Frank Lead Research Articles

Sustainability of spatial QRS-T angle of vectorcardiogram to filtration: a pilot study

Objective: to evaluate sustainability of spatial QRS-T angle of vectorcardiogram to filtration.Materials and methods: Vectorcardiographic records in Frank lead system obtained from 53 randomly included patients with sinus normocardia (28–80 years) were synthesized by means of special algorithm developed in our laboratory based on Bemmel’s matrix. The changes in P, Q, R, S, T amplitudes and in the values of spatial QRS-T angle were analysed at different modes of filtering (70 Гц, 40 Гц, 30 Гц) and without filtering.Results: all of the filtration modes studied diminished the amplitudes of ventricular complex components while no significant changes in the values of spatial QRS-T angle were observed.Conclusion: a new methodology for ECG and VCG parameters sustainability to signal processing (filtration) was developed and tested; the hypothesis about sustainability of spatial QRS-T angle of vectorcardiogram to filtration was approved. Taking into account that spatial QRS-T angle is known as a strong predictor of cardiac diseases, it seems perspective to be implemented in automatic ECG analysis algorythms.

Correlation Of Left Ventricular Ejection Fraction And Spatial Qrs-T Angle In Old Myocardial Infarct Patient

Objective: Spatial QRS-T angle (the angle between the QRS and T vectors) is a strong independent predictor of cardiovascular death. Spatial QRS-T angle calculations can be obtained from the ECG 12 lead with Kors visual transform applications closest to Frank lead system. Half of patients with coronary artery disease (CAD) died from sudden cardiac death (SCD) with Left Ventricular Ejection Fraction (LVEF) as a predictor. The aim of this study was to correlate spatial QRS-T with LVEF in patients with old myocardial infarction (OMI).
 Methods: This is a cross-sectional study in patients with OMI that have not undergone revascularization and have achieved medical therapy. 12-lead electrocardiography (ECG) and echocardiography were done simultaneously. Spatial QRS-T angle was measured by Kors visual transform applications. Statistical analysis was performed using Pearson correlation and multivariate analysis with linear regression.
 Results: 46 patients meet the inclusion criteria. Baseline characteristics: mean age 58 ± 8 years, 89% male, mean spatial QRS-T was 108.72 ± 43° with mean LVEF 39.39 ± 10%. The spatial QRS-T angle and LVEF was strong negative correlation (r=-0.66, p<0.01) after adjusted with left ventricular mass index (LVMI) correlation between spatial QRS-T angle and LVEF decreasing (r=-0.57, p<0.01). The Spatial QRS-T angle and LVEF of patients with OMI is negative correlation.
 Conclusion: The spatial QRS-T angle and LVEF of patients with OMI had negative correlation. Spatial QRS-T angle may be an easier index for assessing cardiac dysfunction in patients with OMI.

Body surface distribution of T wave alternans is modulated by heart rate and ventricular activation sequence in patients with cardiomyopathy.

BackgroundT wave alternans (TWA) is an electrocardiographic marker of heightened sudden death risk from ventricular tachyarrhythmias in patients with cardiomyopathy. TWA is evaluated from the 12-lead electrocardiogram, Frank lead, or Holter lead recordings, however these clinical lead configurations will not record TWA from adjacent regions of the body torso.ObjectiveWe tested the hypothesis that changing heart rate or ventricular activation may alter the body surface distribution of TWA such that the clinical ECG leads fail to detect TWA in some patients; thereby producing a false-negative test.MethodsIn 28 cardiomyopathy patients (left ventricular ejection fraction 28±6%), 114 unipolar electrograms were recorded across the body torso during incremental atrial pacing, followed by atrioventricular pacing at 100, 110 and 120bpm. TWA was measured from each unipolar electrogram using the spectral method. A clinically positive TWA test was defined as TWA magnitude (Valt) ≥1.9 uV with k ≥3 at ≤110bpm.ResultsMaximum Valt (TWAmax) was greater from the body torso than clinical leads during atrial (p<0.005) and atrioventricular pacing (p<0.005). TWAmax was most prevalent in the right lower chest with atrial pacing 100 bpm and shifted to the left lower chest at 120 bpm. TWAmax was most prevalent in left lower chest with atrioventricular pacing at 100 bpm and shifted to the left upper chest at 120 bpm. Using the body torso as a gold standard, the false-negative rate for clinically positive TWA with clinical leads was 21% during atrial and 11% during atrioventricular pacing. Due to TWA signal migration outside the clinical leads, clinically positive TWA became false-negative when pacing mode was switched (atrial→atrioventricular pacing) in 21% of patients.ConclusionsThe body surface distribution of TWA is modulated by heart rate and the sequence of ventricular activation in patients with cardiomyopathy, which can give rise to modest false-negative TWA signal detection using standard clinical leads.

