Biomedical subjects

L Fei

Publications and source records attributed to L Fei.

At least 19 recordsLinked to original sources

PubMed2006

Crura ultrastructural alterations in patients with hiatal hernia: a pilot study.

BACKGROUND: Laparoscopic fundoplication for gastroesophageal reflux disease (GERD) and hiatal hernia has been validated worldwide in the past decade. However, hiatal hernia recurrence still represents the most frequent long-term complication after primary repair. Different techniques for hiatal closure have been recommended, but the problem remains unsolved. The authors theorized that ultrastructural alterations may be implicated in hiatal hernia. Thus, this study was undertaken to investigate the presence of these alterations in patients with or without hiatal hernia. METHODS: Samples from Laimer-Bertelli connective membrane and muscular crura at the esophageal hiatus were collected from 19 patients with GERD and hiatal hernia (HH group), and from 7 patients without hiatal hernia enrolled as the control group (NHH group). Specimens were processed and analyzed by transmission electron microscopy. RESULTS: Muscle and connective samples from the NHH group did not present any ultrastructural alteration that could be detected by transmission electron microscopy. Similarly, connective samples from the HH group showed no ultrastructural alterations. In contrast, all muscle samples from the HH group exhibited sarcolemmal alterations, subsarcolemmal vacuolar degeneration, extended disruption of sarcotubular complexes, increased intermyofibrillar spaces, and sarcomere splitting. CONCLUSION: The evidence of ultrastructural alterations in all the patients in the HH group raises the suspicion that the long-term outcomes of antireflux surgery depend not only on the surgical technique, but also on the underlying muscular diaphragmatic illness.

Adult↗

PubMed2006

Expression of the novel co-stimulatory molecule B7-H4 by renal tubular epithelial cells.

Crosstalk between T cells and renal tubular epithelial cells (TECs) in the pathogenesis of tubular lesions, the most important sign of progressive renal diseases, has not been clarified. Previous work has shown that TECs harbor co-stimulatory signals that promote T-cell activation, which induces tubular lesions. Nevertheless, the expression and functional role of B7-H4, a recently identified co-stimulatory ligand of the B7 superfamily, in pathologic human kidneys is unclear. We investigated the expression of B7-H4 on cryostat renal biopsies from patients with idiopathic membranous nephropathy (n=20), immunoglobulin A nephropathy (n=19), lupus nephritis (n=16), and acute renal allograft rejection (n=15) using immunohistochemistry. In addition, we also analyzed TEC-associated B7-H4 in the regulation of T-cell activation. Immunohistological staining revealed that B7-H4 antigen is restricted to tubular epithelium and that the protein is prominent in sections with severe tubular lesions, although no correlation was observed between tubular B7-H4 expression and levels of serum creatinine, serum urea nitrogen concentration, and 24-h proteinuria in each type of nephropathy. In vitro, mixed lymphocyte reactions revealed that TEC-related B7-H4 promotes cytokine (interleukin-2 and interferon-gamma) production and proliferation of co-cultured T cells. Interestingly, the secretion of interleukin-2 by C10 T cell hybridomas also increased when C10 cells were co-cultured with the B7-H4-transgenic murine TEC line, 3M-1-secreting tubular epithelial cells (MCT) in the presence of the antigen hen egg lysozyme. Our results clearly show that TEC-associated B7-H4 induces T-cell activation and we propose that B7-H4 is a potential activator that promotes tubular lesion.

Animals↗

PubMed2006

Feasibility of primary inguinal hernia repair with a new mesh.

BACKGROUND: The purpose of this study was to evaluate the feasibility of primary inguinal repair with open tension-free and sutureless technique using a new polypropylene "patch and plug system" (Prolene 3D patch), and the quality of the treatment in terms of reduction of postoperative discomfort. METHODS: Fifty-six consecutive patients, mean age 54.5+/-11.2 years, with primary unilateral uncomplicated inguinal hernia, were treated in a day-surgery setting. Collected data included: pain scores at 24 hours, 72 hours, and 7, 15, and 30 days after operation, analgesic medications, return to work and to heavy house and/or moderate sporting activities, and quality of life as measured by Short Form 36 health survey questionnaire (SF-36) before the operation and at 6 months follow-up. RESULTS: Postoperative pain was low: the mean visual analog scale (VAS) scores were 2.8 at 24 h, 1.8 at 72 h, and 0.9, 0.3, and 0.04 at 7, 15, and 30 days, respectively. Analgesic drugs were not used by 66.0% (n=37) of the patients. The mean global time to return to work and to heavy activities was 9.9+/-4.6 and 14.6+/-7.0, days, respectively. Patient satisfaction showed a significant improvement in all SF-36 domain scores at 6 months follow-up (P<0.001). There were no major complications, recurrences, or mortality. CONCLUSIONS: The new mesh seems to satisfy all requirements of a feasible, reliable, and effective device for repairing primary inguinal hernia with high patient comfort.

