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At least 1,225 records · Page 68Linked to original sources
PubMed1987

[Ambulatory 24-hour EEG recording in epileptic infantile spasms].

Twenty-four h cassette recording (MEDILOG 9000) where obtained in 22 untreated infants (23 records) with a West syndrome (idiopathic: n = 12, symptomatic: n = 10). All these infants had had a 3 h polygraphic recording. Tracings were visually analyzed for sleep stages. Electro-clinical seizures and infraclinical discharges were listed according to their type and the stage of vigilance. Two hundred twenty-eight critical events were recorded in 22 cassette recordings: isolated spasms, clusters of spasms, partial or generalized discharges followed or not by clusters of spasms. Sixty per cent of these fits occurred during wakefulness, 27% during non REM sleep, 13% during awakening and none during REM sleep. Partial discharges, followed or not by clusters of spasms, were only present in cases with unfavourable outcome. In benign spasms the hypsarrhythmic pattern was present between spasms in each cluster, but not in cases with unfavourable outcome. Compared with 3 h polygraphic recordings, 24 h cassette recordings gave supplementary data on the presence, type and timing of seizures in 16 of out 22 cases.

Ambulatory Care↗
PubMed2001

Comparison of transient evoked otoacoustic emission thresholds recorded conventionally and using maximum length sequences.

Presenting clicks according to maximum length sequences (MLSs) enables transient evoked otoacoustic emissions (TEOAEs) to be recorded at very high stimulation rates. Despite a decrease in TEOAE amplitude, the very large number of responses obtainable at high rates means that both signal to noise ratio (SNR) and detection sensitivity increase as the click rate increases. This study characterises conventional and MLS TEOAEs near threshold for a group of normally hearing adults. Stimulus presentation rates of 40 clicks/s (conventional) and 5000 clicks/s (MLS) were used. Compared to conventional recordings, the MLS technique enabled smaller responses to be detected, when averaged for the same time and to the same SNR. TEOAE amplitude recorded at detection threshold for MLS responses was 13 dB lower than that recorded conventionally. For each individual, MLS recording also produced clear, repeatable responses at stimulus levels below the detection threshold for conventional TEOAEs. The click level at TEOAE threshold was 12 dB lower for MLS compared to conventional emissions. These results suggest that TEOAE thresholds are not absolute but strongly related to the detection sensitivity of the recording system and physiological noise. The initial growth rates and the shape of input/output functions were found to be similar for the two recording techniques.

Acoustic Stimulation↗
PubMed2002

Origin of the binaural interaction component in wave P4 of the short-latency auditory evoked potentials in the cat: evaluation of serial depth recordings from the brainstem.

There is no general agreement on the origin of the binaural interaction (BI) component in auditory brainstem responses (ABRs). To study this issue the ABRs to monaural and binaural clicks with various interaural time differences (ITDs) were simultaneously recorded from the vertex and from a recording electrode aiming at the superior olive (SO) in cats. Electrode path was along the fibers of the lateral lemniscus (LL). Binaural difference potentials (BDPs), which were computed by subtracting the sum of the two monaural responses from the binaural response, were obtained at systematic depths and across a range of ITD values. It was observed that only a specific BDP deflection recorded at the level at which lemniscal fibers terminate in the nuclei of LL coincided in time with the most prominent BDP in the cat's vertex-recorded ABRs, the BDP in their wave P4. As ITD was increased, the latency shifts and amplitude decrements of the scalp-recorded far-field BDP wave exactly followed those recorded at this lemniscal near-field BDP locus. The data support our hypothesis that the BI component in wave P4 results from a binaural reduction in dischargings of axons ascending in the LL, with this reduction due to contralateral inhibition of the discharge activity of the inhibitory-excitatory units in the lateral nucleus of the SO. Furthermore, at the level of the SO, the BDP in the responses to contra-leading binaural clicks always had larger magnitudes than those evoked by ipsi-leading ones. This bilateral asymmetry is consistent with the view that the BDP in scalp-recorded ABRs is related to the function of sound lateralization.

Acoustic Stimulation↗
PubMed1997

Evaluation of the IITC tail cuff blood pressure recorder in the rat against intraarterial pressure according to criteria for human devices.