Biventricular Paced QRS Area Predicts Acute Hemodynamic CRT Response Better Than QRS Duration or QRS Amplitudes.

Vectorcardiographic (VCG) QRS area of left bundle branch block (LBBB) predicts acute hemodynamic response in cardiac resynchronization therapy (CRT) patients. We hypothesized that changes in QRS area occurring with biventricular pacing (BV) might predict acute hemodynamic CRT response (AHR). VCGs of 624 BV paced electrocardiograms (25 LBBB patients with 35 different pacing configurations) were calculated according to Frank's orthogonal lead system. Maximum QRS vector amplitudes (XAmpl , YAmpl , ZAmpl , and 3DAmp ) and QRS areas (XArea , YArea , ZArea , and 3DArea ) in the orthogonal leads (X, Y, and Z) and in 3-dimensional projection were measured. Volume of the 3D vector loop and global QRS duration (QRSD) on the surface electrocardiogram were assessed. Differences (Δ) in VCG parameters between BV paced and LBBB QRS complexes were calculated. An increase of 10% in dP/dt max was considered as AHR. LBBB conduction is characterized by a large ZArea (109 μVs, interquartile range [IQR]:75;135), significantly larger than XArea (22 μVs, IQR:10;57) and YArea (44 μVs, IQR:32;62, P < 0.001). Overall, QRS duration, amplitudes, and areas decrease significantly with BV pacing (P < 0.001). Of all VCG parameters, 3DAmpl , Δ3DAmpl , ZArea, ΔZArea , Δ3DArea , and ΔQRSD differentiate AHR response from nonresponse (P < 0.05). ΔZArea predicted best positive AHR (area under the curve = 0.813) and outperformed any other VCG parameter or QRSD measurement. Of all VCG parameters, reduction in QRS area, calculated in Frank's Z lead, predicts acute hemodynamic response best. This method mightbe an easy, noninvasive tool to guide CRT implantation and optimization.

Frank vectorcardiographic system from standard 12 lead ECG: An effort to enhance cardiovascular diagnosis

BackgroundVectorcardiogram (VCG) has been repeatedly found useful for clinical investigations. It may not substitute but complement Standard 12-Lead (S12) ECG. There was tremendous research between 1950s to mid-1980s on VCG in general and Frank’s System in particular, however, in last three decades it has been dropped as a routine cardiac test, the major reasons being unconventional electrode placements which required training of the physicians, greater number of electrodes involved when used to supplement S12 system and additional hardware complexity involved, at least in the early days. Although it lost the interest of cardiologists, the engineering community has adopted the VCG as a tool for interdisciplinary research. We envisage that, if accurate Frank’s VCG system is made available avoiding the aforementioned limitations, VCG will complement S12 system in diagnosis of cardiovascular diseases (CVDs). Methods and resultsIn this paper, we propose a methodology to construct Frank VCG from S12 system using Principal Component Analysis (PCA). We have compared our work with state-of-the-art Inverse Dower Transform (IDT) and Kors Transform (KT). Mean R2 statistics and correlation coefficient values, obtained upon comparison of reconstructed and originally measured Frank's leads, for CSE multilead (CSEDB) and PhysioNet's PTBDB databases using our proposed method, IDT and KT were found to be (73.7%,0.869), (57.6%,0.788) and (56.2%,0.781) respectively. From remote healthcare perspective, a reduced 2–3 lead system is desired and Frank lead system seems to be promising as shown by previous works. However, cardiologists are accustomed to S12 system due to its widespread usage and derived Frank lead system might not be sufficient. Hence, to bridge the gap, we have presented the results of personalized reconstruction of S12 system from derived VCG, obtained using proposed PCA-based method and compared it with results obtained when originally measured Frank leads were used. ConclusionsThe proposed methodology, without any modification in the current acquisition system, can be used to obtain Frank VCG from S12 system to complement it in CVD diagnosis. Omnipresent computerized machines can readily apply the proposed methodology and thus, can find widespread clinical application.

