Silvano Di Luzio

Characterization of Fetal Arrhythmias by Means of Fetal Magnetocardiography in Three Cases of Difficult Ultrasonographic Imaging

Characterization of ultrasound detected fetal arrhythmias is generally performed by means of M‐mode and pulsed Doppler echocardiography (fECHO), sonographic techniques that allow only indirect and approximate reconstruction of the true electrophysiological events that occur in the fetal heart. Several studies demonstrated the ability of fetal magnetocardiography (fMCG) to identify fetal arrhythmias. We report on three women, studied after the 32nd gestational week, who were referred for fMCG because of unsatisfying fetal cardiac visualization with fECHO due to maternal obesity, fetus in constant dorsal position hiding the fetal heart, intrauterine growth retardation, and oligohydramnios. Minor pericardial effusion was present in the third patient and digoxin therapy was given. FMCG were recorded with a 77‐channel MCG system working in a shielded room. Independent Component Analysis (FastICA algorithm) was used to reconstruct fetal signals. The good quality of the retrieved fetal signals allowed real‐time detection of arrhythmias and their classification as supraventricular extrasystoles (SVE), with/without aberrant ventricular conduction and/or atrioventricular block. The time course of the fetal cardiac rhythm was reconstructed for the entire recording duration; hence, fetal heart rate variability could be studied in time and frequency. Since isolated extrasystoles may progress to more hazardous supraventricular tachycardias, the noninvasive antenatal characterization of, even transient, fetal arrhythmias and their monitoring during pregnancy can be of great clinical impact.

Measurement of Segmental Transit Through the Gut in Man A Novel Approach by the Biomagnetic Method

The techniques commonly used to evaluate the transit of contents through the gut feature some limitations for being either inaccurate, invasive, inconvenient, or potentially dangerous for the subjects. Aim of this study was to establish a safe, noninvasive and accurate technique for the measurement of segmental oroanal transit time. We localized an orally ingested magnetic marker by means of a biomagnetic instrumentation that allows us to identify in a three-dimensional pattern the position of a biomagnetic source inside the body. The biomagnetic localizations were compared with the anatomical data obtained by magnetic resonance imaging investigations. The study was performed in 12 healthy subjects, and scans were taken every hour up to the arrival of the marker into the cecum; thereafter, scans were taken every 4 hr up to the elimination of the marker. In 99% of the isofield maps obtained from each field scan, the marker was localized within the bowel walls. The mean oroanal transit time was 56±5 hr, the mouth-to-cecum transit time was 13±1.7 hr, and the total colonic transit time was 43.5±5 hr (mean±sem). Segmental colon transit did not show major differences among the regions considered, although most of the time was spent in the right colon. In fact, a good correlation was found between transit time through the right colon and oroanal and total colonic transit (r=0.77,P<0.02,r=0.79,P<0.02 respectively). In conclusion, this method might be a safe alternative to the techniques presently used in the clinical setting for the measurement of intestinal transit.

Beat-to-beat estimate of fetal cardiac time intervals using magnetocardiography: longitudinal charts of normality ranges and individual trends

Background.  Fetal magnetocardiography (fMCG) records fetal cardiac electro‐physiological activity during the second half of gestation. We aimed at assessing normality values, related variability, and trends of fetal cardiac time intervals (fCTI) evaluated longitudinally from beat‐to‐beat fMCG analysis in uncomplicated pregnancies.

Concentric Remodeling Detection by Magnetocardiography in Patients with Recent Onset Arterial Hypertension

The aim of this work was to evaluate a number of magnetocardiographic (MCG) indices in their predictive ability for left ventricular (LV) concentric remodeling. Twenty‐five male patients affected by essential hypertension for no longer than 15 months and presenting signs of LV remodeling participated in the study; 25 normal men volunteers of comparable age were evaluated as controls. All participants underwent echocardiography (ECHO), electrocardiography (ECG), and magnetocardiography (MCG). Several MCG based indices were evaluated, namely the QRS Integral, T Integral, QRS‐T Integral, T/QRS Integral, RS Index, and the variations of the electrical cardiac axis (ECA) orientation. MCG indices were compared with ECHO parameters, i.e., left ventricular mass index (LVMI) and relative wall thickness (RWT), and with ECG parameters, i.e., 12‐lead standard ECG LVH Sokolow‐Lyon and Cornell voltages. QRS Integral values for patients and controls were significantly different (P = 0.03), whereas T Integral values showed only a tendency to differentiate between patients and controls (P = 0.15). No significant correlation between MCG and echocardiographic indices in patients was found; RWT showed a tendency to correlate with QRS Integral (r = 0.34, P = 0.17) and with RS Index (r = 0.49, P = 0.15), and LVMI showed a tendency to correlate with the variations of the ECA orientation (r = 0.38, P = 0.10). Our findings, also supported by preliminary results on patients affected by hypertension induced LV hypertrophy, suggest a potential role of MCG in the evaluation of early electrophysiological alterations due to LV concentric remodeling. (PACE 2004; 27[Pt. I]:709–718)

Skin blood flow rate estimation through functions infrared imaging analysis

Abstract An approximated estimation of the cutaneous blood flow rate has been obtained from the recording of the skin temperature distribution in the thermal-neutral condition. The model assumes that radiative, metabolic, evaporative, convective, and environment heat exchange rate can be neglected. Results from the model may be applied to combine Infrared Functional Imaging to other techniques, such as Laser Doppler imaging. Diagnostic applications to study impaired control of skin blood flow rate can be also attempted.