveform length as one of the features for the tolerance of white Gaussian noise.
Recent advances in the tools available for atrial fibrillation ablation
Published in Expert Review of Medical Devices, 2022
Ahmed Kotb, Shui Hao Chin, G. Andre Ng
The novel multielectrode Globe array is formed of 16 flat ribs with 122 gold-plated electrodes. Each electrode can map, ablate or pace. It also has the advantage of multielectrode contact voltage mapping, which is updated continuously, including during ablation, offering new options in real-time substrate identification. A first clinical study (Global AF) showed its feasibility for single-shot PVI, the Global AF study (Global multielectrode contact-mapping plus ablation with a single catheter in patients with atrial fibrillation) included sixty patients with symptomatic AF undergoing PVI, the globe array catheter was advanced into the antrum of each PV and used for initial PVI and data from the 122 electrodes was then translated into different maps. FLOW and Contact maps were used to determine the amount of tissue contact and hence the optimum electrodes for ablation, a voltage map reflecting the electrogram amplitude for every electrode and a wave map which demonstrated wave front propagation, both maps were continuously updated allowing real-time PVI. Voltage, contact and flow maps were then used to determine the optimum sites for circumferential PVI. At the beginning of this clinical trial, the system was adjusted to ablate at a maximum of 16 electrodes simultaneously. However, this was increased to 24 electrodes in 34 patients to achieve ‘single shot ablation.’ Acute PVI was achieved in (99.1%) of targeted PVs in all sixty patients and in all (100%) targeted PVs in the subgroup treated with ‘single shot ablation’ [75].
Ablation for the treatment of Brugada syndrome: current status and future prospects
Published in Expert Review of Medical Devices, 2020
Alessandro Rizzo, Carlo de Asmundis, Pedro Brugada, Mark La Meir, Gian-Battista Chierchia
The most compelling evidence in support of the depolarization hypothesis derived from Nademanee’s group [40,41]. They recorded fractionated electrogram activity and late potentials from the anterior RVOT epicardium in patients with BrS and showed that after open heart RF ablation at these fibrosis sites, ECG patterns normalized and patients no longer had recurrent VF. Because fragmented electrogram activity is traditionally attributed to conduction abnormalities, the authors concluded that the underlying electrophysiological mechanism in patients with BrS is delayed depolarization over the anterior aspect of the RVOT epicardium [25]. Additionally Nademanee and colleagues demonstrated [40,41] the presence of epicardial interstitial fibrosis and reduced gap junction expression in the RVOT of patients who died suddenly and had BrS family history with negative routine autopsy. The same group found also a significant increase in collagen content in all ventricular walls of the victims diagnosed with BrS over and above the normal collagen content seen in age and sex matched controls. Interestingly Nademanee observed that if radiofrequency energy is effective in creating the lesion, the recorded electrogram voltage amplitude drastically reduces and the mid and late components of the fractionated potentials disappears, indicating the elimination of the intramyocardial substrate.
Interference of cardiovascular implantable electronic devices by static electric and magnetic fields
Published in Expert Review of Medical Devices, 2021
Kai Jagielski, Thomas Kraus, Dominik Stunder
where f is the rotational frequency of the body. The rotational frequency is set constant at 1 Hz for the simulations, and validation has been performed to check the induced voltage’s linear impact. Unipolar and bipolar lead types for CIED were investigated. Unipolar leads measure a voltage between the CIED housing and the lead tip to monitor the intracardiac electrogram (iEGM), while bipolar leads provide two separate electrodes (ring and tip) between which the voltage difference is measured.