Tangible Object Symbols: A Case Study with an Adult with Multiple Disabilities

For special educators and speech-language pathologists who work among adults with multiple disabilities, tangible object symbols may be an appropriate avenue for communication enhancement. Many of these adults use presymbolic communicative actions (Cascella, 2005), and these symbols may enable them to transition from presymbolic into symbolic communication. Collateral evidence for this transition comes from promising results of tangible symbol applications among children who also have presymbolic communication actions (Parker, Banda, Davidson, & Liu-Gitz, 2010; Rowland & Schweigert, 2000; Sigafoos et al., 2008; Trief, Cascella, & Bruce, 2013). Yet, there is a paucity of research on tangible symbol treatments among adults. To address this gap, the paper presented here describes a case study (A-B treatment design) where a tangible object symbol was introduced to an adult (pseudonym Frank) with multiple disabilities and visual impairment at his day habilitation program. The tangible object symbol was introduced in a functional manner, so that it related specifically to Frank's interests and motivation, as well as the interpersonal characteristics (that is, daily activities, partner expectations) of his environment. Two questions were addressed: Would a tangible object symbol enhance Frank's communication skills? and How quickly might Frank learn to use the tangible object symbol? METHODS Participant Frank was a 53-year-old man with a history of profound intellectual disability, autism spectrum disorder, and severe visual impairment (also known as severe low vision or legal blindness) of a degenerative nature the onset of which occurred more than five years before the initiation of the intervention. Notably, Frank did not tolerate vision testing and he does not wear eyeglasses. Three years of reports (nursing, social work, psychology, and speech-language pathology) indicated no prior or recent exposure to tangible object symbols, graphic symbols, or voice-output technology. Records indicated that Frank had functional hearing, some independent ambulation in known environments, and generally good physical health. Frank attended an adult day habilitation program where there were consistent morning activities (a beverage, arts and crafts, puzzle activities, simple meal preparation, and lunch) and afternoon events (looking at magazines, watching a news program, shopping at local businesses, going to a park, and having another beverage before departure). Frank required intermittent support to engage in activities, and his instructors (one lead, one assistant) reported that he was cooperative during daily routines and sometimes preferred being left on his own when occupied by an activity. The case study presented here began after Frank's lead instructor inquired about whether Frank could learn to more directly communicate that he wanted a drink. The instructor reported that Frank would stand up at his seat, but not directly approach or call out to a staff member, when he wanted a drink. After discussion, it was decided to introduce Frank to a tangible object symbol and a voice-output communication device (BIG-Mack Communicator). To address the methodological challenges of tangible object symbol research cited by Sigafoos et al. (2008), the case study presented here includes a detailed description of the baseline and methodology (for evaluation and replication) but not a matched control or videotape sampling, since these would have been impractical in this setting. The City University of New York Institutional Review Board (IRB) approved this study. Frank's communication status at prebaseline Two tools were used to assess Frank's communication status prior to baseline, the Communication Matrix (Rowland, 2004) and the Functional Communication Profile (Kleinman, 2003). Though nonstandardized, these tools document communication forms and functions via interview with a familiar staff member, a technique that has proven useful when compared to direct structured sampling tasks (Cascella, 2005). …

Visual transform applications for estimating the spatial QRS–T angle from the conventional 12-lead ECG: Kors is still most Frank

BackgroundThe 12-lead ECG-derived spatial QRS–T angle has prognostic and diagnostic utility, but most ECG machines currently fail to report it. The primary goal was to determine if reasonably accurate methods exist for rapid visual estimations of the spatial peaks QRS–T angle from conventional 12-lead ECG tracings. Methods and ResultsSimultaneous 12-lead and Frank XYZ-lead recordings were obtained from a publicly available database for 100 post-myocardial infarction patients and 50 controls. ANOVA, Pearson's correlation coefficients and concordance plots were used to evaluate agreement for spatial peaks QRS–T angle results from the true Frank leads versus from several visually applied 12-to-Frank XYZ-lead transforms. The latter included Kors et al.'s regression and quasi-orthogonal, Bjerle and Arvedson's quasi-orthogonal, Dower's inverse, and Hyttinen et al.'s, Dawson et al.'s and Guillem et al.'s transforms. Spatial peaks QRS–T angles derived from the true Frank leads were not statistically significantly different from those derived from any visually applied transform. Of the visually applied transforms, the Kors' regression and Kors' quasi-orthogonal yielded the highest Pearson correlation coefficients against the gold-standard true Frank lead results [0.84 and 0.77, respectively, when individuals with bundle branch blocks were included (N=150), and 0.88 and 0.80, respectively, when individuals with bundle branch blocks were excluded (N=137)]. Bland–Altman 95% confidence intervals showed similar results, with the two Kors'-related methods also having the narrowest confidence intervals. ConclusionsWhen visually applied, the Kors' regression-related and quasi-orthogonal transforms allow for reasonably precise spatial peaks QRS–T estimates and thus a potentially practical way to visually estimate spatial peaks QRS–T angles from conventional 12-lead ECGs.

