scholarly journals Diagnostic Accuracy of the Electrocardiogram for Detection of Atrial and Ventricular Overloads in Dogs

2021 ◽  
Vol 49 ◽  
Author(s):  
Monique Machado Louredo Machado Louredo Teles Bombardelli ◽  
Tatiana Champion ◽  
Julio Cezar Juk Fischborn ◽  
Ana Bianca Ferreira Gusso
Keyword(s):  
Right Atrium ◽  
Wave Amplitude ◽  
Reference Value ◽  
Standard Test ◽  
The Body ◽  
P Wave ◽  
S Wave ◽  
Cardiac Chamber ◽  
Qrs Duration ◽  
The Right

Background: Analysis of the electrocardiogram may suggest atrial and ventricular overloads. However, it has a low sensitivity and specificity for diagnosis of cardiac chamber overload. The accuracy of electrocardiographic interpretation can be improve using new cut-offs for the duration and amplitude of the electrocardiographic waves. Our objective was to evaluate the use of the electrocardiogram in the diagnosis of atrial and ventricular overload, using echocardiography as the gold standard test for the diagnosis of atrioventricular overload. We aimed to define new cut-off values that would increase the sensitivity and specificity of the electrocardiogram for diagnosis of chamber overload in dogs.Materials, Methods & Results: Eletrocardiogram records were obtained in 81 dogs divided into 3 groups: Group 1A (healthy dogs 10 kg); Group 1B (dogs 10 kg with mitral or tricuspid valve disease); Group 2 (dogs weighing between 10.1 and 20 kg) and Group 3 (dogs > 20.1 kg). Duration in milliseconds (ms) and amplitude in millivolts (mV) of P waves and QRS complexes, PR and QT segment, T wave amplitude and ST segment were evaluated in lead DII. Using leads I and III, the mean cardiac electrical axis in the frontal plane, expressed in degrees, was determined as the mean of three consecutive measurements. For Group 1A and 1B the duration of P wave was < 45 ms and QRS duration < 55 ms. In Group 2 the duration of P wave was < 47 ms and QRS duration < 57 ms. In Group 3 the duration of P wave was < 50 ms and duration QRS < 64 ms. These values (duration of P wave and QRS duration) were compared with echocardiographic measurements of the left atrium, considering the reference value AE/Ao < 1.4 and measurements of the left ventricle in M-mode according to the body weight, respectively. A P wave amplitude < 0.4 mV suggested that the right atrium size was normal and this was compared with the area of the right atrium measured on the echocardiogram. The right ventricle was assessed using the amplitude of S wave and right axis deviation and compared with the right ventricular area obtained by echocardiography. The reference value of the right atrium and right ventricle is according to the body weight. For both the right and left atria, there was concordance between the diagnoses with electrocardiography and echocardiography. For the right and left ventricle was no agreement between the diagnoses. All criteria examined had low sensitivities, usually with high specificities. But it was not possible to determine a new cut-off that would improve the sensitivity of the electrocardiogram for diagnosis of atrial and ventricular overload in dogs. Discussion: The electrocardiogram analysis produced false interpretations for the measures indicative of atrioventricular overloads and should not be used alone, for diagnosis of cardiac chamber overload. The standard electrocardiographic reference values, for P wave duration and amplitude, were excellent for identification of normal atrial size. However, QRS duration, R wave amplitude (dependent of the dog’s weight) and S wave amplitude, associated with cardiac electrical axis cannot be used for diagnosis of ventricle overload. Electrocardiographic analysis should not be used as a tool to assess cardiac chamber overload, which should be diagnosed by echocardiography and clinical investigation. Based on our findings echocardiogram is the gold standard test indicated to identify overload of cardiac chambers.

scholarly journals Electrocardiographic parameters in captive, clinically healthy, Amazona ochrocephala

2015 ◽  
pp. 5037-5045
Author(s):  
Claudia Guerrero S ◽  
Janeth Bolivar B ◽  
Piero Vargas-Pinto ◽  
Pedro Vargas-Pinto ◽  
Claudia Brieva-Rico
Keyword(s):  
Heart Rate ◽  
Wave Amplitude ◽  
P Wave ◽  
S Wave ◽  
Wave Duration ◽  
T Wave ◽  
P Wave Duration ◽  
Electrocardiographic Examination ◽  
Qrs Duration ◽  
Electrocardiographic Parameters

