Precordial Electrode Placement Research Articles

Normal electrocardiogram values of healthy children.

Aim:Electrocardiography is an important diagnostic tool in the evaluation of cardiac diseases. Normal electrocardiograms are age-dependent and may also vary due to several factors. Many studies have been performed to establish the normal values for the childhood period. The aim of this study was to determine the normal electrocardiograms values for healthy Turkish children in Aydın.Material and Methods:All children underwent physical examination by a pediatrician and the electrocardiograms were analyzed by the same pediatrician. In the event of improper or insufficient data, the analyses were repeated. Children with a suspicious electrocardiograms or physical examination were recalled and examined by same pediatric cardiologist in outpatient clinic.Results:In this study, electrocardiogram records were collected randomly from 1163 children with a sampling rate of 500 Hz. Of the children, 562 were female (47.4%) and 601 were male (52.6%). The total population was divided into ten age groups. Significant differences in normal limits were determined compared with previously published studies.Conclusion:The observed differences in various electrocardiograms parameters could be related to biologic variability and to some technical details such as precordial electrode placement and visual checking of the records in addition to race.

Precordial electrode placement accuracy by nurses in a large midwestern tertiary care hospital.

A quality improvement project to increase the knowledge of nurses and the accuracy of electrocardiogram precordial lead placement among intensive care unit and progressive care unit staff was conducted using a single-group, pretest-posttest preexperimental design. Educational interventions based on the theory of planned behavior were developed from focus group data. A tip card, poster, and video were sequentially presented to more than 1,600 nurses. This resulted in statistically significant gains in both knowledge and accuracy (p < 0.02). This project supports the use of focus groups and the theory of planned behavior to guide education related to quality improvement.

Precordial electrode placement for optimal ECG monitoring: Implications for ambulatory monitor devices and event recorders

IntroductionDetection of QRS complexes, P-waves and atrial fibrillation f-waves in electrocardiographic (ECG) signals is critical for the correct diagnosis of arrhythmias. We aimed to find the best bipolar lead (BL) with the highest signal amplitude and shortest inter-electrode spacing. MethodsECG signals (120seconds) were recorded in 36 patients with 16 precordial electrodes placed in a standardized pattern. An average signal was analysed for each of 120 possible BLs obtained by calculating the difference between pairs of unipolar leads. Peak-to-peak amplitudes of QRS waves (50ms around R-peak) and P waves (270–70ms before R-peak) were calculated. For patients with atrial fibrillation, power of the fibrillatory (f) wave was used instead. Maximum values at each distance were considered and differentiation analysis was performed based on incremental changes (amplitude to distance). ResultsThere was a significant correlation between distance and QRS-amplitude (r=0.78, p<0.001), P-wave amplitude (r=0.60, p<0.01) and f-wave power (r=0.79, p<0.001). The range of values was: QRS-amplitude 0.7–2.33mV, P-wave amplitude 0.07–0.18mV, and f-wave power 0.55–2.12mV2/s. The maximum value for the shortest distance was on a heart-aligned axis over the left ventricle for the QRS complex (1.9mV at 8.7cm) and over the atria for the P-wave (0.98mV) and f-waves (1.45mV2/s at 8cm, respectively). ConclusionThere is a strong positive correlation between electrode distance and ECG signal-amplitude. Distance of 8cm on a heart-aligned axis and over the relevant heart-chamber provides the highest signal amplitude for the shortest distance. These findings are essential for the design and use of ambulatory monitoring devices.

The 12-lead ECG in the emergency medical service setting: how electrode placement and paramedic gender are experienced by women

AimThe aim of this study was to explore women’s attitudes to precordial electrode placement and 12-lead ECG acquisition in the emergency medical service setting.MethodFifty participants were recruited from university campuses....

Would different routine precordial electrode positions be more useful? Answer: not likely.

There are reasons to wonder if the current precordial electrode positions are the best ones to study the electrical forces of the heart. Theoretically, more horizontal electrode positions and several superior and inferior electrode positions that are perpendicular to the horizontally placed electrode positions should make a superior lead system. A study was designed to determine if that was true. The result of the study indicated that such a system did not solve all of the problems that were posed by the current system. Although the new system was easier to use, the findings did not justify a change from the presently used system of precordial electrode placement.