A Simplified 3D Model of Whole Heart Electrical Activity and 12-Lead ECG Generation

We present a computationally efficient three-dimensional bidomain model of torso-embedded whole heart electrical activity, with spontaneous initiation of activation in the sinoatrial node, incorporating a specialized conduction system with heterogeneous action potential morphologies throughout the heart. The simplified geometry incorporates the whole heart as a volume source, with heart cavities, lungs, and torso as passive volume conductors. We placed four surface electrodes at the limbs of the torso: V R, V L, V F and V GND and six electrodes on the chest to simulate the Einthoven, Goldberger-augmented and precordial leads of a standard 12-lead system. By placing additional seven electrodes at the appropriate torso positions, we were also able to calculate the vectorcardiogram of the Frank lead system. Themodel was able to simulate realistic electrocardiogram (ECG) morphologies for the 12 standard leads, orthogonal X, Y, and Z leads, as well as the vectorcardiogram under normal and pathological heart states. Thus, simplified and easy replicable 3D cardiac bidomain model offers a compromise between computational load and model complexity and can be used as an investigative tool to adjust cell, tissue, and whole heart properties, such as setting ischemic lesions or regions of myocardial infarction, to readily investigate their effects on whole ECG morphology.

Organic Lead Toxicology

Lead is one of the oldest known and most widely studied occupational and environmental poison. Despite intensive study, there is still debate about the toxic effects of lead, both from low-level exposure in the general population owing to environmental pollution and historic use of lead in paint and plumbing and from exposure in the occupational setting. Significant position have organic lead compounds used more than 60 years as antiknock additives in gasoline. Chemical and toxicological characteristics of main tetraalkyl leads used as gasoline additives are discussed in this article. The majority of industries historically associated with high lead exposure have made dramatic advances in their control of occupational exposure. However, cases of unacceptably high exposure and even of frank lead poisoning are still seen, predominantly in the demolition and tank cleaning industries. Nevertheless, in most industries blood lead levels have declined below levels at which signs or symptoms are seen and the current focus of attention is on the subclinical effects of exposure. The significance of some of these effects for the overt health of the workers is often the subject of debate. Inevitably there is pressure to reduce lead exposure in the general population and in working environments, because current studies show that no level of lead exposure appears to be a 'safe' and even the current 'low' levels of exposure, especially in children, are associated with neurodevelopmental deficits.

Vectorcardiographic lead systems for the characterization of atrial fibrillation

Objective The aim of the study was to design a vectorcardiographic lead system dedicated to the analysis of atrial fibrillation (AF). Methods Body surface potentials during AF were simulated by using a biophysical model of the human atria and thorax. The XYZ components of the equivalent dipole were derived from the Gabor-Nelson equations. These served as the gold standard while searching for an optimal orthogonal lead system for the estimation of the heart vector while using a limited number of electrode positions. Six electrode configurations and their dedicated transfer matrices were tested by using 10 different episodes of simulated AF and 25 different thorax geometries. Results Root-mean-square–based relative estimation error of the vectorcardiogram using the Frank electrodes was 0.39. An adaptation of 4 of the 9 electrode locations of the standard electrocardiogram, with 1 electrode moved to the back, reduced the error to 0.24. Conclusion The Frank lead system is suboptimal for estimating the equivalent dipole components (VCG) during AF. Alternative electrode configurations should include at least 1 electrode on the back.

Lead toxicity.