Activities of Daily Living↗

PubMed2005

New devices for inguinal hernia repair in elderly patients.

A recent meta-analysis concluded that there was a lower incidence of recurrences after mesh hernioplasty, as opposed to non-mesh open methods. Inguinal mesh and plug hernioplasties have been performed using prostheses of different sizes and shapes, either sutured or not to the tissues. However, hernia repair using mesh is sometimes associated with postoperative pain, more or less severe and/or persistent. As a consequence it may interfere with the time required to return to work and to normal daily activities. Finally, concerning the postoperative complications and recurrences, the data presented in our study confirm the very low rate for both aspects; then, as regards the time to return to work, our good results are similar to those of other studies available in literature. In conclusion the tension-free hernia repair described, based upon the use of Prolene 3D patch, is a safe operation, simple to be acquired, it can be performed on an outpatient basis, with a low complication rate, a low level of pain, and an excellent quality of life thereafter. The new device seems to satisfy all requisites of a feasible, reliable and effective system for repairing primary inguinal hernia, at low cost, high patient comfort, and with low risk of recurrences.

Adult↗

PubMed2004

Psycho-biological correlates of hypoactive sexual desire in patients with erectile dysfunction.

We studied the psychological and biological correlates of hypoactive sexual desire (HSD) in a consecutive series of 428 patients with erectile dysfunction (ED), by using the structured interview SIEDY. A complete physical examination and a series of biochemical, hormonal, psychometric, and penile vascular tests were also performed. Among the patients studied, 22.8% reported a mild, 12.9% a moderate, and 4.6% a complete loss of sexual interest. Patients reporting HSD showed significantly lower testosterone (T) levels than the rest of the sample, although the prevalence of hypogonadism (T<10 nM) was comparable in the two groups. Only a minority (<2%) had severe hyperprolactinemia (>700 mU/l), which, nonetheless, was closely associated with a relevant HSD. Both mental disorders and use of medication interfering with sexual function were significantly associated with HSD, as well as depressive and anxiety symptoms. HSD patients showed significantly higher scores in SIEDY scale 2, which explores the relational component of ED. In particular, perceived partner's libido and climax were crucially associated with an impairment of patients' sexual desire. In conclusion, HSD in ED is associated with several biological, psychological, and relational factors that can be simultaneously identified and quantified using the SIEDY structured interview.

Adult↗

PubMed2001

Advances in cardiac electrophysiology and pacing.

Significant advances have been made in the management of cardiac arrhythmias. New technology has enhanced the ability to understand and treat a variety of tachycardias. Excitement and caution surround ablative approaches for atrial fibrillation. The role of ICDs and class III antiarrhythmic drugs in the management of patients at risk for sudden cardiac death has been clarified. A new indication for cardiac pacing is evolving as a supplemental treatment for patients with refractory congestive heart failure. These and other advances provide numerous exciting options for management of cardiac patients.

Arrhythmias, Cardiac↗

PubMed2001

Clinical analysis on 149 old patients with craniocerebral injury.

OBJECTIVE: To study the clinical features of craniocerebral injury (CI) in the aged. METHODS: The data of 149 old patients with CI hospitalized in t he department from July 1991 to May 2000 were studied retrospectively in this study. The causes of injury, traumatic pathology, clinical manifestation and cause s of death were analyzed, too. RESULTS: Automobiles were the main victim-makers, and falls we re the second. And there was no significant difference between the first two kin ds of victim-makers. The patients suffered mainly from cerebral contusion, intracerebral hematomas and subdural hematomas, and relatively fewer from epidural hematomas. The scores of Glasgow Coma Scale (GCS) were related closely to the prognosis when hospitalized or before surgical treatment. The total mortality rate was 37.5% in this study. The main cause of death was brain injury. CONCLUSIONS: The old patients with CI have a high mortality rat e. And the causes of injury, traumatic pathology and clinical manifestation are peculiar in the aged.