National standards govern the manufacture and marketing of medical devices in the United States, including those for indirect blood pressure measurement in man. There are no comparable standards for devices for recording in laboratory animals. Noninvasive tail cuff blood pressure (BP) recording in the rat is widely accepted, but beset by methodologic difficulties. Intraarterial recording is regarded as the "gold standard" but is invasive and also susceptible to methodologic error. We compared the IITC Mark 12 photoelectric/oscillometric tail cuff system (IITC Life Sciences, Woodland Hills, CA) versus simultaneous femoral intraarterial recordings in spontaneously hypertensive rats, during anesthesia and 1 to 2 days after recover (150 recordings under each condition), according to the guidelines for human data collection and analysis suggested the American National Standard for automated sphygmomanometers. Within- and between-observer disagreements in estimates made by two observers from 40 anesthetized recordings were less for intraarterial measurements than for the tail cuff method. Within-observer differences (mean +/- SD of differences [SDD]) for systolic, diastolic, and mean pressure were 0 +/- 1, 0 +/- 1, and 0 +/- 1 mm Hg for intraarterial versus -1 +/- 3, 0 +/- 8, and 0 +/- 5 mm Hg for tail cuff. Between-observer differences were 0 +/- 2, 0 +/- 1, and 6 +/- 2 mm Hg versus 5 +/- 4, 13 +/- 7, and 0 +/- 5 mm Hg, respectively. Differences between tail cuff and intraarterial methods were 16 +/- 13, -5 +/- 11, and 2 +/- 8 mm Hg in anesthetized animals and 8 +/- 14, -5 +/- 9, and 0 +/- 9 mm Hg in conscious animals (39% to 82% of differences exceeded 5 mm Hg). The upper limits of clinically acceptable disagreement in the American National Standard are: mean of 5 mm Hg, SDD of 8 mm Hg. The disagreement between tail cuff and intraarterial recordings cannot be ascribed to either method with certainty. These findings do not support the manufacturer's guarantee of tail-cuff readings within "5 mm Hg of intraarterial." Inaccuracy and unreliability of devices intended for laboratory animal use have considerable scientific, fiscal, and ethical implications. Marketing of these devices should also be governed by rigorous standards.

Anesthesia↗
PubMed2000

Active stabilization of electrodes for intracellular recording in awake behaving animals.

Intracellular recording is a powerful electrophysiology technique that has revealed much of what is known about the biophysical properties of neurons. However, neuronal properties are strongly affected by activity dependent and modulatory influences, making it essential, ultimately, to study these properties in behaving animals. Unfortunately, intracellular recording has only been widely applied in vitro, since cardiac and respiratory pulsations make intracellular recording difficult in vivo. In awake behaving animals, spontaneous movements make intracellular recording nearly impossible. Here I present a novel technique to dynamically stabilize the position of a recording electrode relative to the brain. Physiological signals that are predictive of brain motion at the recording site, such as the electrocardiogram (EKG), respiratory pressure, or cranial motion, are used to control a piezoelectric manipulator, making possible stable intracellular recordings in awake active animals.

Animals↗
PubMed1999

Wavelength dependence of the optically recorded action potentials in guinea pig atrial muscles.

The optically recorded action potentials of the frog atrial muscles which lack transverse tubules showed different features from those reported by Heiny and Vergara (Heiny JA, Vergara J. Optical signals from surface and T system membranes in skeletal muscle fibers. J Gen Physiol 1982;80:203-230) in skeletal muscles (Fujishiro N, Kawata H. The wavelength dependence of optically recorded action potentials in the atrial muscles of the bullfrog (Rana catesbeiana). Comp Biochem Physiol 1996;114A:153-157). We examined whether or not the differences were consistent in other atrial muscles which lack transverse tubules with guinea pig atrial muscles. Two dyes (merocyanine rhodanine and merocyanine oxazolone) were used, and the dependence of the maximum rising phase of the optical signals on the wavelength of the incident beam was analyzed. No dependence was observed between them, and this finding was consistent with the structure of the membrane system of the guinea pig atrial muscles. The optical signals recorded at 718 nm of the incident beam from the guinea pig atrial muscles which stained with merocyanine oxazolone showed a more prominent second rising phase after the initial rapid rising phase of the optical signal than that recorded in the frog atrial muscles. This phase was not observed in the optical signals recorded at other wavelengths. The features of the optically recorded action potentials in guinea pig atrial muscles were consistent with those recorded in frog atrial muscles. Nifedipine did not affect the second rising phase.

Action Potentials↗
PubMed2001

Source generators of the early somatosensory evoked potentials to tibial nerve stimulation: an intracerebral and scalp recording study.