Lead is one of the oldest known and most widely studied occupational and environmental toxins. Despite intensive study, there is still vigorous debate about the toxic effects of lead, both from low-level exposure in the general population owing to environmental pollution and historic use of lead in paint and plumbing and from exposure in the occupational setting. The majority of industries historically associated with high lead exposure have made dramatic advances in their control of occupational exposure. However, cases of unacceptably high exposure and even of frank lead poisoning are still seen, predominantly in the demolition and tank cleaning industries. Nevertheless, in most industries blood lead levels have declined below levels at which signs or symptoms are seen and the current focus of attention is on the subclinical effects of exposure. The significance of some of these effects for the overt health of the workers is often the subject of debate. Inevitably there is pressure to reduce lead exposure in the general population and in working environments, but any legislation must be based on a genuine scientific evaluation of the available evidence.

Effects of Basic Anthropometric Relationships in the Chest Cavity on Vector-Cardiographic Measurements: A Model Study

A method is described for measuring the orthogonal electrocardiogram and vector cardiogram by means of a corrected orthogonal Frank lead system. To examine the sensitivity to individual anthropometric parameters, simulation has been performed on a simplified model for the thorax in the form of an electroconducting parallelepiped having the same relation between the main parameters as does the chest cavity. Approximate formulas are derived for measuring the components of the heart vector as influenced by the individual anthropometric parameters.

Setting a New Gold Standard

Setting a New Gold Standard

Sex differences and frequency content of the frank lead signal-averaged ECG in a normal population

To quantify the content of the signal-averaged electrocardiogram (ECG) in normal subjects, 100-beat signal-averaged Frank lead ECGs at a sampling rate of 1,000 Hz and with 16-bit resolution were recorded from 88 women and 102 men with a combined average age of 22 years. The QRS portion of each lead was digitally filtered in four bandwidths: 0–10, 10–60, 60–150, and 150–250 Hz. The root-mean-square voltage of each filtered signal was calculated as an absolute value and normalized as a percentage of the sum of the four filters. Women had significantly lower root-mean-square values in all filtered bands in Frank leads X and Z ( P < .01). Normalized data, however, showed no sex difference ( P > .05). Sex differences may affect quantitative measurement of the frequency content of the signal-averaged ECG.

Frequency content and sex difference of the frank lead signal-averaged ECG in a population with significant coronary artery disease: Comparison with concurrent 12-lead ECG morphology

The 12-lead electrocardiogram (ECG) and a 100-beat signal-averaged Frank lead ECG (SAECG) at a sampling rate of 1,000 Hz and with 16-bit resolution were recorded from 52 women and 256 men with significant coronary artery disease presenting for coronary artery revascularization. The QRS portion of each Frank lead was digitally filtered in four bandwidths: 0–10, 10–60, 60–150, and 150–250 Hz. The root-mean-square (RMS) voltage of each filtered signal was calculated as an absolute value and normalized as a percentage of the sum of the four filters, creating 27 variables. Three groups were formed using the presenting 12-lead ECG: N-ECG, ST-ECG, and MI-ECG. Despite variation in 12-lead morphology, concordance was dominant in the RMS values of the SAECG in sex comparisons within and between groups. There was significant sex difference of the RMS values in 6 of the 15 absolute RMS variables within the three groups. Women had no significant between-group difference, and men had a significant between-group differences in five absolute values and one normalized RMS value. P was considered significant at < .05.

Vectorcardiography in experimental myocardial infarction. Serial changes and correlation between QRS loop change and the infarction size.