ABSTRACT Objective. To stablish the electrocardiographic parameters of individuals of the species Amazona ochrocephala, from the Unidad de Rescate y Rehabilitacion de Animales Silvestres at the Universidad Nacional de Colombia. Materials and methods. The electrocardiographic examination was performed under inhaled anesthesia with isoflurane. Leads I, II, III, aVL, aVR and aVF were measured. Results. Electrocardiographic parameters obtained in Lead II. P wave Duration: 0.015-0.044 s, P wave amplitude: 0.031 to 0.6 mv, R wave duration: 0.015-0.022 s, amplitude R: 0.034-0.038 mv, S wave Duration: 0.019- 0.042 s, amplitude S: 0.194-0.815 mv, T wave Duration: 0.025-0.064 s, T-wave amplitude: 0.010 to 0.5 mv, PQ Duration: 0.021-0.076 s, QRS Duration: 0.036-0.068 s, QT Duration: 0.070-0.015 s, RR Duration: 0.104-0.324 s, EEM: -111° to -80°, FC: 240-600 ppm. Conclusions. The results showed different values for amplitude and duration of the P, R and T waves in comparison to those obtained in other studies. However, they were similar for heart rate, MEA and duration of the PQ/R, QT and QRS segments.

Effect of caval occlusion on the magnitude of unipolar atrial electrograms in dogs

1983 ◽  
Vol 245 (4) ◽  
pp. H580-H583
Author(s):  
R. A. Bedont ◽  
J. A. Abildskov ◽  
R. L. Lux ◽  
L. S. Green
Keyword(s):  
Right Atrium ◽  
Superior Vena ◽  
Vena Cava ◽  
P Wave ◽  
Radial Excitation ◽  
Heart Volume ◽  
Atrial Electrograms ◽  
Acute Changes ◽  
The Right ◽  
Brody Effect

Studies were done on eight mongrel dogs anesthetized with pentobarbital sodium to assess the effects of acute changes in heart volume on the magnitude of electrocardiographic potentials recorded from the right atrium. Following midsternotomy, acute changes in heart volume were produced by occlusion of the superior vena cava (SVC), inferior vena cava (IVC), or both vena cavae while heart rate was controlled by pacing the right atrium. P-wave area, defined by integrating absolute value of the P wave over time, increased by 8.2 +/- 7.4% during SVC occlusion, 13.3 +/- 8.5% during IVC occlusion, and 23.6 +/- 16.2% during occlusion of both vena cavae. Areas of ventricular complexes appearing in atrial electrograms decreased by 6.6 +/- 6.2% during SVC occlusion, 11.1 +/- 6.7% during IVC occlusion, and 15.2 +/- 9.2% during occlusion of both vena cavae. These results are compatible with predominately tangential activation of the atrium and radial excitation of the ventricle and provide experimental confirmation of the "Brody effect."

Reflection and refraction of elastic waves at a corrugated interface

1966 ◽  
Vol 56 (1) ◽  
pp. 201-221
Author(s):  
Shuzo Asano
Keyword(s):  
Wave Amplitude ◽  
Normal Incidence ◽  
P Wave ◽  
Irregular Waves ◽  
Angle Of Incidence ◽  
S Wave ◽  
Reflected Waves ◽  
S Waves ◽  
Significant Difference ◽  
Almost All

abstract The effect of a corrugated interface on wave propagation is considered by using the method that was first applied to acoustical gratings by Rayleigh. The problem is what happens when a plane P wave is incident on a corrugated interface that separates two semi-infinite media. As is well known, there are irregular (scattered) waves as well as regular waves. By assuming both the amplitude and the slope of a corrugated interface to be small, quantities of the order of the square of corrugation amplitude are taken into account. In the case of normal incidence for three models considered, the effect of corrugation on reflection is larger than the effect of corrugation on refraction; the amplitude of the regularly reflected waves decreases, and that of the regularly refracted waves and of the irregular waves increases, as the corrugation amplitude becomes larger. Generally, the larger the velocity contrast, the larger the variation of wave amplitude with the wavelength and the amplitude of corrugation. The S wave component generally becomes larger as the wavelength of corrugation becomes smaller. Boundary waves exist, depending upon the ratio of wavelength of corrugation to that of the incident wave. For a specified interface, it is possible that there is a significant difference in wave amplitude as a function of the elastic constants. In the case of oblique incidence, computation was carried out for angles of incidence smaller than 15° for one model. For these small angles of incidence, almost all results for the case of normal incidence still hold. Furthermore, it can be concluded that the effect of the angle of incidence on reflected S waves is larger than for the other waves and that large differences in the amplitudes of waves at different angles of incidence may be expected for the irregular waves.