OBJECTIVE: To investigate the location of the cerebral generators of the early scalp somatosensory evoked potentials (SEPs) after tibial nerve stimulation. METHODS: Tibial nerve SEPs were recorded in 15 patients, suffering from Parkinson's disease, who underwent implantation of intracerebral (IC) electrodes in the subthalamic nucleus, in the globus pallidum or in the thalamic ventralis intermediate nucleus. SEPs were recorded both from the scalp surface and from the IC leads. RESULTS: The lemniscal P30 response was recorded by all the electrodes. The IC waveforms included a negative N40IC response, followed by a positive (P50IC) and a negative (N60IC) potential. The N40IC, the P50IC and the N60IC potentials did not differ in latency from the P40, the N50 and the P60 responses recorded by the Cz electrode. In 6 patients, in which SEPs were recorded also during the voluntary movement of the stimulated foot (active gating), an amplitude reduction of the SEP components following the P30 potential was observed during movement at the vertex and in the IC traces. Instead, in the contralateral temporal traces the SEP components (N40temp and P50temp) were not modified by active gating, and in the ipsilateral parietal traces only the positive potentials at about 60ms of latency was decreased. CONCLUSIONS: Two differently oriented generators are active in the contralateral hemisphere at both 40 and 50ms of latency after tibial nerve stimulation. One source is oriented perpendicularly to the mesial hemispheric surface and generates the potentials recorded by the contralateral temporal and the ipsilateral parietal leads; the other dipolar source is radial to the hemispheric convexity, and generates the potentials at the vertex and those recorded by the IC electrodes.

Brain↗
PubMed2004

Canine electroencephalographic recording technique: findings in normal and epileptic dogs.

OBJECTIVE: The absence of a standardized recording technique and of normal reference patterns may have hindered the use of experimental electroencephalography (EEG) in dogs and in veterinary medicine as well. Therefore, the aim of the present work was to develop a recording technique for brachycephalic, mesocephalic and dolichocephalic breeds of dogs that would standardize the recording parameters, including the electrical activity of the rhinencephalon and prorean gyrus, and to prove its feasibility for detecting abnormal activity. METHODS: We accomplished this task by employing 12 recording electrodes. Three different doses of xylazine (0.5, 1 and 1.5 mg/kg) were used to determine which gave enough sedation to obtain a recording free of artifact. Fifty normal dogs were studied; for comparison 9 epileptic dogs were also explored. RESULTS: We found specific anatomical skull sites where the EEG recording electrodes should be attached; the location of these sites is, in practical terms, the same for every dog, regardless of their skull type. A dose of 1 mg/kg xylazine was chosen for restraining. Normal dogs displayed predominant 6-12 Hz waves which could be recognized all over the cortex. Epileptic dogs were individualized because of the appearance of paroxysmal discharges, composed of spikes, sharp and anomalous sinusoidal waves which usually started in one area, spreading to the whole cortex later on, in the clinical interictal periods. CONCLUSIONS: It was possible to obtain more extensive electrophysiological coverage of the canine cerebral cortex, including the rhinencephalon and prorean gyrus, than previously described in the literature. Intramuscular or subcutaneous xylazine, at a dose of 1 mg/kg, proved to produce the best restraint for recordings. The technique allowed to distinguish abnormal activity in epileptic dogs.

Adrenergic alpha-Agonists↗
PubMed1991

Preoperative electroencephalographic investigation in temporal lobe epilepsy: extracranial and intracranial recordings.

Preoperative EEG investigations of patients with temporal lobe seizures include extracranial interictal and ictal recordings during wakefulness and sleep, including long-term EEG and video-monitoring. Interictal epileptiform discharges when evaluated conservatively and in conjunction with other EEG and non-EEG localizing information, provide valuable guidance for the identification of the area to be resected, as do ictal recordings. When extracranial EEG features in conjunction with non-EEG data provide conflicting localizing information, intracranial recordings with stereotaxically implanted depth and epidural electrodes are used. Intracranial recordings must be designed to avoid biasing the exploration strategy in favor of one's preferred localizing hypothesis. Patients with evidence for bitemporal epileptogenic dysfunction in extracranial EEG recordings are suitable candidates for intracranial recordings. The majority of the patients explored in this manner show that all or more than 80% of their seizures arise from one temporal lobe. Excision of that lobe yields satisfactory results in a fair proportion of these patients. The number of satisfactory outcomes is however, still somewhat less than in patients with unilateral temporal foci in extracranial EEG recordings.

