China
Africa
Explore chapters and articles related to this topic
Fetal echocardiography
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Caroline K. Lee, Erik C. Michelfelder, Gautam K. Singh
Magnetocardiography elucidates electrical signals in the fetal heart by detecting and analyzing the related magnetic fields. It processes the sequence of electrical events rather than mechanical events of the heart and can provide the capability of measuring different electrical time intervals such as QRS and QT intervals (85). Therefore, potentially it can reveal the mechanisms of fetal arrhythmias and aid in the differential diagnosis of fetal tachycardia such as in distinguishing VT with 1:1 conduction versus SVT as well as VT with AV dissociation versus junctional ectopic tachycardia (73). Discerning the mechanisms of fetal arrhythmias will help select the appropriate anti-tachyarrhythmic agents and unify the approach to the treatment of fetal arrhythmias. This modality is not in clinical use yet because of its need to be performed in a magnetically shielded room. Advancement has been made in the use of the technique at the bedside in an unshielded environment, which may bring it for wider use in the clinical practice (85).
Magnetocardiographic technology for human heart investigation
Published in Waldemar Wójcik, Andrzej Smolarz, Information Technology in Medical Diagnostics, 2017
M.A. Primin, I.V. Nedayvoda, A. Smolarz, W. Surtel, B. Suleimenov
Upon excitation of the myocardium, there is an electromagnetic field in the human body and in the surrounding area. Magnetocardiography (MCG) realises the registration and analysis of the magnetic component of the field, and the ECG—the electric component. Therefore, the same biophysical model is used in order to explain the nature and characteristics of an MCG signal, as well as the ECG signal. Variation of the magnetic field corresponding to cardiocycles is called an MCG-curve. The MCG-curve has a similar shape and is described by the same set of names of the peaks, segments and intervals as an electrocardiogram. Note that the MCG signal of adults is as low as tens of pT (10−12Tesla), so it is a million times smaller than the external magnetic field of the earth in the measurement point. Thus magnetic signal requires special, more complex and expensive registration systems compared to the ECG. Measurements of the magnetic signal of the heart are provided by using SQUID magnetometer systems. Accordingly, magnetocardiography must possess a high diagnostic efficiency compared to the ECG to ensure “right to use” in a clinical practice. MCG has a diagnostic efficiency, in our opinion, due to fundamental differences between this method and potential methods (ECG, mapping of the body surface potentials—BSPM). Specifically, the MCG measurements are performed not only non-invasive, but non-contact; a magnetometric system itself has no effect on the electrophysiological processes in the heart since under registration of diagnostic information; it does not radiate any energy. It is also known that the conductive volume of the human body is “transparent” to the magnetic field of the heart with a high degree of accuracy and does not affect the signal detected by the magnetometer system. Thus, when measuring using MCG, we obtain a direct information on the currents in the heart, when using ECG—on currents flowing in the human body and intermediary in heart.
Cardiac arrhythmias in pregnant women: need for mother and offspring protection
Published in Current Medical Research and Opinion, 2020
Theodora A. Manolis, Antonis A. Manolis, Evdoxia J. Apostolopoulos, Despoina Papatheou, Helen Melita, Antonis S. Manolis
Fetal VT with rates >200 bpm has been noted in fetuses with AV block, cardiac tumors, acute myocarditis, channelopathies (e.g. LQTS), and CHD146. Prenatal diagnosis and treatment of VT remains a difficult task152. Fetal M-mode can help diagnose VT by showing ventricular rate higher than atrial rate with AV dissociation153. In cases of VT where there is a retrograde 1:1 VA conduction, it is not possible to differentiate VT from SVT by fetal cardiac ultrasound. LQTS may be suspected when tachyarrhythmias and bradyarrhythmias coexist; fetal magnetocardiography (fMCG) may aid in rendering a specific diagnosis by revealing QT prolongation and TdP154,155. Fetal LQTS may be diagnosed by an fMCG-recorded QTc >490 ms with a reported 89% sensitivity and specificity; fetal TdP has been noted when QTc is ≥620 ms156. In a series of 173 pediatric cases with cardiac tumors, with rhabdomyoma being the most common (∼60%) and fibromas the second most common type (∼15%), arrhythmias occurred in 24%, with VT being the most common arrhythmia, more frequently (64%) associated with fibromas; a significant percentage of patients (42%) with rhabdomyomas was diagnosed during a prenatal ultrasound157.
Fragmentation of the QRS complex: the latest electrocardiographic craze?
Published in Acta Cardiologica, 2019
Some have advocated the use of a more quantitative approach of fQRS, for instance the derivative of dV/dT [5]. One could also figure out to perform a high precision analysis, sort of signal-averaged processing as for the search of late potentials, but inside the whole QRS complex [17]. Magnetocardiography has also been suggested, but it is not in routine use to-day. However, vectorcardiography can be utilised: a study with the quantitative assessment of vector loop morphology (roundness, planarity, thickness, rotational, and dihedral angles) showed that fQRS detected from the 12-lead ECG had low sensitivity (31%) for detecting QRS loop folding on the VCG [18].
Angiography derived assessment of the coronary microcirculation: is it ready for prime time?
Published in Expert Review of Cardiovascular Therapy, 2022
Jinying Zhou, Yoshinobu Onuma, Scot Garg, Nozomi Kotoku, Shigetaka Kageyama, Shinichiro Masuda, Kai Ninomiya, Yunlong Huo, Johan H.C. Reiber, Shengxian Tu, Jan J. Piek, Javier Escaned, Divaka Perera, Christos Bourantas, Hongbing Yan, Patrick W. Serruys
Current ongoing trials involving noninvasive IMR are summarized in Table 4. FLASH III aims to investigate the diagnostic accuracy of caIMR in 116 patients. PIONEER IV will conduct a post-hoc analysis of angiography-derived IMR and perhaps expand both diagnostic and prognostic evidence. Other imaging modality-based microvascular resistance metrics, namely CT derived (NCT04554004) and Magnetocardiography-derived (NCT05150054), are also under development and validation.