The partition of radiated energy between P and S waves

1984 ◽  
Vol 74 (2) ◽  
pp. 361-376
Author(s):  
John Boatwright ◽  
Jon B. Fletcher
Keyword(s):  
Wave Energy ◽  
Body Wave ◽  
Focal Mechanisms ◽  
The Body ◽  
Body Waves ◽  
P Wave ◽  
Corner Frequency ◽  
S Wave ◽  
S Waves ◽  
Radiated Energy

Abstract Seventy-three digitally recorded body waves from nine multiply recorded small earthquakes in Monticello, South Carolina, are analyzed to estimate the energy radiated in P and S waves. Assuming Qα = Qβ = 300, the body-wave spectra are corrected for attenuation in the frequency domain, and the velocity power spectra are integrated over frequency to estimate the radiated energy flux. Focal mechanisms determined for the events by fitting the observed displacement pulse areas are used to correct for the radiation patterns. Averaging the results from the nine events gives 27.3 ± 3.3 for the ratio of the S-wave energy to the P-wave energy using 0.5 〈Fi〉 as a lower bound for the radiation pattern corrections, and 23.7 ± 3.0 using no correction for the focal mechanisms. The average shift between the P-wave corner frequency and the S-wave corner frequency, 1.24 ± 0.22, gives the ratio 13.7 ± 7.3. The substantially higher values obtained from the integral technique implies that the P waves in this data set are depleted in energy relative to the S waves. Cursory inspection of the body-wave arrivals suggests that this enervation results from an anomalous site response at two of the stations. Using the ratio of the P-wave moments to the S-wave moments to correct the two integral estimates gives 16.7 and 14.4 for the ratio of the S-wave energy to the P-wave energy.

Abstract 13804: Correlation between Electrocardiographic Features and Local Activation Pattern in Arrhythmogenic Right Ventricular Dysplasia

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Tanyanan Tanawuttiwat ◽  
Anneline S Te Riele ◽  
Binu Philips ◽  
Cynthia A James ◽  
Brittney Murray ◽  
...  
Keyword(s):  
Right Ventricular ◽  
Arrhythmogenic Right Ventricular Dysplasia ◽  
Anterior Wall ◽  
Activation Pattern ◽  
S Wave ◽  
Basal Angle ◽  
Right Ventricular Dysplasia ◽  
Surface Ecg ◽  
Qrs Duration ◽  
The Right

Background: Depolarization abnormalities in the terminal portion of the QRS are frequently seen in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C). The purpose of this study was to correlate the electroanatomic activation pattern of the RV endocardium and epicardium to the surface ECG. Methods: Thirty consecutive ARVD/C patients (Mean age 33.1 +/- 11.2 years, 16 (53%) men) underwent detailed endocardial and epicardial electroanatomical mapping (EAM). Local sinus rhythm activation was annotated at the sharpest intrinsic deflection of the bipolar electrogram, including late potentials. ECG features were classified into 5 major patterns; 1. Normal QRS (12 patients) 2. Epsilon wave (5 patients) 3. Incomplete RBBB (5 patients) 4. Atypical complete RBBB (6 patients) and 5. Prolonged terminal activation duration (TAD) (2 patients) Results: The earliest endocardial and epicardial RV activation occurred on the mid anteroseptal wall on all ECG patterns. Figure 1 represented activation area (purple) after the QRS or during the delayed depolarization phase. Nearly all endocardial and epicardial RV was activated well within the QRS duration in patients with normal QRS but was activated during R’ in patients with CRBBB. The delayed activation during Epsilon wave consistently occurred in basal anterior wall and basal angle of RV. In patients with TAD, the activation of RVOT and basal angle RV represented slurred S wave. Conclusion: ECG features in ARVD/C are correlated with late activation in specific regions of RV and total endocardial activation time. The delay activation of basal anterior wall and basal angle of RV represents the Epsilon wave in the right precordial ECG.