Electroencephalography↗
PubMed2002

Atmospherc mercury deposition during the last 270 years: a glacial ice core record of natural and anthropogenic sources.

Mercury (Hg) contamination of aquatic ecosystems and subsequent methylmercury bioaccumulation are significant environmental problems of global extent. At regional to global scales, the primary mechanism of Hg contamination is atmospheric Hg transport. Thus, a better understanding of the long-term history of atmospheric Hg cycling and quantification of the sources is critical for assessing the regional and global impact of anthropogenic Hg emissions. Ice cores collected from the Upper Fremont Glacier (UFG), Wyoming, contain a high-resolution record of total atmospheric Hg deposition (ca. 1720-1993). Total Hg in 97 ice-core samples was determined with trace-metal clean handling methods and low-level analytical procedures to reconstruct the first and most comprehensive atmospheric Hg deposition record of its kind yet available from North America. The record indicates major atmospheric releases of both natural and anthropogenic Hg from regional and global sources. Integrated over the past 270-year ice-core history, anthropogenic inputs contributed 52%, volcanic events 6%, and background sources 42%. More significantly, during the last 100 years, anthropogenic sources contributed 70% of the total Hg input. Unlike the 2-7-fold increase observed from preindustrial times (before 1840) to the mid-1980s in sediment-core records, the UFG record indicates a 20-fold increase for the same period. The sediment-core records, however, are in agreement with the last 10 years of this ice-core record, indicating declines in atmospheric Hg deposition.

Air Pollutants↗
PubMed2002

Quantifying the benefits of additional channels of multifocal VEP recording.

For some individuals and for some locations, multifocal visual evoked potentials (mfVEP) may be too small or appear 'too noisy' to be reliably measured. By adding electrodes, especially electrodes placed lateral to the midline, and by recording with multiple channels, the amplitude of the signal can be increased in some field locations. However, the addition of electrodes involves certain costs; the set-up time is longer and the data analysis more time consuming and complex. The objective of this study was to assess the benefits of adding electrodes by quantifying these benefits using a signal-to-noise measure. In addition to the typical midline placement of electrodes, two electrodes were placed 1 cm above and 4 cm lateral to the inion on each side. This allowed for 3 channels of recording and 3 additional, derived channels. The mfVEPs were recorded with a 60 sector, pattern-reversing display presented to one eye. Two 7 min records were obtained from 14 individuals with no known visual problems. The two records were averaged and a signal-to-noise (SNR) measure was obtained for every response from all 6 channels. For each sector of the display and each subject, the benefits of additional electrodes were quantified by comparing the SNR from the traditional midline channel to the best SNR from amongst the 6 channels. The number of responses exceeding any given criterion SNR value was increased with the additional channels. For example, 79% of the responses for the typical midline channel exceeded a SNR of 0.6 (a false positive rate of about 2.5%) and this increased to 93% when the best SNR value was used. As expected, summing the mfVEP responses from contiguous sectors also increased the SNR values. Additional electrodes and multiple channels of recording substantially improve the quality of the mfVEP records and the SNR measure provides a useful metric for assessing these benefits.

Adult↗
PubMed2003

Utility of patient-activated cardiac event recorders in the detection of cardiac arrhythmias.

BACKGROUND: Patient-activated event recorders are useful for the diagnosis of arrhythmia in patients with palpitation and presyncope. However, the utility of event recorders in patients suspected of arrhythmia but presenting with other symptoms is not clear. Furthermore, the factors influencing their utility have not been evaluated. METHODS: Event recorder reports of six hundred and sixty consecutive patients referred due to clinical suspicion of cardiac arrhythmia were reviewed. We divided symptoms into four groups: palpitation, presyncope, chest tightness, and dyspnea. We calculated the diagnostic yield according to patients' symptoms reported on the record, and analyzed the factors affecting the utility of event recorders. RESULTS: The overall diagnostic yield was 64%, and those of palpitation, presyncope, chest tightness, and dyspnea were 66%, 57%, 51% and 60%, respectively. The most common five findings in our patients were sinus rhythm (36%), sinus tachycardia (30%), atrial premature complex (14%), ventricular premature complex (12%), and atrial fibrillation/atrial flutter (7%). The recording duration (8 +/- 4 days) was short in the present study, but the overall diagnostic yield was similar to those of previous ones. Women had lower diagnostic yields than men, especially in atrial flutter-fibrillation. The diagnostic yield was not influenced by age, ordered doctors, or history of cardiovascular disease. CONCLUSIONS; Patient-activated event recorders provided a good diagnostic yield in patients with different presentations of cardiac arrhythmia, and women had lower diagnostic yield in atrial flutter-fibrillation.