Accuracy in ECG lead placement among technicians, nurses, general physicians and cardiologists

The objective of the study was to determine the reliability of ECG precordial electrode placement by doctors and nurses involved in the emergency care of patients admitted with suspected cardiac diseases. A total of 120 subjects were recruited within 2 days from six hospitals. They comprised physicians, nurses and cardiac technicians involved in the clinical assessment and care of patients with suspected cardiac disease. Subjects were asked to complete a questionnaire and marked on two diagrams of the chest wall the positions they would place precordial electrodes V1-V6. This study showed wide inter-individual and inter-group variations in the placement of electrodes. Notably, V1 and V2 were frequently incorrectly positioned in the second intercostal space, especially by physicians. The correct position of V1 in the fourth right intercostal space was identified by 90% of cardiac technicians, 49% of nurses, 31% of physicians (excluding cardiologists) and--most disappointing of all--only 16% of cardiologists (p<0.001 for inter-group differences). V5 and V6 were also often mispositioned, too high on the lateral chest wall. Nurses and doctors (especially cardiologists) do not know the correct positions for ECG electrodes. Because incorrect positioning of the precordial electrodes changes the ECG significantly, patients are at risk of potentially harmful therapeutic procedures. Equally, doctors who are aware of the possibility of lead misplacement may be inclined to ignore some ECG changes that may be genuine evidence of ischaemia. The only safe solution is proper precordial electrode placement, which requires training and an environment supporting precision.

The relative accuracies of ECG precordial lead waveforms derived from EASI leads and those acquired from paramedic applied standard leads

Accurate precordial electrode placement can be difficult in emergency situations leading either to loss of time or diminished accuracy. A possible solution is the quasi-orthogonal EASI lead system, with only five electrodes and easily defined landmarks to provide a derived 12-lead electrocardiogram (ECG). The purpose of this study was to test the hypothesis that precordial waveforms in EASI-derived ECGs have no greater deviation from those in gold standard ECGs, than do the precordial waveforms in paramedic acquired standard ECGs. Twenty paramedics applied the standard precordial electrodes employing the routine procedure. A certified ECG technician applied the 6 standard precordial electrodes in their correct gold standard positions, and the EASI electrodes. 12-lead ECGs were obtained from the paramedics’ standard leads, and derived from the EASI leads, for comparison with the gold standard ECG. In each precordial lead recording, 6 computer-measured QRS-T waveform parameters were considered. Differences between ΔEASI-gold standard versus Δparamedic-gold standard were calculated for every waveform in every lead resulting in 720 comparisons. EASI and paramedic results were “equally accurate” in 47%, the paramedic was more accurate in 31%, and EASI was more accurate in the remaining 22%. The differences from gold standard recording of precordial waveforms in ECGs derived from the EASI leads and those acquired via paramedic-applied standard electrodes are similar. The results suggest that the EASI lead system may provide an alternative to the standard ECG precordial leads to facilitate data acquisition and possibly save valuable time in emergency situations.

Variability of precordial electrode placement during routine electrocardiography

Placement of precordial electrodes by 30 experienced technicians during routine electrocardiography was compared with anatomically ascertained sites marked by ink visible only under ultraviolet “black light” in three men and five women. The distance and direction from each marked site to the center of the applied electrode was measured to allow calculation of both the linear magnitude of difference (derived from the square root of the sum of the squares of rise and run) and also the direction of difference (in quadrants) between the anatomically established location and the electrode at each precordial site. The average difference from the applied electrodes to the corresponding marked sites was 1.14 inches, ranging from a mean of 1.31 inches at lead V 1 to 0.98 inches at lead V 4. Overall, 64% of precordial electrodes were placed within a radius of 1.25 inch, ranging from 56% for lead V 6 to 74% for lead V 4, and 27% of precordial electrodes were placed within a radius of 0.625 inch. There was superior quadrant displacement of more than 0.625 inch in more than 50% of routine applications of leads V 1 and V 2, indicating that these electrodes are commonly placed both high and wide of their anatomically defined precordial sites. Similarly, there was an inferior and left-ward displacement of more than 0.625 inch in 30–50% leads of routine applications of V 4 through V 6, indicating that these lateral precordial electrodes are commonly placed both low and wide of their respective anatomic sites.

Precordial voltage variation in the normal electrocardiagram

Intra-individual precordial voltage variation was examined in serial 12 lead electrocardiograms (ECGs) performed at 10 minute and 24 hour intervals in sixteen young, healthy males forming two age matched groups. Significant variation was found in repeat ECGs at both periods. When precordial electrodes remained in situ between serial 10 minute recordings variation was reduced by approximately 60% We conclude that significant precordial voltage variation is present in serial electrocardiography, even when performed over the short term. Alteration in precordial electrode placement accounts for the major proportion of variation and this may be sufficiently large to interfere with the accurate interpretation of serial precordial voltage changes in an individual subject.