Aged↗

PubMed2000

Ambulatory oesophageal pH-metry. Position paper of the Working Team on Oesophageal pH-metry by the GISMAD (Gruppo Italiano di Studio sulla Motilità dell'Apparato Digerente).

In the last three decades, oesophageal pH monitoring has progressed from a physiological research tool to a routine outpatient clinical investigation in patients with suspected gastro-oesophageal reflux disease, one of the most common gastrointestinal disorders. Technological progress has considerably simplified both the procedure and the interpretation of data obtained, and there is currently reasonable consensus as to the parameters that best discriminate between physiological and pathological reflux. There remains a need for internationally agreed definitions and standards with regard to indexes to quantitate the extent and the significance of the relationship between occurrence of symptoms and reflux episodes during the examination. It is felt that national or local normal values are to be used to circumvent different eating habits and other socio-cultural differences which may influence gastro-oesophageal reflux. The reproducibility of the test appears, at present, to be at least good enough to allow classification of the patient as a pathological or physiological refluxer, albeit wide day-to-day variations seem to exist as far as concerns the extent of gastro-oesophageal reflux. Clinical applications of the technique have increased with better knowledge of the protean clinical manifestations of gastro-oesophageal reflux disease, and include the evaluation of "typical" gastro-oesophageal reflux disease patients with negative endoscopy or refractory oesophagitis, the "atypical" manifestations of gastro-oesophageal reflux disease and the pre- and post-operative evaluation of patients undergoing antireflux surgery.

Calibration↗

PubMed1999

Effects of multisite ventricular pacing on cardiac function in normal dogs and dogs with heart failure.

INTRODUCTION: We studied the effects on cardiac function of pacing two right and two left ventricular sites in normal and failing hearts with a normal QRS duration. METHODS AND RESULTS: Hemodynamic parameters were studied in isoflurane-anesthetized dogs with normal hearts and dogs with heart failure induced by rapid ventricular pacing. Unipolar intramyocardial electrodes were placed at the high right atrium and the apex (A) and base (B) of the left (L) and right (R) ventricles (V). Data were collected after pacing for 5 to 20 minutes. In normal dogs, without bundle branch block (BBB), pacing at either the apex or the base of the left ventricle increased cardiac output by approximately 10% compared with right ventricular apex (RVA) pacing with an AV delay of 0 msec. Positive dP/dt increased approximately 10% during four-site left and right ventricular apex and base (LRVAB) pacing compared with RVA pacing. In dogs with heart failure but without BBB, cardiac output increased by 8.5% (P < 0.01) during four-site ventricular pacing with AV delays of 0 and 60 msec compared with RVA pacing. Positive dp/dt increased by 23.5% (P < 0.001) with an AV delay of 0 msec and 9.6% (P < 0.001) with an AV delay of 60 msec during LRVAB pacing compared with RVA pacing. His-bundle pacing was associated with increased cardiac output compared with RVA pacing. CONCLUSIONS: We conclude that pacing simultaneously at two right and two left ventricular sites significantly improves cardiac function compared with single RVA pacing, with or without sequential AV synchrony, in dogs with rapid ventricular pacing-induced heart failure and no BBB.

Animals↗

PubMed1997

Intrapericardial delivery of L-arginine reduces the increased severity of ventricular arrhythmias during sympathetic stimulation in dogs with acute coronary occlusion: nitric oxide modulates sympathetic effects on ventricular electrophysiological properties.