Arrhythmias, Cardiac↗
PubMed2026

Multichannel genomic recording of biological information with ENGRAM.

Molecular recording is an emerging paradigm for measuring biology over time. Enhancer-mediated genomic recording of activity in multiplex (ENGRAM) is a recently described synthetic biology circuit architecture that converts the transient activity of cis-regulatory elements (CREs) into stable genomic records that can be retrospectively recovered via DNA sequencing. Here we provide a step-by-step protocol for conducting ENGRAM experiments and analyzing the resulting data. We also describe key design considerations for ENGRAM recorders, summarize the strengths and limitations of ENGRAM, and highlight applications, including multiplex signal recording and high-throughput CRE screening. In contrast to other systems for DNA-based recording in mammalian systems, ENGRAM relies on prime editing-mediated insertions to record the activity of a given CRE, such that it is inherently multiplexable-for example, four-base-pair insertions can represent the activities of up to 256 distinct CREs. A further contrast lies with ENGRAM's compatibility with DNA Typewriter, which facilitates the capture of signal order. For users with basic skills in molecular biology, mammalian cell culture and DNA sequencing analysis, ENGRAM experiments can typically be completed within 5-6 weeks.

Genomics↗
PubMed2006

Are consecutive nightly recordings required for valid evaluation of sleep-associated erections?

We questioned the need for more than one RigiScan recording for accurate assessment of sleep-associated penile erections and determine the necessity of consecutive nightly recordings for valid evaluation of sleep-associated erections. Men complaining of erectile dysfunction (ED) and referred to RigiScan evaluation for the first time participated. Recordings were performed at the patient's home during two consecutive nights, and data on test time, number of erections, erection duration, minimal and maximal base and tip tumescence and rigidity were retrieved for both nights. Normal erectile function was defined with the recording of at least one erection (70 out of 100% tip rigidity lasting for at least 10 min during either night). The main outcome measures were RigiScan recordings. Group 1 consisted of 29 men (mean age 42.4+/-13.8 years, range 22-71) who had normal erections, all during the first night. Group 2 consisted of 26 men (mean age 48.6+/-13.5 years, range 25-70) who failed to fulfill both criteria for normal erection. In Group 2, only the values for penile base rigidity and erection duration were normal during the first night: the parameters of maximal base tumescence, tip rigidity, number of effective erections and duration of effective erections that were impaired during the first night were significantly worse (P<0.01) during the second night. The required information for the diagnosis of psychogenic ED was obtained during the first night in >50% of the participants. Men with normal erections during the first night can be spared the inconvenience and cost of re-testing. Consecutive night recording should be reserved for patients whose recorded data during the first night did not fulfill the criteria for normal erection.

Adult↗
PubMed1984

Comparison of the Auditec and Rintelmann recordings of the NU-6.

Word discrimination scores were obtained for 30 normally hearing listeners using Auditec and Rintelmann recordings of the NU-6 presented at 60 and 70 dB SPL in quiet and in a background of multitalker noise at signal-to-noise (S/N) ratios of +12, +6, 0, and -6 dB. This was done to obtain normative data and to determine whether these two recordings of the same word lists were equivalent at conversational levels in quiet and in a noisy background. The word discrimination scores for each recording in quiet and at each S/N ratio were not significantly different when presented at 60 and 70 dB SPL. However, the word discrimination scores were significantly poorer as the S/N ratio became more severe, and the scores obtained with the Auditec recording were significantly poorer than those obtained with the Rintelmann recording at each S/N ratio. These differences between word discrimination scores using the Auditec and Rintelmann recordings were primarily attributed to the recorded level of the test word and secondarily attributed to carrier phrase and talker differences.

Adult↗
PubMed1998

A novel portable perfused manometric system for recording of small intestinal motility.