The objectives of this study were to examine the serial vectorcardiographic changes following acute myocardial infarct and to assess the relationship between QRS loop changes and infarct size. Fifty adult male Long-Evans rats of 250-350 gm body weight were used to study experimental acute myocardial infarction induced by coronary artery ligation. Vectorcardiograms (VCG) of the Frank lead system were recorded before, and 1 day and 7 days after operation. Animals were sacrificed on the 7th day for histological quantitation of infarct area ratios. We found that (1) before operation, rats have ST elevation, probably due to early repolarization. (2) After coronary artery ligation, ECG showed characteristic dome-shaped ST elevation at 1 hr after ligation which returned to normal during the first day. Abnormal Q waves appeared thereafter. (3) After ligation, maximum QRS vector, ST vector and maximum T vector were reduced in magnitude the first day and recovered by the 7th day. The vectors tended to shift their direction to the right and to the posterior. QRS-T angle, however, widened as time went on. About half of the rats revealed changes in the inscription direction of the QRS loop and abnormal QRS morphology also appeared in about half of the ligated rats. (4) Those in whom abnormal QRS loop morphology and/or biting appeared had significantly larger infarct area ratios (p < 0.01). (5) Change in QRS loop inscription direction seemed not to be related to the infarct size. (6) In the LS plane, the difference in max QRS vector magnitude between the 1st and 7th days significantly correlated with the infarct area ratio (r = 0.533, p < 0.05). In the H plane, the change in the max QRS vector magnitude at the 7th day correlated with the infarct area ratio (r = -0.531, p < 0.05). In the F plane, changes in the direction of the max QRS vector were significantly correlated to the infarct area ratio both on the first (r = 0.431, p < 0.05) and 7th days (r = 0.531, p < 0.05). It is concluded that the VCG, like the ECG, had evolutional changes in AMI and that the QRS loop seen on vectorcardiography has only a slight correlation with the histological myocardial infarct size.

Signal-averaged ECG parameters in cardiac normals using Frank lead system and Fourier transform filter and gender specific differences: a multicenter study.

There is only limited data on normal reference values for signal-averaged electrocardiograms (SAECGs) using Frank leads and fast Fourier transform filter (FFT). Furthermore, the influence of gender on reference values and their relation to body characteristics was only the subject of a few studies on small series of normals. One hundred eighty-five cardiac normals (85 women and 100 men) were examined in this multicenter study. The obtained SAECG values (mean +/- standard deviation) are as follows: filtered QRS duration (FQRSD) = 108.6 +/- 7.5 msec; low amplitude signal duration < 40 microV (LASD) = 30.4 +/- 8.4 msec; and root mean square voltage in the terminal 40 msec (RMSV) = 43.5 +/- 20.6 microV. Between men and women, significant differences were found in FQRSD (111.7 +/- 6.5 vs 105.0 +/- 7.0 msec, P < 0.001) and in RMSV (38.6 +/- 17.4 vs 49.4 +/- 22.7 microV, P < 0.001). No difference was observed for LASD. After normalizing the three SAECG parameters for body characteristics, FQRSD normalized for height was the only variable where gender differences were eliminated. For FQRSD and LASD the 90th percentile and for RMSV the 10th percentile are proposed as cut-off values. Only for the 90th percentile of FQRSD a clear difference between men and women was observed. The following gender specific normal values for SAECG, at 40-Hz high pass filtering, using Frank leads and an FFT filter are proposed: for males, FQRSD < 122 msec; for females, FQRSD < 115 msec; for both genders, LASD < 41 msec and RMSV > 20 microV.

The Manor, the Plowman, and the Shepherd: Agrarian Themes and Imagery in Late Medieval and Early Renaissance English Literature by Ordelle G. Hill