BACKGROUND: Nitric oxide (NO) modulates autonomic effects on myocardial contractility and sinus and atrioventricular nodal function of the heart. Whether NO influences autonomic actions on ventricular electrophysiological properties and arrhythmogenesis is not known. METHODS AND RESULTS: Four groups consisting of 43 autonomically denervated dogs were studied. To "superfuse" sympathetic nerves innervating the ventricles, test drugs were introduced into the pericardial sac for 30 minutes, and their effects on ventricular effective refractory period (ERP) and arrhythmia development were assessed before and during sympathetic stimulation (SS). In group 1 (n=12), ventricular ERPs showed no significant difference between control and superfusion with L-arginine, a NO precursor (222+/-20 versus 222+/-19 ms, P=.485). However, L-arginine significantly reduced SS-induced ERP shortening compared with control (9+/-7 versus 13+/-7 ms, P<.001). Simultaneous administration of N(G)-monomethyl-L-arginine (2 mg/mL) abolished the inhibitory effects of L-arginine (13+/-7 versus 13+/-7 ms, P=.885). In group 2 (n=15), the severity of ventricular arrhythmias significantly increased during SS. L-Arginine reduced this increase caused by SS. In group 3 (n=8), plasma norepinephrine spillover measured from the coronary sinus significantly increased during SS and was reduced by pericardial superfusion with L-arginine compared with control (6005.2+/-1525.6 versus 8503.4+/-2044.5 pg/min, P=.012). In group 4 (n=8), L-arginine pericardial superfusion significantly increased NO overflow measured from the coronary sinus during SS (93.25+/-59.20 versus 114.82+/-74.92 nmol/min, P=.043). CONCLUSIONS: Pericardial L-arginine reduces ERP shortening and increased severity of ischemic ventricular arrhythmias during SS in dogs. NO-induced reduction of norepinephrine release in the heart may be one of the underlying mechanisms.

Animals↗

PubMed1996

Short- and long-term assessment of heart rate variability for risk stratification after acute myocardial infarction.

Depressed heart rate variability (HRV) has been shown to be a powerful and independent risk factor in patients following acute myocardial infarction (AMI). A detailed comparison of the predictive values between short- and long-term HRV has not been made. The predictive value of short-term HRV for 1-year total cardiac mortality was studied in 700 consecutive patients after AMI. All patients underwent 24-hour Holter monitoring before discharge from the hospital (5 to 8 days after AMI) and were followed up for 1 year. Short-term HRV was computed as the standard deviation of all normal RR intervals (SDNN) from a 5-minute stationary period selected from 24-hour Holter electrocardiographic recordings. Long-term HRV was computed as an HRV index over the entire 24 hours. There was a significant but relatively poor correlation between SDNN and HRV index (r = 0.51, p <0.001). The positive predictive accuracy of SDNN for 1-year mortality (13% to 18%) was lower than the HRV index (17% to 43%) over a range of sensitivity of 25% to 75%. Assessment of HRV index in > or = 35% of the patients preselected by the lowest SDNN was able to achieve predictive power similar to that of HRV index assessed in all the patients. These data suggest that lower predischarge short-term HRV is associated with increased 1-year total cardiac mortality in patients after AMI. Analysis of long-term HRV for postinfarction risk stratification can safely be limited to patients preselected by depressed short-term HRV measures.

Analysis of Variance↗

PubMed1996

Chronotropic incompetence--Part I: Normal regulation of the heart rate.

Knowledge of normal adjustment of heart rate and its response to exercise is essential for understanding and management of chronotropic incompetence. The autonomic nervous system plays an important role in the modulation of normal heart rate. Chronotropic responses of a normal heart to exercise are associated with parallel hemodynamic changes in order to meet the metabolic demand of the body. Determination of chronotropic incompetence is widely based on the assessment of maximal heart rate. However, maximal effort should always be confirmed before an attempt to measure a maximal heart rate is made.

Animals↗

PubMed1996

Chronotropic incompetence--Part II: Clinical implications.

The definition of chronotropic incompetence as inadequate chronotropic response to metabolic demand is, in theory, quite satisfactory. However, the method used in clinical practice for determination of chronotropic incompetence is far from established. The determination of chronotropic incompetence has important diagnostic, therapeutic, and prognostic implications although the exact mechanism underlying chronotropic incompetence is at present unclear. From a pacing viewpoint, chronotropic incompetence is clinically relevant only when there is a functional improvement associated with rate-responsive pacing. Rate-responsive pacing has improved the physiologic approach to artificial pacing.

Arrhythmias, Cardiac↗

PubMed1996

Effects of hypothyroidism on the vulnerability to ventricular fibrillation in dogs: a comparative study with amiodarone.