The development of solid-state catheters with miniature pressure transducers and portable dataloggers with a large memory capacity has allowed recording of gastrointestinal motility in ambulant subjects. Developments in silicone rubber extrusion technology made it possible to build a perfused manometric system, using a perfused manometric assembly requiring a low volume of perfusate. In the present study the feasibility of recording and automated analysis of small intestinal motility using a perfused multiple lumen manometric system was evaluated in seven healthy volunteers. Pressures were recorded from 12 sideholes arranged in four clusters spaced at 10-cm intervals from the catheter tip. Each channel was perfused at 0.15 mL min-1 with degassed water by a portable, low-compliance, perfusion pump. The 12 sidehole recording channels were connected to external transducers mounted on a belt. Pressure data were stored in two dataloggers. Motility was recorded in the sitting (30 min), and supine (30 min) position, during walking (30 min) and postprandially (90 min). Using purpose-built software baseline variations were corrected for and manometric variables (number of pressure waves, mean amplitude and motility index) calculated. Bench testing of the manometric assembly showed a median baseline pressure offset of 4.2 kPa (range 3.7-10.1) and upon occlusion a rise rate of 27.8 kPa sec-1 (range 19.7-30.8). Changes in body position affected baseline pressures so that compared to the supine position changes in baseline pressure varied between 1.5 +/- 0.7 kPa and 1.9 +/- 0.6 kPa during sitting (P < 0.02), and between 1.7 +/- 0.7 kPa and 1.5 +/- 0.9 kPa during walking (P < 0.03). Manometric recordings obtained during the fasting period showed an increase in small intestinal motor activity during walking. In the postprandial period no differences in motility variables were observed within one cluster and in time. Recording of small intestinal motility with a multiple-channel silicone rubber manometric assembly with a portable perfusion system is a feasible technique which is relatively inexpensive. Computer-assisted data processing allows for adequate elimination of artefacts and automated numerical analysis.

Adult↗
PubMed2001

Prolonged recording of oesophageal and lower oesophageal sphincter pressure using a portable water-perfused manometric system.

The aim of our study was to investigate the recording fidelity of a water-perfused micromanometric catheter with incorporated sleeve combined with a newly developed portable water-perfused manometric system for pharyngeal, oesophageal and lower oesophageal sphincter (LOS) pressure recording. The system's performance was assessed in prolonged recordings in ambulant gastro-oesophageal reflux disease (GORD) patients. Eighty 24-h studies in GORD patients, carried out with the perfused portable manometric system, were evaluated. Twelve of these recordings were analysed in detail in order to compare oesophageal and LOS motor patterns with those described previously. Paired 2-h manometric recordings of the pharynx, oesophagus, LOS and stomach, using the new system and a conventional perfused stationary manometric system, were performed in eight healthy subjects. With the portable manometric system oesophageal contractions, transient LOS relaxations, swallow-associated prolonged LOS relaxations and LOS pressures were recorded with equal fidelity to the conventional manometric system. Recordings obtained with the portable system showed meal-related and diurnal variations in oesophageal and LOS variables that were similar to these found in studies using conventional equipment. The new manometric system, consisting of a perfused micromanometric catheter with incorporated sleeve and a portable perfusion system, enables prolonged studies on oesophageal and LOS motor patterns in ambulant subjects.

Adult↗
PubMed2002

A retrospective case study to assess the value of the implantable loop recorder for the investigation of undiagnosed syncope.

If not diagnosed by history, examination, or ECG, the diagnosis of syncope can be difficult with a low yield from echocardiography, ambulatory ECG recording, electrophysiological study, and tilt table testing. During 2 years, 48 patients with unexplained syncope or presyncope from three hospitals in one city underwent the implantation of a Medtronic Reveal implantable loop recorder capable of cardiac monitoring for 14 months. All patients had at least two prior episodes of syncope or presyncope. Fifty-two percent of patients had electrophysiological studies, all of which were negative. The implantable loop recorder remained implanted until a diagnostic event was recorded, or until the end of the battery life. After a mean follow-up of 5.6 +/- 5.7 months, symptoms reoccurred in 25 (52.1%) patients at a mean of 2.8 +/- 2.1 months after insertion of an implantable loop recorder. No further symptoms occurred in 23 (47.9%) patients. Of the 25 patients who had a symptom and recorded an event, an arrhythmia was seen in 10 (40%) patients. Seven patients had bradycardia; 4 with profound sinus bradycardia/sinus arrest, 1 with complete heart block, and 2 in association with the cardioinhibitory component of vasovagal syncope. Three patients had tachycardias; two with supraventricular tachycardia and one with atrialflutter. Fifteen (60%) of the 25 patients who activated their device due to syncope or presyncope were in sinus rhythm during the event. The implantable loop recorder was effective in making a cardiological or noncardiological diagnosis for unexplained syncope or presyncope in 52.1% of the patients.

Adult↗