Source dynamics of the Dasht-e Bayāz earthquake of August 31, 1968

1969 ◽  
Vol 59 (5) ◽  
pp. 1843-1861
Author(s):  
Mansour Niazi
Keyword(s):  
Stress Drop ◽  
Main Shock ◽  
Mean Value ◽  
The Body ◽  
P Wave ◽  
Polarization Angle ◽  
S Wave ◽  
Long Duration ◽  
First Motion ◽  
Complicated Pattern

abstract Radiation patterns of the P-wave first motion and S-wave polarization angle of the Dasht-e Bayāz earthquake of August 31, 1968, as well as its principal aftershock which occurred about 20 hours after the main shock are studied. The main shock data are consistent with the observed left-lateral strike-slip fault which accompanied it. The radiation pattern of the aftershock differs somewhat from that of the main shock and agrees with the directions of the secondary faulting in the area. Several lines of evidence pointing to a multiple source for the main shock are presented. They include complexity of the body phases, low value of the rupture speed as studied from the analysis of the surface wave spectra, reported long duration of shaking and complicated pattern of striations produced by faulting. Energy, moment and stress drop associated with the main shock are estimated. The resulting mean value of stress drop over the faulted surface has a range of 40-100 bars. Based on the age of some well-built structures in the area, it is proposed that no earthquake as severe as the recent one has occurred near the location of the August 31, 1968 earthquake during the last 800 years.

Amplitude balancing in separating P- and S-waves in 2D and 3D elastic seismic data

Geophysics ◽  
2011 ◽  
Vol 76 (3) ◽  
pp. S103-S113 ◽  
Author(s):  
Robert Sun ◽  
George A. McMechan ◽  
Han-Hsiang Chuang
Keyword(s):  
Wave Amplitude ◽  
Amplitude Ratio ◽  
Velocity Ratio ◽  
Displacement Component ◽  
P Wave ◽  
Elastic Displacement ◽  
Reverse Time ◽  
S Wave ◽  
Near Surface ◽  
S Waves

The reflected P- and S-waves in elastic displacement component data recorded at the earth’s surface are separated by reverse-time (downward) extrapolation of the data in an elastic computational model, followed by calculations to give divergence (dilatation) and curl (rotation) at a selected reference depth. The surface data are then reconstructed by separate forward-time (upward) scalar extrapolations, from the reference depth, of the magnitude of the divergence and curl wavefields, and extraction of the separated P- and S-waves, respectively, at the top of the models. A P-wave amplitude will change by a factor that is inversely proportional to the P-velocity when it is transformed from displacement to divergence, and an S-wave amplitude will change by a factor that is inversely proportional to the S-velocity when it is transformed from displacement to curl. Consequently, the ratio of the P- to the S-wave amplitude (the P-S amplitude ratio) in the form of divergence and curl (postseparation) is different from that in the (preseparation) displacement form. This distortion can be eliminated by multiplying the separated S-wave (curl) by a relative balancing factor (which is the S- to P-velocity ratio); thus, the postseparation P-S amplitude ratio can be returned to that in the preseparation data. The absolute P- and S-wave amplitudes are also recoverable by multiplying them by a factor that depends on frequency, on the P-velocity α, and on the unit of α and is location-dependent if the near-surface P-velocity is not constant.

P-wave morphology and atrial activation in the domestic fowl

1980 ◽  
Vol 239 (5) ◽  
pp. R483-R488 ◽  
Author(s):  
J. R. Hill ◽  
J. M. Goldberg
Keyword(s):  
Developmental Stage ◽  
Right Atrium ◽  
Domestic Fowl ◽  
P Wave ◽  
Pacemaker Activity ◽  
Wave Morphology ◽  
Changing Patterns ◽  
Atrial Activation ◽  
The Right ◽  
Spontaneous Conversion

The purpose of this study was to define the P-wave morphology in the open chest, anesthetized fowl, and to map the corresponding pattern of atrial epicardial activation. Using back lead electrocardiograms (ECG) recorded between the base of the neck and tail, seven P-wave morphologies were identified. Four of these morphologies were upright, two were inverted, and one was biphasic. Spontaneous conversion from one morphology to another was common. During the most common P-wave morphology, activation of the atrial epicardium was mapped by comparing the onset of up to 68 local electrograms with the onset of the P wave of the ECG. Pacemaker activity was found near the base of the left sinoatrial valve and preferential conduction was demonstrated caudally along the base of that valve and medially along the rostral border of the right atrium. Changes in P-wave morphology were shown to correspond with changing patterns of atrial activation. Spontaneous changes in P-wave morphology and epicardial activation indicate a labile pacemaker region in the bird and suggest a developmental stage of evolution similar to both their reptilian ancestors and to their mammalian counterparts.

P-Wave Changes Associated with Chiari Network in the Right Atrium

2020 ◽  
Vol 41 (8) ◽  
pp. 1773-1776
Author(s):  
Ahmet Irdem ◽  
Melis Akpinar ◽  
Ebru Celebi ◽  
Fatih Aygun ◽  
Hasan Dursun
Keyword(s):  
Right Atrium ◽  
P Wave ◽  
Chiari Network ◽  
The Right
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