It has been shown that thyroid hormone has a significant effect on the heart and that suppression of thyroid function may contribute to the antiarrhythmic effect of amiodarone. The study was aimed at investigating the effects of hypothyroidism, compared with those of amiodarone, on vulnerability to ventricular fibrillation in dogs. In this study, 25 adult dogs were randomly divided into three groups: a hypothyroid group following total thyroidectomy (n = 9), an amiodarone group (n = 8, 400 mg per day, 4 weeks), and a control group (n = 8). Both amiodarone and control groups were subjected to sham surgery. Five to 8 weeks after surgery, ventricular fibrillation threshold and other electrophysiological parameters were determined. Right ventricular effective refractory period, monophasic action potential duration, and ventricular fibrillation threshold were significantly increased in both the thyroidectomized and amiodarone-treated animals. There was no significant change in monophasic action potential duration dispersion. The incidence of ventricular fibrillation during ischemia and reperfusion was significantly reduced in both treated groups compared with the sham-operated euthyroid controls. These observations suggest that hypothyroidism has a significant antifibrillatory effect in dogs. Homogeneous prolongation of repolarization and refractoriness may contribute to the antifibrillatory action of hypothyroidism.

Action Potentials↗

PubMed1996

Predictive power of increased heart rate versus depressed left ventricular ejection fraction and heart rate variability for risk stratification after myocardial infarction. Results of a two-year follow-up study.

OBJECTIVES: The aim of this study was to compare the predictive value of mean RR interval assessed from predischarge Holter recordings with that of heart rate variability and left ventricular ejection fraction for risk stratification after myocardial infarction. BACKGROUND: Heart rate variability is a powerful tool for risk stratification after myocardial infarction. Although heart rate variability is related to heart rate, little is known of the prognostic value of 24-h mean heart rate. METHODS: A total of 579 patients surviving the acute phase of myocardial infarction were followed up for at least 2 years. Predischarge heart rate variability, 24-h mean RR interval and left ventricular ejection fraction were analyzed. RESULTS: During the first 2 years of follow-up, there were 54 deaths, 42 of which were cardiac (26 sudden). Shorter mean RR interval was a better predictor of all-cause mortality as well as cardiac and sudden death than depressed left ventricular ejection fraction. Depressed heart rate variability predicted the risk of death better than mean RR interval for sensitivities < 40%. For sensitivities > or = 40%, mean RR interval was as powerful as heart rate variability. All three variables performed equally well in predicting nonsudden cardiac death. For cardiac death prediction, a left ventricular ejection fraction < 35% had a 40% sensitivity, 78% specificity and 14% positive predictive accuracy; a mean RR interval < 700 ms had a 45% sensitivity, 85% specificity and 20% positive predictive accuracy; and a heart rate variability < 17 U had a 40% sensitivity, 86% specificity and 20% positive predictive accuracy. CONCLUSIONS: Predischarge 24-h mean heart rate is a strong predictor of mortality after myocardial infarction that can compete with left ventricular ejection fraction and heart rate variability.

Cohort Studies↗

PubMed1996

QT dispersion and RR variations on 12-lead ECGs in patients with congestive heart failure secondary to idiopathic dilated cardiomyopathy.

Increased QT dispersion, which has been proposed as a marker of ventricular repolarization inhomogeneity, may predispose to ventricular arrhythmias. Data on QT dispersion in patients with congestive heart failure are scarce. In this study, conventional 12-lead ECGs were recorded in 135 consecutive patients with congestive heart failure secondary to idiopathic dilated cardiomyopathy. Seventy-five patients were excluded from QT interval assessments due to one or more of the following reasons: (1) low amplitude of the T wave (n = 3), (2) atrial fibrillation (n = 26) and (3) bundle branch block (n = 46). QT dispersion was calculated as (1) QT-range: the difference between the maximum and minimum QT intervals on any of the 12 leads and (2) QT-SD: the standard deviation of the QT interval in all the 12 leads. RR intervals were measured in leads II, aVL, V2 and V5. QT-SD (20.85 +/- 5.00 ms) was significantly (r = 0.8997, P < 0.001) related to QT-range (65.65 +/- 15.77 ms), but not to the QT interval. Neither QT-range nor QT-SD was significantly related to age, left ventricular dimensions, left ventricular end diastolic pressure, left ventricular ejection fraction or left ventricular wall thickness. There was no significant difference in QT dispersion between survivors and those who died (n = 8) or were transplanted (n = 9) during 34 +/- 23 month follow-up. No significant difference in QT dispersion was observed between patients with and without ventricular tachycardia (> or = three consecutive beats) detected on 24-h Holter ECGs. RR interval variation was significantly lower in patients who died compared with survivors (standard deviation: 10.37 +/- 3.61 vs 36.02 +/- 35.03 ms, P < 0.001; coefficient of variance: 1.87 +/- 0.7% vs 4.50 +/- 4.9%, P = 0.001). This was also true in patients with bundle branch block. These observations suggest that QT dispersion in idiopathic dilated cardiomyopathy is not significantly related to either QT interval or cardiac size and function and does not predict death. The application of QT dispersion assessment is limited by the commonly encountered atrial fibrillation and bundle branch block in this patient population. However, reduced RR variation on standard 12-lead ECGs has important prognostic implications in these patients.