REVIEWS crucial vision ofGod and goes on to analyze the failure ofConscience in the last two passus, which continue, and even intensify, the poem's series of defeats.In particular he traces the similarities between Dobest and the Visio, noting the crucial differences (the roles of Piers and Conscience) as the results ofthe discoveries made in the Vita. I like his discussion ofredde quod debes, which roughly follows R.W. Frank's lead in keeping it within the context of the parable of the debtor, and so seeing it as an injunction to be charitable.But this world seems fundamentally flawed.No longer are "conformity to the moral conscience and possession of the virtues ...pre­ conditions for pardon" (p.129); "the Church is merely an institution ex­ pected to suffice in the absence of belief" (p. 132).Even remorse and suffering, the two guides to Will in the Vita, are undermined by the Friars and by Need.Only an awareness in the Conscience of God's divine love as knight, king, and conqueror can offer hope.And in the last chapter Har­ wood shows that Piers himself possessed such knowledge at the moment when he tore the pardon, when "suffering itself has become cognitive" (p.138).In conformity with his almost Calvinist interpretation of Lang­ land, he sees this moment as the point where Piers's complacency is shat­ tered, and he realizes that God has "bou3te" him too.Clearly salvation depends on grace, whether experienced as a vision ofGod or as the "sudden blow" at which a Christian realizes his dependence on Him.Harwood's view of the poem is at least dramatic, though it is, eventually, too personal to have converted me. ANNA BALDWIN Cambridge University OR.DELLE G.HILL.The Manor, the Plowman, and the Shepherd: Agrarian Themes and Imagery in Late Medieval and Early Renaissance English Litera­ ture. Selinsgrove, Pa.: Susquehanna University Press, 1993.Pp.2 57. $42.50. Beginning and ending his text with a meditation on Brueghel's Icarus, Ordelle G.Hill capably argues that Brueghel was ahead of his time in foregrounding the figure of the plowman, for now in the wake of New Historicism in Renaissance and medieval studies, constellated by the names Stephen Greenblatt, Gary Waller, Stephen Knight, and Lee Patter207 STUDIES IN THE AGE OF CHAUCER son, the life of the plowman along with his fellow laborers is getting the attention it deserves for indeed creating the world on which the literature of the period is to a certain extent dependent. Although the subject of this book is in vogue, this is not by any means a trendy cultural critique. In fact, it is a rather traditional, often referentialist, treatment of the history and artistic representation of farming in England from the thirteenth to the sixteenth centuries. While some readers may look for a more problematized view of history and while others will find the absence of it comforting, both will find this work a most welcome addition to their libraries because of its thorough cataloguing of pastoral and agrarian images, themes, and symbols in the literature under discussion; and for its pictures, charts, and maps, docu­ menting the changing history of agrarian economy; and finally for the exceptional bibliography and notes. In the preface Hill confesses that his book began in the 1950s as a humble attempt to add some footnotes to Piers Plowman on the history of plowing. The resulting study offers an interesting star-crossed history of the plowman and the shepherd. The manorial system and the farmers attached to the manor began to fragment in the fourteenth century, and as a result the plowmen either became poorer, sometimes rebels associated with thugs (pace the Peasants' Revolt), or became somewhat prosperous franklins, providing they were able to manage successfully in the new cash economy and leasing of enclosed lands. As the fifteenth and sixteenth cen­ turies played out the changes in agrarian economy, however, the plowman began to disappear from the literature as a significant figure, and the shep­ herd took his place in the pastoral literature of the Renaissance. Since the chapter on Piers is the heart of the book, Hill precedes that discussion with a...

Normal limits of derived vectorcardiogram in Chinese

Derived vectorcardiograms from 503 healthy Chinese individuals (248 men and 255 women) were analyzed to determine the normal ranges of scalar and vector measurements in a Chinese population. In both sexes, the magnitude of the maximal spatial QRS and T vectors decreased significantly with age and was significantly smaller in women in all age groups. The results of this study were concordant with the results of previous studies using the Frank lead system in Caucasians, but the derived vectorcardiogram has the advantage of not requiring any leads additional to those used for recording the conventional 12-lead electrocardiogram. In conclusion, it was found that for healthy Chinese individuals there are significant age and sex related influences on the normal ranges of derived vectorcardiograms. Therefore, vectorcardiographic diagnostic criteria for Chinese individuals should be age-related and sex-related.

A 10-year follow-up study by orthogonal Frank lead ECG on patients with progressive muscular dystrophy of the Duchenne type

A 10-year follow-up study by orthogonal Frank lead electrocardiography was performed on 25 patients with progressive muscular dystrophy of the Duchenne type (DMD). With advancing age, no apparent changes were observed in the duration and amplitude of the P wave or in the PR interval, whereas the duration of the QRS complex tended to increase. The amplitudes of the R wave in lead X (R x) and lead Y (R y) tended to decrease from 1.75 ± 0.90 and 1.96 ± 0.59 mV to 0.80 ± 0.63 and 1.39 ± 0.62 mV (p < 0.01), whereas the amplitude of the S wave in lead X tended to increase from 0.24 ± 0.23 mV to 0.53 ± 0.36 mV in 10 years after initiation of the study (p < 0.01). It is noteworthy that the R y amplitude began to decrease markedly from the seventh year after the initiation of this study, whereas the R x amplitude showed a gradual and unceasing decline through the 10-year period. Observation of the sequential changes of the QRS loops in three planes clearly demonstrated that the electrical force tended to decrease in the leftward and inferior directions and increase in the rightward direction. It is of interest that the frequency of occurrence of the deep Q wave was found to be quite high even in the early stages of DMD and that it did not display a direct relation to the sequential evolution of this disease. It can be concluded that observation of the sequential changes in the QRS complex allows estimation of the extent and direction of myocardial involvement in DMD.