Adult↗

PubMed1996

Decreased heart rate variability in patients with congestive heart failure and chronotropic incompetence.

UNLABELLED: Heart rate variability was studied in 41 patients (aged 48 +/- 12 years) with congestive heart failure secondary to idiopathic dilated cardiomyopathy. All patients underwent a treadmill exercise test and 24-hour Holter ECG monitoring. Chronotropic incompetence was defined as the failure to achieve > or = 80% of the predicted maximal heart rate response given by 220--age (years) at peak exercise. Spectral heart rate variability was analyzed from 24-hour Holter ECGs and was expressed as total (0.01-1.00 Hz), low (0.04-0.15 Hz), and high (0.15-0.40 Hz) frequency components. The standard deviation of all normal RR intervals (SDNN) was also computed. Chronotropic incompetence was observed in ten patients. Peak oxygen consumption was significantly lower in patients with chronotropic incompetence compared with those without chronotropic incompetence. The total (5.11 +/- 1.26 ln [ms2] vs 6.41 +/- 0.92 ln [ms2]; P = 0.009) and low (3.38 +/- 1.65 ln [ms2] vs 5.45 +/- 1.34 ln [ms2]; P = 0.003), but not the high (3.42 +/- 1.04 ln [ms2] vs 4.00 +/- 1.12 ln [ms2]; P = 0.249) frequency components of heart rate variability were significantly lower in patients with chronotropic incompetence, although there was no significant difference in mean heart rate (88 +/- 20 beats/min vs 86 +/- 15 beats/min; P = 0.831) or left ventricular ejection fraction (22% +/- 10% vs 24% +/- 10%; P = 0.619). SDNN was also significantly lower in patients with chronotropic incompetence compared with those without chronotropic incompetence (64 +/- 34 ms vs 102 +/- 37 ms; P = 0.030). CONCLUSIONS: The observation that heart rate variability is significantly decreased in patients with congestive heart failure who have chronotropic incompetence suggests that chronotropic incompetence may relate to an abnormal autonomic influence on the heart in these patients.

Autonomic Nervous System↗

PubMed1996

[Reproducibility of signal-averaged electrocardiography].

The reproducibility of the parameters defining the presence of late potentials on the signal-averaged electrocardiogram is one of the limiting factors of the method. The authors studied the coefficients of correlation and reproducibility of these parameters in patients with coronary artery disease. In addition, they tried to determine which parameter was most often responsible for changing a diagnostic conclusion (i.e., presence or absence of late potentials). Two signal-averaged ECGs were recorded one after the other in 127 patients. The presence of late potentials was defined as the presence of a least two of the following criteria: total amplified and averaged QRS duration (tQRS) > 114 ms: duration of the last signal of under 40 microV (LAS) > 38 ms, and root mean square of the amplitude of the last 40 ms (RMS) < 20 microV. The correlation coefficients were 0.98, 0.96 and 0.94 for the duration of tQRS, LAS and RMS respectively (p < 0.0001). The coefficients of reproducibility were 7.0 ms. 7.0 ms and 16.1 microV respectively. Late potentials were present in 22% of patients. A change in diagnosis between the first and second recording was observed in 10 subjects (8% of the population). A combined change in LAS and RMS was responsible for 6 of these revised diagnoses, a change in LAS alone in 2 cases, of the RMS alone in 1 case and the tQRS alone in 1 case. In patients with coronary artery disease, the immediate reproducibility of the diagnosis of late potentials is affected by changes in LAS and RMS. The tQRS is only rarely responsible for a change in diagnosis. This study suggests that the result of the signal-averaged ECG should be interpreted with caution when the LAS or RMS are near their threshold values.

Action Potentials↗